CN106070550B - Composite color protection liquid for longan drying and drying method - Google Patents
Composite color protection liquid for longan drying and drying method Download PDFInfo
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Abstract
The invention discloses a composite color protection liquid for longan drying and a drying method, wherein the color protection liquid comprises the following components in percentage by mass: 0.05 to 0.15 percent of ascorbic acid, 0.06 to 0.10 percent of malic acid, 0.10 to 0.30 percent of calcium chloride, 0.10 to 0.30 percent of sodium bicarbonate and the balance of water; the drying method comprises the following steps: pruning, selecting and grading fresh longan, blanching and inactivating enzyme on the graded fresh longan, putting the blanched longan into the color protection liquid for color protection treatment, and drying the longan after the color protection treatment by hot air. The composite color protection liquid for longan drying can effectively inhibit browning reaction in the longan drying process, reduces the loss of nutrients of longan in the drying process, and has the advantages of good color protection effect, no toxicity, high safety and convenience in operation.
Description
Technical Field
The invention belongs to the technical field of fruit and vegetable processing, and particularly relates to a composite color protection liquid for longan drying and a longan drying method.
Background
Longan (Dimocarpus longan Long.) is a fruit tree of the genus Dimocarpus of the family Sapindaceae, and the fruit is rich in carbohydrate, amino acids, and vitamins. Longan is picked in high-temperature seasons, and after the longan is picked, physiological metabolism is vigorous, the longan is easy to deteriorate and rot, and the edible value of the longan is lost. In order to reduce economic loss caused by easy decomposition of longan and increase the edible value of longan, dry longan (longan) is mostly prepared from fresh longan by a drying method at present. In recent years, the drying technology of longan has been developed rapidly, and many studies have been made on vacuum freeze drying, infrared drying, microwave drying and combined drying, but hot air drying and superheated steam drying, which have low requirements for equipment, are mainly used in actual production at present. The longan is very easy to brown in the drying process, the sensory quality of the longan is reduced, and the commodity value of the longan is influenced.
The main reason for causing longan deterioration and losing the edible value is browning, which can be divided into enzymatic browning and non-enzymatic browning according to the difference of browning mechanisms. Enzymatic browning is that longan hulls are damaged under the influence of external heating and drying conditions or mechanical damage, a large amount of oxygen enters the tissues to activate the action of enzyme, phenolic substances in the tissues are catalyzed to be oxidized into quinones, and the quinones are polymerized again to form brown substances which cause tissue discoloration. In intact longan tissue cells, phenolic substances as respiratory transmission substances are in dynamic equilibrium between phenol-quinone. The longan shell is damaged once, so that air can directly contact with the longan pulp, polyphenol substances are oxidized into o-quinone under the existence of oxygen and the catalytic action of enzyme substances, trihydroxy compounds are oxidized into hydroxyquinone under the strong oxidizing capability of the o-quinone, red hydroxyquinone is polymerized to be brown, and then the red hydroxyquinone is changed into black brown, so that the longan pulp is browned and discolored. The color protection treatment is carried out before the longan is dried, so that the occurrence of brown stain can be effectively inhibited, and the deformation and atrophy of longan pulp can be reduced.
The commonly used color protection liquid mainly aims at the color protection treatment of longan pulp, requires the shelling treatment of longan and the like, and does not study much on the color protection treatment of dried longan with shell. And commonly used color protection liquids are divided into two types, the first type contains SO2Salts, such as sodium sulfite, sodium metabisulfite, sodium bisulfite and the like, are commonly used preservatives that inhibit enzyme activity at lower concentrations, thereby inhibiting enzymatic browning, SO2Can be combined with organic peroxide to prevent generation of hydrogen peroxide, SO that peroxidase POD loses oxidation effect and SO2And in addition, the diluted acid environment generated by hydrosulfite makes the carbonyl ammonia condensation product of the Maillard reaction easy to hydrolyze, thereby inhibiting the nonenzymatic browning caused by the Maillard reaction. But SO2The residue of the (D) has potential safety hazard to human health; the second is sulfur-free color protection, and the color protection mode usually uses citric acid, ascorbic acid, malic acid and the like as color protection components, mainly acts on polyphenol oxidase, and simultaneously improves the sensory quality of fruits and vegetables, but the color protection effect is not obvious.
