CN115598255A

CN115598255A - Detection and classification method of dried orange peel

Info

Publication number: CN115598255A
Application number: CN202211312374.8A
Authority: CN
Inventors: 陈明权; 商雪莹; 孙东; 石洪超; 何风雷; 覃仁安
Original assignee: Guangzhou Baiyunshan Chen Liji Pharmaceutical Factory Co ltd
Current assignee: Guangzhou Baiyunshan Chen Liji Pharmaceutical Factory Co ltd
Priority date: 2021-10-12
Filing date: 2021-10-12
Publication date: 2023-01-13
Anticipated expiration: 2041-10-12
Also published as: CN114252520B; CN114252520A; CN115598255B

Abstract

The invention relates to a method for detecting and grading dried orange peel, which adopts a high performance liquid chromatography, particularly combines with proper high performance liquid chromatography conditions to detect different components existing among dried orange peels with different quality grades, analyzes peak areas of the different components, particularly the ratio of the peak areas of the different components to the area of a Weianning-2 peak, determines the type of the dried orange peel to be detected, and finally realizes the quality evaluation of the dried orange peel to be detected. Moreover, the detection grading method has the characteristics of good practicability and correlation, and can promote the high-quality development of the dried orange peel industry. Meanwhile, the invention breaks through the traditional concept of quality based on annual theory and provides a new idea and a new technical support for the improvement of the quality standard of the dried orange peel.

Description

Detection and classification method of dried orange peel

The application is a divisional application entitled "method for detecting and grading pericarpium Citri Tangerinae" with application number of 202111186037.4 and application date of 2021, 10 months and 12 days.

Technical Field

The invention belongs to the technical field of quality control of traditional Chinese medicinal materials, and particularly relates to a method for detecting and grading dried orange peel.

Background

The 2020 edition of Chinese pharmacopoeia defines "pericarpium Citri Tangerinae" as dried mature pericarp of Citrus reticulata Blanco and its cultivated varieties (Citrus reticulata 'Chachi' etc.), wherein the pericarp of Citrus reticulata from Rutaceae is "Guang Chen Pi".

With the increase of storage years, the appearance color of the naturally aged orange peel gradually becomes darker, and the price is higher. Therefore, the old and new skin camouflage of the old and new old aged dried orange peels in the market earns high profits, and the market disorder seriously affects the healthy development of the dried orange peel industry. When consumers buy Guanghong dried orange peels in the market, the high-age dried orange peels with dark appearance colors are generally considered to be the dried orange peels with good quality. However, the appearance of the aged orange peel is influenced by a number of factors, such as "place of production", "maturity", "storage method", "storage environment", "drying method", "storage time", and artificial aging treatment. On the premise of no corresponding objective evaluation standard, the quality is unreasonable in the aspect of 'year'.

The traditional evaluation method for the quality of the dried orange peel comprises the following steps: the local standard DB 4407/T70-2021 geographical indication product Xinhui dried orange peel carries out quality classification on dried orange peels with different maturity, such as green tangerine peels, reddish peel, scarlet peel and the like, and the classified dried orange peels are divided into three grades, namely 'first grade', 'second grade' and 'third grade', and the method for inspecting the quality grade of the dried orange peels by the local standard mainly comprises the traditional experience identification methods, such as a visual method, a hand feeling method, an olfaction method and the like; most of the traditional sensory evaluation methods have strong subjectivity, relatively poor accuracy, difficult experience inheritance and poor reproducibility of evaluation results.

Therefore, how to objectively and accurately evaluate the dried orange peel is a technical problem to be solved urgently.

Disclosure of Invention

Based on the above, the main purpose of the invention is to provide a method for detecting and grading dried orange peel, and the dried orange peel is detected by adopting the method for detecting and grading the dried orange peel, and the obtained result can objectively and accurately reflect the quality of the dried orange peel.

The purpose of the invention can be realized by the following technical scheme:

a method for detecting and grading dried orange peel comprises the following steps:

providing a reference solution containing Velcrinnine-2 and 5-hydroxymethyl furfural, preparing a test solution of pericarpium Citri Tangerinae to be tested, detecting the reference solution and the test solution by high performance liquid chromatography,

detecting under the detection wavelength of 215 nm-225 nm to obtain a detection spectrum I, wherein the detection spectrum I comprises a chromatographic peak Ia and a chromatographic peak Ib, the chromatographic peak Ia is the chromatographic peak of the viscapine-2, the retention time ratio of the chromatographic peak Ib to the chromatographic peak Ia is 0.1-0.12,

detecting under the detection wavelength of 255-265 nm to obtain a detection map II, wherein the detection map II comprises a chromatographic peak IIa, a chromatographic peak IIb, a chromatographic peak IIc, a chromatographic peak IId and a chromatographic peak IIe, the chromatographic peak IIa is the chromatographic peak of the viscapine-2, the chromatographic peak IIb is the chromatographic peak of 5-hydroxymethylfurfural, the retention time ratios of the chromatographic peak IIc, the chromatographic peak IId, the chromatographic peak IIe to the chromatographic peak IIa are respectively 0.32-0.34, 0.70-0.72 and 0.71-0.73,

analyzing peak areas of the chromatographic peak Ia and the chromatographic peak Ib in the detection map I and peak areas of the chromatographic peak IIa, the chromatographic peak IIb, the chromatographic peak IIc, the chromatographic peak IId and the chromatographic peak IIe in the detection map II, and determining the quality grade of the dried orange peel to be detected according to an analysis result of a chromatographic peak area ratio.

In one embodiment, the chromatographic peak Ib is a chromatographic peak of a difference component having a negative correlation change relation with the aging degree of the dried orange peel, the chromatographic peak IIc and the chromatographic peak IId are chromatographic peaks of the difference component having a positive correlation change relation with the aging degree of the dried orange peel respectively and independently, and the chromatographic peak IIe is a chromatographic peak of a component specific to the tea-water-dyed dried orange peel relative to other dried orange peels,

the relative positions of the chromatographic peak Ib and the viscapine-2 in the detection spectrum I are basically shown as a No. 1 peak and a No. 3 peak in a figure 2,

the relative positions of the chromatographic peak IIc, the chromatographic peak IId and the chromatographic peak IIe with respect to the viscapine-2 in the detection spectrum II are basically shown as a No. 2 peak, a No. 3 peak, a No. 4 peak and a No. 5 peak in a figure 7.

In one embodiment, the conditions of the high performance liquid chromatography include: the stationary phase is a C18 chromatographic column, the mobile phase A is methanol, the mobile phase B is phosphoric acid aqueous solution with the phosphoric acid volume percentage of 0.08-0.12%, and gradient elution is adopted.

In one embodiment, the procedure of gradient elution comprises: 0min to 5min, the volume percentage of the mobile phase A is 5 percent and 5min to 10min, the volume percentage of the mobile phase A is increased from 5 percent to 10 percent and 10min to 15min, the volume percentage of the mobile phase A is 10 percent and 15min to 25min, the volume percentage of the mobile phase A is increased from 10 percent to 20 percent and 25min to 35min, the volume percentage of the mobile phase A is increased from 20 percent to 25 percent and 35min to 50min, the volume percentage of the mobile phase A is increased from 25 percent to 40 percent and 50min to 55min, the volume percentage of the mobile phase A is 40 percent and 55min to 60min, the volume percentage of the mobile phase A is increased from 40 percent to 50 percent and 60min to 65min, and the volume percentage of the mobile phase A is 50 percent.

In one embodiment, the conditions of the high performance liquid chromatography further comprise: the flow rate is 0.8mL/min to 1.2mL/min, or/and the column temperature is 28 ℃ to 32 ℃, or/and the sample injection amount is 8 mu L to 12 mu L.

In one embodiment, the step of preparing the test solution comprises: and extracting the dried orange peel to be detected by using an extraction solvent, collecting an extracting solution, and preparing the test solution.

In one embodiment, the extraction solvent comprises an aqueous methanol solution having a methanol volume percentage of 10% to 35%.

In one embodiment, the extraction mode adopts ultrasonic extraction.

In one embodiment, the solvent in the control solution comprises an aqueous solution of methanol having a methanol volume percentage of 45% to 55%.

In one embodiment, determining the quality level of the pericarpium citri reticulatae to be detected according to the analysis result includes:

r1 is more than or equal to 0.7, the pericarpium citri reticulatae to be detected corresponds to high-temperature accelerated aging pericarpium citri reticulatae or high-humidity accelerated aging pericarpium citri reticulatae,

r2 is more than 0.1, the tangerine peel to be detected corresponds to tea-dyed tangerine peel,

r1 is less than 0.7, R2 is less than or equal to 0.1, R3 is more than or equal to 0.9, the dried orange peel to be tested corresponds to the dried orange peel which is burned or stored under the condition that the air permeability is less than 5mm/s and is naturally aged,

r1 is less than 0.7, R2 is less than or equal to 0.1, R3 is less than 0.9, one of R4 and R5 is more than 0.6, the pericarpium citri reticulatae to be tested corresponds to the naturally aged pericarpium citri reticulatae which is less than seven years old and stored under the condition that the air permeability is less than or equal to 80mm/s and is less than five years old and stored under the condition that the air permeability is more than 80mm/s,

r1 is less than 0.7, R2 is less than or equal to 0.1, R3 is less than 0.9, R4 and R5 are both more than 0.6, the dried orange peel corresponds to the dried orange peel which is aged naturally for more than or equal to seven years and stored under the condition that the air permeability is less than or equal to 80mm/s and is stored for more than or equal to five years and stored under the condition that the air permeability is more than 80mm/s or is aged in other aging ways,

wherein, R1, R2, R4 and R5 are the peak area ratios of the chromatographic peak IIb, chromatographic peak IIe, chromatographic peak IIc, chromatographic peak IId and chromatographic peak IIa respectively, and R3 is the peak area ratio of the chromatographic peak Ib and the chromatographic peak Ia.

A construction method of a characteristic spectrum of dried orange peel comprises the following steps:

providing a reference substance solution containing vesanine-2 or/and hesperidin, preparing a test solution of dried orange peel, detecting the reference substance solution and the test solution by adopting a high performance liquid chromatography, detecting at 255-265 nm to obtain a reference chromatogram and a detection chromatogram, introducing the detection chromatogram into a traditional Chinese medicine chromatogram fingerprint similarity evaluation system for analysis to obtain a pattern chromatogram, and performing characteristic peak identification on the pattern chromatogram by referring to the reference chromatogram to obtain a characteristic chromatogram of the dried orange peel.

In one embodiment, the procedure of gradient elution comprises: 0 min-5 min, the volume percentage of the mobile phase A is 5 percent,

5-10 min, the volume percentage of the mobile phase A is increased from 5% to 10%, 10-15 min, the volume percentage of the mobile phase A is 10%, 15-25 min, the volume percentage of the mobile phase A is increased from 10% to 20%, 25-35 min, the volume percentage of the mobile phase A is increased from 20% to 25%, 35-50 min, the volume percentage of the mobile phase A is increased from 25% to 40%, 50-55 min, the volume percentage of the mobile phase A is 40%, 55-60 min, the volume percentage of the mobile phase A is increased from 40% to 50%, 60-65 min, and the volume percentage of the mobile phase A is 50%.

In one embodiment, the step of preparing the test solution comprises: and extracting the dried orange peel by using an extraction solvent, collecting an extracting solution, and preparing the test solution. In one embodiment, the extraction solvent comprises 10% to 35% methanol by volume in water. In one embodiment, the extraction mode adopts ultrasonic extraction.

In one embodiment, the solvent in the control solution comprises an aqueous methanol solution with a methanol volume percentage of 45% to 55%.

In one embodiment, the pericarpium Citri Reticulatae comprises low-staling pericarpium Citri Reticulatae, medium-staling pericarpium Citri Reticulatae, high-temperature accelerated pericarpium Citri Reticulatae, tea-dyed pericarpium Citri Reticulatae, worm-eaten pericarpium Citri Reticulatae, high-humidity accelerated pericarpium Citri Reticulatae, other old-fashioned pericarpium Citri Reticulatae, and baked pericarpium Citri Reticulatae; the dried orange peels with low ageing degree correspond to dried orange peels which are naturally aged under the condition that the air permeability is less than 5mm/s, the dried orange peels with medium ageing degree correspond to dried orange peels which are less than seven years old and are naturally aged under the condition that the air permeability is less than or equal to 5mm/s or less than 80mm/s or dried orange peels which are naturally aged under the condition that the air permeability is greater than 80mm/s and are less than five years old, and the dried orange peels with high ageing degree correspond to dried orange peels which are naturally aged under the condition that the air permeability is greater than or equal to 5mm/s or less than 80mm/s or dried orange peels which are naturally aged under the condition that the air permeability is greater than 80mm/s and are greater than or equal to five years old.

