Fresh-keeping method for inhibiting lignification of picked pea sprouting vegetables

Abstract

The invention discloses a preservation method for inhibiting lignification of picked pea sprouting vegetables. The method comprises the following steps: cutting roots of pea sprouting vegetables with roots, airing, soaking the pea sprouting vegetables in a phenyllactic acid solution with the concentration of 2-8mM, dehydrating the treated pea sprouting vegetables in a vegetable dehydrator, airing and storing. According to the method, the pea sprouting vegetables which are prone to lignification in the refrigeration environment and difficult to maintain the eating quality in the storage period are used as research objects, phenyllactic acid is used as a preservative, and the research shows that phenyllactic acid solution treatment has a very remarkable effect on inhibition of postharvest lignification of the pea sprouting vegetables, weightlessness is remarkably inhibited, and the quality of the pea sprouting vegetables is remarkably improved. And the original quality and flavor can be well maintained.

Description

Technical Field

[0001] The invention belongs to the technical field of fruit and vegetable preservation, and relates to a preservation method for inhibiting post-harvest lignification of pea sprouts by treating with phenyllactic acid. Background Art

[0002] Sprouts, also known as "biological vegetables" or "living vegetables", refer to sprouts, bulbs, young stems, young shoots and tender shoots cultivated under certain conditions using seeds or nutritional organs. Sprouts are rich in nutrition, unique in flavor, crisp and tender in taste, short in production cycle, green and pollution-free, and high in economic benefits. They are very popular among producers and consumers in my country, Japan, South Korea, the European Union, the United States and other places.

[0003] Pea sprouts are green seedlings produced by germinating and cultivating pea seeds under certain conditions. They are fragrant, tender, smooth and palatable. They are environmentally friendly, high-quality and nutritious green vegetables. They have been very popular in the vegetable market in recent years. Pea sprouts contain a variety of nutrients needed by the human body, rich in protein, various vitamins and minerals, and various trace elements. However, pea sprouts are crisp and tender in texture, and are very easy to soften and rot when stored at room temperature. They are prone to lignification when stored at low temperatures after harvesting, which affects the taste. Lignin is one of the important components of plant cell walls. The synthesis process of lignin monomers is completed in the cytoplasm, and then transferred to the cell wall for dehydrogenation polymerization to form lignin. The enzymes involved in lignin synthesis mainly include phenylalanine ammonialyse (PAL), 4-coumarateacid coenzyme A ligase (4CL), cinnamoyl-CoA reductase (CCR), cinnamylalcohol dehydrogenase (CAD), polyphenol oxidase (PPO) and peroxidase (POD). Among them, PAL is the starting enzyme of the phenylpropanoid metabolic pathway and is generally considered to be the marker enzyme for the beginning of lignification. CAD participates in the final stage of lignin monomer synthesis, mainly reducing cinnamaldehyde to the corresponding alcohol to form lignin monomer. Therefore, how to control the post-harvest lignification of pea sprouts, maintain its commodity quality and extend its shelf life has always been a problem that researchers are eager to solve.

[0004] Transcriptomics is a discipline that systematically studies gene transcription profiles from the overall transcription level and reveals the molecular mechanisms of complex biological pathways and trait regulatory networks. It has a wide range of applications in studying cell phenotypes and functions, and can also detect the expression and regulation of important genes in life processes. Therefore, the development of transcriptomics is crucial to analyzing the genetic network of biological systems, discovering important candidate genes, and performing functional verification.

[0005] Phenyllactic acid is a new type of biological preservative with broad-spectrum antibacterial effect. It has the advantages of high safety, wide sources, strong stability, and good hydrophilicity. It is widely used in the preservation of meat products, fruits and vegetables, and aquatic products. For example, the use of phenyllactic acid in the preservation of bananas can prevent the occurrence of banana anthracnose; the use of phenyllactic acid in the preservation of winter jujube can maintain the post-harvest quality of winter jujube by activating the ascorbic acid metabolic pathway; the use of phenyllactic acid in the preservation of early pears can maintain the storage quality of early pears by regulating respiration and energy metabolism pathways, but the use of phenyllactic acid to inhibit post-harvest lignification of fruits and vegetables has not been reported. Summary of the invention

[0006] The invention aims to overcome the deficiencies of the prior art and provide a preservation method for inhibiting the post-harvest lignification of pea sprouts. The method is safe, non-toxic, convenient and hygienic, and can effectively inhibit the post-harvest lignification of pea sprouts, thereby achieving the purpose of preservation.