Disclosure of Invention
In view of the above, the present invention provides a composite color protection solution for longan drying and a drying method thereof, which can effectively inhibit browning reaction in the longan drying process, reduce loss of nutrients in the longan drying process, and have the advantages of good color protection effect, no toxicity, high safety and convenient operation.
In order to solve the technical problem, the invention discloses a composite color protection liquid for longyan drying, which comprises the following components in percentage by mass: 0.05 to 0.15 percent of ascorbic acid, 0.06 to 0.10 percent of malic acid, 0.10 to 0.30 percent of calcium chloride, 0.10 to 0.30 percent of sodium bicarbonate and the balance of water.
Preferably, the composition comprises the following components in percentage by mass: ascorbic acid 0.1%, malic acid 0.08%, calcium chloride 0.3%, sodium bicarbonate 0.1%, and water in balance.
The invention also discloses a longan drying method, which comprises the following steps:
pruning, selecting and grading fresh longan, blanching the graded fresh longan with a blanched inactivating enzyme, putting the blanched longan into a color protection solution for color protection treatment, and drying the longan after the color protection treatment by hot air; the color protection liquid comprises the following components in percentage by mass: 0.05 to 0.15 percent of ascorbic acid, 0.06 to 0.10 percent of malic acid, 0.10 to 0.30 percent of calcium chloride, 0.10 to 0.30 percent of sodium bicarbonate and the balance of water.
Further, the color protection liquid comprises the following components in percentage by mass: ascorbic acid 0.1%, malic acid 0.08%, calcium chloride 0.3%, sodium bicarbonate 0.1%, and water in balance.
Further, the pruning and selecting classification specifically comprises: selecting fresh longan with similar fruit maturity and no insect pest, selecting those without external mechanical damage, pruning and grading after leaving about 0.5cm of stem, and selecting fresh longan with proper and uniform size for later use.
Further, the blanching inactive enzyme is specifically: soaking the classified fresh longan in hot water of 100 deg.C, blanching for 3min, and cooling at room temperature.
Further, the time of color protection treatment is 30min, and the material-liquid ratio is 1: 1.5.
Further, the hot air drying adopts a sectional drying mode: the first stage drying temperature is 65 ℃, the drying time is 6h, and the hot air speed is 1.5m/s, the second stage drying temperature is 75 ℃, the drying time is 12h, and the hot air speed is 1.5m/s, and the third stage drying temperature is 70 ℃, the drying time is 6h, and the hot air speed is 1.5 m/s.
Further, the hot air drying adopts two layers of longan to be baked.
Compared with the prior art, the invention can obtain the following technical effects:
(1) the ascorbic acid in each component can be combined with the new-born quinones, can complex the prosthetic group of polyphenol oxidase, directly acts on enzyme, prevents enzymatic browning, and has reducibility, so that the coloring matter in the pulp can be prevented from being oxidized; the calcium chloride can keep the brittleness of the fruits and vegetables, prevent the fruits and vegetables from shrinking and deforming in the processing process, and can be used as a color fixative to inhibit the browning of the fruits and vegetables; the malic acid and the sodium bicarbonate are used in combination with the ascorbic acid, the calcium chloride and the like, so that the browning inhibition effect is enhanced, the browning reaction in the longan drying process is effectively inhibited, the loss of nutrients in the longan drying process is reduced, and the storage life of the dried longan is further prolonged;
(2) the color protection solution is used for carrying out color protection treatment on the longan, so that the color of dried longan pulp is obviously improved, the browning degree of the dried longan is effectively reduced, the loss of nutrient substances such as soluble protein and saccharides is reduced, and PPO and POD are passivated;
(3) the color protection liquid has the characteristics of good comprehensive color protection effect, no toxicity, high safety, convenience in operation and the like.
Of course, it is not necessary for any one product in which the invention is practiced to achieve all of the above-described technical effects simultaneously.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:
FIG. 1 is a graph showing the comparison of browning levels of longan pulp in accordance with the present invention;
FIG. 2 is a comparison graph of color difference of longan pulp according to the embodiment of the present invention;
FIG. 3 is a graph comparing the soluble protein content of longan pulp according to the present invention;
FIG. 4 is a graph comparing the reducing sugar content of longan pulp according to the present invention;
FIG. 5 is a comparison graph of PPO enzyme activity in longan pulp according to an embodiment of the present invention;
FIG. 6 is a comparison of POD enzyme activity in longan pulp according to the present invention.
