阅读说明：本技术 一种防止鲜切莲藕褐变的保鲜方法及其应用 (Preservation method for preventing browning of fresh-cut lotus roots and application thereof ) 是由 张鹏 李江阔 贾晓昱 于 2021-03-04 设计创作，主要内容包括：本发明提供一种防止鲜切莲藕褐变的保鲜方法及其应用。该方法为鲜切莲藕放置于复合防褐变剂溶液(0.6～1.0%无水柠檬酸+0.06～0.1%抗坏血酸钙+0.1～0.3%L-天门冬氨酸不同复配防褐变剂)中浸泡3～5min,沥干水分,放置于冷藏(4±1℃)环境贮藏,通过对鲜切莲藕褐变度的测定得出最佳优化防褐变剂配方为1.0%无水柠檬酸+0.1%抗坏血酸钙+0.2%L-天门冬氨酸。进一步验证得出优化防褐变剂处理的鲜切莲藕可明显延缓褐变发生。本发明可以抑制鲜切莲藕的褐变,实现了鲜切莲藕贮藏保鲜,贮藏期长达6d。(The invention provides a preservation method for preventing browning of fresh-cut lotus roots and application thereof. The method comprises the steps of placing fresh-cut lotus roots into a compound anti-browning agent solution (0.6-1.0% of anhydrous citric acid, 0.06-0.1% of calcium ascorbate and 0.1-0.3% of L-aspartic acid different compound anti-browning agents) to be soaked for 3-5 min, draining water, placing the lotus roots in a refrigerated (4 +/-1 ℃) environment to be stored, and obtaining the optimal optimized anti-browning agent formula of 1.0% of anhydrous citric acid, 0.1% of calcium ascorbate and 0.2% of L-aspartic acid through measuring the browning degree of the fresh-cut lotus roots. Further verification shows that the fresh-cut lotus roots treated by the optimized anti-browning agent can obviously delay the browning. The invention can inhibit the brown stain of the fresh-cut lotus root, realizes the storage and the fresh keeping of the fresh-cut lotus root, and the storage period is as long as 6 days.)

1. A fresh-keeping method for preventing brown stain of fresh-cut lotus roots is characterized by comprising the following steps:

soaking the lotus root slices in the compound preservative for 3-5 min; taking out the fresh-cut lotus root slices, draining, placing in an experimental bowl, and repeating all the treatments for four times; placing in a refrigeration environment for storage, and placing the experimental bowl filled with the fresh-cut lotus roots in a refrigerator at 4 +/-1 ℃; and (4) storing for 4 days, and measuring the browning degree value to obtain the optimized compound preservative with the lowest browning degree, wherein the optimized compound preservative is 1.0% of anhydrous citric acid, 0.1% of calcium ascorbate and 0.2% of L-aspartic acid.

2. Use of the method of claim 1 for effectively inhibiting browning of fresh-cut lotus roots during storage and for extending storage life.

Technical Field

The invention relates to a fresh-keeping method for preventing fresh-cut lotus roots from browning, in particular to a green fresh-keeping method for refrigerating and optimizing and verifying an optimal formula of a response surface.

Background

The lotus roots (Nelumbo nucifera Gaertn), called lotus for short, are also called lotus vegetables, lotus roots and the like, are aquatic vegetables with the widest planting area in China and are mainly produced in Yangtze river delta, Dongting lake and Zhujiang delta. The lotus root has rich nutrition, crisp and tender tissue, white meat quality and crisp and sweet taste. Has good nutritive value and medicinal value, and is popular with consumers. Recently, fresh-cut lotus roots are receiving more and more attention as a novel processed vegetable as the life style of consumers is changed. Browning is one of the main problems of fresh-cut lotus roots in the storage process, not only affects the appearance, but also reduces the nutritional value, causes the reduction of antioxidant ingredients, seriously affects the commodity value of the lotus roots and hinders the development of the fresh-cut lotus root industry. Reducing or inhibiting browning is therefore critical to maintaining the quality of fresh-cut lotus roots.

A large number of research results show that citric acid, ascorbic acid and aspartic acid have a good effect of inhibiting browning of fruits and vegetables. The research of Wangqiucheng et al shows that 1.5 percent of citric acid treatment has better color protection effect; zhang Ting and the like adopt 1.0 percent ascorbic acid to soak fresh-cut apples for 3min, and the better browning inhibition effect is found; fresh-cut potatoes such as Liu dustpan and the like are used as experimental materials, and are treated by 1.0% of aspartic acid, so that the fresh-cut lotus roots can be maintained to be not brown for 5 days. The better anti-browning agent for inhibiting the browning of the fresh-cut lotus roots is screened out through an early stage single factor experiment: 0.6 percent, 0.8 percent, 1.0 percent of anhydrous citric acid, 0.06 percent, 0.08 percent, 0.1 percent of calcium ascorbate, 0.1 percent, 0.2 percent and 0.3 percent of L-aspartic acid, which lays a foundation for the experiment. According to the method, a three-factor three-level response surface experiment is performed on the basis of an early-stage single-factor experiment, the fresh-cut lotus root composite anti-browning agent is optimized, the influence of the optimized anti-browning agent on the quality of the fresh-cut lotus root is further researched, and a new technical requirement for delaying the browning of the fresh-cut lotus root is provided.