[0007] In order to solve the above problems, the present invention proposes a preservation method for inhibiting the post-harvest lignification of pea sprouts, comprising the following steps:

[0008] The roots of the pea sprouts with roots are cut and dried, and then immersed in a phenyllactic acid solution with a concentration of 2-8 mM. The processed pea sprouts are dehydrated in a vegetable dehydrator, and dried and stored.

[0009] Preferably, the soaking time is 5-10 min, more preferably 5 min.

[0010] Preferably, the concentration of the phenyllactic acid solution is 4 mM.

[0011] Preferably, the drying is drying at room temperature.

[0012] Preferably, the dehydration is carried out in a vegetable dehydrator for 1-5 minutes, more preferably for 1 minute.

[0013] Preferably, the storage is to put the pea sprouts into a basket and store them at 4-22° C., more preferably 10° C. after packaging with a polyethylene film.

[0014] Preferably, the pea variety is maple pea.

[0015] The phenyllactic acid solution consists of phenyllactic acid and pure water.

[0016] The second object of the present invention is to provide the application of phenyllactic acid in the preservation of pea sprouts.

[0017] Preferably, the method is used for inhibiting postharvest lignification of pea sprouts.

[0018] Preferably, the method for inhibiting postharvest lignification of pea sprouts is to reduce the postharvest lignin content of pea sprouts, reduce the activity of enzymes related to lignin synthesis (PAL, CAD) and the expression level of related genes.

[0019] The phenyllactic acid effectively reduces the weight loss rate during the preservation of pea sprouts, maintains the nutritional quality, and retains vitamin C, total flavonoids, etc. in the pea sprouts.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The present invention takes pea sprouts, which are prone to lignification in a refrigerated environment and difficult to maintain edible quality during storage, as the research object, and uses phenyllactic acid as a preservative. Studies have shown that phenyllactic acid solution treatment has a very significant effect on inhibiting post-harvest lignification of pea sprouts, and significantly inhibits weight loss, and can better maintain the original quality and flavor.

[0022] (2) The present invention can not only be used to inhibit the post-harvest lignification of pea sprouts, reduce weight loss, and maintain post-harvest nutritional quality, but can also be applied to inhibit the lignification of other fruits and vegetables. The method of the present invention is simple to handle, has a good preservation effect, is highly innovative, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a bar graph showing the effects of five treatments of 0mM (control) and 2mM, 4mM, 6mM, and 8mM phenyllactic acid solutions on the sensory evaluation of pea sprouts;

[0024] Figure 2 It is a bar graph showing the effects of five treatments of 0mM (control) and 2mM, 4mM, 6mM, and 8mM phenyllactic acid solutions on the lignin content of pea sprouts;

[0025] Figure 3 It is a line graph showing the effects of 0 mM (control) and 4 mM phenyllactic acid solution treatment on the sensory evaluation of pea sprouts;

[0026] Figure 4 It is a line graph showing the effect of 0mM (control) and 4mM phenyllactic acid solution treatment on the weight loss rate of pea sprouts;

[0027] Figure 5It is a line graph showing the effect of 0 mM (control) and 4 mM phenyllactic acid solution treatment on the lignin content of pea sprouts;

[0028] Figure 6 It is a line graph showing the effect of 0mM (control) and 4mM phenyllactic acid solution treatment on the cellulose content of pea sprouts;

[0029] Figure 7 It is a line graph showing the effect of 0mM (control) and 4mM phenyllactic acid solution treatment on the total flavonoid content of pea sprouts;

[0030] Figure 8 It is a line graph showing the effect of 0mM (control) and 4mM phenyllactic acid solution treatment on the vitamin C content of pea sprouts;

[0031] Fig. 9 It is a line graph showing the effect of 0 mM (control) and 4 mM phenyllactic acid solution treatment on PAL activity of pea sprouts;

[0032] Fig.10 It is a line graph showing the effect of 0 mM (control) and 4 mM phenyllactic acid solution treatment on CAD activity of pea sprouts;

[0033] Fig.11 This is a gene heat map showing the effects of 0 mM (control) and 4 mM phenyllactic acid solution treatment on the expression levels of lignin synthesis-related enzyme genes in pea sprouts (the expression levels of each gene were uniformly normalized by Z-score). DETAILED DESCRIPTION

[0034] The technical scheme of the present invention is further described in detail below through specific embodiments and drawings. The following embodiments are only preferred embodiments of the present invention and are not intended to limit the present invention in other forms. Any technician familiar with the profession may use the above disclosed technical content to change it into an equivalent embodiment with equivalent changes. Any simple modification or equivalent change made to the following embodiments based on the technical essence of the present invention without departing from the content of the present invention is within the protection scope of the present invention.

