CN114246218A

CN114246218A - Method for removing smell of goat milk

Info

Publication number: CN114246218A
Application number: CN202111651123.8A
Authority: CN
Inventors: 侯俊财; 姜瞻梅; 刘越; 马佳歌; 马月
Original assignee: Northeast Agricultural University
Current assignee: Northeast Agricultural University
Priority date: 2021-12-30
Filing date: 2021-12-30
Publication date: 2022-03-29

Abstract

The invention discloses a method for removing the smell of mutton milk, belonging to the technical field of food processing. The method for removing the smell of goat milk comprises the following steps: sterilizing fresh goat milk, adding a de-odoring agent, and homogenizing to obtain the de-odored goat milk. The method optimizes and researches the goat milk smell removing method, takes beta-cyclodextrin and whey protein isolate subjected to different physical treatments as smell removing agents on the basis of the traditional smell removing process, utilizes the protein network structure of the beta-lactoglobulin in the whey protein isolate and the hydrophobic cavity of the beta-cyclodextrin to be combined with the goat milk smell substances, effectively eliminates the smell substances, does not damage the nutrient components in the goat milk, and completely preserves the nutrient components in the goat milk.

Description

Method for removing smell of goat milk

Technical Field

The invention relates to the technical field of food processing, in particular to a method for removing the smell of goat milk.

Background

The goat milk is rich in various nutritional ingredients and active substances, contains various fatty acids, dozens of enzymes and 25 minerals, and is rich in protein and vitamins and various in variety. The content of short-chain fatty acid in the goat milk is 5 times that of the goat milk, but the diameter of the fat globules is only about 2 microns, and the smaller fat globules can be dispersed in the goat milk more uniformly, so that a larger surface area is provided, the lipase is degraded conveniently, the digestion of fat is facilitated, and the fat is easier to digest and absorb by a human body. Meanwhile, the milk fat can carry vitamin A, and the absorption of calcium by the body is promoted. The goat milk has high protein content and soft protein clot, and mainly consists of casein and whey protein. The content of alpha S1-CN in the goat milk is 5.6 percent of the total casein, the content is lower, the content is close to that in the human milk, and the phenomenon of allergy is not easy to cause. Compared with cow milk, the goat milk has low lactose content and abundant ATP, and can promote the decomposition and utilization of lactose. The goat milk contains various minerals, wherein calcium and phosphorus are 4-6 times of those of human milk, and the content of zinc and iodine is higher than that of the human milk. Compared with cow milk, the goat milk contains more vitamin A, vitamin D, nicotinic acid, vitamin B1, vitamin B6 and riboflavin vitamin C. The goat milk is rich in nutrition, the texture of protein clot is softer than that of cow milk, the components of the goat milk are closer to those of human milk, and the goat milk is an excellent substitute of cow milk for lactose intolerance patients.

Goat milk taint may be due to short-medium chain free fatty acids (SM-FFA). The content of caproic acid (C6), caprylic acid (C8) and capric acid (C10) in goat milk is more abundant than that in cow milk. Another possibility is that goat milk taint may be the result of SM-FFA interactions, as goat taint is not present in the presence of these several SM-FFAs alone.

According to the formation mechanism of the goat milk smell, people usually adopt various ways to eliminate or reduce the goat milk smell in practice. The method comprises the steps of sheep breeding, male and female sheep separation breeding, cold chain transportation and rapid transportation of raw milk, processing, a certain de-odoring process, low-temperature and light-resistant product storage and other measures. The main methods usually adopted in the production and processing process of the goat milk include physical, chemical and biological de-odoring methods. However, the method has certain limitation, and the flash evaporation method has higher requirements on technical equipment, so that the industrial production cannot be realized. However, most people are not receptive to the smell of the goat milk and the products thereof, so that the production, processing and sale of the goat milk and the products thereof are severely restricted.

The physical de-odoring is to remove the odor of mutton in the processing process of the goat milk by adopting some physical methods. The purpose of removing the smell of goat milk is achieved by utilizing the embedding principle of beta-cyclodextrin and a flash evaporation physical method. The embedding and de-odoring of the beta-cyclodextrin is to utilize hollow hydrophobic cavity cavities in the molecules of the beta-cyclodextrin to combine with goat milk odor substances to form an inclusion compound so as to remove the goat milk odor. The flash steaming de-smelling principle is that the pressure is changed to cause the change of the boiling point of the goat milk solution, and the vacuum steaming is carried out to remove the smell-causing components. The flash evaporation method is usually adopted in the processing process of the goat milk powder to remove the smell of the goat milk. The chemical de-odoring is to add some specific substances into the goat milk to combine with the components of the goat milk to generate chemical reaction, so as to achieve the purpose of de-odoring the goat milk. The goat milk is usually added with tea, bitter almond, orange peel, tangerine, thyme essential oil and the like to play a role in removing the smell of the mutton. Or adding de-odoring agent into goat milk to remove the smell of mutton, but the method is strictly used according to the food additives approved by the state. However, the addition of these substances has a great influence on the color, texture, taste and the like of the goat milk, and the process is complicated, so that the method is not suitable for industrial mass production. How to effectively remove the smell of the goat milk becomes a technical problem to be solved urgently by technical personnel in the field.