Disclosure of Invention

The invention aims to fill up the blank of previous research and provides a fresh-keeping method for preventing the browning of fresh-cut lotus roots. The invention provides a preservation technology for preventing fresh-cut lotus roots from browning, and particularly relates to a green preservation method for refrigerating and optimally verifying and applying an optimal formula of a response surface.

In order to achieve the purpose, the invention discloses the following technical contents:

a fresh-keeping method for preventing brown stain of fresh-cut lotus roots is characterized in that: the method comprises the following steps:

step 1: soaking the lotus root slices in the compound preservative of the response surface design scheme for 3-5 min; taking out the fresh-cut lotus root slices, draining, placing in an experimental bowl, and repeating all the treatments for four times; placing in a refrigeration environment for storage, and placing the experimental bowl filled with the fresh-cut lotus roots in a refrigerator (4 +/-1 ℃); and (4) storing for 4 days, and measuring the browning degree value to obtain the optimized compound preservative with the lowest browning degree, wherein the optimized compound preservative is 1.0% of anhydrous citric acid, 0.1% of calcium ascorbate and 0.2% of L-aspartic acid.

Step 2: soaking the processed fresh cut lotus root in an optimized anti-browning agent (1.0% anhydrous citric acid +0.1% calcium ascorbate +0.2% L-aspartic acid) solution for 3min, with no processing as a control; the fresh-cut lotus root slices were taken out, drained and placed in an experimental bowl, and all treatments were repeated four times. Storing in cold storage environment, placing the experimental bowl containing fresh-cut rhizoma Nelumbinis in refrigerator (4 + -1 deg.C), and measuring browning degree and total phenol content every 2 d.

The invention discloses a formula of an optimized compound preservative, which comprises 1.0 percent of anhydrous citric acid, 0.1 percent of calcium ascorbate and 0.2 percent of L-aspartic acid. Temperature control program parameters of the refrigerated storage environment: 4 +/-1 ℃.

The invention further discloses application of the preservation method for preventing the fresh-cut lotus roots in inhibiting browning of the fresh-cut lotus roots in the storage period. The invention relates to a cold storage preservation method by optimizing 1.0 percent of anhydrous citric acid, 0.1 percent of calcium ascorbate and 0.2 percent of L-aspartic acid of an anti-staling agent. The method can inhibit browning of fresh-cut rhizoma Nelumbinis during storage, and the storage period is up to 6 days.

Compared with the prior art, the fresh-keeping method for preventing the browning of the fresh-cut lotus roots and the application thereof disclosed by the invention have the positive effects that:

(1) compared with the traditional preservative, the technology emphasizes the low use amount of the preservative, and provides the compounding of anhydrous citric acid, calcium ascorbate and L-aspartic acid with different low concentrations, so that the consumption of cost is reduced to the maximum extent, and a better browning inhibition effect is achieved. The research result of the experiment shows that the combination of 1.0 percent of anhydrous citric acid, 0.1 percent of calcium ascorbate and 0.2 percent of L-aspartic acid with the refrigeration storage can effectively slow down the occurrence of browning of the fresh-cut lotus roots during the storage.

(2) Compared with the existing compound preservative, the compound anti-browning agent with the best browning inhibition effect is obtained through a response surface experiment in the experiment, and further through a storage verification experiment, compared with a control, the compound anti-browning agent is obtained through 1.0% of anhydrous citric acid, 0.1% of calcium ascorbate and 0.2% of L-aspartic acid, and can effectively inhibit the browning of the lotus roots during the storage period. According to market demands, anti-browning agents are sold.

(3) Based on the report that the antistaling agent is used on various fruits and vegetables, the difference of the patent is as follows: the formula of the preservative is different, the using amount of the preservative is small, the suitable preservative using amounts of different fruits and vegetables are different, the formula of the preservative obtained in the patent is obtained by comparing the formula of the preservative with sensory quality on the basis of multiple actual loads, and the preservative has reliability and operability. In addition, the patent is different in that the optimized browning inhibitor mentioned for the fresh-cut lotus roots has a good browning inhibition effect on the fresh-cut lotus roots through the verification of a later-stage storage experiment of a response surface.

The invention mainly solves the problem of browning of fresh-cut lotus roots during storage, mainly investigates the inhibiting effect of anti-browning agents with different formulas in combination with refrigeration on browning of the fresh-cut lotus roots during storage, and mainly aims to screen and verify the optimized anti-browning agents.

Drawings

FIG. 1 optimizes the influence of the anti-browning agent on the browning degree of fresh-cut lotus roots;

FIG. 2 optimizes the effect of anti-browning agent on the total phenol content of fresh-cut lotus root.