Detailed Description
The following embodiments are described in detail with reference to the accompanying drawings, so that how to implement the technical features of the present invention to solve the technical problems and achieve the technical effects can be fully understood and implemented.
The invention relates to a composite color protection liquid for longyan dryness, which comprises the following components in percentage by mass: 0.05 to 0.15 percent of ascorbic acid, 0.06 to 0.10 percent of malic acid, 0.10 to 0.30 percent of calcium chloride, 0.10 to 0.30 percent of sodium bicarbonate and the balance of water.
Preferably, the composition comprises the following components in percentage by mass: ascorbic acid 0.1%, malic acid 0.08%, calcium chloride 0.3%, sodium bicarbonate 0.1%, and water in balance.
The highest value of the content of each component is within the use range defined by the national standard 2760, and meets the use standard of additives; secondly, through tests, the drying and color-protecting effect of the shelled longan is relatively optimal within the range of the components; finally, considering the production cost, if the concentration is increased, the use amount of each component is increased, namely the cost is increased. Therefore, in view of the above considerations, the ranges of the contents of the components are the above ranges.
The color protection liquid protects the color of the longan before drying, does not need to peel the longan, and ensures the integrity of the dried fruits. The color protection liquid takes ascorbic acid, malic acid, calcium chloride, sodium bicarbonate and the like as color protection components, wherein the ascorbic acid can complex auxiliary groups of polyphenol oxidase and directly act on the enzyme to prevent enzymatic browning, and meanwhile, the ascorbic acid has reducibility and can prevent color-forming substances in pulp from being oxidized; calcium chloride is a commonly used hardening agent, can keep the brittleness of fruits and vegetables, prevent the fruits and vegetables from shrinking and deforming in the processing process, and can be used as a color fixative to inhibit the browning of the fruits and vegetables. The malic acid and the sodium bicarbonate are used in combination with ascorbic acid, calcium chloride and the like, and have an effect of enhancing browning inhibition.
A longan drying method comprises the following steps:
s01, pruning and sorting
Selecting healthy and insect-free fresh longans with similar fruit maturity, selecting those without external mechanical damage, pruning and grading after the stalks are left for about 0.5cm, and selecting fresh longans with proper and uniform sizes for later use;
s02 blanching inactivating enzyme
Soaking the classified fresh longan in hot water of 100 deg.C, blanching for 3min, and cooling at room temperature;
s03, color protection processing
Putting the blanched longan into a color protection solution for color protection treatment, and draining at room temperature after treatment; the color protection liquid comprises the following components in percentage by mass: 0.05 to 0.15 percent of ascorbic acid, 0.06 to 0.10 percent of malic acid, 0.10 to 0.30 percent of calcium chloride, 0.10 to 0.30 percent of sodium bicarbonate and the balance of water.
Preferably, the color protection liquid consists of the following components in percentage by mass: ascorbic acid 0.1%, malic acid 0.08%, calcium chloride 0.3%, sodium bicarbonate 0.1%, and water in balance.
Further, the time of color protection treatment is 30min, and the material-liquid ratio is 1: 1.5.
The color protection time is selected for 30min, because the longan subjected to color protection by the method is not subjected to shelling treatment, the color protection liquid cannot enter the fruits to dip and dye the pulp if the soaking time is too short, and the longan shell is too weak and easy to damage if the soaking time is too long. When the ratio of the materials to the liquid is lower than 1:1.5, the longan can not be completely immersed in the color protection liquid, so that the color protection effect is influenced; when the feed liquid ratio is higher than 1:1.5, the waste caused by excessive color protection liquid is easily caused, and the economic cost is improved, so the feed liquid ratio is selected to be 1: 1.5.
S04, drying with hot air
And (5) drying the longan subjected to color protection treatment by hot air.
Further, the hot air drying adopts a sectional drying mode: the first stage drying temperature is 65 ℃, the drying time is 6h, and the hot air speed is 1.5m/s, the second stage drying temperature is 75 ℃, the drying time is 12h, and the hot air speed is 1.5m/s, and the third stage drying temperature is 70 ℃, the drying time is 6h, and the hot air speed is 1.5 m/s.