In one embodiment, the dried orange peel is dried orange peel with low aging degree, the characteristic spectrum comprises a peak 4, a peak 6, a peak 7, a peak 9, a peak 10, a peak 11 and a peak 12, the peak 9 is a chromatographic peak of viscapine-2, the relative positions of each characteristic peak and the peak 9 are basically as shown in figure 9,

the dried orange peel is dried orange peel with medium aging degree, the characteristic spectrum comprises a peak 1, a peak 3, a peak 4, a peak 6, a peak 7, a peak 9, a peak 10, a peak 11 and a peak 12, the peak 9 is a chromatographic peak of vesanin-2, the relative positions of each characteristic peak and the peak 9 are basically shown in figure 10,

the dried orange peel is the dried orange peel with high aging degree, the characteristic spectrum comprises a peak 1, a peak 3, a peak 4, a peak 5, a peak 6, a peak 7, a peak 9, a peak 10, a peak 11 and a peak 12, the peak 9 is a chromatographic peak of the vesanin-2, the relative positions of each characteristic peak and the peak 9 are basically shown in figure 11,

the dried orange peel is high-temperature accelerated dried orange peel, the characteristic spectrum comprises a peak 2, a peak 3, a peak 4, a peak 5, a peak 6, a peak 7, a peak 9, a peak 10, a peak 11 and a peak 12, the peak 9 is a chromatographic peak of the viscapine-2, the relative positions of the characteristic peaks and the peak 9 are basically shown in figure 12,

the dried orange peel is tea-dyed dried orange peel, the characteristic spectrum comprises a peak 4, a peak 5, a peak 6, a peak 7, a peak 8, a peak 9, a peak 10, a peak 11 and a peak 12, the peak 9 is a chromatographic peak of viscapine-2, the relative positions of each characteristic peak and the peak 9 are basically shown in figure 13,

the dried orange peel is a worm-eaten dried orange peel, the characteristic spectrum comprises a peak 1, a peak 3, a peak 4, a peak 5, a peak 9, a peak 10, a peak 11 and a peak 12, the peak 9 is a chromatographic peak of the Weikaning-2, the relative positions of the characteristic peaks and the peak 9 are basically shown in a figure 14,

the dried orange peel is a high-humidity accelerated dried orange peel, the characteristic spectrum comprises a peak 2, a peak 3, a peak 4, a peak 6, a peak 7, a peak 9, a peak 10, a peak 11 and a peak 12, the peak 9 is a chromatographic peak of the vesanin-2, the relative positions of the characteristic peaks and the peak 9 are basically shown in figure 16,

the dried orange peel is dried orange peel in other old-making modes, the characteristic map comprises peak 1, peak 3, peak 4, peak 5, peak 6, peak 7, peak 9, peak 10, peak 11 and peak 12, peak 9 is a chromatographic peak of visanning-2, the relative positions of each characteristic peak and peak 9 are basically shown in figure 15,

the dried orange peel is baked skin, the characteristic spectrum comprises a peak 2, a peak 4, a peak 5, a peak 6, a peak 7, a peak 9, a peak 10, a peak 11 and a peak 12 shown in figure 17, the peak 9 is a chromatographic peak of viscapine-2, and the relative positions of the characteristic peaks and the peak 9 are basically shown in figure 17;

taking the peak 12 corresponding to hesperidin as a reference peak, wherein the relative retention time of the rest characteristic peaks is within +/-10% of a corresponding specified value, and the specified value of each characteristic peak is as follows: peak 1 was 3.9min, peak 2 was 11.4min, peak 3 was 13.8min, peak 4 was 15.5min, peak 5 was 23.9min, peak 6 was 29.8min, peak 7 was 30.6min, peak 8 was 31.9min, peak 9 was 43.2min, peak 10 was 45.5min, peak 11 was 46.7min; or, taking the peak 9 corresponding to the visanin-2 as a reference peak, wherein the relative retention time of the rest characteristic peaks is within +/-10% of the corresponding specified value, and the specified value of each characteristic peak is as follows: peak 1 was 3.9min, peak 2 was 11.4min, peak 3 was 13.8min, peak 4 was 15.5min, peak 5 was 23.9min, peak 6 was 29.8min, peak 7 was 30.6min, peak 8 was 31.9min, peak 10 was 45.5min, peak 11 was 46.7min, peak 12 was 56.4min.

constructing characteristic maps of the dried orange peels with different quality grades according to the construction method, wherein the quality grades of the dried orange peels comprise low-aging-degree dried orange peels, medium-aging-degree dried orange peels, high-temperature accelerated dried orange peels, tea-dyed dried orange peels, worm-eaten dried orange peels, high-humidity accelerated dried orange peels, other old-making-way dried orange peels and burned orange peels,

preparing a test solution of pericarpium citri reticulatae to be detected, detecting the test solution by adopting a high performance liquid chromatography, and obtaining a detection map at 255-265 nm;

and comparing the detection map with the characteristic maps of the dried orange peels with different quality levels, and determining the quality level of the dried orange peels to be detected according to the comparison result of the characteristic peak types.

In one embodiment, the detection grading method further comprises: and if the chromatographic peak contained in the detection spectrum is consistent with the characteristic peak contained in the characteristic spectrum of the high-aging-degree pericarpium citri reticulatae, introducing the detection spectrum and the characteristic spectrum of the high-aging-degree pericarpium citri reticulatae into a traditional Chinese medicine chromatographic fingerprint similarity evaluation system to obtain a similarity coefficient, and determining the quality grade of the pericarpium citri reticulatae to be detected according to the similarity coefficient.

In one embodiment, the procedure of gradient elution comprises: the volume percentage of the mobile phase A is 5 percent and 5min to 10min, the volume percentage of the mobile phase A is increased from 5 percent to 10 percent and 10min to 15min, the volume percentage of the mobile phase A is 10 percent and 15min to 25min, the volume percentage of the mobile phase A is increased from 10 percent to 20 percent and 25min to 35min, the volume percentage of the mobile phase A is increased from 20 percent to 25 percent and 35min to 50min, the volume percentage of the mobile phase A is increased from 25 percent to 40 percent and 50min to 55min, the volume percentage of the mobile phase A is 40 percent and 55min to 60min, the volume percentage of the mobile phase A is increased from 40 percent to 50 percent and 60min to 65min, and the volume percentage of the mobile phase A is 50 percent.

In one embodiment, the conditions of the high performance liquid chromatography include: the flow rate is 0.8mL/min to 1.2mL/min. In one embodiment, the conditions of the high performance liquid chromatography include: the column temperature is 28-32 ℃. In one embodiment, the conditions of the high performance liquid chromatography include: the sample injection amount is 8-12 mu L. In one embodiment, the step of preparing the test solution comprises: and extracting the dried orange peel to be detected by using an extraction solvent, collecting an extracting solution, and preparing the test solution.

In one embodiment, the extraction mode adopts ultrasonic extraction.

constructing a characteristic map of the dried orange peel with high aging degree by referring to the construction method;

providing a reference substance solution containing vesanine-2 or/and hesperidin, preparing a test solution of the dried orange peel to be detected, detecting the reference substance solution and the test solution by adopting a high performance liquid chromatography, obtaining a reference map and a detection map at 255-265 nm, comparing the detection map with the characteristic map of the dried orange peel with high ageing degree by referring to the reference map, and determining the quality grade of the dried orange peel to be detected according to a comparison result of the lack of characteristic peaks.

In one embodiment, the conditions of the high performance liquid chromatography include: the flow rate is 0.8mL/min to 1.2mL/min. In one embodiment, the conditions of the high performance liquid chromatography include: the column temperature is 28-32 ℃. In one embodiment, the conditions of the high performance liquid chromatography include: the sample injection amount is 8-12 mu L.

In one embodiment, the step of preparing the test solution comprises: and extracting the dried orange peel to be detected by using an extraction solvent, collecting an extracting solution, and preparing the test solution. In one embodiment, the extraction solvent comprises an aqueous methanol solution having a methanol volume percentage of 10% to 35%. In one embodiment, the extraction mode adopts ultrasonic extraction.

A method for detecting and grading dried orange peel comprises the following steps: providing a dried orange peel sample, determining the quality grade of the dried orange peel sample according to the ratio of chromatographic peak areas by referring to the detection and classification method, determining the quality grade of the dried orange peel sample according to the similarity coefficient by referring to the detection and classification method, determining the comprehensive quality grade of the dried orange peel sample according to the following quality classification method,

and detecting and grading the dried orange peel sample according to the determined comprehensive quality grade.

Compared with the prior art, the invention has the following beneficial effects: the method adopts the high performance liquid chromatography, particularly matches with the proper high performance liquid chromatography condition to detect the different components existing among the dried orange peels with different quality levels, analyzes the peak areas of the different components, particularly the ratio of the peak areas of the different components to the peak area of the Weicaining-2 (known and stable component in the dried orange peels), determines the type of the dried orange peels to be detected, and finally realizes the quality evaluation of the dried orange peels to be detected. In addition, the detection and classification method has the characteristics of good practicability (rapidness, simplicity and convenience) and relevance (the difference of the dried orange peels from different sources can be better reflected), and can promote the high-quality development of the dried orange peel industry. Meanwhile, the invention breaks through the traditional concept of quality by year theory and provides a new idea and a new technical support for the perfection of the quality standard of the dried orange peel.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a technical scheme of the present invention;

FIG. 2 is an HPLC chromatogram (220 nm) of a dried orange peel sample in three different storage modes;

FIG. 3 is an HPLC chromatogram (260 nm) of a dried orange peel sample in three different storage modes;

FIG. 4 is a 3D plot of HPLC full wavelength scan; wherein A is a chromatogram of the samples S11 and S17 under the wavelength of 260nm; b is a full-wavelength scanning equivalent graph of S13; c is a full-wavelength scanning equivalent graph of S12;

FIG. 5 is a chromatogram of a full-wavelength scanning equivalence chart of HPLC and corresponding wavelength of 260nm;

FIG. 6 is an HPLC chromatogram (260 nm) of dried orange peel with three extraction solvents of different concentrations;

FIG. 7 is an HPLC chromatogram (260 nm) of dried orange peels from different sources;

FIG. 8 is a graph of the aging degree of dried orange peel;

FIG. 9 is a low aging pericarpium Citri Tangerinae HPLC characteristic map;

FIG. 10 is a medium age pericarpium Citri Tangerinae HPLC profile;

FIG. 11 is a high aging pericarpium Citri Tangerinae HPLC characteristic map;

FIG. 12 is a high temperature accelerated dried orange peel HPLC profile;

FIG. 13 is an HPLC characteristic spectrum of tea-dyed dried orange peel;

FIG. 14 is HPLC characteristic spectrum of worm-eaten dried orange peel;

FIG. 15 is an HPLC characteristic spectrum of dried orange peel in other old-fashioned manners;

FIG. 16 is a high humidity accelerated dried orange peel HPLC profile;

FIG. 17 is a burned skin HPLC profile;

FIG. 18 is a comparison of control profiles for different quality grades of citrus peel;

FIG. 19 is a microscopic-level chart of the quality grade of citrus grandis.

Detailed Description

In order to facilitate an understanding of the present invention, the present invention will be described in more detail below. It should be understood, however, that the present invention may be embodied in many different forms and should not be construed as being limited to the embodiments or examples set forth herein. Rather, these embodiments or examples are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments or examples only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of two or more of the associated listed items, including any and all combinations of two or more of the associated listed items, any and all combinations of the associated listed items, or any and all combinations of the associated listed items.

The terms: in the present invention, "first aspect", "second aspect", "third aspect", "fourth aspect" and the like are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or quantity, nor as implying an importance or quantity indicating the technical feature indicated.

In the present invention, the technical features described in the open type include a closed technical solution composed of the listed features, and also include an open technical solution including the listed features. In the present invention, the numerical range is defined to include both end points of the numerical range unless otherwise specified. The percentage contents referred to in the present invention mean, unless otherwise specified, mass percentages for solid-liquid mixing and solid-solid phase mixing, and volume percentages for liquid-liquid phase mixing. The percentage concentrations referred to in the present invention refer to the final concentrations unless otherwise specified. The final concentration refers to the ratio of the additive component in the system to which the component is added. The temperature parameter in the present invention is not particularly limited, and is allowed to be a constant temperature treatment or a treatment within a certain temperature range. The constant temperature process allows the temperature to fluctuate within the accuracy of the instrument control. The method for detecting and grading the dried orange peel and the method for constructing the characteristic spectrum provided by the invention have no time sequence limitation on the related steps.