Disclosure of Invention

The invention aims to provide a method for removing the smell of mutton to solve the problems in the prior art, and by taking beta-cyclodextrin and whey protein isolate subjected to different physical treatments as a smell removing agent, on the premise of not damaging the nutrient components in the mutton milk and completely preserving the nutrient substances in the mutton milk, the smell removing substance is effectively removed.

In order to achieve the purpose, the invention provides the following scheme: a method for removing the smell of goat milk comprises the following steps: sterilizing fresh goat milk, adding a de-odoring agent, and homogenizing to obtain de-odored goat milk;

the de-odoring agent comprises one or two of whey protein isolate and beta-cyclodextrin.

Whey protein isolate has high nutritional value and is a widely used protein in food industry production. Whey protein isolate mainly comprises beta-lactoglobulin, alpha-lactalbumin, bovine serum albumin and immunoglobulin, wherein the content of the beta-lactoglobulin is the highest, and the functional property of the whey protein isolate is determined. β -LG is capable of binding small hydrophobic ligands such as retinol, vitamins and fatty acids. The structure of beta-lactoglobulin may be modified. Beta-lactoglobulin has good ability to bind hydrophobic substances, and is a suitable delivery vehicle for lipid-soluble drugs or physiologically active ingredients. The whey protein isolate can be embedded by combining with free fatty acid of goat milk smell-causing component to remove the goat milk smell.

Further, the mass/volume percentage of the de-odoring agent to the fresh goat milk is 0.1-0.9%.

Still further, the mass/volume percent is g/mL × 100%.

Further, when the odor removing agent is whey protein isolate, the method further comprises any one of the following treatments of the whey protein isolate:

(1) carrying out high-pressure homogenization treatment;

(2) carrying out superfine grinding treatment;

(3) and (5) extruding and puffing.

Further, the high-pressure homogenization treatment specifically includes: and homogenizing the whey protein isolate under the pressure of 30-60 MPa.

Further, the high-pressure homogenization treatment specifically includes: dissolving Whey Protein Isolate (WPI) in deionized water to prepare a whey protein isolate solution with the concentration of 50mg/mL, then placing the whey protein isolate solution on a magnetic stirrer to be fully stirred for 2-3 h, adjusting the pH value to 7.0 by using 1mol/L NaOH, then carrying out high-pressure homogenization treatment, wherein the pressure is 30-60 MPa, the cycle time is 4 times, and the time of each homogenization is 2-4 min, obtaining the WPI solution after high-pressure homogenization, and freeze-drying the WPI solution to obtain the high-pressure homogenized whey protein isolate.

Further, the ultrafine grinding treatment specifically comprises: grinding whey protein isolate at 480r/min for 8 h.

Further, the micronization treatment specifically comprises: separating whey protein isolate from grinding balls in a volume ratio of 6: 1, putting the mixture into a ceramic pot, grinding the mixture by using a planetary ball mill at the grinding speed of 480r/min for 8 hours to obtain the ultra-micro atomized whey protein isolate after grinding.

Further, the extrusion puffing treatment specifically comprises: carrying out extrusion and expansion treatment on whey protein isolate at the adding speed of 1g/min and the rotating speed of 240 r/min; the whey protein isolate passes through 8 independent heating zones in the extrusion and expansion treatment process, wherein the temperature of the 1 st zone is 25 ℃, the temperature of the 2 nd zone is 35 ℃, the temperature of the 3 rd zone is 45 ℃, the temperature of the 4 th to 6 th zones is 50-125 ℃, the temperature of the 7 th zone is 45 ℃, and the temperature of the 8 th zone is 25 ℃.

Furthermore, the water inlet speed in the extrusion and expansion treatment process is 5.5 mL/min.

Further, when the de-odoring agent is whey protein isolate and beta-cyclodextrin, the mass ratio of the beta-cyclodextrin to the whey protein isolate is 1-4: 1 to 4.

Further, when the de-odoring agent is whey protein isolate and beta-cyclodextrin, the mass ratio of the beta-cyclodextrin to the whey protein isolate is 3: 2.

further, the temperature of the 4 th to 6 th zones is 125 ℃.

When the temperature of the 4 th-6 th area is 125 ℃, preparing 125 ℃ extruded and puffed whey protein isolate, and taking the 125 ℃ extruded and puffed whey protein isolate as a de-odoring agent, the mass/volume percentage of the de-odoring agent to the liquid goat milk is as follows: 0.1 to 0.9 percent.

Furthermore, when the deodouring agent is beta-cyclodextrin, the mass/volume percentage of the beta-cyclodextrin to the liquid goat milk is as follows: 0.1 to 0.9 percent.

Further, when the deodorizing agent is beta-cyclodextrin and 125 ℃ extruded and puffed whey protein isolate, the mass ratio of the beta-cyclodextrin to the 125 ℃ extruded and puffed whey protein isolate is 1-4: 1 to 4.