[0035] The phenyllactic acid solutions used in the following embodiments of the present invention are all composed of phenyllactic acid and pure water. The phenyllactic acid solutions are all prepared by the following method, and the specific steps are as follows:

[0036] Accurately weigh phenyllactic acid in proportion, add it to a beaker filled with pure water, then use an ultrasonic device to assist in dissolution, and then adjust the volume to the required concentration to finally form a transparent, clear, non-turbid phenyllactic acid solution.

[0037] Taking the preparation of a phenyllactic acid solution with a phenyllactic acid concentration of 2 mM as an example, the following steps are used to prepare it:

[0038] First, turn on the electronic balance, put the weighing paper on it, and use a medicine spoon to accurately weigh 3.33g from the phenyllactic acid reagent, then put them into the beaker, add a small amount of pure water and stir with a glass rod, and dissolve them under ultrasound at room temperature and 100W for 10 minutes, and finally adjust the volume to 10L, mix well, and store at room temperature for later use. This is a 2mM concentration of phenyllactic acid solution.

[0039] Example 1

[0040] A preservation method for inhibiting post-harvest lignification of pea sprouts in this embodiment specifically comprises the following steps:

[0041] (1) Soak all the utensils and supplies to be used in 1% sodium hypochlorite, disinfect for 15 minutes, then remove and dry;

[0042] (2) Cut the roots of the pea sprouts with scissors and dry them at room temperature for 1 hour;

[0043] (3) preparing a treatment solution with phenyllactic acid at a concentration of 2 mM;

[0044] (4) soaking the treated pea sprouts in a phenyllactic acid treatment solution for 5 minutes;

[0045] (5) dehydrating the processed pea sprouts in a vegetable dehydrator for 1 min, and drying them at room temperature for 30 min;

[0046] (6) After drying, the pea sprouts were placed in a basket, wrapped with polyethylene film and stored at 10°C.

[0047] Example 2

[0048] A preservation method for inhibiting post-harvest lignification of pea sprouts in this embodiment specifically comprises the following steps:

[0049] (1) Soak all the utensils and supplies to be used in 1% sodium hypochlorite, disinfect for 15 minutes, then remove and dry;

[0050] (2) Cut the roots of the pea sprouts with scissors and dry them at room temperature for 1 hour;

[0051] (3) preparing a treatment solution with phenyllactic acid at a concentration of 4 mM;

[0052] (4) soaking the treated pea sprouts in a phenyllactic acid treatment solution for 5 minutes;

[0053] (5) dehydrating the processed pea sprouts in a vegetable dehydrator for 1 minute, and air-drying them at room temperature for 30 minutes; (6) after the air-drying is completed, placing the pea sprouts in a basket, packaging them with polyethylene film, and storing them at 10°C.

[0054] Example 3

[0055] A preservation method for inhibiting post-harvest lignification of pea sprouts in this embodiment specifically comprises the following steps:

[0056] (1) Soak all the utensils and supplies to be used in 1% sodium hypochlorite, disinfect for 15 minutes, then remove and dry;

[0057] (2) Cut the roots of the pea sprouts with scissors and dry them at room temperature for 1 hour;

[0058] (3) preparing a treatment solution with phenyllactic acid at a concentration of 6 mM;

[0059] (4) soaking the treated pea sprouts in a phenyllactic acid treatment solution for 5 minutes;

[0060] (5) dehydrating the processed pea sprouts in a vegetable dehydrator for 1 minute, and air-drying them at room temperature for 30 minutes; (6) after the air-drying is completed, placing the pea sprouts in a basket, packaging them with polyethylene film, and storing them at 10°C.

[0061] Example 4

[0062] A preservation method for inhibiting post-harvest lignification of pea sprouts in this embodiment specifically comprises the following steps:

[0063] (1) Soak all the utensils and supplies to be used in 1% sodium hypochlorite, disinfect for 15 minutes, then remove and dry;

[0064] (2) Cut the roots of the pea sprouts with scissors and dry them at room temperature for 1 hour;

[0065] (3) preparing a treatment solution with phenyllactic acid at a concentration of 8 mM;

[0066] (4) soaking the treated pea sprouts in a phenyllactic acid treatment solution for 5 minutes;

[0067] (5) dehydrating the processed pea sprouts in a vegetable dehydrator for 1 min, and drying them at room temperature for 30 min;

[0068] (6) After drying, the pea sprouts were placed in a basket, wrapped with polyethylene film and stored at 10°C.