The drying process is mainly divided into three steps, wherein in the first step, heating is carried out at a lower temperature, so that the evaporation rate of water is lower than the migration rate of internal water in the longan drying process, and the phenomena that most residual water is blocked in longan shells to cause hard outside, soft inside and rapid reduction of the drying rate and the like due to the fact that a layer of hard film is formed on the longan shells because the surfaces of the longans are too strongly dried are prevented; in the second stage, the drying is carried out at a higher temperature, so that the drying efficiency is improved; the heating in the third stage aims at supplementary heating of longan with large fruit, thick meat or high air humidity, which does not reach the drying standard.
Furthermore, the hot air drying adopts two layers of dried longan, and the mode does not need to turn over in the drying process.
S05, cooling
And cooling and storing the dried longan.
The color protection liquid is used for treating the longan, so that the browning reaction in the longan drying process can be effectively inhibited, the loss of nutrient substances of the longan in the drying process is reduced, and the activities of polyphenol oxidase and peroxidase are reduced, thereby being beneficial to prolonging the storage life of the dried longan.
Examples
Selecting healthy and insect-free fresh longans with similar fruit maturity, selecting those without external mechanical damage, pruning and grading after the stalks are left for about 0.5cm, and selecting fresh longans with proper and uniform sizes for later use; soaking the graded fresh longan in hot water of 100 deg.C for blanching for 3min, and cooling at room temperature; putting the blanched longan into a color protection liquid for color protection treatment for 30min, wherein the material-liquid ratio is 1:1.5, the mixture ratio of the color protection liquid is shown in table 1, the mixture ratios of the color protection liquid with different mixture ratios and the color protection liquid with a comparative example are listed in table 1, and the balance is water; carrying out hot air drying on the longan subjected to color protection treatment, wherein the hot air drying adopts a sectional drying mode: the first stage drying temperature is 65 ℃, the drying time is 6h, and the hot air speed is 1.5m/s, the second stage drying temperature is 75 ℃, the drying time is 12h, and the hot air speed is 1.5m/s, and the third stage drying temperature is 70 ℃, the drying time is 6h, and the hot air speed is 1.5 m/s.
TABLE 1 color-protecting liquid compounding ratio
The comparative examples without color protection and the dried longans according to the color protection liquid ratio in table 1 were tested:
the evaluation index and the measuring method comprise the following steps:
(1) determination of the degree of browning
Weighing 2g of the pulp sample after denucleation, fully grinding, adding 20mL of 2% (v/v) acetic acid solution, fully mixing, and performing uniform mixing at 8000r min-1Centrifuging for 10min, and sucking supernatant. Adding 20mL of acetone into the supernatant, mixing uniformly at 8000r min-1Centrifuging for 10min, and sucking supernatant. The optical density was measured at a wavelength of 420nm and the result was represented by D420nmAnd (4) showing.
(2) Determination of chromatic aberration
And (3) measuring the color difference of the dried longan pulp by a color difference meter, wherein each sample is measured for 5 times, and each time, 3 different angles are taken.
(3) Determination of reducing sugar content
The content of reducing sugar is determined by 3, 5-dinitrosalicylic acid colorimetry (Wangcoquini. plant physiological and biochemical experiment principle and technology [ M ]. Beijing: advanced education Press, 2006: 202-.
(4) Soluble protein content determination
Soluble protein content was determined using the Bradford method (Bradford MM. A rapid and sensitive method for the identification of microbial qualities of protein digestion the principle of protein-dye binding [ J ]. Analytical Biochemistry,1976,72: 248. 254.).
(5) Determination of POD and PPO Activity
Taking about 2g of longan dry pulp, cutting up, putting into a mortar, adding a proper amount of phosphate buffer (pH 6.8) in an ice bath environment, grinding into homogenate, adding a total of 6mL of buffer, transferring into a centrifuge tube, freezing and centrifuging at the rotating speed of 9000r/min for 20min, and storing at a low temperature for later use.