Further, when the deodouring agent is beta-cyclodextrin and 125 ℃ extruded and puffed whey protein isolate, the mass ratio of the beta-cyclodextrin to the 125 ℃ extruded and puffed whey protein isolate is 3: 2.

further, the method for removing the smell of the goat milk also comprises any one of the following treatment modes:

(1) adding fruit juice into de-odored goat milk, and fermenting the goat milk to obtain a goat milk product;

(2) concentrating fresh goat milk before de-odoring, adding fruit juice after de-odoring, and fermenting to obtain goat milk product.

The invention discloses the following technical effects:

(1) the main component of whey protein isolate in the present invention is beta-lactoglobulin, which exhibits a remarkable ability to bind fatty acids through hydrophobic bonds. And beta-lactoglobulin can bind most of saturated and unsaturated fatty acids.

(2) The whey protein isolate obtained by different physical treatments can reduce the smell of goat milk, wherein the extruded and puffed whey protein isolate has a larger network space structure and can be combined with more free fatty acid in goat milk to embed the whey protein isolate, so that the content of the free fatty acid in the goat milk is reduced. Compared with untreated raw material Whey Protein Isolate (WPI), high-pressure homogenized whey protein isolate and ultra-micronized whey protein isolate, the extruded and puffed whey protein isolate has better de-odoring effect, wherein the extruded and puffed whey protein isolate at 125 ℃ is the best.

(3) The beta-cyclodextrin of the invention effectively reduces the goat milk smell by embedding the goat milk smell substance formed by complexing free fatty acid in the goat milk through the hydrophilic periphery and the hydrophobic inner cavity in the ring structure.

(4) The invention carries out optimization research on the goat milk de-odoring method, on the basis of the traditional de-odoring process, beta-cyclodextrin and whey protein isolate treated by different physical methods are used as de-odoring agents, the protein network structure of beta-lactoglobulin in the whey protein isolate and the hydrophobic cavity of the beta-cyclodextrin are combined with the de-odoring substances in the goat milk, the de-odoring substances are effectively eliminated, meanwhile, the nutritional ingredients in the goat milk are not damaged, and the nutritional substances in the goat milk are completely preserved, wherein the beta-cyclodextrin and the whey protein isolate extruded and puffed at 125 ℃ are compounded to have better using effect, and the de-odoring effect is more obvious compared with the de-odoring effect of the whey protein isolate which is added with the beta-cyclodextrin and extruded and puffed at 125 ℃.

Drawings

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

FIG. 1 is a graph showing the effect of different deodouring agents on the free fatty acid content of goat milk in example 5 of the present invention;

FIG. 2 is a graph showing the effect of different deodouring agents on the free fatty acid content of lonicera edulis juice fermented goat milk in example 6 of the present invention;

FIG. 3 is a graph showing the effect of different deodouring agents on the free fatty acid content of concentrated goat milk in example 7 of the present invention;

fig. 4 is an electronic nose test chart of the influence of different de-odoring agents on the goat milk odor in example 5 of the present invention.

Detailed Description

Reference will now be made in detail to various exemplary embodiments of the invention, the detailed description should not be construed as limiting the invention but as a more detailed description of certain aspects, features and embodiments of the invention.

It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Further, for numerical ranges in this disclosure, it is understood that each intervening value, between the upper and lower limit of that range, is also specifically disclosed. Every smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in a stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

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. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference herein for the purpose of disclosing and describing the methods and/or materials associated with the documents. In case of conflict with any incorporated document, the present specification will control.

It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the present disclosure without departing from the scope or spirit of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification. The specification and examples are exemplary only.

As used herein, the terms "comprising," "including," "having," "containing," and the like are open-ended terms that mean including, but not limited to.

The following examples all used mass/volume percentages of g/mL × 100%.

The following examples were prepared using the following starting materials:

preparing extruded and puffed whey protein isolate:

(1) adding the whey protein isolate into a cylinder of an extruder at a feeding speed of 1g/min, and simultaneously controlling the water inlet speed to be 5.5mL/min and the screw rotation speed to be 240r/min so that the whey protein isolate passes through 8 independent heating zones of the extruder; 7 built-in heating zones and 1 external die heating zone in 8 independent heating zones of the extruder; the temperature of the 1 st zone is 25 ℃, the temperature of the 2 nd zone is 35 ℃, the temperature of the 3 rd zone is 45 ℃, the temperature of the 4 th to 6 th zones is 50 ℃, the temperature of the 7 th zone is 45 ℃, and the temperature of the 8 th zone (neck ring mold heating zone) is 25 ℃; the whey protein isolate extruded and puffed at 50 ℃ is obtained through the treatment.

(2) The method is the same as the step (1) except that the temperature of the 4 th to 6 th zones is 75 ℃, and the extrusion puffing whey protein isolate at the temperature of 75 ℃ is obtained.

(3) The method is the same as the step (1) except that the temperature of the 4 th to 6 th zones is 100 ℃, and the extruded and puffed whey protein isolate at the temperature of 100 ℃ is obtained.

(4) The method is the same as the step (1) except that the temperature in the 4 th to 6 th zones is 125 ℃, and the 125 ℃ extruded and puffed whey protein isolate is obtained.