[0069] Example 5

[0070] A preservation method for inhibiting post-harvest lignification of pea sprouts in this embodiment is to perform a verification test after performing concentration screening and determining the optimal concentration, which specifically includes the following steps:

[0071] (1) Soak all the utensils and supplies to be used in 1% sodium hypochlorite, disinfect for 15 minutes, then remove and dry;

[0072] (2) Cut the roots of the pea sprouts with scissors and dry them at room temperature for 1 hour;

[0073] (3) preparing a treatment solution with phenyllactic acid at a concentration of 4 mM;

[0074] (4) soaking the treated pea sprouts in a phenyllactic acid treatment solution for 5 minutes;

[0075] (5) dehydrating the processed pea sprouts in a vegetable dehydrator for 1 min, and drying them at room temperature for 30 min;

[0076] (6) After drying, the pea sprouts were placed in a basket, wrapped with polyethylene film and stored at 10°C.

[0077] Comparative Example 1

[0078] The method for preserving pea sprouts after harvest by inhibiting lignification in comparative example 1 is basically the same as that in embodiment 1, except that the pea sprouts are treated by immersion in pure water in this comparative example without treatment with phenyllactic acid.

[0079] The quality change test of pea sprouts during storage was carried out under different methods in Examples 1-5 and Comparative Example 1. The pea sprouts were refrigerated and various indicators were measured once, as follows:

[0080] Sensory evaluation

[0081] The sensory evaluation used a 100-point scale to assess pea sprouts based on four different parameters: appearance, morphology, texture and characteristic smell.

[0082] Pea sprouts sensory scoring table

[0083]

[0084] Weight loss rate

[0085] Weighing method (electronic balance): use an electronic balance to weigh the mass change of pea sprouts during fresh-keeping storage and calculate according to the following formula.

[0086] Weight loss rate (%) = (mass before storage - mass after storage) / mass before storage × 100

[0087] Lignin

[0088] Frozen tissue (0.05 g) was homogenized with 1.0 mL of 95% cold ethanol and then centrifuged at 12000 g for 20 min at 4 °C. The precipitate was washed twice with 95% ethanol and once with ethanol: hexane (1:2). The precipitate was collected and dried at 75 °C for 3 h, then dissolved with 0.5 mL of acetic acid and incubated at 80 °C for 30 min; 0.75 mL of 2.0 mol / L sodium hydroxide solution was added to terminate the reaction. The absorbance was measured at 280 nm.

[0089] Cellulose

[0090] Weigh 0.1g of fresh pea sprouts into a centrifuge tube, add 1mL of 80% ethanol solution, and place in an 80℃ water bath for 40min. After cooling the solution to room temperature, centrifuge at 5000g for 10min to extract the precipitate. Wash the precipitate repeatedly with 0.1mol / L sodium hydroxide solution, hot distilled water and acetone in turn, add 1.5mL of 60% sulfuric acid solution to the washed precipitate, stir evenly and place in a 4℃ refrigerator for cold hydrolysis for 24h, take it out and filter out the precipitate with a filter membrane, keep the supernatant, add the supernatant (1.3mL) to a centrifuge tube, add 3.7mL of 60% sulfuric acid to make it 5mL. Pipette 0.1mL of the above cellulose extract into a test tube, add 0.45mL of distilled water and 2.5mL of anthrone-sulfuric acid reagent in an ice water bath, and mix well after all are added. Take it out after 100℃ water bath for 10min, immediately cool it to room temperature with tap water, and measure the absorbance at a wavelength of 620nm.

[0091] Total flavonoids

[0092] The total flavonoids content was determined by aluminum chloride colorimetry. Accurately weigh 0.2g of dry powder and mix with 8ml of 70% methanol, then put it into an ultrasonic instrument for extraction for 30min, and then centrifuge it at 8000r / min for 15min. 1mL of supernatant, add 2mL 0.1moL / L aluminum chloride solution, then add 3mL 1moL / L potassium acetate solution, react in the dark at room temperature for 30min, measure the OD value at a wavelength of 420nm, and do a blank test (1mL 70% methanol solution, 2mL 0.1moL / L aluminum chloride solution and 3mL 1moL / L potassium acetate solution) at the same time, and calculate the total flavonoids content in pea sprouts according to the rutin standard curve.