The reaction system for measuring POD enzyme activity contained 1.8mL of 0.05mol.L-1Phosphate buffer (pH 6.8), 1.0mL 2% H2O2Solution, 1.0mL, 0.05mol.L-1Guaiacol solution and 0.2mL enzyme solution. Three replicates were performed with the enzyme solution heated in boiling water for 5min as a control. And (3) timing after adding the enzyme solution into the reaction system, immediately placing the reaction system into an ultraviolet spectrophotometer sample chamber, and carrying out absorbance determination every 0.5min, wherein the wavelength is 470 nm. The increase of 1 in absorbance change per gram of sample per minute is taken as one peroxidase activity unit, delta OD470G/min. The calculation is referred to equation 1.
Δ OD in the formula: the absorbance change per minute at 470nm of the sample; v: the total volume of the sample extracting solution is mL; vs: the volume of the extracted solution of the sample is mL during the determination; m: sample mass g.
Preparation of enzyme solution for PPO Activity measurement the buffer was changed to phosphate buffer at pH 5.8 in the same manner as the POD measurement. The reaction system for measuring the enzyme activity comprises 1.5mL of 0.05mol.L-1Phosphate buffer (pH 7), 1.0ml0.05mol-1Catechol solution and 0.5mL of enzyme solution. Three replicates were performed using enzyme solution heated in boiling water for 5min as a control. Adding enzyme solution into the reaction system, timing, immediately placing into a sample chamber of an ultraviolet spectrophotometer, and measuring absorbance every 0.5min at wavelengthIs 470 nm. The specific activity of the dried longan pulp PPO is calculated according to the formula 1.
II, testing results:
(1) changes in flesh browning and color difference
The browning degree of the longans treated by different composite color protection liquids after hot air drying is shown in figure 1 (different lower case letters in the figure indicate that the different treatments have significant difference, p<0.05, the same below), it can be seen that the longan is subjected to color protection treatment before drying to reduce browning reaction in the drying process, and the browning degree of example 5 is 0.046D420nmMuch lower than the other embodiments. Statistical analysis of the new repolarization differences shows that: the example 5 has significant difference (P < 0.05) with the examples 1, 2 and 3, and the groups of the examples 1, 2, 3 and 7 have no significant difference (P > 0.05).
For the dried longan, the smaller the color difference is, the closer the color of the dried longan pulp is to the fresh longan. The influence of different composite color protection solutions on the color of dried longan pulp is shown in fig. 2, the numerical difference among the components is small, and the statistical analysis of new standard differences shows that: there was no significant difference between the comparative example and example 8 (P > 0.05).
(2) Variation of soluble protein and reducing sugar content
The effect of different treatments of the color protection solution on the soluble protein content of dried longan is shown in figure 3, and the soluble protein content of dried longan is the highest in example 6 shown in figure 3. Statistical analysis of the new repolarization differences shows that: there was no significant difference (P > 0.05) between example 6 and the groups of examples 3, 4, 5, 7, 9, significant difference (P < 0.05) between example 6 and the groups of comparative examples, examples 1, 2, 8, and significant difference (P < 0.05) between example 5 and the groups of comparative examples, example 2.
The influence of different color protection liquid treatments on the reducing sugar content of dried longan is shown in figure 4, and the reducing sugar content of dried longan is the highest in example 5 shown in figure 4. Statistical analysis of the new repolarization differences shows that: the example 5 has significant difference (P < 0.05) with the comparative example and the example 4, and the comparative example has significant difference (P < 0.05) with the examples 3 and 9.
(3) Changes in PPO and POD Activity
Generally, peroxidase and polyphenol oxidase are key enzymes causing browning of fruits and vegetables, and the higher the activities of PPO and POD, the faster the browning speed of longan in the drying process.
FIG. 5 shows the PPO enzyme activity measurement results, and the new repolarization statistical analysis results are as follows: the example 5 has significant difference (P < 0.05) with the comparative examples and the examples 7 and 9, and the examples 9 and 7 have no significant difference (P > 0.05). FIG. 6 shows the POD enzyme activity assay results, which are the following statistical analysis results of the new difference in repolarization: there is no significant difference (P > 0.05) between examples 5 and 3, and POD enzyme activities of examples 5 and 3 are significantly lower than those of other groups. As can be seen from FIGS. 5 and 6, PPO and POD in example 5 are the lowest, and the enzymatic activity of the PPO enzyme of the dried longan after the color protection solution treatment is 0.088 delta OD470/(min. g), POD enzyme activity was 3.181. delta. OD470V (min g), significantly lower than the other examples.