(II) preparing high-pressure homogeneous whey protein isolate:

(1) dissolving Whey Protein Isolate (WPI) in deionized water to prepare a whey protein isolate solution with the concentration of 50mg/mL, then placing the whey protein isolate solution on a magnetic stirrer to be fully stirred for 3 hours, adjusting the pH value to 7.0 by using 1mol/L NaOH, then carrying out high-pressure homogenization treatment, wherein the pressure is 30MPa, the cycle time is 4 times, and each homogenization is 3min, obtaining the WPI solution after high-pressure homogenization, and freeze-drying the WPI solution to obtain the 30MPa high-pressure homogeneous whey protein isolate.

(2) The same as the step (1) except that the pressure is 60MPa, and 60MPa high-pressure homogeneous whey protein isolate is obtained.

(III) preparation of the ultramicro-pulverization whey protein isolate:

separating whey protein isolate from grinding balls in a volume ratio of 6: 1, putting the mixture into a ceramic pot, grinding the mixture by using a planetary ball mill at the grinding speed of 480r/min for 8 hours to obtain the ultra-micro atomized whey protein isolate after grinding.

Sensory evaluation and free fatty acid content determination methods of the de-odored goat milk prepared in the following examples are as follows:

(1) sensory evaluation: according to sensory evaluation standards (table 1), the experimental results are subjected to a ten-point scale method for sensory evaluation analysis, and a sensory evaluation group consists of 10 members receiving course training of food sensory evaluation and respectively scores the smell, taste, color and tissue state of the goat milk. In the evaluation process, a member rinses before sensory evaluation every time, in order to avoid inaccurate scoring caused by adaptation to the smell of mutton, when different samples are scored, the member needs to have a rest for 2-3 min after rinsing in the middle to evaluate the next sample. And calculating the sensory score by using a fuzzy mathematical sensory evaluation method.

TABLE 1 sensory evaluation criteria Table

Establishing a sensory evaluation system by applying a fuzzy mathematical model:

establishing a factor set and a comment set: according to the sensory evaluation index of the goat milk, the smell (u) of the goat milk is used₁) And taste (u)₂) Color and luster (u)₃) Tissue state (u)₄) As a factor, so as to obtain a factor set U ═ U of goat milk₁，u₂，u₃，u₄}. The evaluation grade of the goat milk is determined to be very good (v) through the discussion of the evaluation group₁) Preferably (v)₂) Good (v)₃) General (v)₄) A difference of (v)₅) Obtaining the comment set V ═ { V ═ V of the goat milk₁，v₂，v₃，v₄，v₅}. The standard is 10 points, each index is better when the score is more than 8 points, the score is better when the score is 6-8 points, the score is good when the score is 4-6 points, the score is general when the score is 2-4 points, and the score is worse when the score is less than 2 points. In order to make the results of sensory evaluation more obvious, the intermediate scores of all grades are selected as the final sensory score, namely V is {9, 7, 5, 3, 1 }.

Determination of the weights: the weight is determined by frequency statistics, 10 persons fill the rate of the importance degree of each factor of smell, taste, color and organization state in the table, and the single factor weight statistics test is performed on each factor to obtain the quality factor weight set X ═ 0.4, 0.4, 0.1, 0.1 }.

Establishing a fuzzy matrix and fuzzy conversion: the method comprises the steps of firstly counting scores of all indexes through sensory evaluation of 10 evaluators, then dividing the votes of all levels by 10 to obtain a fuzzy relation matrix R, processing the sensory evaluation result of the goat milk, and synthesizing a quality factor weight set X and the fuzzy relation matrix R to obtain a fuzzy relation evaluation set Y-X R, so that the evaluation result of the goat milk sample Y-X R is obtained. Finally, a comprehensive scoring matrix T is introduced to process a fuzzy relation evaluation set Y, and evaluation grades are set according to the particularity of sensory evaluationSet K ═ K₁，k₂，k₃，k₄，k₅And obtaining a fuzzy comprehensive evaluation total score T of the goat milk sample, namely Y multiplied by K.

(2) And (3) measuring the content of free fatty acid:

sample pretreatment: to a 20mL headspace bottle (75.5 mm. times.22.5 mm) was added 12mL of the milk sample and 3.6g of NaCl, and the headspace bottle was rapidly sealed with a gasket. And (3) balancing the mixture by water bath shaking at 30 ℃ for 30 min.

And (3) detection: insert 75 μm CAR/PDMS extraction head into gas chromatography injection port, age 1h at 250 ℃. And inserting the aged CAR/PDMS extraction head into a headspace bottle, pushing out the extraction fiber head, performing headspace extraction at a distance of 1cm from the liquid level, and extracting at 50 ℃ for 40 min. After extraction, the extraction fiber is retracted, the extraction head is pulled out, the extraction head is rapidly inserted into a GC sample inlet, the solution is analyzed for 5min at 250 ℃, the number of peaks and the area of the peaks are taken as detection indexes, and each sample is repeated for 3 times.

Gas chromatography conditions: adopting a temperature programming mode, wherein the initial temperature is 80 ℃, keeping the temperature for 3min, raising the temperature to 230 ℃ at the speed of 5 ℃/min, keeping the temperature for 10min, taking nitrogen as a carrier gas, and the flow rate is 3.0 mL/min; the split ratio is 3: 1.

Mass spectrum conditions: the mass spectrometer iron source was maintained at 230 ℃ for the full scan. The electron impact mode is 70eV, and the mass range is (20-500) m/z.