The industry standard DB44T 604-2009 geographical indication product Xinhui dried orange peel divides the years of the Xinhui dried orange peel into three categories, namely the production year, the historical year and the aging year, and explains the three years. Wherein (1) the production year refers to the year of harvesting the fruits and processing the fruits into peels, and indicates the production year of the sample; (2) the historical year refers to the year calculated by subtracting the production year and one year from the inspection year, and indicates how long the sample is; (3) the aging year refers to the aging degree of the dried orange peel expressed by years, and indicates that the sample achieves the aging level of a corresponding grade. Also, other terms of art are defined by the standard, such as: aging is as follows: under the condition of natural dry and ventilation, the product is stored in a packaging container with good air permeability, and the color, the fragrance, the taste and the components of the dried orange peel are changed along with the change of the fading and the growth of the effective contents of the dried orange peel. "degree of aging": the sensory properties of Xinhui dried orange peel in different periods are expressed by years. "burn skin": the fresh orange peel contains more sugar, is easy to absorb moisture, and if the fresh orange peel is stacked for a long time and is not turned and dried in the sun in time, the temperature is increased, rapid sugar alcoholysis is induced, and carbonization and black peel deterioration are caused. "worm eaten": during the storage period, the dried skin is mainly eaten by pests such as a khaki, a coffee bean weevil and the like, the dried skin is eaten in an orange channel, and then the dried skin is perforated by an orange hole and finally becomes moth powder to lose the commodity value. "other distressing means": other distressing means besides high temperature acceleration, tea dyeing and high humidity acceleration. The correspondence in the invention is only used for limiting the state, but not for limiting the acquisition mode. Also contemplated are citrus peels of the same or similar quality obtained in different ways.

In a first aspect, the invention provides a method for detecting and grading dried orange peel, which comprises the following steps:

detecting under the detection wavelength of 215-225 nm to obtain a detection spectrum I, wherein the detection spectrum I comprises a chromatographic peak Ia and a chromatographic peak Ib, the chromatographic peak Ia is the chromatographic peak of the visanin-2, the retention time ratio of the chromatographic peak Ib to the chromatographic peak Ia is 0.1-0.12,

analyzing peak areas of the chromatographic peak Ia and the chromatographic peak Ib in the detection spectrum I and peak areas of the chromatographic peak IIa, the chromatographic peak IIb, the chromatographic peak IIc, the chromatographic peak IId and the chromatographic peak IIe in the detection spectrum II, and determining the quality grade of the dried orange peel to be detected according to the analysis result.

In one example, the chromatographic peak ib is a chromatographic peak of a difference component having a negative correlation change relationship with the aging degree of the dried orange peel, the chromatographic peak iic and the chromatographic peak iid are each independently a chromatographic peak of a difference component having a positive correlation change relationship with the aging degree of the dried orange peel, the chromatographic peak ie is a chromatographic peak of a component specific to the tea-dyed dried orange peel relative to other dried orange peels, the relative positions of the chromatographic peak ib and the visanin-2 in the detection spectrum i are substantially shown as a peak 1 and a peak 3 in fig. 2, and the relative positions of the chromatographic peak iic, the chromatographic peak iid and the chromatographic peak ie and the visanin-2 in the detection spectrum ii are substantially shown as a peak 2, a peak 3, a peak 4 and a peak 5 in fig. 7.

The method for detecting and grading the dried orange peel can be used for conveniently identifying chromatographic peaks, and the adopted reference substance solution can further contain hesperidin and the like.

In one example, the conditions of the high performance liquid chromatography include: the stationary phase is a C18 chromatographic column, the mobile phase A is methanol, the mobile phase B is phosphoric acid aqueous solution with the phosphoric acid volume percentage of 0.08-0.12%, and gradient elution is adopted. The volume percent phosphoric acid in the aqueous phosphoric acid solution may be selected from, including but not limited to, any one of the following concentrations or a range of concentrations between any two of the following concentrations: 0.08%, 0.09%, 0.10%, 0.11%, 0.12%.

In one example, the procedure of gradient elution includes: 0min to 5min, the volume percentage of the mobile phase A is 5 percent and 5min to 10min, the volume percentage of the mobile phase A is increased from 5 percent to 10 percent and 10min to 15min, the volume percentage of the mobile phase A is 10 percent and 15min to 25min, the volume percentage of the mobile phase A is increased from 10 percent to 20 percent and 25min to 35min, the volume percentage of the mobile phase A is increased from 20 percent to 25 percent and 35min to 50min, the volume percentage of the mobile phase A is increased from 25 percent to 40 percent and 50min to 55min, the volume percentage of the mobile phase A is 40 percent and 55min to 60min, the volume percentage of the mobile phase A is increased from 40 percent to 50 percent and 60min to 65min, and the volume percentage of the mobile phase A is 50 percent.

In one example, the conditions of the high performance liquid chromatography further comprise: the flow rate is 0.8 mL/min-1.2 mL/min. The flow rate may be selected from, including but not limited to, any one or a range of flow rates between any two of the following: 0.8mL/min, 0.85mL/min, 0.9mL/min, 0.95mL/min, 1mL/min, 1.05mL/min, 1.1mL/min, 1.15mL/min, 1.2mL/min. In one example, the conditions of the high performance liquid chromatography further comprise: the column temperature is 28-32 ℃. The column temperature may be selected from, including but not limited to, any of the following column temperatures or a range of column temperatures between any two column temperatures: 28 ℃, 28.5 ℃, 29 ℃, 29.5 ℃, 30 ℃, 30.5 ℃, 31 ℃, 31.5 ℃ and 32 ℃. In one example, the conditions of the high performance liquid chromatography further comprise: the sample injection amount is 8-12 mu L. The sample amount may be selected from, including but not limited to, any of the following sample amounts or a range of sample amounts between any two sample amounts: 8. Mu.L, 8.5. Mu.L, 9. Mu.L, 9.5. Mu.L, 10. Mu.L, 10.5. Mu.L, 11. Mu.L, 11.5. Mu.L, 12. Mu.L.

In one example, the step of preparing the test solution comprises: and extracting the dried orange peel by using an extraction solvent, collecting an extracting solution, and preparing the test solution. In one example, the extraction solvent comprises an aqueous methanol solution having a methanol volume percentage of 10% to 35%. The extraction solvent comprises methanol in volume percent and may be selected from, including but not limited to, any one of the following concentrations or a range of concentrations between any two of the following concentrations: 10%, 15%, 20%, 25%, 30%, 35%. In one example, the extraction mode is ultrasonic extraction. Further, the duration of ultrasonic extraction is 20min to 40min, such as 20min, 25min, 30min, 35min, 40min. It will be appreciated that during the course of extraction, if there is a loss of extraction solvent, the addition of said extraction solvent may be continued to fill the loss. In the present invention, the manner of collecting the extract is not particularly limited, and for example, a centrifugation method may be employed in which the supernatant is collected after centrifugation and then filtered with a microporous filter membrane. The centrifugation conditions may be 8000 rpm-12000 rpm for 8 min-12 min, such as 8000rpm for 12min, 12000rpm for 8min, 10000rpm for 10min.

In one example, the solvent in the control solution comprises an aqueous methanol solution having a methanol volume percentage of 45% to 55%. The concentration of methanol in the aqueous methanol solution may be selected from, including but not limited to, any one of the following concentrations or a range of concentrations between any two of the following concentrations: 45%, 50% and 55%.

In one example, determining the quality grade of the pericarpium citri reticulatae to be detected according to the analysis result comprises: r1 is more than or equal to 0.7, the pericarpium citri reticulatae to be detected corresponds to high-temperature accelerated ageing pericarpium citri reticulatae or high-humidity accelerated ageing pericarpium citri reticulatae, R2 is more than 0.1, the pericarpium citri reticulatae to be detected corresponds to tea-water dyed pericarpium citri reticulatae, R1 is less than 0.7, R2 is less than or equal to 0.1, R3 is more than or equal to 0.9, the pericarpium citri reticulatae to be detected corresponds to burned peel or naturally aged pericarpium citri reticulatae stored under the condition that the air permeability is less than 5mm/s, R1 is less than 0.7, R2 is less than or equal to 0.1, R3 is less than 0.9, one of R4 and R5 is more than 0.6, the pericarpium citri reticulatae to be detected corresponds to naturally aged pericarpium citri reticulatae stored under the condition that the air permeability is less than or equal to 5mm/s and less than or equal to 80mm/s, and the naturally aged pericarpium citri reticulatae stored under the condition that the air permeability is more than 80mm/s, R1 is less than 0.7, R2 is less than or equal to 0.1, R3 is less than 0.9, R4 and R5 are both greater than 0.6, the dried orange peel corresponds to the dried orange peel with the year of more than or equal to seven years and is stored in the dried orange peel naturally aged under the condition that the air permeability is less than or equal to 5mm/s and less than or equal to 80mm/s, the dried orange peel naturally aged under the condition that the air permeability is more than 80mm/s or the dried orange peel aged by other aging ways with the year of more than or equal to five years, wherein R1, R2, R4 and R5 are respectively the peak area ratios of the chromatographic peak IIb, the chromatographic peak IIe, the chromatographic peak IIc, the chromatographic peak IId and the chromatographic peak IIa, and R3 is the peak area ratio of the chromatographic peak Ib to the chromatographic peak Ia.

The construction method of the characteristic spectrum of the dried orange peel can be used for constructing the characteristic spectrum of the common dried orange peel quality grade, and the correspondingly obtained characteristic spectrum can reflect the component characteristics of the dried orange peel and can distinguish the dried orange peels with various quality grades.

In a second aspect, a method for constructing a characteristic spectrum of dried orange peel comprises the following steps: providing a reference substance solution containing vesanine-2 or/and hesperidin, preparing a test solution of dried orange peel, detecting the reference substance solution and the test solution by adopting a high performance liquid chromatography, detecting at 255-265 nm to obtain a reference chromatogram and a detection chromatogram, introducing the detection chromatogram into a traditional Chinese medicine chromatogram fingerprint similarity evaluation system for analysis to obtain a pattern chromatogram, and performing characteristic peak identification on the pattern chromatogram by referring to the reference chromatogram to obtain a characteristic chromatogram of the dried orange peel.

In one example, the conditions of the high performance liquid chromatography include: the stationary phase is a C18 chromatographic column, the mobile phase A is methanol, the mobile phase B is phosphoric acid aqueous solution with the phosphoric acid volume percentage of 0.08-0.12%, and gradient elution is adopted. The volume percent of phosphoric acid in the aqueous phosphoric acid solution may be selected from, including but not limited to, any one of the following concentrations or a range of concentrations between any two of the following concentrations: 0.08%, 0.09%, 0.10%, 0.11%, 0.12%. In one example, the procedure of gradient elution includes: 0min to 5min, the volume percentage of the mobile phase A is 5 percent and 5min to 10min, the volume percentage of the mobile phase A is increased from 5 percent to 10 percent and 10min to 15min, the volume percentage of the mobile phase A is 10 percent and 15min to 25min, the volume percentage of the mobile phase A is increased from 10 percent to 20 percent and 25min to 35min, the volume percentage of the mobile phase A is increased from 20 percent to 25 percent and 35min to 50min, the volume percentage of the mobile phase A is increased from 25 percent to 40 percent and 50min to 55min, the volume percentage of the mobile phase A is 40 percent and 55min to 60min, the volume percentage of the mobile phase A is increased from 40 percent to 50 percent and 60min to 65min, and the volume percentage of the mobile phase A is 50 percent. In one example, the conditions of the high performance liquid chromatography further comprise: the flow rate is 0.8mL/min to 1.2mL/min. The flow rate may be selected from, including but not limited to, any one or a range of flow rates between any two of the following: 0.8mL/min, 0.85mL/min, 0.9mL/min, 0.95mL/min, 1mL/min, 1.05mL/min, 1.1mL/min, 1.15mL/min, 1.2mL/min.

In one example, the conditions of the high performance liquid chromatography further comprise: the column temperature is 28-32 ℃. The column temperature may be selected from, including but not limited to, any of the following column temperatures or a range of column temperatures between any two column temperatures: 28 ℃, 28.5 ℃, 29 ℃, 29.5 ℃, 30 ℃, 30.5 ℃, 31 ℃, 31.5 ℃ and 32 ℃. In one example, the conditions of the high performance liquid chromatography further comprise: the sample amount is 8-12 μ L. The sample size may be selected from, including but not limited to, any of the following sample sizes or a range of sample sizes between any two sample sizes: 8. Mu.L, 8.5. Mu.L, 9. Mu.L, 9.5. Mu.L, 10. Mu.L, 10.5. Mu.L, 11. Mu.L, 11.5. Mu.L, 12. Mu.L.