The color protection solution is used for carrying out color protection treatment on longan, the color of dried longan pulp is obviously improved, the browning degree of the dried longan is effectively reduced, the loss of nutrient substances such as soluble protein and sugar is reduced, and the passivation effect on PPO and POD is realized. When the composite color protection liquid contains 0.10 percent of ascorbic acid, 0.08 percent of malic acid, 0.30 percent of calcium chloride and 0.10 percent of sodium bicarbonate, the quality of dried longan is better, and the brown degree of the longan treated by the color protection liquid is 0.046D420nmPPO enzyme activity 0.088. delta. OD470/(min. g), POD enzyme activity was 3.181. delta. OD470/(min·g)。
As used in the specification and claims, certain terms are used to refer to particular components or methods. As one skilled in the art will appreciate, different regions may refer to a component by different names. The present specification and claims do not intend to distinguish between components that differ in name but not in name. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. "substantially" means within an acceptable error range, and a person skilled in the art can solve the technical problem within a certain error range to substantially achieve the technical effect. The following description is of the preferred embodiment for carrying out the invention, and is made for the purpose of illustrating the general principles of the invention and not for the purpose of limiting the scope of the invention. The scope of the present invention is defined by the appended claims.
It is also noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a good or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such good or system. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a commodity or system that includes the element.
While the foregoing description shows and describes several preferred embodiments of the invention, it is to be understood, as noted above, that the invention is not limited to the forms disclosed herein, but is not to be construed as excluding other embodiments and is capable of use in various other combinations, modifications, and environments and is capable of changes within the scope of the inventive concept as expressed herein, commensurate with the above teachings, or the skill or knowledge of the relevant art. And that modifications and variations may be effected by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (5)
1. A longan drying method is characterized by comprising the following steps:
pruning, selecting and grading fresh longan, blanching the graded fresh longan with a blanched inactivating enzyme, putting the blanched longan into a color protection solution for color protection treatment, and drying the longan after the color protection treatment by hot air; the color protection liquid comprises the following components in percentage by mass: 0.05 to 0.15 percent of ascorbic acid, 0.06 to 0.10 percent of malic acid, 0.10 to 0.30 percent of calcium chloride, 0.10 to 0.30 percent of sodium bicarbonate and the balance of water;
the hot air drying adopts a sectional drying mode: the first stage drying temperature is 65 ℃, the drying time is 6h, and the hot air speed is 1.5m/s, the second stage drying temperature is 75 ℃, the drying time is 12h, and the hot air speed is 1.5m/s, the third stage drying temperature is 70 ℃, the drying time is 6h, and the hot air speed is 1.5 m/s;
the time of color protection treatment is 30min, and the material-liquid ratio is 1: 1.5.
2. The longan drying method according to claim 1, wherein the color protection liquid comprises the following components in percentage by mass: ascorbic acid 0.1%, malic acid 0.08%, calcium chloride 0.3%, sodium bicarbonate 0.1%, and water in balance.
3. The longan drying method of claim 1, wherein the pruning and selecting grading specifically comprises: selecting fresh longan with similar fruit maturity and no insect pest, selecting those without external mechanical damage, pruning and grading after leaving about 0.5cm of stem, and selecting fresh longan with proper and uniform size for later use.
4. The longan drying method according to claim 1, wherein the blanching inactivating enzyme is specifically: soaking the classified fresh longan in hot water of 100 deg.C, blanching for 3min, and cooling at room temperature.
5. The longan drying method according to claim 1, wherein the hot air drying is carried out by drying two layers of longans.
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| CN1279023A (en) * | 1999-06-26 | 2001-01-10 | 广西大学 | Ordinary-temp antistaling tachnology for litchi and longan |
| CN1659969A (en) * | 2005-01-28 | 2005-08-31 | 广东省农业科学院果树研究所 | Keeping fresh and protecting color for fruits of longan |
| CN102742711A (en) * | 2012-07-03 | 2012-10-24 | 西北大学 | Method for preparing preserved kiwi fruit by vacuum freeze drying |
| CN102726510A (en) * | 2012-07-19 | 2012-10-17 | 福建农林大学 | Sulfur-free color protection method for controlling browning of dried leechee and longan pulps |
| CN105101819A (en) * | 2013-01-15 | 2015-11-25 | 有机治愈控股公司 | Preservative composition and solution |
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