Qualitative and quantitative analysis: and (4) retrieving and qualifying each peak in the total ion current chromatogram with mass spectrum data of known substances in a database, and taking the matching degree of more than 800 as an identification basis. Taking the free fatty acid peak area as an index, carrying out quantitative analysis by adopting a peak area normalization method, and calculating the relative change of each free fatty acid according to the following formula.

(3) The electronic nose detection technology comprises the following steps:

sample pretreatment: a20 mL headspace bottle (75.5 mm. times.22.5 mm) was charged with 12mL of the milk sample and the headspace bottle was quickly sealed with a gasket.

Setting electronic nose test parameters: sample preparation time, detection time 60s, measurement count 1s, auto-zero time 10 s.

Data processing: principal Component Analysis (PCA) was performed on the data.

Example 1

Method for removing smell of goat milk

(1) Pasteurization: sterilizing fresh Lac Caprae Seu Ovis at 65 deg.C for 30 min;

(2) removing the smell of mutton: dividing the goat milk sterilized in the step (1) into 5 parts, numbering 1-5, adding 50 ℃ extrusion puffing whey protein isolate, 75 ℃ extrusion puffing whey protein isolate, 100 ℃ extrusion puffing whey protein isolate and 125 ℃ extrusion puffing whey protein isolate into No. 2-5 parts respectively, wherein the mass volume ratio of the 4 extrusion puffing whey protein isolate to the goat milk is 0.5%, and then shaking and stirring the mixture at the temperature of 35 ℃ for 30min respectively to obtain 4 different goat milks;

(3) and (3) homogenizing the goat milk prepared in the step (2) under the pressure of 20MPa to obtain the de-odored goat milk.

(4) No. 1 goat milk without the addition of the expanded whey protein isolate is taken as a control group to be subjected to sensory evaluation, the result is shown in Table 2, and the comprehensive evaluation result after the treatment by the fuzzy mathematical method is shown in Table 3.

TABLE 2 impact of extruded WPI on goat milk sensory evaluation results

As shown in Table 2, when the odor of the goat milk sample No. 1 was used as an example, U was obtained when 0 evaluated 8 to 10, 0 evaluated 6 to 8, 0 evaluated 4 to 6, 3 evaluated 2 to 4, and 7 evaluated 2 or less₁When the value is {0, 0, 0, 0.3, 0.7}, U can be obtained by the same method₂＝{0，0，0，0.2，0.8}，U₃＝{0.8，0.2，0，0，0}，U₄0.8, 0.2, 0, 0, 0. Will calculate the obtained U₁、U₂、U₃、U₃The evaluation results of 4 single-factor fuzzy matrixes are written into a matrix, namely:

according to the formula Y ═ X × R, Y is obtained from X ═ {0.4, 0.4, 0.1, 0.1}₁＝{0.16，0.04，0，0.2，0.6}，Y₂＝{0.32，0.52，0.16，0，0}，Y₃＝{0.36，0.48，0.16，0，0}，Y₄＝{0.53，0.35，0.12，0，0}，Y₅0.65, 0.35, 0, 0, 0 }. The fuzzy comprehensive evaluation total score T is Y × K, and is calculated from the evaluation grade set K {9, 7, 5, 3, 1}, and is shown in table 3.

TABLE 3 impact of extruded WPI on goat milk sensory evaluation composite score

Grouping	Sensory evaluation composite score
		Control group	2.92
50 ℃ extrusion puffing WPI	7.32
		WPI extruded and puffed at 75 DEG C	7.40
100 ℃ extrusion puffing WPI	7.82
		WPI extruded and puffed at 125 DEG C	8.30

As can be seen from Table 3, the WPI extruded and puffed at 125 ℃ has the best effect of removing the mutton smell of goat milk, the addition amount is 0.5%, and the mutton smell score is 8.30 at the moment. The extruded protein forms a protein network structure that may be capable of including the mutton smelling substances to reduce the mutton smelling substances in the goat milk. The higher the extrusion temperature is, the denser the formed protein network structure is, and more mutton smelling substances can be combined.

Example 2

(2) removing the smell of mutton: mixing the goat milk and the de-odoring agent according to the raw material proportion in the table 4, and then shaking and stirring the mixture for 30min at the temperature of 35 ℃.

TABLE 4 Deodorizing agent and raw materials ratio

Wherein the heated whey protein isolate is: after the mutton smell removing agent is added, a heat treatment step is added before shaking and stirring, wherein the heat treatment temperature is 65 ℃ and the time is 30 min.

(4) The goat milk without the added expanded whey protein isolate is used as a control group, and No. 1-15 groups are numbered 1-16 respectively for sensory evaluation, wherein No. 1 is used as the control group, No. 2 is used as the 1 st group, and the rest is done in the same way, and the results are shown in Table 5. The results of the comprehensive evaluation after the treatment by the fuzzy mathematical method are shown in Table 6.