In one example, the step of preparing the test solution comprises: and extracting the dried orange peel by using an extraction solvent, collecting an extracting solution, and preparing the test solution. In one example, the extraction solvent comprises an aqueous methanol solution having a methanol volume percentage of 10% to 35%. The extraction solvent comprises methanol in volume percent and may be selected from, including but not limited to, any one of the following concentrations or a range of concentrations between any two of the following concentrations: 10%, 15%, 20%, 25%, 30%, 35%. In one example, the extraction mode is ultrasonic extraction. Further, the duration of ultrasonic extraction is 20min to 40min, such as 20min, 25min, 30min, 35min, 40min. It will be appreciated that during the course of extraction, if there is a loss of extraction solvent, the addition of said extraction solvent may be continued to fill the loss. In the present invention, the manner of collecting the extract is not particularly limited, and for example, centrifugation may be employed, and the supernatant may be collected after centrifugation and then filtered through a microporous filter membrane. The centrifugation conditions may be 8000 rpm-12000 rpm for 8 min-12 min, such as 8000rpm for 12min, 12000rpm for 8min, 10000rpm for 10min.

In one example, the solvent in the control solution comprises an aqueous methanol solution having a methanol volume percentage of 45% to 55%. The concentration of methanol in the aqueous methanol solution may be selected from, including but not limited to, any one of the following concentrations or a range of concentrations between any two of the following concentrations: 45%, 50%, 55%.

In one example, the pericarpium Citri Reticulatae comprises low-staling pericarpium Citri Reticulatae, medium-staling pericarpium Citri Reticulatae, high temperature accelerated pericarpium Citri Reticulatae, tea-dyed pericarpium Citri Reticulatae, worm-eaten pericarpium Citri Reticulatae, high humidity accelerated pericarpium Citri Reticulatae, other old style pericarpium Citri Reticulatae, and baked pericarpium Citri Reticulatae; the dried orange peels with low ageing degree correspond to dried orange peels which are naturally aged under the condition that the air permeability is less than 5mm/s, the dried orange peels with medium ageing degree correspond to dried orange peels which are less than seven years old and are naturally aged under the condition that the air permeability is less than or equal to 5mm/s or less than 80mm/s or dried orange peels which are naturally aged under the condition that the air permeability is greater than 80mm/s and are less than five years old, and the dried orange peels with high ageing degree correspond to dried orange peels which are naturally aged under the condition that the air permeability is greater than or equal to 5mm/s or less than 80mm/s or dried orange peels which are naturally aged under the condition that the air permeability is greater than 80mm/s and are greater than or equal to five years old.

In one example, the dried orange peel is dried orange peel with low aging degree, the characteristic spectrum comprises a peak 4, a peak 6, a peak 7, a peak 9, a peak 10, a peak 11 and a peak 12, the peak 9 is a chromatographic peak of viscapine-2, the relative positions of each characteristic peak and the peak 9 are basically as shown in figure 9,

the dried orange peel is dried orange peel with medium aging degree, the characteristic spectrum comprises peak 1, peak 3, peak 4, peak 6, peak 7, peak 9, peak 10, peak 11 and peak 12, peak 9 is chromatographic peak of viscapine-2, relative positions of each characteristic peak and peak 9 are basically shown in figure 10,

the dried orange peel is a high-humidity accelerated dried orange peel, the characteristic spectrum comprises a peak 2, a peak 3, a peak 4, a peak 6, a peak 7, a peak 9, a peak 10, a peak 11 and a peak 12, the peak 9 is a chromatographic peak of the viscapine-2, the relative positions of the characteristic peaks and the peak 9 are basically shown in figure 16,

the dried orange peel is dried orange peel in other distressing modes, the characteristic spectrum comprises a peak 1, a peak 3, a peak 4, a peak 5, a peak 6, a peak 7, a peak 9, a peak 10, a peak 11 and a peak 12, the peak 9 is a chromatographic peak of Weikaning-2, the relative positions of each characteristic peak and the peak 9 are basically shown in figure 15,

taking the peak 12 corresponding to hesperidin as a reference peak, wherein the relative retention time of the rest characteristic peaks is within +/-10% of a corresponding specified value, and the specified value of each characteristic peak is as follows: peak 1 was 3.9min, peak 2 was 11.4min, peak 3 was 13.8min, peak 4 was 15.5min, peak 5 was 23.9min, peak 6 was 29.8min, peak 7 was 30.6min, peak 8 was 31.9min, peak 9 was 43.2min, peak 10 was 45.5min, peak 11 was 46.7min; or, taking the peak 9 corresponding to the visanin-2 as a reference peak, and the relative retention time of the rest characteristic peaks is within +/-10% of the corresponding specified value, wherein the specified value of each characteristic peak is as follows: peak 1 was 3.9min, peak 2 was 11.4min, peak 3 was 13.8min, peak 4 was 15.5min, peak 5 was 23.9min, peak 6 was 29.8min, peak 7 was 30.6min, peak 8 was 31.9min, peak 10 was 45.5min, peak 11 was 46.7min, peak 12 was 56.4min.

In a third aspect, the invention provides a method for detecting and grading dried orange peel, which comprises the following steps:

constructing the characteristic maps of the dried orange peels with different quality grades according to the construction method, wherein the quality grades of the dried orange peels comprise low-aging-degree dried orange peels, medium-aging-degree dried orange peels, high-temperature accelerated dried orange peels, tea-dyed dried orange peels, worm-eaten dried orange peels, high-humidity accelerated dried orange peels, other old-making-way dried orange peels and burnt peels,

According to the detection and classification method provided by the invention, the detection map is compared with the characteristic maps of the dried orange peels with different quality levels, and the dried orange peel quality level corresponding to the characteristic map keeping the same characteristic peak of the detection map is the quality level of the dried orange peel to be detected.

In one example, the detection grading method further comprises: and if the chromatographic peak contained in the detection spectrum is consistent with the characteristic peak contained in the characteristic spectrum of the high-aging-degree pericarpium citri reticulatae, introducing the detection spectrum and the characteristic spectrum of the high-aging-degree pericarpium citri reticulatae into a traditional Chinese medicine chromatographic fingerprint similarity evaluation system to obtain a similarity coefficient, and determining the quality grade of the pericarpium citri reticulatae to be detected according to the similarity coefficient. By comparing the characteristic maps of the dried orange peels with different quality grades, the dried orange peels with various quality grades can be distinguished, but the dried orange peels with high ageing degree and the dried orange peels with other ageing modes cannot be distinguished. Therefore, the method can lead the to-be-detected chromatogram to a traditional Chinese medicine chromatogram fingerprint similarity evaluation system, and if the similarity of the to-be-detected chromatogram and the characteristic chromatogram of the high-aging-degree dried orange peel is lower than 0.6, the to-be-detected dried orange peel is the dried orange peel in other aging ways.

In one example, the conditions of the high performance liquid chromatography include: the stationary phase is a C18 chromatographic column, the mobile phase A is methanol, the mobile phase B is phosphoric acid aqueous solution with the phosphoric acid volume percentage of 0.08-0.12%, and gradient elution is adopted. In one example, the procedure of gradient elution includes: the volume percentage of the mobile phase A is 5 percent and 5min to 10min, the volume percentage of the mobile phase A is increased from 5 percent to 10 percent and 10min to 15min, the volume percentage of the mobile phase A is 10 percent and 15min to 25min, the volume percentage of the mobile phase A is increased from 10 percent to 20 percent and 25min to 35min, the volume percentage of the mobile phase A is increased from 20 percent to 25 percent and 35min to 50min, the volume percentage of the mobile phase A is increased from 25 percent to 40 percent and 50min to 55min, the volume percentage of the mobile phase A is 40 percent and 55min to 60min, the volume percentage of the mobile phase A is increased from 40 percent to 50 percent and 60min to 65min, and the volume percentage of the mobile phase A is 50 percent.

In one example, the conditions of the high performance liquid chromatography further comprise: the flow rate is 0.8 mL/min-1.2 mL/min. The flow rate may be selected from, including but not limited to, any one or a range of flow rates between any two of the following: 0.8mL/min, 0.85mL/min, 0.9mL/min, 0.95mL/min, 1mL/min, 1.05mL/min, 1.1mL/min, 1.15mL/min, 1.2mL/min. In one example, the conditions of the high performance liquid chromatography further comprise: the column temperature is 28-32 ℃. The column temperature may be selected from, including but not limited to, any of the following column temperatures or a range of column temperatures between any two column temperatures: 28 ℃, 28.5 ℃, 29 ℃, 29.5 ℃, 30 ℃, 30.5 ℃, 31 ℃, 31.5 ℃ and 32 ℃. In one example, the conditions of the high performance liquid chromatography further comprise: the sample amount is 8-12 μ L. The sample size may be selected from, including but not limited to, any of the following sample sizes or a range of sample sizes between any two sample sizes: 8. Mu.L, 8.5. Mu.L, 9. Mu.L, 9.5. Mu.L, 10. Mu.L, 10.5. Mu.L, 11. Mu.L, 11.5. Mu.L, 12. Mu.L.

In one example, the step of preparing the test solution comprises: and extracting the dried orange peel by using an extraction solvent, collecting an extracting solution, and preparing the test solution. In one example, the extraction solvent comprises an aqueous methanol solution having a methanol volume percentage of 10% to 35%. The extraction solvent comprises methanol in volume percent and may be selected from, including but not limited to, any one of the following concentrations or a range of concentrations between any two of the following concentrations: 10%, 15%, 20%, 25%, 30%, 35%. In one example, the extraction mode is ultrasonic extraction. Further, the duration of ultrasonic extraction is 20min to 40min, such as 20min, 25min, 30min, 35min, 40min. It will be appreciated that during the extraction process, if there is a loss of extraction solvent, the addition of said extraction solvent may be continued to fill the loss. In the present invention, the manner of collecting the extract is not particularly limited, and for example, a centrifugation method may be employed in which the supernatant is collected after centrifugation and then filtered with a microporous filter membrane. The centrifugation condition can be 8000 rpm-12000 rpm for 8 min-12 min, such as 8000rpm for 12min, 12000rpm for 8min, 10000rpm for 10min.

In a fourth aspect, the invention provides a method for detecting and grading dried orange peel, which comprises the following steps:

constructing a characteristic map of the dried orange peel with high ageing degree by referring to the construction method;

providing a reference substance solution containing vesanine-2 or/and hesperidin, preparing a test solution of the pericarpium citri reticulatae to be detected, detecting the reference substance solution and the test solution by adopting a high performance liquid chromatography, obtaining a reference map and a detection map at 255-265 nm, comparing the detection map with the characteristic map of the pericarpium citri reticulatae with high ageing degree by referring to the reference map, and determining the quality grade of the pericarpium citri reticulatae to be detected according to the comparison result of the loss of characteristic peaks. The quality grade of the dried orange peel to be detected can be determined by referring to the missing condition of each spectrum peak on the obtained detection spectrum relative to the characteristic spectrum of the aged orange peel.

In one example, the detection grading method further comprises: and if the chromatographic peak contained in the detection spectrum is consistent with the characteristic peak contained in the characteristic spectrum of the high-aging-degree pericarpium citri reticulatae, introducing the detection spectrum and the characteristic spectrum of the high-aging-degree pericarpium citri reticulatae into a traditional Chinese medicine chromatographic fingerprint similarity evaluation system to obtain a similarity coefficient, and determining the quality grade of the pericarpium citri reticulatae to be detected according to the similarity coefficient. According to the invention, the atlas to be detected is led into the traditional Chinese medicine chromatogram fingerprint similarity evaluation system, and if the similarity of the atlas to be detected and the characteristic atlas of the high-aging-degree dried orange peel is lower than 0.6, the dried orange peel to be detected is the dried orange peel in other old-making modes.