Detailed Description

The invention is described below by means of specific embodiments. Unless otherwise specified, the technical means used in the present invention are well known to those skilled in the art. In addition, the embodiments should be considered illustrative, and not restrictive, of the scope of the invention, which is defined solely by the claims. It will be apparent to those skilled in the art that various changes or modifications to the preferred anti-browning agents of these embodiments in combination with refrigeration temperature parameters without departing from the spirit and scope of the invention are also within the scope of the invention. The anhydrous citric acid, calcium ascorbate and L-aspartic acid used in the present invention are commercially available.

Example 1

Screening of fresh-cut lotus root compound anti-browning agent

Fresh cut lotus roots are purchased from the market, and the fresh cut lotus roots with uniform quality are selected, cleaned from field soil and peeled. Then cutting fresh-cut lotus roots into slices with the thickness of 5mm along the cross section of the fresh-cut lotus roots by using a sharp stainless steel knife, soaking the slices in distilled water, placing the slices in a refrigerator at 4 ℃ for precooling for 15min, taking out the slices, drying the surface water of the slices, respectively soaking the slices in a composite anti-browning agent solution formed by combining three anti-browning agents of table 2 for 3min, taking out the fresh-cut lotus roots, draining the water, placing the slices in a bowl for experiments, repeating all the treatments for four times, then placing the slices in the refrigerator at 4 ℃ for storage, and measuring the indexes for 4d storage.

On the basis of a single-factor test, according to the design principle of a Box-Behnken test, anhydrous citric acid, calcium ascorbate and L-aspartic acid are used as independent variables, the browning degree is used as a response value, a response surface analysis test is designed, and factors and level values of the test are set on the basis of the previous single-factor test (Table 1).

As can be seen from Table 2, the model is extremely significant (P < 0.0001), and the coefficient of determination R is²=0.9896, which shows that the response value of browning degree (Y) to 3 factors of citric acid anhydrous (a), calcium ascorbate (B) and L-aspartic acid (C) can be predicted by using the model. The P value of the selected regression model is less than 0.0001, which indicates that the integral model has obvious influence on the experimental result and has reliability; the P value of the mismatching item is 0.2632 and is more than 0.05, the test of the mismatching item is not obvious, and the model is selected properly; the decision coefficient of this model is 0.9896, indicating that the model has high confidence.

The optimal extraction conditions of the browning degree obtained by analysis of Design-Expert response surface analysis software RSM are as follows: 1.0 percent of anhydrous citric acid, 0.1 percent of calcium ascorbate and 0.2 percent of L-aspartic acid. Under the condition, the fresh-cut lotus roots are stored for 4 days, and the browning degree value is 0.222.

TABLE 1 factor level table

Table 2 response surface design and experimental results

TABLE 3 analysis of variance of experimental results

Note: significant difference, P < 0.05; is the most significant difference, P < 0.01.

Example 2

Optimizing the action of the anti-browning agent in the preservation of fresh-cut lotus roots

Fresh cut lotus roots are purchased from the market, and the fresh cut lotus roots with uniform quality are selected, cleaned from field soil and peeled. Then, cutting the fresh-cut lotus roots into slices with the thickness of 5mm along the cross sections of the fresh-cut lotus roots by using a sharp stainless steel knife, soaking the slices in distilled water, placing the slices in a refrigerator with the temperature of 4 ℃ for precooling for 15min, taking out the slices, draining the surface water of the slices, respectively soaking the slices in an optimized anti-browning agent solution for 3min for treatment, taking out the fresh-cut lotus roots, draining the water of the slices, placing the slices in an experimental bowl, repeating all the treatments for four times, then placing the slices in the refrigerator with the temperature of 4 ℃ for storage, and measuring the indexes after 2. The results are as follows:

FIGS. 1-2 are the changes in browning level and total phenol content during storage for both treatments. The browning degree can reflect the browning degree of a cut sample, and is the embodiment that phenolic substances in fruits and vegetables are oxidized into brown substances. As can be seen from fig. 1, in the storage process, the browning degree of the lotus root is gradually increased, the browning degree of the lotus root is gradually enhanced, wherein the control browning degree is the largest and the browning is the most serious, and the optimized browning inhibitor treatment group has the lowest browning degree and the weakest browning degree.

The phenolic substances are important substrates for enzymatic browning of fresh-cut lotus roots. The fresh-cut lotus roots are easy to brown in the storage process, and the edible value and the commodity of the fresh-cut lotus roots are seriously reduced, so that the economic value of the fresh-cut lotus roots is reduced. As can be seen from FIG. 2, the total phenol content of lotus root is gradually reduced, and the total phenol content of the optimized anti-browning agent treatment group is higher, which indicates that the treatment can better maintain the phenolic substances of lotus root, reduce the oxidation of the phenolic substances to quinone, and further inhibit browning.