TABLE 5 influence of WPI on sheep milk by different physical treatments sensory evaluation results

From Table 5, U of each group is obtained₁，U₂，U₃，U₄Will calculate the obtained U₁、U₂、U₃、U₄The evaluation results of 4 single-factor fuzzy matrixes are written into a matrix, namely:

according to the formula Y ═ X × R, Y is obtained from X ═ {0.4, 0.4, 0.1, 0.1}₁＝{0.16，0.04，0，0.20，0.60}，Y₂＝{0.53，0.35，0.12，0，0}，Y₃＝{0.17，0.39，0.44，0，0}，Y₄＝{0.17，0.47，0.36，0，0}，Y₅＝{0.16，0.36，0.48，0，0}，Y₆＝{0.17，0.35，0.4，0.08，0}，Y₇＝{0.65，0.35，0，0，0}，Y₈＝{0.32，0.48，0.20，0，0}，Y₉＝{0.36，0.44，0.20，0，0}，Y₁₀＝{0.24，0.56，0.20，0，0}，Y₁₁＝{0.17，0.35，0.48，0，0}，Y₁₂＝{0.65，0.35，0，0，0}，Y₁₃＝{0.36，0.48，0.16，0，0.6}，Y₁₄＝{0.24，0.50，0.36，0，0}，Y₁₅＝{0.32，0.48，0.20，0，0}，Y₁₆0.24, 0.52, 0.24, 0, 0 }. The fuzzy comprehensive evaluation total score T is Y × K, and is calculated from the evaluation grade set K {9, 7, 5, 3, 1}, and is shown in table 6.

TABLE 6 Effect of different physical treatments of WPI on sheep milk sensory evaluation composite score

As can be seen from Table 6, the sensory evaluation score of the goat milk gradually increased with the increase of the added amount of whey protein isolate of different physical treatments, which indicates that the smell of the goat milk decreased with the increase of the added amount of whey protein isolate of different physical treatments. Compared with several whey protein isolates subjected to different physical treatments, the whey protein isolate extruded and puffed at 125 ℃ has better odor removing effect.

The milk whey protein isolate extruded and puffed at 125 ℃ has better smell removing effect than the milk whey protein isolate subjected to high-pressure homogenization treatment and superfine grinding treatment, probably because the milk whey protein isolate subjected to extrusion and puffing forms a more compact network space structure and can embed the smell substances in the milk of sheep.

Example 3

(1) Pasteurization: sterilizing the homogenized goat milk at 65 deg.C for 30 min.

(2) Mixing goat milk and a de-odoring agent according to the raw material proportion of Table 7, and then shaking and stirring for 30min at 35 ℃; the deodouring agent consists of beta-cyclodextrin with the total addition of 0.5 percent and extruded whey protein isolate with the temperature of 125 ℃, and different compounding proportions of the deodouring agent are changed.

TABLE 7 mixture ratio of deodouring agent and raw materials

(4) And (3) taking goat milk without the added de-odoring agent as a control group, numbering the goat milk with groups 1-7 again, and performing sensory evaluation on the goat milk with groups 1-8, wherein the group 1 is the control group, the group 2 is the group 1, and the rest is done by analogy, and the results are shown in a table 8. The results of the comprehensive evaluation after the treatment by the fuzzy mathematical method are shown in Table 9.

TABLE 8 sensory evaluation of the Effect of different beta-cyclodextrin and 125 ℃ extrusion puffing WPI compounding ratios on goat milk

From Table 8, U of each group was obtained₁，U₂，U₃，U₄Will calculate the obtained U₁、U₂、U₃、U₄The evaluation results of 4 single-factor fuzzy matrixes are written into a matrix, namely:

according to the formula Y ═ X × R, Y is obtained from X ═ {0.4, 0.4, 0.1, 0.1}₁＝{0.16，0.04，0，0.2，0.6}，Y₂＝{0.65，0.35，0，0，0}，Y₃＝{0.65，0.23，0.12，0，0}，Y₄＝{0.69，0.31，0，0，0}，Y₅＝{0.73，0.27，0，0，0}，Y₆＝{0.81，0.15，0.04，0，0}，Y₇＝{0.90，0.10，0，0，0}，Y₈＝{0.81，0.19，0，0，0}。The fuzzy comprehensive evaluation total score T is Y × K, and is calculated from the evaluation grade set K {9, 7, 5, 3, 1}, and is shown in table 9.

TABLE 9 influence of different compounding ratios of beta-cyclodextrin and 125 deg.C extruded and puffed WPI on the sensory integration score of goat milk

Grouping	Sensory evaluation composite score
		Blank space	2.92
Group 1	8.30
		Group 2	8.06
Group 3	8.38
		Group 4	8.46
Group 5	8.54
		Group 6	8.80
Group 7	8.62

As can be seen from table 9, in the case where the total amount of added β -cyclodextrin and 125 ℃ extruded and puffed WPI (extruded and puffed whey protein isolate) was 0.5%, the ratio of β -cyclodextrin to extruded and puffed whey protein isolate was 3: the best effect of removing the smell of mutton is achieved at the time 2. Under the condition of certain total addition amount, the compounded goat milk has more aromatic flavor and better taste than the goat milk added with single beta-cyclodextrin, so that the mutton smell removing effect of the compound of the beta-cyclodextrin and the extrusion puffing WPI is better. However, the amount of the β -cyclodextrin added is not so large that the dissolution is difficult due to the excessive addition.