[0093] Vitamin C

[0094] The vitamin C content was determined by the molybdenum blue colorimetric method. Accurately weigh 0.5 g of pea seedlings, then add 1 mL of oxalic acid-EDTA solution. Transfer the mixture to a test tube and centrifuge it at 4°C, 10,000 g for 10 min. The supernatant is the crude extract. 400 μL of the supernatant is mixed with 50 μL of metaphosphoric acid-acetic acid solution, 100 μL of 5% sulfuric acid, and 200 μL of 5% ammonium molybdate. The mixture is incubated at 30°C for 15 min, and the absorbance is measured at a wavelength of 760 nm. Ascorbic acid (1 mg / mL) is used as the standard solution. Vitamin C is expressed as mgAAE / 100 g.

[0095] PAL activity

[0096] The activity of PAL was determined using a PAL activity kit (Suzhou Grace Biotechnology Co., Ltd.).

[0097] CAD activity

[0098] Weigh 0.1g of fresh sample into an EP tube, add 1mL of extracting solution (0.1mol / L Tris-HCl buffer (pH 8.0); 5% ethylene glycol; 2% PVP; 0.1mol / L β-mercaptoethanol), grind quickly on ice to form a homogenate, centrifuge at 10000g, 4℃ for 10min, take the supernatant and place it on ice for the determination of CAD enzyme activity. Add 0.2mL of enzyme solution, 2mmol / L nicotinamide adenine dinucleotide phosphate (NADP), and 1mmol / L trans-cinnamic acid to the determination tube in sequence, with a total volume of 1mL; add 0.1mL of distilled water to the blank tube without adding enzyme solution, mix well, react at 37℃ for 30min, add 0.2mL 6mol / L HCl to terminate the reaction, measure the absorbance of the reaction solution at 340nm, and the enzyme activity is expressed as one enzyme activity unit when the absorbance value changes by 0.01, and the result is expressed as U / g.

[0099] Transcriptomic analysis

[0100] After RNA extraction, purification and library construction, the samples were subjected to paired-end (PE) sequencing using the next-generation sequencing (NGS) technology based on the Illumina sequencing platform.

[0101] Test results:

[0102] Depend on Figure 1 It can be seen that the sensory scores of the 2mM, 4mM, 6mM and 8mM phenyllactic acid treatment groups were significantly higher than those of the 0mM control group, especially the 2mM and 4mM phenyllactic acid treatment groups maintained the sensory quality of pea sprouts better in the later storage period. These results show that phenyllactic acid treatment can maintain the sensory quality of pea sprouts to a certain extent.

[0103] Depend on Figure 2 It can be seen that the lignin content of pea sprouts generally showed a fluctuating upward trend. However, in the later storage period, such as storage days 9 and 12, the phenyllactic acid treatment group inhibited the increase in lignin content to a certain extent, especially the 4mM treatment group. These results show that the 4mM treatment group can significantly inhibit the increase in lignin content in pea sprouts to a certain extent.

[0104] Depend on Figure 3 It can be seen that the sensory scores of the 4mM treatment group were significantly higher than those of the 0mM control group during storage, and the 4mM phenyllactic acid treatment group maintained the sensory quality of pea sprouts better in the later storage period. Phenyllactic acid treatment can maintain the sensory quality of pea sprouts to a certain extent.

[0105] Depend on Figure 4 It can be seen that the weight loss rate of the 4mM treatment group was significantly lower than that of the 0mM control group during storage, which indicates that the 4mM treatment group can inhibit the increase of the weight loss rate of pea sprouts to a certain extent.

[0106] Depend on Figure 5 It can be seen that the lignin content of pea sprouts generally showed a fluctuating upward trend. Compared with the 0mM control group, the 4mM treatment group well suppressed the lignin content of pea sprouts in the early stage of storage. For example, the lignin content of the 0mM control group on the third day of storage was 1.2 times that of the 4mM treatment group, and the lignin content of the 0mM control group on the sixth day of storage was 1.3 times that of the 4mM treatment group. This shows that the 4mM treatment group can inhibit the increase of lignin content in pea sprouts to a certain extent.