In one example, the conditions of the high performance liquid chromatography include: the stationary phase is a C18 chromatographic column, the mobile phase A is methanol, the mobile phase B is phosphoric acid aqueous solution with the phosphoric acid volume percentage of 0.08-0.12%, and gradient elution is adopted. The volume percent of phosphoric acid in the aqueous phosphoric acid solution may be selected from, including but not limited to, any one of the following concentrations or a range of concentrations between any two of the following concentrations: 0.08%, 0.09%, 0.10%, 0.11%, 0.12%. In one example, the procedure of gradient elution includes: 0min to 5min, the volume percentage of the mobile phase A is 5 percent and 5min to 10min, the volume percentage of the mobile phase A is increased from 5 percent to 10 percent and 10min to 15min, the volume percentage of the mobile phase A is 10 percent and 15min to 25min, the volume percentage of the mobile phase A is increased from 10 percent to 20 percent and 25min to 35min, the volume percentage of the mobile phase A is increased from 20 percent to 25 percent and 35min to 50min, the volume percentage of the mobile phase A is increased from 25 percent to 40 percent and 50min to 55min, the volume percentage of the mobile phase A is 40 percent and 55min to 60min, the volume percentage of the mobile phase A is increased from 40 percent to 50 percent and 60min to 65min, and the volume percentage of the mobile phase A is 50 percent. In one example, the conditions of the high performance liquid chromatography further comprise: the flow rate is 0.8mL/min to 1.2mL/min. The flow rate may be selected from, including but not limited to, any one or a range of flow rates between any two of the following: 0.8mL/min, 0.85mL/min, 0.9mL/min, 0.95mL/min, 1mL/min, 1.05mL/min, 1.1mL/min, 1.15mL/min, 1.2mL/min. In one example, the conditions of the high performance liquid chromatography further comprise: the column temperature is 28-32 ℃. The column temperature may be selected from, including but not limited to, any of the following column temperatures or a range of column temperatures between any two column temperatures: 28 ℃, 28.5 ℃, 29 ℃, 29.5 ℃, 30 ℃, 30.5 ℃, 31 ℃, 31.5 ℃ and 32 ℃. In one example, the conditions of the high performance liquid chromatography further comprise: the sample amount is 8-12 μ L. The sample size may be selected from, including but not limited to, any of the following sample sizes or a range of sample sizes between any two sample sizes: 8. Mu.L, 8.5. Mu.L, 9. Mu.L, 9.5. Mu.L, 10. Mu.L, 10.5. Mu.L, 11. Mu.L, 11.5. Mu.L, 12. Mu.L.

In one example, the step of preparing the test solution comprises: and extracting the dried orange peel by using an extraction solvent, collecting an extracting solution, and preparing the test solution. In one example, the extraction solvent comprises an aqueous methanol solution having a methanol volume percentage of 10% to 35%. The extraction solvent comprises methanol in volume percent selected from, including but not limited to, any one of the following concentrations or a range of concentrations between any two of the following concentrations: 10%, 15%, 20%, 25%, 30%, 35%. In one example, the extraction mode is ultrasonic extraction. Further, the duration of ultrasonic extraction is 20min to 40min, such as 20min, 25min, 30min, 35min, 40min. It will be appreciated that during the course of extraction, if there is a loss of extraction solvent, the addition of said extraction solvent may be continued to fill the loss. In the present invention, the manner of collecting the extract is not particularly limited, and for example, a centrifugation method may be employed in which the supernatant is collected after centrifugation and then filtered with a microporous filter membrane. The centrifugation condition can be 8000 rpm-12000 rpm for 8 min-12 min, such as 8000rpm for 12min, 12000rpm for 8min, 10000rpm for 10min.

In a fourth aspect, a method for detecting and grading dried orange peel comprises the following steps: providing a dried orange peel sample, determining the quality grade of the dried orange peel sample according to the ratio of chromatographic peak areas by referring to the detection and classification method, determining the quality grade of the dried orange peel sample according to the similarity coefficient by referring to the detection and classification method, determining the comprehensive quality grade of the dried orange peel sample according to the following quality classification method,

and detecting and grading the dried orange peel sample according to the determined comprehensive quality grade. The method can be used for screening low-grade pericarpium Citri Tangerinae.

In the above method of the present invention, preferred high performance liquid chromatography conditions include: the stationary phase is a C18 chromatographic column, the mobile phase A is methanol, the mobile phase B is phosphoric acid aqueous solution with the phosphoric acid volume percentage of 0.08-0.12%, gradient elution is adopted, and the procedure of the gradient elution comprises the following steps: the volume percentage of the mobile phase A is increased from 5% to 10% and 10min to 15min, the volume percentage of the mobile phase A is increased from 10% to 20% and 25min to 35min, the volume percentage of the mobile phase A is increased from 20% to 25% and 35min to 50min, the volume percentage of the mobile phase A is increased from 25% to 40% and 50min to 55min, the volume percentage of the mobile phase A is 40% and 55min to 60min, the volume percentage of the mobile phase A is increased from 40% to 50% and 60min to 65min, the volume percentage of the mobile phase A is 50%, the flow rate is 0.8mL/min to 1.2mL/min, the column temperature is 28 ℃ to 32 ℃, and the sample injection amount is 8mL to 12mL.

In the method, in view of the fact that the components of the dried orange peel which are subjected to oxidation reaction in the aging process generally have higher polarity, the low-concentration methanol is used as an extraction solvent, and the components with higher polarity in the dried orange peel can be fully extracted; meanwhile, the reagent can be saved, and the environment is protected. The test methods described in the following examples of the present invention are all conventional methods unless otherwise specified; the reagents and biomaterials, if not specifically mentioned, are commercially available. In the following embodiment, pericarpium citri reticulatae of different years, different maturity and different storage modes are taken as research objects, an HPLC technology is adopted, an HPLC 3D full-wavelength spectrum is combined, the pericarpium citri reticulatae of different storage modes are firstly used for finding out difference characteristic peaks, and chromatographic conditions are optimized; then, from the angles of the HPLC characteristic peak ratio and the characteristic spectrum of the dried orange peel, respectively establishing corresponding dried orange peel quality grading methods; and finally, combining the two orange peel quality grading methods to construct the orange peel quality grade from a microscopic level.

1 Instrument and reagent

1.1 Instrument Agilent 1260 high performance liquid chromatography (Agilent, USA), eclipse XDB-C18 column (5 μm,4.6 × 250mm, agilent, USA), ZORBAX SB-C18 column (5 μm,4.6 × 250mm, agilent, USA), eclipse Plus-C18 column (5 μm,4.6 × 250mm, agilent, USA), superfex JX-C18 column (5 μm,4.6 × 250mm, tianjin medicine science and technology Limited), XPR 26/A ppm electronic balance (Mettler-Toyoto, switzerland BS420S Wan electronic balance, TGL-15B centrifuge (Shanghai' S science and technology Co., ltd.), milli-Qrreference water purifier (SB-5200 DT) ultrasonic cleaning apparatus (New Biotechnology technologies, inc.),

Nylon 66 0.22 μm microporous filter membrane, WXJ type pulverizer (Shanghai Kaixuan Chinese medicine machinery manufacturing Co., ltd.).

1.2 reagent chromatography grade methanol (Merck, germany), ultrapure water, methanol (guangzhou chemical reagent works); 5-hydroxymethylfurfural standard, abbreviated as "5-HMF" (purity 99.50%, batch No. 111626-202013, china institute for testing food and drug); virginine-2 standard, abbreviated as "V2" (purity 99.57%, batch number: 19121201, chengdu Gelipu Biotech limited); hesperidin standard (purity 95.30%, batch number: 110721-202019, institute of food and drug testing, china).

1.3 test samples the main sources of the test samples in the research are the collection of a new-party dried orange peel base, the purchase of a new-party production area, the directional purchase from a local dried orange peel planting company or a cooperative, and the like, the numbers of the test samples are S1-S43, the obtained dried orange peel samples are aged by adopting three different storage modes (see table 1), and the dried orange peel samples are placed in a dry and ventilated environment; meanwhile, the information of the inner capsule character, the maturity and the like of all the dried orange peel samples is described and detailed in table 2. The above samples were identified as pericarp of Citrus reticulata of Rutaceae by professor yellow sea wave of the institute of Chinese medicine identification and development of Guangzhou university of traditional Chinese medicine.

TABLE 1 storage of dried orange peel samples

Serial number	Storage mode	Air permeability	Air permeability (mm/s)	Encoding
					1	Sacks, net cages, etc	Good air permeability	＞80	DZ
2	Plastic bag open mouth, paper box package and the like	General permeability	5～80	CK
					3	Sealing bags, glass jar seals, etc	Poor air permeability	＜5	MF

TABLE 2, tangerine peel sample information sheet

Note: samples S30 to S34 are judged as 'high-temperature accelerated dried orange peel' in the literature 'research on aging mode for judging dried orange peel based on 5-hydroxymethylfurfural content and appearance color difference'; the inner capsule of the dried orange peel has dark inside and light outside, and the outer orange peel presents a raised white ridge-shaped stripe, which is called as 'white ridge'. "-" represents sample information in no detail.

2 methods and results

2.1 grading of quality based on peak area ratio of HPLC chromatogram peak of pericarpium Citri Tangerinae

Related documents report that the intrinsic components of the dried orange peel change in the aging process, most researches at present mainly rely on a single component or a plurality of index components to evaluate the quality of the dried orange peel, but the integral characteristics of the dried orange peel cannot be represented by a plurality of indexes. Therefore, a chemical characterization spectrum of main components in the orange peel aging process is researched and established, the aging characteristic of the orange peel is characterized by the chemical characteristic, reference can be provided for scientific explanation of 'good old person' of the orange peel, and data support can be provided for quality grading of the orange peel.

2.1.1 study on growth and length change rules of different components in the aging process of pericarpium Citri Tangerinae with different storage modes

Because the change of the internal components of the dried orange peel is influenced by a plurality of factors such as the production place, the maturity, the storage mode, the storage environment and the storage time, in order to avoid the interference of the above influencing factors, the research firstly takes the dried orange peel (S11, S17 and S18) with the same source (same production place, same production year and same maturity) and different storage environments as a research object, the research samples are collected from the same Xinhui dried orange peel in 11 months in 2017, after the dried orange peel is dried in the sun, the S11, S17 and S18 are respectively stored by three storage modes of a sealing bag packaging (MF), a jute bag packaging (DZ) and a carton packaging (CK), and after the dried orange peel is stored for three years, the internal component difference among the three samples is compared. Firstly, performing HPLC-DAD full-wavelength scanning on dried orange peel samples in the three different storage modes according to HPLC chromatographic conditions in earlier-stage research results of project groups (see the literature, new-Congress dried orange peel quality control research); then, by comparing the existence and the size of the spots in the spectrogram after 3D imaging, finding out all the spots with obvious differences, and determining the difference peak corresponding to the spots in the HPLC three-dimensional map according to the peak-appearing time and the optimal absorption wavelength; then, optimizing HPLC chromatographic conditions based on the separation degree of the difference peak to determine the optimal chromatographic conditions; and finally, comparing the peak areas of the difference peaks in the samples, and analyzing the length-diminishing change rule of the difference peaks.

2.1.1.1 chromatographic conditions

Agilent 1260 high performance liquid chromatograph with Agilent XDB-C18 (4.6 mm × 250mm,5 μm) column flow rate of 1.0mL/min; the column temperature is 30 ℃; the sample size is 10 mu L; the detection wavelength is 220nm and 260nm; gradient elution is carried out by taking methanol-0.1% phosphoric acid aqueous solution as a mobile phase, and the elution procedure is as follows: 5% methanol (0 min-5 min), 5% -10% methanol (5 min-10 min), 10% methanol (10 min-15 min), 10% -20% methanol (15 min-25 min), 20% -25% methanol (25 min-35 min), 25% -40% methanol (35 min-50 min), 40% methanol (50 min-55 min), 40% -50% methanol (55 min-60 min), 50% methanol (60 min-65 min). In the elution procedure, for example, in the description of "5% to 10% methanol", the concentration refers to a variable concentration, and the percentage refers to the volume ratio of methanol.

The HPLC chromatogram of the control and the sample are shown in FIG. 2 and FIG. 3. FIG. 2 is a chromatogram (220 nm) of dried orange peel sample in three different storage modes, and FIG. 3 is a chromatogram (260 nm) of dried orange peel sample in three different storage modes.

(1) Determination of difference peak: in order to highlight the change condition of different components in the aging process of the dried orange peels with different storage modes, the corresponding dried orange peel samples (S11, S17) with two different storage modes (MF, DZ) with larger differences of appearance properties are selected to carry out HPLC-DAD full-wavelength scanning, which is shown in figure 4; then, by comparing the presence and size of the spots in the 3D imaged spectrum equivalence map (see fig. 5), all the spots with obvious differences, i.e., difference peaks (Y, M1, M2, M3), were found.

(2) Optimization of chromatographic conditions and screening of characteristic peaks: as can be seen from fig. 4 and 5, the optimal absorption wavelengths of the difference peaks are mainly focused on 200nm (Y) and 260nm (M1, M2, M3), and it is considered that the sample is likely to generate solvent peak interference at a wavelength of 200 nm; therefore, the present study uses wavelengths 220nm and 260nm as detection wavelengths. Meanwhile, the mobile phase is continuously optimized based on the separation degree of each difference peak, and the optimal mobile phase is determined. The separation degree of the difference peak M1 is less than 1.5 under the optimized chromatographic condition, the peak-off time is short, and the interference is too large, so that the difference peak M1 is not considered; therefore, the research uses the difference peaks Y, M2 and M3 as the difference characteristic components of the dried orange peel samples in three different storage modes in the aging process.