Example 4

(2) Mixing goat milk and a de-odoring agent according to the raw material proportion in the table 10, and then shaking and stirring the mixture for 30min at the temperature of 35 ℃; the deodouring agent consists of beta-cyclodextrin and 125 ℃ extruded and puffed whey protein isolate, and the proportion of the beta-cyclodextrin to the 125 ℃ extruded and puffed whey protein isolate is 3: 2 was kept constant and the amount added was varied.

TABLE 10 mixture ratio of deodouring agent and raw materials

(4) And (3) taking goat milk without the added de-odoring agent as a control group, and numbering the goat milk with groups 1-5 again to be No. 1-6, wherein No. 1 is the control group, No. 2 is the group 1, and so on, carrying out sensory evaluation, and obtaining results shown in table 11. The results of the comprehensive evaluation after the treatment by the fuzzy mathematical method are shown in Table 12.

TABLE 11 influence of different beta-cyclodextrin and 125 deg.C extruded and puffed WPI compound addition on goat milk sensory evaluation

From Table 11, U of each group is obtained₁，U₂，U₃，U₄Will calculate the obtained U₁，U₂，U₃，U₄The evaluation results of 4 single-factor fuzzy matrixes are written into a matrix, namely:

according to the formula Y ═ X × R, Y is obtained from X ═ {0.4, 0.4, 0.1, 0.1}₁＝{0.16，0.04，0，0.2，0.6}，Y₂＝{0.36，0.52，0.12，0，0}，Y₃＝{0.60，0.28，0.12，0，0}，Y₄＝{0.73，0.15，0.12，0，0}，Y₅＝{0.81，0.15，0.04，0，0}，Y₆0.89, 0.11, 0, 0, 0 }. The fuzzy comprehensive evaluation total score T is Y × K, and is calculated from the evaluation grade set K {9, 7, 5, 3, 1}, and is shown in table 12.

TABLE 12 influence of the compounding amount of beta-cyclodextrin and 125 ℃ extrusion puffing WPI on goat milk sensory evaluation comprehensive score

As can be seen from Table 12, when the ratio of beta-cyclodextrin to the extruded whey protein isolate (3: 2) was constant, the higher the amount of beta-cyclodextrin added, the better the deodorizing effect. The total addition amount of the composite is 0.5%, and compared with the single addition of 0.5% of beta-cyclodextrin and extrusion puffing whey protein isolate, the composite has better mutton smell removing effect, stronger frankincense flavor and better taste, so the composite of the beta-cyclodextrin and the extrusion puffing whey protein isolate has better mutton smell removing effect on sheep milk.

Beta-cyclic pastes are macrocyclic compounds consisting of a variable number of D- (+) -glucopyranose residues linked by alpha (14) linkages. The number of glucose units determines the size of the cavity. Beta-cyclodextrin contains 7 glucose units. The beta-cyclodextrin has the capacity of forming inclusion compound, can embed various components, especially hydrophobic molecules, and effectively reduces the goat milk smell by embedding short-medium chain free fatty acid. The beta-cyclodextrin and the extruded and puffed whey protein isolate are compounded for use, so that the single use effect of the beta-cyclodextrin and the extruded and puffed whey protein isolate is enhanced.

Example 5

(2) Mixing goat milk and the deodouring agent according to the raw material ratio in Table 13, and stirring for 30min at 35 ℃.

Table 13 deodouring agent and raw material ratio

(4) And (3) taking goat milk without the mutton smell removing agent as a blank control group to detect the content of the free fatty acid and the electronic nose, and calculating the relative peak area of the free fatty acid according to the following relative peak area calculation formula. The results of the electronic nose measurement are shown in FIG. 4, the peak area of the free fatty acid is shown in FIG. 1, and the results of the relative peak area of the free fatty acid are shown in Table 14.

TABLE 14 Effect of different deodouring agents on free fatty acids in goat milk

As can be seen from table 14 and fig. 1, the peak areas of the three free fatty acids were reduced after the addition of the de-odoring agent, wherein the reduction in the compounded group was the greatest, i.e., the free fatty acid content was reduced, which is consistent with the sensory evaluation results, indicating that the free fatty acid content of the three C6, C8, and C10 was related to the odorous substances, the content was reduced, and the odor was reduced.

From fig. 4, the PC1 variance contribution rate was 59.2% and the PC2 variance contribution rate was 20.7% in the PCA plot, totaling 79.9%. And (3) determining that the sample is partially overlapped and partially not overlapped, wherein the flavor of the whole goat milk is determined by the electronic nose technology, and therefore, the overlapped part is deduced that the smell removing agent only buries the smell of the goat milk without changing other flavors of the goat milk. The compound group has better smell removing effect by combining with sensory evaluation results and does not change other flavors of the goat milk.

Example 6

(2) Mixing goat milk and the deodouring agent according to the raw material ratio shown in Table 15, and stirring for 30min at 35 ℃.

Table 15 deodouring agent and raw material ratio

(4) Fermentation: adding 4% concentrated indigo fruit juice and 0.01% starter, fermenting for 10 hr, and after-ripening for 24 hr at 4 deg.C.