[0107] Depend on Figure 6 It can be seen that the cellulose content of pea sprouts generally showed an upward trend. Compared with the 0mM control group, the 4mM treatment group maintained the cellulose content of pea sprouts during storage. For example, the cellulose content of the 4mM treatment group on the 3rd day of storage was 1.4 times that of the 0mM control group, and the cellulose content of the 4mM treatment group on the 12th day of storage was 1.1 times that of the 0mM control group. This shows that the 4mM treatment group can inhibit the degradation of the cellulose content of pea sprouts to a certain extent.

[0108] Depend on Figure 7 It can be seen that the total flavonoid content of pea sprouts showed a fluctuating upward trend overall. Compared with the 0mM control group, the 4mM treatment group maintained the total flavonoid content of pea sprouts during storage, and the total flavonoid content on the 3rd and 12th days of storage was significantly higher than that of the 0mM control group. This shows that the 4mM treatment group can increase the total flavonoid content of pea sprouts during storage to a certain extent.

[0109] Depend on Figure 8It can be seen that the vitamin C content of pea sprouts generally showed a fluctuating upward trend. Compared with the 0mM control group, the 4mM treatment group significantly increased the vitamin C content of pea sprouts during storage. For example, the vitamin C content on the 9th day of storage was 1.3 times that of the 0mM control group. This shows that the 4mM treatment group can increase the vitamin C content of pea sprouts to a certain extent.

[0110] Depend on Fig. 9 It can be seen that the PAL enzyme activity of pea sprouts generally showed a fluctuating upward trend. Compared with the 0mM control group, the 4mM treatment group inhibited the PAL enzyme activity of pea sprouts during storage. On the 12th day of storage, the PAL enzyme activity of the 0mM control group was 1.2 times that of the 4mM treatment group. This shows that the 4mM treatment group can inhibit the increase of PAL enzyme activity in pea sprouts to a certain extent.

[0111] Depend on Fig.10 It can be seen that the CAD enzyme activity of pea sprouts showed an overall upward trend. Compared with the 0mM control group, the 4mM treatment group inhibited the CAD enzyme activity of pea sprouts during storage, especially before the 9th day of storage, the CAD enzyme activity of the 4mM treatment group was significantly lower than that of the 0mM control group. This shows that the 4mM treatment group can inhibit the increase of CAD enzyme activity in pea sprouts to a certain extent.

[0112] Depend on Fig.11 It can be seen that the expression of pea sprouts and lignin synthesis-related enzyme genes generally showed an upward trend. Compared with the 0mM control group, the expression of pea sprouts and lignin synthesis-related enzyme genes in the 4mM treatment group during storage was significantly lower. This shows that the 4mM treatment group can inhibit the expression of pea sprouts and lignin synthesis-related enzyme genes to a certain extent.

Claims

1. A method for preserving pea sprouts after harvest by inhibiting lignification, characterized in that: The steps include: The roots of the pea sprouts with roots are cut and dried, and then immersed in a phenyllactic acid solution with a concentration of 2-8 mM. The processed pea sprouts are dehydrated in a vegetable dehydrator, and dried and stored.

2. The preservation method according to claim 1, characterized in that: The soaking time is 5-10 minutes, preferably 5 minutes.

3. The preservation method according to claim 1, characterized in that: The concentration of the phenyllactic acid solution is 4 mM.

4. The preservation method according to claim 1, characterized in that: The drying is drying at room temperature.

5. The preservation method according to claim 1, characterized in that: The dehydration is carried out in a vegetable dehydrator for 1-5 minutes, preferably 1 minute.

6. The preservation method according to claim 1, characterized in that: The storage is to put the pea sprouts into a basket and store them at 4-22°C, preferably 10°C, after packaging with a polyethylene film.

7. The preservation method according to claim 1, characterized in that: The pea variety is maple pea.

8. Application of phenyllactic acid in the preservation of pea sprouts.

9. The use according to claim 8, characterized in that: The invention is used for inhibiting the post-harvest lignification of pea sprouts.

10. The use according to claim 9, characterized in that: The method for inhibiting postharvest lignification of pea sprouts is to reduce the postharvest lignin content of pea sprouts, reduce the activity of enzymes related to lignin synthesis (PAL, CAD) and the expression of related genes, or the application of phenyllactic acid in the preservation of pea sprouts effectively reduces the weight loss rate, maintains the nutritional quality, and keeps the vitamin C and total flavonoids in the pea sprouts.

Images