2.1.1.2 preparation of Mixed control solutions

Weighing appropriate amount of 5-hydroxymethylfurfural, vespertine-2 and hesperidin as reference substances, placing in a volumetric flask, adding 50% methanol water to prepare a mixed reference substance solution, and storing in a refrigerator at 4 ℃.

2.1.1.3 preparation of test solutions

Taking 0.5g of pericarpium citri reticulatae sample powder (sieved by a 45-mesh sieve), precisely weighing, placing in a 150mL conical flask with a plug, adding 25mL of 30% methanol, weighing, carrying out ultrasonic treatment for 30min, cooling, weighing, and supplementing the weight with 30% methanol; and centrifuged for 10min (10000 r.min) ^-1 ) Taking the supernatant, filtering with a 0.22 μm microporous membrane,and (4) obtaining the product.

The research compares the influence of several extraction solvents with different methanol concentrations, namely 10%, 30% and 50% methanol, on the peak areas of the different characteristic components Y, M1, M2 and M3 of the dried orange peel sample. The results show that: under the condition of wavelength of 220nm, the peak area size of the difference component Y is 10% methanol and more than 50% methanol of 30% methanol; under the condition of the wavelength of 260nm (see figure 6), the peak area size of the difference component M1 is 10% methanol > 30% methanol > 50% methanol, the peak area size of the difference component M2 is 10% methanol and 30% methanol > 50% methanol, and the peak area size of the difference component M3 is equivalent to that of the three concentrations of methanol. Therefore, 10% methanol and 30% methanol are suitable as the extraction solvent for dried orange peel.

In the present invention, the extraction solvent described by "50% methanol" for example means an aqueous methanol solution containing 50% by volume of methanol.

2.1.1.4 results and analysis

Taking pericarpium Citri Tangerinae samples of three different storage modes, preparing test solution according to the method under item "2.1.1.3", and determining according to the chromatographic condition under item "2.1.1.1", wherein the determination results of the peak areas of the different components (Y, M2, M3) are shown in Table 3.

TABLE 3 comparison of the peak areas of the different components in the dried orange peel samples in three different storage modes

As can be seen from Table 3, the peak areas of 3 different components in the dried orange peel samples with three different storage modes are obviously different.

Under the condition that the detection wavelength is 220nm, the peak area size of the different component Y of each sample is S11 (7.914) > S18 (1.013) > S17 (1.006) in sequence, and the storage mode air permeability of the three dried orange peel samples is S17 > S18 > S11 in sequence according to the table 1; therefore, the peak area of the difference component Y in the aging process is in an inverse relationship with the good air permeability of the storage mode, namely the area of the peak of the difference component Y is smaller when the air permeability of the storage mode is better, and the area of the peak of the difference component Y is larger when the air permeability of the storage mode is opposite.

Under the condition that the detection wavelength is 260nm, the peak area sizes of different components M2 and M3 of each sample are S17 > S18 > S11; as can be seen from the table 1, the storage modes of the three dried orange peel samples have good air permeability, namely S17 > S18 > S11; therefore, the peak areas of the different components M2 and M3 in the aging process are positively correlated with the good air permeability of the storage mode, namely the areas of the different components M2 and M3 are larger when the air permeability of the storage mode is better, and the areas of the different components M2 and M3 are smaller when the air permeability of the storage mode is smaller.

In conclusion, in the aging process of the dried orange peel in the three different storage modes, the 'elimination' of the differential component Y and the 'long' change rules of the differential components M2 and M3 explain the concept of 'aging' in the industry standard DB44T 604-2009 geographical indication product Xinhui dried orange peel, namely, under the condition of natural dry and ventilated, the effective content of the dried orange peel can change along with the change of time. The sample S17 with the highest aging degree has the smallest peak area of the different component Y (namely, the fastest disappearance) and the largest peak areas of the different components M2 and M3 (namely, the fastest growth); samples with moderate degree of aging were S18 times; the sample S11 with the lowest aging degree has the largest peak area (slowest disappearance) of the differential component Y and the smallest peak areas (slowest growth) of the differential components M2 and M3.

The results show that the aging degree of the dried orange peel is sequentially DZ dried orange peel > CK dried orange peel > MF dried orange peel, so that the aged dried orange peel needs to contact with oxygen and water in the environment, and the storage mode is an important factor influencing the aging degree of the dried orange peel and has the influence degree greater than the storage year.

Because the sample amount is too small and the source is single, the representativeness of the sample has limitation, therefore, samples from different sources and different years need to be introduced to verify the change rule of the difference components, such as 'elimination' and 'long' and the influence degree of the air permeability of the dried orange peel storage container on aging.

2.1.2 verification of growth and reduction of differential composition

On the basis of the dried orange peel samples (S11, S17 and S18) with the three different storage modes, introducing samples (S1-S43) with different sources, different years and different aging modes to verify the change rules of the difference components such as 'elimination' and 'long'; meanwhile, the influence degree of the air permeability of the dried orange peel storage container on aging is inspected.

Since the above-mentioned difference components Y, M2 and M3 are unknown components, the content thereof cannot be measured. Therefore, in the research, the known component 'visanning-2' (abbreviated as V2) which has stable properties and is not changed by storage environment and time in the dried orange peel content is taken as a reference substance, and the objective expression of the data of the difference component is homogenized by a method for calculating the ratio of the peak area of the difference component to the peak area of the reference substance (V2) under the same chromatographic condition, so that the universality of the detection and classification method is improved.

Meanwhile, in view of the fact that the introduced sample contains the dried orange peel accelerated by high temperature and the dried orange peel dyed by tea water, the dried orange peel can generate 5-hydroxymethyl furfural (5-HMF) due to Maillard reaction accelerated by high temperature, and after the dried orange peel is dyed by the tea water, a component (with a code of 'CR') with good water solubility in the tea can remain in an inner capsule of the dried orange peel; therefore, the present study also conducted the above 3 differential components together with the components 5-HMF and CR as the differential components.

2.1.2.1 the chromatographic conditions were the same as under "2.1.1.1". Chromatograms of naturally aged pericarpium Citri Tangerinae, high temperature accelerated pericarpium Citri Tangerinae and tea water dyed pericarpium Citri Tangerinae at wavelength of 260nm are shown in FIG. 7.

2.1.2.2 preparation of the Mixed control solution the same procedure as in "2.1.1.2" was followed.

2.1.2.3 preparation of test solutions the same procedure as in "2.1.1.3".

2.1.2.4 methodology investigation

(1) And (3) precision test: precisely sucking 10 mu L of the control solution, continuously injecting samples for 6 times according to the chromatographic condition under the item of '2.1.1.1', respectively integrating and recording peak area values of 5-HMF, visanin-2 and hesperidin, and calculating relative standard deviation, wherein the results show that RSD values of 5-HMF (RSD = 1.52%), visanin-2 (RSD = 0.74%) and hesperidin (RSD = 0.51%) are all less than 2%, which indicates that the precision of the instrument is good.

(2) And (3) repeatability test: 6 parts of the same sample (S24) to be tested is precisely weighed, the sample solution to be tested is prepared according to the method under the item 2.1.1.3, the chromatographic condition under the item 2.1.1 is used for detection, the peak areas are recorded, the relative standard deviation is calculated, and the results show that the RSD values of the peak areas of 5-HMF, viscapine-2 and hesperidin are respectively 3.31%, 1.53% and 2.10%, which indicates that the method has good repeatability.

(3) And (3) stability test: taking the test solution, respectively measuring the test solution under the chromatographic condition of the item of 2.1.1.1 at 0 hour, 4 hours, 8 hours, 12 hours, 24 hours and 72 hours, recording peak areas, and respectively calculating the RSD values of the peak areas of 5-HMF, viscapine-2 and hesperidin to be 1.11 percent, 0.85 percent and 1.03 percent, which indicates that the test solution is stable within 72 hours.

(4) Durability examination of the method: durability examination is carried out on 3 different chromatographic columns respectively, and three chromatographic columns are selected respectively, wherein Col.1 is a Superfex JX-C18 chromatographic column (5 mu m,4.6 multiplied by 250mm, tianjin Ji medicine science and technology Co., ltd.); col.2 is an Eclipse Plus-C18 column (5 μm, 4.6X 250mm, agilent, USA); col.3 is ZORBAX SB-C18 column (5 μm, 4.6X 250mm, agilent, USA). Comparing the measured results of three different chromatographic columns with the original method (namely the method under the item of 2.1.1.1), the aging peaks can be effectively separated on Col.1, col.2 and Col.3, and the peak area and the retention time of each difference peak are close to the ratio of the Vignanin-2 measured results of the original column Col.4, see tables 4 and 5, so that the method has good durability.

TABLE 4 comparison of retention time ratios of different chromatographic column difference peaks to reference peak

TABLE 5 comparison of peak area ratios of different chromatographic column difference peaks to reference peak

Note: col.1 is Superfex JX-C18 column (5 μm, 4.6X 250mm, tianjin Ji division pharmaceutical science and technology Co., ltd.); col.2 is an Eclipse Plus-C18 column (5 μm, 4.6X 250mm, agilent, USA); col.3 is ZORBAX SB-C18 column (5 μm, 4.6X 250mm, agilent, USA); col.4 is an Eclipse XDB-C18 column (5 μm, 4.6X 250mm, agilent, USA) selected in the establishment of the method.

2.1.2.5 results and analysis

Dried orange peel samples (S1 to S34) were taken, a test solution was prepared under the section "2.1.2.3", and the measurement was carried out under the chromatographic conditions under the section "2.1.2.1", and the measurement results of the peak areas of the various different components (Y, M2, M3, 5-HMF, CR) and the peak area of the reference substance (V2) are shown in Table 6.

The chromatogram obtained under 220nm is taken as a detection chromatogram I, wherein, the chromatogram peak of the Virginine-2 is taken as a chromatogram peak Ia, and the chromatogram peak of the difference component Y is taken as a chromatogram peak Ib;

a chromatogram obtained under 260nm is taken as a detection spectrum II, wherein a chromatogram peak of the Viburnin-2 is taken as a chromatogram peak IIa, a chromatogram peak of the 5-HMF is taken as a chromatogram peak IIb, and chromatogram peaks of the difference components M2, M3 and CR are respectively taken as a chromatogram peak IIc, a chromatogram peak IId and a chromatogram peak IIe.

TABLE 6 measurement results of peak areas of respective different components of the samples

Note: n.a. represents no detection.

As can be seen from Table 6, the peak areas of the different components (Y, M2, M3, 5-HMF, CR) of the citrus peel from different sources are significantly different. As can be seen from Table 2, at a detection wavelength of 220 nm: for the storage time, the peak areas of the different component Y in the naturally aged dried orange peels show a gradually decreasing trend along with the prolonging of the storage time, namely the chromatographic peak of the different component Y gradually disappears; the peak area of the naturally aged tangerine peel component Y stored in MF is 4.282-20.520, and the peak areas of the naturally aged tangerine peel component Y stored in CK and DZ are both less than or equal to 1.013 according to the storage method, except for the sample S6 (the peak area is 13.751) stored in DZ and the historical year is less than three years. Under the condition that the detection wavelength is 260 nm: for the storage time, the peak areas of the difference components M2 and M3 in the naturally aged pericarpium citri reticulatae show a gradually increasing trend along with the extension of the storage time, namely the chromatographic peaks of the difference components M2 and M3 gradually grow; for the storage mode, the peak areas of two different components of the naturally aged tangerine peel with the storage mode of MF are represented by M2 & lt 0.6 and M3 & lt 0.817, the peak areas of CK and DZ are represented by M2 & gt 1.0 and M3 & gt 1.1, and the storage mode is except for a sample S6 with the storage mode of DZ and the historical years of less than three years, and worm-eaten samples S38 and S39. The results show that the natural aged pericarpium citri reticulatae stored in MF mode has lower aging degree no matter the storage time; naturally aged tangerine peels with the historical years less than three years have lower aging degree no matter the air permeability of the storage mode, and naturally aged tangerine peels with the storage mode of CK and DZ and the historical years more than three years have higher aging degree.

In summary, the better the storage mode of the dried orange peel aged under natural conditions is, the higher the aging degree is; the longer the storage time, the higher the degree of aging; the higher the degree of aging (the stronger the aging reaction), the smaller the peak area of the difference component Y and the larger the peak areas of the difference components M2 and M3. The verification of dried orange peels from different sources shows that the change rules of the different components are consistent with the conditions mentioned above. For the non-naturally aged pericarpium citri reticulatae, according to the peak area of the index of the difference components of the pericarpium citri reticulatae in the modes of high humidity acceleration, high temperature acceleration and other aging ways, the aging degree of the pericarpium citri reticulatae is higher than that of the naturally aged pericarpium citri reticulatae in the mode of MF storage and less than three years in the historical years. As can be seen from the table 2, the intrinsic components of the citrus grandis can be changed correspondingly whether the citrus grandis is naturally aged or is subjected to accelerated aging or old-making treatment. The peak area of the differential component Y of the tea water dyed orange peel samples (S35, S36 and S37) is between 2.201 and 3.773, and is lower than the peak area (7.914) of the orange peel sample S11 which is from the same source and is not dyed by tea water; and the peak areas of the different components (M2 and M3) are larger than that of the dried orange peel sample S11 which is from the same source and is not dyed by tea, so that the condition that the dried orange peel undergoes component growth and degradation change, namely an aging reaction, in the process that the sample S11 is dyed by tea and then dried in the sun or dried at low temperature can be shown. The above results again confirm that the aging reaction of the citrus peel requires ambient oxygen and moisture.

2.1.4 quality grading

Based on the peak areas of the respective difference components in Table 6 and the reference Vignan-2, the ratios between the peak areas of the difference components (Y, M2, M3, 5-HMF, CR) and Vignan-2 (V2) were calculated, and the results are shown in Table 7. And then, using the ratio of the 5 difference components to the viscapine-2 as an evaluation index to classify the quality grades of the citrus grandis.

TABLE 7 ratio of peak area of difference component to peak area of reference

Note: "-" represents the presence of undetected sample in the ratio.

As can be seen from Table 7, there is a large difference in the ratio between the peak area of the different component of each type of Citrus reticulata and the peak area of the reference substance (V2). Comparing the specific value R1 (5-HMF/V2) of various dried orange peels, wherein the R1 values of the high-temperature accelerated dried orange peels (S30-S34) and the high-humidity accelerated dried orange peels (S42) are more than or equal to 0.7, and the R1 values of the dried orange peels of other quality grades are less than 0.7; therefore, the two types of the dried orange peels, namely the high-temperature and high-humidity accelerated dried orange peels, can be distinguished from the dried orange peels with other quality grades through the ratio R1. Similarly, comparing the ratio R2 (CR/V2) of various dried tangerine peels, the R2 values of the dried tangerine peels dyed with tea water (S35-S37) are all more than 1.0, and the R2 values of the dried tangerine peels with other quality grades are all less than or equal to 0.1 and are far lower than the R2 value of the dried tangerine peels dyed with tea water; therefore, the tea water dyed orange peel can be distinguished from the orange peels of other quality grades through the ratio R2.

The results show that the high-temperature accelerated tangerine peel, the high-humidity accelerated tangerine peel and the tea water dyed tangerine peel can be distinguished from other tangerine peels with quality grades through the ratio R1 and R2; and grading the quality of the naturally aged pericarpium citri reticulatae on the basis that R1 is less than 0.7 and R2 is less than or equal to 0.1.

By comparing the ratio R3 (Y/V2), the R3 values of MF naturally aged pericarpium citri reticulatae with lower aging degree are all more than or equal to 0.9, and the R3 values of CK and DZ naturally aged pericarpium citri reticulatae with higher aging degree are all less than 0.9; similarly, on the basis that R3 is less than 0.9, by comparing the values of the ratios R4 (M2/V2) and R5 (M3/V2), the values of R4 and R5 of DZ naturally aged pericarpium citri reticulatae older than five years and CK naturally aged pericarpium citri reticulatae older than seven years are both more than 0.6.

Based on the results, the quality of the dried orange peels from different sources can be graded according to the ratio angle between the peak area of the characteristic peak and the peak area of the reference object, and the aging degree of the naturally aged dried orange peels can be graded, and the grading results are shown in table 8 and figure 8.

TABLE 8 quality grading of citrus peel based on characteristic peak area ratios

Note: the greater the "+" number, the better the quality. The quality of the orange peel eaten by worms is not graded because the appearance and the character of the orange peel are obvious and the quality is poor.

As can be seen from Table 8, the ratio R1 (5-HMF/V2) can be used to determine whether the sample is high-temperature high-humidity accelerated pericarpium Citri Tangerinae; and judging whether the sample is the tea-dyed dried orange peel or not according to the value of the ratio R2 (CR/V2). As can be seen from the graph 8, the aging degree of the dried orange peel can be divided into three grades of 'low aging degree', 'medium aging degree' and 'high aging degree' by the peak area ratio (R3-R5) of the chromatographic peak with 'vanish' and 'long' changes. However, the peak area ratios (R1-R5) of the chromatographic peaks of the non-naturally aged tangerine peels and the tangerine peels (S40 and S41) in other aging ways can also meet the conditions specified by the quality grade "++++" and the high aging degree grade. Therefore, the ratio of the peak areas of the chromatographic peaks can be used as one of evaluation methods for grading the quality of the dried orange peel, but the comprehensive evaluation needs to be carried out by combining internal indexes such as similarity of characteristic spectrums.

2.2 quality grading based on dried orange peel HPLC characteristic spectrum

The characteristic spectrum can comprehensively reflect the characteristics of multiple components of the traditional Chinese medicine, and the UV spectrum can reflect certain structural characteristics of chemical components, so that the research utilizes the HPLC characteristic spectrum and the UV spectrum to analyze the dynamic change condition of the chemical components of the pericarpium citri reticulatae in the aging process, compares the difference characteristic peaks in the pericarpium citri reticulatae spectrums from different sources, and grades the quality of the pericarpium citri reticulatae by the existence of the difference characteristic peaks; and researching and establishing an aging characteristic map of the dried orange peel in the aging process.

2.2.1 Establishment of HPLC characteristic map

According to the method under the item of '2.1.2.3', various test solution such as naturally aged pericarpium citri reticulatae, high-temperature accelerated pericarpium citri reticulatae, high-humidity accelerated pericarpium citri reticulatae, tea-colored pericarpium citri reticulatae, burned peel, worm-eaten pericarpium citri reticulatae and other old-making pericarpium citri reticulatae are respectively prepared. Wherein, the naturally aged pericarpium citri reticulatae samples are classified according to the aging degree, and the following can be known by combining the table 8: MF naturally aging the dried orange peel to a quality level with a lower aging degree; CK naturally aged tangerine peel with the year less than seven years and DZ naturally aged tangerine peel with the year less than five years are in medium-grade quality level; CK naturally aged tangerine peel with the year more than seven years and DZ naturally aged tangerine peel with the year more than five years are of higher quality grade with higher aging degree. The measurement was carried out under the chromatographic conditions under the item "2.1.2.1", and the 260nm wavelength chromatogram was mainly recorded in the present study in view of the abundance of chromatographic information under the 260nm wavelength condition. Matching the chromatograms by using a traditional Chinese medicine chromatogram fingerprint similarity evaluation system 2012A issued by the State pharmacopoeia Commission, and determining that the common peak numbers of natural aged tangerine peels with low aging degree, medium aged tangerine peels and high aged tangerine peels are respectively 7, 9 and 10, and the common peak numbers of high-temperature accelerated tangerine peels, tea-dyed tangerine peels, worm-eaten tangerine peels and other distressed tangerine peels with old ways are respectively 10, 8, 9 and 10, as shown in a figure 9 (low aging degree), a figure 10 (medium aging degree), a figure 11 (high aging degree), a figure 12 (high-temperature acceleration), a figure 13 (tea-dyed), a figure 14 (worm-eaten), a figure 15 (other distressed ways), a figure 16 (high-humidity acceleration) and a figure 17 (burnt skin).

Regarding the establishment of the control characteristic maps of various types of dried orange peels, for the dried orange peels with low aging degree (as shown in figure 9), S1 is taken as a reference map, and the control characteristic maps are generated by average numbers; establishing characteristic maps of the dried orange peels with medium ageing degree, the dried orange peels with high temperature acceleration, the dried orange peels dyed by tea water, the dried orange peels damaged by worms and the dried orange peels with other old-making modes (see figure 18); wherein, the high-humidity accelerated dried orange peel (S42) and the burned peel (S43) are single samples, and the chromatograms represent the characteristic maps of the respective quality grades. Meanwhile, calculating the similarity in the quality grade groups of low, medium and high-aging-degree tangerine peels; as a result, the similarity of the low-aging orange peels in the group is more than 0.9, and the similarity of the medium-aging orange peels and the high-aging orange peels in the group is also more than 0.9.

2.2.2 quality grading

3 chromatographic peaks were identified by control retention time and HPLC-DAD: the No. 2 peak is 5-hydroxymethyl furfural, the No. 9 peak is visannin-2, and the No. 12 peak is hesperidin; and the peak is in one-to-one correspondence with the characteristic peaks of the difference, namely, the peak 1 is the characteristic peak M1, the peak 3 is the characteristic peak M2, the peak 7 is the characteristic peak M3, and the peak 8 is the tea staining peak CR, as shown in FIG. 18. Meanwhile, the feature spectrums of the three kinds of the dried orange peels with aging degrees, the dried orange peels accelerated at high temperature, the dried orange peels accelerated at other ageing modes, the dried orange peels accelerated at high humidity, the dried orange peels dyed by tea water, the dried orange peels burned and the dried orange peels damaged by worms are compared, and the similarity result is shown in a table 10. The characteristic spectrums of the dried orange peels from different sources are observed by naked eyes, for the naturally aged dried orange peels, compared with the naturally aged dried orange peels with high aging degree (figure 18-TP 3), the dried orange peels with medium aging degree (figure 18-TP 2) have the defect of No. 5 characteristic peak, the common characteristic peaks between the two characteristic spectrums are basically consistent, and the similarity is 0.676; and compared with the low-aging-degree dried orange peel (figure 18-TP 1), the low-aging-degree dried orange peel has the defects of

characteristic peaks

1, 3 and 5, and the similarity is 0.518. For non-naturally aged pericarpium Citri Tangerinae, compared with naturally aged pericarpium Citri Tangerinae with high aging degree (FIG. 18-TP 3), the increase of No. 2 characteristic peak appears in pericarpium Citri Tangerinae (FIG. 18-TP 9) accelerated by high temperature, and the increase of No. 8 characteristic peak appears in pericarpium Citri Tangerinae dyed with tea water (FIG. 18-TP 8); the burned pericarpium Citri Tangerinae (FIG. 18-TP 4) has loss of

characteristic peaks

1 and 3, the worm-eaten pericarpium Citri Tangerinae (FIG. 18-TP 7) has loss of

characteristic peaks

6 and 7, and the high-humidity accelerated pericarpium Citri Tangerinae (FIG. 18-TP 6) has loss of

characteristic peaks

1 and 5; the other old-fashioned tangerine peels (figure 18-TP 5) also have 10 characteristic peaks, and the similarity of the characteristic peaks with the tangerine peels with high aging degree is 0.631, but is less than the similarity of the characteristic peaks with the tangerine peels with medium and high aging degrees, namely 0.676.

TABLE 9 summary of characteristic peaks in the characteristic spectrum of pericarpium Citri Reticulatae at each quality level

TABLE 10 similarity of characteristic profiles of citrus peel of different quality grades

Similarity of the two	TP1	TP2	TP3	TP4	TP5	TP6	TP7	TP8	TP9
										TP1
	1
										TP2	0.977	1
TP3	0.518	0.676	1
										TP4	0.924	0.896	0.456	1
TP5	0.968	0.982	0.631	0.925	1
										TP6	0.981	0.975	0.540	0.928	0.978	1
TP7	0.862	0.821	0.411	0.892	0.875	0.834	1
										TP8	0.687	0.657	0.201	0.613	0.618	0.689	0.518	1
TP9	0.955	0.957	0.559	0.908	0.956	0.986	0.814	0.626	1

Note: TP1: pericarpium Citri Tangerinae with low aging degree; and TP2: pericarpium Citri Tangerinae with moderate aging degree; and TP3: pericarpium Citri Tangerinae with high aging degree; and TP4: baking the skin; and TP5: other old-making methods are dried orange peel; and TP6: accelerating the speed of the dried orange peel under high humidity; TP7: boring pericarpium Citri Tangerinae; and TP8: dyeing the dried orange peel with tea; TP9: accelerating the speed of the dried orange peel at high temperature.

The results show that the characteristic maps of the dried orange peels with different aging degrees are different, and the characteristic maps of the non-naturally aged dried orange peels from different sources are also obviously different. Accordingly, the quality of the citrus reticulata blanco can be divided into four grades of "+", "+ +", "+ + + + + + + + +" according to the indexes such as the existence and the similarity of characteristic peaks, as shown in table 11; meanwhile, based on the age grade of the naturally aged pericarpium citri reticulatae, the characteristic maps of the pericarpium citri reticulatae with low, medium and high age degrees are respectively established, and are shown in fig. 18-TP1, fig. 18-TP2 and fig. 18-TP3.

TABLE 11 quality grading based on dried orange peel profile

As can be seen from table 11, it can be determined whether the sample is high temperature accelerated tangerine peel or tea-dyed tangerine peel by the similarity of characteristic maps of tangerine peel. The quality grades of the dried orange peels can be accurately divided basically through the existence and the similarity of characteristic peaks in the characteristic map, but the characteristic peaks and the similarity of the non-naturally aged dried orange peels in other old-making modes (S40 and S41) can also meet the conditions specified by the quality grade' ++++; in combination with table 8, the quality of the citrus peel samples S40, S41 is also in the category of the grade "+++"; therefore, the quality grade of the dried orange peel in other old-making modes is not enough to be divided by internal indexes, and the comprehensive evaluation needs to be carried out by combining appearance characters.

3 establishing the quality grade of the citrus grandis from the microscopic level

In conclusion, the quality of the dried orange peel can be classified to a certain degree based on the existence of the characteristic peak of the dried orange peel HPLC, the similarity of the characteristic spectrum and other internal evaluation indexes. As can be seen from tables 8 and 11, the quality grades of the dried orange peels classified by only a single classification method are not comprehensive. In addition, correlation analysis is carried out on the two quality grading methods, and the quality grades divided by the 2-type grading method are basically the same and are mutually complemented; therefore, the quality grade of the constructed pericarpium citri reticulatae is more comprehensive and reliable by combining the two quality grading methods. Considering that the aging of the dried orange peel is influenced by a plurality of factors such as 'storage mode', 'storage environment', 'drying method', 'storage time' and the like, and meanwhile, the dried orange peel with high storage years is not necessarily high in 'aging degree' by combining the table 2 and the table 8; the storage years of the dried orange peels with high aging degree are higher. Therefore, the aging degree is more suitable for being used as an index for evaluating the quality of the dried orange peel than the year.

The research firstly integrates microscopic indexes such as HPLC (high performance liquid chromatography) chromatographic peak area ratio, characteristic spectrum similarity and the like, and divides the quality of the dried orange peel into four grades of 'inferior grade', 'low aging degree good grade', 'middle aging degree superior grade' and 'high aging degree superior grade' by combining 'aging degree', and the result is shown in figure 19. In fig. 19: R1-R5 represent the ratio of peak areas of chromatographic peaks; wherein R1 is 5-hydroxymethyl furfural/visanin-2, R2 is a tea dyeing peak CR/visanin-2, R3 is a characteristic peak Y/visanin-2, R4 is a characteristic peak M2/visanin-2, and R5 is a characteristic peak M3/visanin-2.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features. The above-mentioned embodiments only express several embodiments of the present invention, so as to understand the technical solutions of the present invention specifically and in detail, but not to be understood as the limitation of the protection scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. It should be understood that the technical solutions provided by the present invention, which are obtained by logical analysis, reasoning or limited experiments, are within the scope of the present invention as set forth in the appended claims. Therefore, the protection scope of the present invention should be subject to the content of the appended claims, and the description and the drawings can be used for explaining the content of the claims.

Claims

1. A construction method of a characteristic spectrum of dried orange peel is characterized by comprising the following steps:

providing a reference substance solution containing vesanine-2 or/and hesperidin, preparing a test solution of dried orange peel, detecting the reference substance solution and the test solution by adopting a high performance liquid chromatography, respectively obtaining a reference chromatogram and a detection chromatogram under the detection of 255-265 nm, introducing the detection chromatogram into a traditional Chinese medicine chromatogram fingerprint similarity evaluation system for analysis to obtain a pattern chromatogram, and carrying out characteristic peak identification on the pattern chromatogram by referring to the reference chromatogram to obtain a characteristic chromatogram of the dried orange peel;

the conditions of the high performance liquid chromatography include: the stationary phase is a C18 chromatographic column, the mobile phase A is methanol, the mobile phase B is phosphoric acid aqueous solution with the phosphoric acid volume percentage of 0.08-0.12%, and gradient elution is adopted;

the procedure for gradient elution included:

0 min-5 min, the volume percentage of the mobile phase A is 5 percent,

5-10 min, the volume percentage of the mobile phase A is increased from 5 percent to 10 percent,

10-15 min, the volume percentage of the mobile phase A is 10%,

15 min-25 min, the volume percentage of the mobile phase A is increased from 10 percent to 20 percent,

25-35 min, the volume percentage of the mobile phase A is increased from 20 percent to 25 percent,

35 min-50 min, the volume percentage of the mobile phase A is increased from 25 percent to 40 percent,

50 min-55 min, the volume percentage of the mobile phase A is 40 percent,

55-60 min, the volume percentage of the mobile phase A is increased from 40% to 50%,

60-65 min, and the volume percentage of the mobile phase A is 50%.

2. The method for constructing the characteristic spectrum of dried orange peel according to claim 1, wherein the conditions of the high performance liquid chromatography include: the flow rate is 0.8mL/min to 1.2mL/min, or/and the column temperature is 28 ℃ to 32 ℃, or/and the sample injection amount is 8 mu L to 12 mu L.

3. The method for constructing the characteristic spectrum of dried orange peel according to claim 1 or 2, wherein the preparation step of the test solution comprises: extracting the dried orange peel by using an extraction solvent, collecting an extracting solution, and preparing the test solution; preferably, the extraction solvent comprises 10-35% by volume methanol in water; preferably, the extraction mode adopts ultrasonic extraction; or/and the solvent in the reference solution comprises a methanol water solution with the methanol volume percentage of 45-55%.

4. The method for constructing a characteristic spectrum of citrus peel according to claim 1 or 2, wherein said citrus peel comprises low-aging citrus peel, medium-aging citrus peel, high-temperature accelerated citrus peel, tea-colored citrus peel, worm-eaten citrus peel, high-humidity accelerated citrus peel, other old-style citrus peel and burned citrus peel; wherein the content of the first and second substances,

the dried orange peel with low aging degree is correspondingly stored in the dried orange peel which is naturally aged under the condition that the air permeability is less than 5mm/s,

the dried orange peel with medium ageing degree corresponds to dried orange peel which is less than seven years old and is stored under the condition that the air permeability is less than or equal to 80mm/s and is naturally aged when the year is less than five years old and is stored under the condition that the air permeability is more than 80mm/s,

the high-aging-degree pericarpium citri reticulatae corresponds to the pericarpium citri reticulatae which is aged naturally under the condition that the air permeability is more than or equal to seven years and is stored under the condition that the air permeability is more than or equal to 5 and less than or equal to 80mm/s or the pericarpium citri reticulatae which is aged naturally under the condition that the air permeability is more than or equal to 80mm/s and is stored for more than or equal to five years.

5. The method for constructing the dried orange peel characteristic spectrum according to claim 4, wherein the dried orange peel is dried orange peel with low aging degree, the characteristic spectrum comprises peak 4, peak 6, peak 7, peak 9, peak 10, peak 11 and peak 12, peak 9 is a chromatographic peak of viscapine-2, the relative positions of each characteristic peak and peak 9 are substantially as shown in figure 9,

the dried orange peel is dried orange peel with high aging degree, the characteristic spectrum comprises peak 1, peak 3, peak 4, peak 5, peak 6, peak 7, peak 9, peak 10, peak 11 and peak 12, peak 9 is a chromatographic peak of viscapine-2, the relative positions of each characteristic peak and peak 9 are basically shown in figure 11,

the dried orange peel is high-temperature accelerated dried orange peel, the characteristic spectrum comprises a peak 2, a peak 3, a peak 4, a peak 5, a peak 6, a peak 7, a peak 9, a peak 10, a peak 11 and a peak 12, the peak 9 is a chromatographic peak of viscapine-2, the relative positions of the characteristic peaks and the peak 9 are basically shown in figure 12,

the dried orange peel is the burned peel, the characteristic spectrum comprises a peak 2, a peak 4, a peak 5, a peak 6, a peak 7, a peak 9, a peak 10, a peak 11 and a peak 12 which are shown in figure 17, the peak 9 is a chromatographic peak of visanin-2, and the relative positions of the characteristic peaks and the peak 9 are basically shown in figure 17;

taking the peak 12 corresponding to hesperidin as a reference peak, wherein the relative retention time of the rest characteristic peaks is within +/-10% of a corresponding specified value, and the specified value of each characteristic peak is as follows: peak 1 was 3.9min, peak 2 was 11.4min, peak 3 was 13.8min, peak 4 was 15.5min, peak 5 was 23.9min, peak 6 was 29.8min, peak 7 was 30.6min, peak 8 was 31.9min, peak 9 was 43.2min, peak 10 was 45.5min, peak 11 was 46.7min;

or, taking the peak 9 corresponding to the visanin-2 as a reference peak, and the relative retention time of the rest characteristic peaks is within +/-10% of the corresponding specified value, wherein the specified value of each characteristic peak is as follows: peak 1 was 3.9min, peak 2 was 11.4min, peak 3 was 13.8min, peak 4 was 15.5min, peak 5 was 23.9min, peak 6 was 29.8min, peak 7 was 30.6min, peak 8 was 31.9min, peak 10 was 45.5min, peak 11 was 46.7min, peak 12 was 56.4min.

6. The method for detecting and grading the dried orange peel is characterized by comprising the following steps of:

constructing a feature map of dried orange peels of different quality grades including low-staling dried orange peels, medium-staling dried orange peels, high-temperature accelerated dried orange peels, tea-dyed dried orange peels, worm-eaten dried orange peels, high-humidity accelerated dried orange peels, other old-finish dried orange peels and baked peels by referring to the construction method of any one of claims 1 to 5,

preparing a test solution of pericarpium citri reticulatae to be detected, detecting the test solution by adopting a high performance liquid chromatography, and obtaining a detection map at the wavelength of 255-265 nm;

7. The method for detecting and grading the dried orange peel is characterized by comprising the following steps:

constructing a feature map of the high-aging-degree dried orange peel with reference to the construction method described in any one of claims 1 to 5;

providing a reference substance solution containing vesanine-2 or/and hesperidin, preparing a test solution of the pericarpium citri reticulatae to be tested, detecting the reference substance solution and the test solution by adopting a high performance liquid chromatography, obtaining a reference map and a detection map at 255-265 nm, comparing the detection map with the characteristic map of the pericarpium citri reticulatae with high ageing degree by referring to the reference map, and determining the quality grade of the pericarpium citri reticulatae to be tested according to the comparison result of characteristic peak deletion.

8. The method for detecting and grading dried orange peel according to claim 6 or 7, characterized in that the method further comprises: and if the chromatographic peak contained in the detection spectrum is consistent with the characteristic peak contained in the characteristic spectrum of the high-aging-degree pericarpium citri reticulatae, introducing the detection spectrum and the characteristic spectrum of the high-aging-degree pericarpium citri reticulatae into a traditional Chinese medicine chromatographic fingerprint similarity evaluation system to obtain a similarity coefficient, and determining the quality grade of the pericarpium citri reticulatae to be detected according to the similarity coefficient.

9. The method for detecting and classifying dried orange peel according to claim 6 or 7, wherein the conditions of the high performance liquid chromatography include: the stationary phase is a C18 chromatographic column, the mobile phase A is methanol, the mobile phase B is phosphoric acid aqueous solution with the phosphoric acid volume percentage of 0.08-0.12%, and gradient elution is adopted;

preferably, the procedure of gradient elution comprises:

0 min-5 min, the volume percentage of the mobile phase A is 5 percent,

10-15 min, the volume percentage of the mobile phase A is 10%,

15-25 min, the volume percentage of the mobile phase A is increased from 10 percent to 20 percent,

50 min-55 min, the volume percentage of the mobile phase A is 40 percent,

60-65 min, wherein the volume percentage of the mobile phase A is 50%;

and/or, the conditions of the high performance liquid chromatography comprise: the flow rate is 0.8mL/min to 1.2mL/min, or/and the column temperature is 28 ℃ to 32 ℃, or/and the sample injection amount is 8 mu L to 12 mu L.

10. The method for detecting and grading pericarpium citri reticulatae according to claim 6 or 7, wherein the preparation step of the test solution comprises the following steps: extracting the dried orange peel to be detected by using an extraction solvent, collecting an extracting solution, and preparing the test solution;

preferably, the extraction solvent comprises 10-35% by volume methanol in water;

preferably, the extraction mode adopts ultrasonic extraction.