(5) And (3) detecting the content of free fatty acid by taking the Lonicera edulis juice fermented goat milk of the 1 st group as a blank control group, and calculating the relative peak area of the free fatty acid according to the following relative peak area calculation formula. The free fatty acid peak area is shown in FIG. 2, and the relative peak area results are shown in Table 16.

TABLE 16 Effect of different deodouring agents on free fatty acids in goat milk with Lonicera edulis juice acid

As can be seen from table 16 and fig. 2, the peak areas of the three free fatty acids were reduced after the addition of the de-odoring agent, wherein the reduction in the compounded group was the greatest, i.e., the free fatty acid content was reduced, which is consistent with the sensory evaluation results, indicating that the free fatty acid contents of C6, C8, and C10 are related to the odorous substances, the content is reduced, and the odor is reduced.

Example 7

(2) Concentration: the goat milk was divided into 5 portions by using a rotary evaporator (48 ℃), and water of 25% of the total volume was concentrated off.

(3) Removing the smell of mutton: mixing goat milk, sucrose and a de-odoring agent according to the raw material proportion shown in the table 17, preheating at 50-65 ℃, stirring to dissolve the goat milk, homogenizing under 20MPa, and heating at 65 ℃ for 30min to sterilize.

Table 17 deodouring agent and raw material ratio

(4) Cooling the goat milk prepared in the step (3) to 35-42 ℃, and adding 0.01 per mill (w/v) (namely the mass/volume percentage of the leavening agent to the goat milk is 0.01 per mill) of leavening agent on a sterile operating platform; uniformly stirring the mixture of the leavening agent and the goat milk, filling the mixture into a glass bottle, fermenting the mixture in an incubator at 42 ℃ for 7-9 hours, and after the fermentation is finished, placing the mixture in a refrigerator at 4 ℃ for after-ripening for 24 hours.

(5) And (3) detecting the content of the free fatty acid by taking the concentrated fermented goat milk of the group 1 as a blank control group, and calculating the relative peak area of the free fatty acid according to the following relative peak area calculation formula. The free fatty acid peak area is shown in FIG. 3, and the relative peak area results are shown in Table 18.

TABLE 18 Effect of different deodouring agents on the free fatty acids of concentrated fermented goat milk

As can be seen from table 18 and fig. 3, the peak areas of the three free fatty acids were reduced after the addition of the de-odoring agent, wherein the reduction in the compounded group was the most, i.e., the free fatty acid content was reduced, which is consistent with the sensory evaluation results, indicating that the free fatty acid contents of C6, C8, and C10 are related to the odorous substances, the content is reduced, and the odor is reduced.

The goat milk smell obtained by the goat milk de-odoring process is remarkably reduced, and the extruded and puffed WPI is used for de-odoring the goat milk through combination of beta-lactoglobulin and a smell substance and embedding of a protein network structure. The homogenization ensures that the tissue state of the goat milk is more uniform and stable.

The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.

Claims

1. The method for removing the smell of goat milk is characterized by comprising the following steps of: sterilizing fresh goat milk, adding a de-odoring agent, and homogenizing to obtain de-odored goat milk;

2. The method for removing the smell of mutton of claim 1, wherein the mass/volume percentage of the smell removing agent to fresh goat milk is 0.1-0.9%.

3. The method for removing the smell of mutton of claim 1, wherein when the smell removing agent is whey protein isolate, the method further comprises any one of the following treatments of the whey protein isolate:

(1) carrying out high-pressure homogenization treatment;

(2) carrying out superfine grinding treatment;

(3) and (5) extruding and puffing.

4. The method for removing the smell of mutton of claim 3, wherein the high-pressure homogenization treatment specifically comprises: and homogenizing the whey protein isolate under the pressure of 30-60 MPa.

5. The method for removing the smell of mutton as claimed in claim 3, wherein the micronization treatment comprises: grinding whey protein isolate at 480r/min for 8 h.

6. The method for removing the smell of mutton of claim 3, wherein the extrusion puffing treatment specifically comprises the following steps: carrying out extrusion and expansion treatment on whey protein isolate at the adding speed of 1g/min and the rotating speed of 240 r/min; the whey protein isolate passes through 8 independent heating zones in the extrusion and expansion treatment process, wherein the temperature of the 1 st zone is 25 ℃, the temperature of the 2 nd zone is 35 ℃, the temperature of the 3 rd zone is 45 ℃, the temperature of the 4 th to 6 th zones is 50-125 ℃, the temperature of the 7 th zone is 45 ℃, and the temperature of the 8 th zone is 25 ℃.

7. The method for removing the smell of mutton of claim 1, wherein when the smell removing agent is whey protein isolate and beta-cyclodextrin, the mass ratio of the beta-cyclodextrin to the whey protein isolate is 1-4: 1 to 4.

8. The method for removing the smell of mutton of claim 1, wherein when the smell removing agent is whey protein isolate and beta-cyclodextrin, the mass ratio of the beta-cyclodextrin to the whey protein isolate is 3: 2.

9. the method for removing the smell of goat milk according to claim 6, wherein the temperature of the 4 th to 6 th zones is 125 ℃.

10. The method for removing the smell of mutton according to claim 1, which is characterized by further comprising any one of the following treatment methods: