Composite coating preservative and application thereof in Oudemansiella radicata preservation

Abstract

The invention discloses a composite coating preservative and application thereof in Oudemansiella radicata preservation, the preservative comprises the following main action components: okra polysaccharide, NaHS, polylysine and L-cysteine, and specifically, the concentration of the okra polysaccharide is 0.625 g / L, the concentration of the NaHS is 0.16 mmol / L, the concentration of the polylysine is 0.25 g / L, and the concentration of the L-cysteine is 0.1 g / L. The composite coating preservative reduces the weight loss rate of oudemansiella radicata, slows down the color change, maintains good soluble protein and reducing sugar content, reduces the H2O2 content and the O2 <-> production rate, improves the activity of SOD, PAL, CAT, GR and PPO, slows down the reduction of POD activity, inhibits the accumulation of malondialdehyde, reduces the activity of LOX, inhibits the growth of aerial hyphae, and improves the quality of oudemansiella radicata. The transcriptional regulation effect on oxidative phosphorylation, sulfur metabolism and other pathways is achieved. The raw materials of the composite coating preservative have the characteristics of being safe, non-toxic, green and pollution-free, and the composite coating preservative has a good preservation effect on oudemansiella radicata, and can effectively relieve the weight loss of oudemansiella radicata during storage and reduce the chromaticity change.

Description

Technical Field

[0001] The invention relates to the technical field of fresh-keeping, and in particular to a composite coating preservative and application thereof in the fresh-keeping of Root Oyster Mushroom. Background Art

[0002] Oudemansiella radicata, also known as long-rooted small Ode mushroom, black-skinned chicken mushroom, and large hairy grass mushroom, is a valuable medicinal and edible mushroom newly developed in recent years. Compared with the southern region, the cultivation technology of Oudemansiella radicata in the north is more mature.

[0003] The long root mushroom has a crisp texture and delicious taste. Due to its high content of sodium glutamate, its freshness and deliciousness are far superior to MSG. It is very rich in nutrients such as protein, unsaturated fatty acids, polysaccharides, vitamins, etc., so it can nourish the skin and has the effect of removing free radicals from the human body. It also contains alkaloids, shiitake mushrooms, taurine, triterpenes, folic acid and other active nutrients. Many of these nutrients are often used in analgesia and anti-inflammation, regulating human immunity, regulating heart function, lowering blood lipids, healing damaged organs and improving body functions, so the edible value of this mushroom is very high.

[0004] At 30℃, the long root mushroom will soften and have a slight odor after two days, and will become completely sour and softened after four days. At 24℃, the long root mushroom cap will soften slightly after two days and will have a slight odor; the odor will worsen after five days, and the softening will spread to the stipe, and aerial hyphae will burst out in large numbers, and will completely rot after a week. At 4℃, aerial hyphae will begin to appear after three days of storage of the long root mushroom, and the cap will change color and soften after fourteen days, but there will be no obvious odor. Most of the current research related to the long root mushroom is about the culture medium and how to improve artificial cultivation technology. There has not been much research on other aspects of the long root mushroom.

[0005] Edible cling film is a film made of pure natural edible substances. It is covered on the surface or inside of food in various forms to preserve food. It is divided into polysaccharides, proteins, lipids and composite coatings. Edible cling film can generally provide physical protection for the surface of fruits and vegetables, effectively block gas and moisture, prevent invasion by external microorganisms, improve commercial value, and extend the storage period of food. Polysaccharide edible film has been used in fruit and vegetable preservation for a long time due to its uniform distribution and good film-forming properties. It is generally made of chitosan and its derivatives, modified cellulose, and animal and plant glue raw materials. It is cheap, widely available, and easy to operate.

[0006] Okra polysaccharide has high viscosity and good film-forming effect, which plays a positive role in the preservation of fruits and vegetables. However, the preservation effect of single okra polysaccharide on fruits and vegetables is not as significant as expected. Therefore, in order to better maintain the quality of long root mushroom during storage, the present invention combines three green and non-toxic chemical preservatives: polylysine, NaHS and L-cysteine.

[0007] Okra polysaccharides are mainly composed of galactose, glucuronic acid, rhamnose, etc., which have anti-cancer effects and can inhibit the growth of cancer cells; the viscous substances and arabinan in them can help the gastrointestinal tract digestion and absorption, replenish physical strength, and relieve fatigue. Therefore, okra polysaccharides have very broad development potential in coating preservation. Summary of the invention

[0008] The present invention aims to solve the above problems and provides a composite coating preservative and its application in preserving Oyster mushroom.

[0009] The specific technical solutions are as follows: In a first aspect, the present invention provides a composite coating preservative, wherein main active ingredients of the preservative include okra polysaccharide, NaHS, polylysine and L-cysteine.

[0010] Furthermore, the okra polysaccharide concentration is 0.5-0.8 g / L, the NaHS concentration is 0.1-0.3 mmol / L, the polylysine concentration is 0.1-0.4 g / L, and the L-cysteine ​​concentration is 0.05-0.2 g / L.

[0011] Specifically, the okra polysaccharide concentration is 0.625 g / L, the NaHS concentration is 0.16 mmol / L, the polylysine concentration is 0.25 g / L, and the L-cysteine ​​concentration is 0.1 g / L.

[0012] Furthermore, the preparation method of the preservative is: okra polysaccharide, NaHS, polylysine, and L-cysteine ​​are prepared in a volume ratio of 1:1:1:1, and stirred evenly.

[0013] In the second aspect, based on the same invention, the present invention also provides the use of the composite coating preservative as described above in the preservation of Oyster mushroom.

[0014] In a third aspect, the present invention further provides a method for preserving Root Oyster Mushrooms, comprising soaking fresh Root Oyster Mushrooms in the composite coating preservative as described above, and storing the fresh Root Oyster Mushrooms at 4°C after soaking.

[0015] Furthermore, the time for soaking the fresh Oyster mushroom in the composite coating preservative is 2-5 minutes.

[0016] The present invention has the following advantages: The raw materials of the composite coating preservative of the invention are safe, non-toxic, green and pollution-free, and have a good preservative effect on Root Oyster Mushroom, and can effectively alleviate the weight loss of Root Oyster Mushroom during storage and reduce color change.

[0017] The experimental results show that the composite coating preservative of the present invention can increase the content of soluble protein and reducing sugar in Oyster mushroom, which means that after being treated with the composite preservative, Oyster mushroom still maintains good nutrients and exhibits a good preservation effect.

[0018] In addition, the H2O2 content and O 2- The production rate of the composite preservative was lowered, which showed that it was beneficial to reduce the accumulation of reactive oxygen and improve the preservation effect. It increased the activities of SOD, PAL, CAT, GR and PPO, slowed down the decrease of POD activity, inhibited the accumulation of malondialdehyde and reduced the activity of LOX, inhibited the growth of aerial mycelium, and had a transcriptional regulatory effect on oxidative phosphorylation and sulfur metabolism. It showed that under the treatment of the composite preservative, the integrity of the cell membrane could be effectively protected, the cell membrane damage caused by aging could be prevented and treated, and the quality of the long root mushroom during storage could be effectively improved. During the storage period, the external stress could be resisted through the action of multiple enzymes, which improved the anti-aging ability of the long root mushroom during storage. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the experimental cases or the description of the prior art. Obviously, the drawings described below are only an experimental case of the present invention. For ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0020] Figure 1 : The chromaticity changes of Okra polysaccharide, NaHS, polylysine and L-cysteine ​​treated with different concentrations of Okra polysaccharide, NaHS, polylysine and L-cysteine ​​after storage at 4℃ for 0, 3, 6, 9 and 12 days; A is Okra polysaccharide, B is NaHS, C is polylysine and D is L-cysteine; Figure 2 :The changes of chromaticity of Oregano Root Agaricus treated with different proportions of okra polysaccharide, NaHS, polylysine and L-cysteine ​​coating solution after storage at 4℃ for 0, 3, 6, 9 and 12 days Figure 3 :The changes of weight loss rate of Oyster mushroom stored at 4℃ for 0, 3, 6, 9 and 12 days by the preservation method used in the experimental case; Figure 4 :The color change of Oyster mushroom stored at 4℃ for 0, 3, 6, 9 and 12 days by the preservation method used in the experimental case; Figure 5: Changes in the soluble protein (A) and reducing sugar (B) contents of Oyster mushroom stored at 4°C for 0, 3, 6, 9 and 12 days according to the preservation methods used in the experimental case; Figure 6 :The preservation method used in the experimental case stored at 4℃ for 0 days, 3 days, 6 days, 9 days and 12 days. 2- Changes in the production rate (B); Figure 7 : Changes of malondialdehyde (MDA) (A) and lipoxygenase (LOX) (B) in Oyster mushrooms stored at 4℃ for 0, 3, 6, 9 and 12 days according to the preservation methods used in the experimental case; Figure 8 : Changes of superoxide dismutase (SOD) (A), peroxidase (POD) (B) and catalase (CAT) (C) in Oyster mushrooms stored at 4°C for 0, 3, 6, 9 and 12 days according to the preservation method used in the experimental case; Fig. 9 : Changes of polyphenol oxidase (PPO) (A), phenylalanine ammonia lyase (PAL) (B) and glutathione reductase (GR) (C) in Oyster mushrooms stored at 4℃ for 0, 3, 6, 9 and 12 days according to the preservation method used in the experimental case.

[0021] Fig.10 : The preservation method used in the experimental case showed changes in the browning degree and aerial hyphae of Oyster mushroom stored at 4℃ for 0 and 12 days.

[0022] Fig.11 : Fig.10 Magnified image of browning; Fig.12 : Fig.10 Magnified image of aerial hyphae; Fig.13 : Volcano plot analysis of differentially expressed genes in transcriptional sequencing of the preservation method used in the experimental case compared with the control group.

[0023] Fig.14 : KEGG enrichment pathway bubble chart analysis of transcriptional sequencing of the preservation method used in the experimental case compared with the control group. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the implementation cases of the present invention to clearly and completely describe the technical solutions in the implementation cases of the present invention. Obviously, the implementation cases described are only part of the implementation cases of the present invention, rather than all the implementation cases. Based on the implementation cases in the present invention, all other implementation cases obtained by those skilled in the art without creative work are within the scope of protection of the present invention. In the present invention, unless otherwise specified, the equipment and raw materials used can be purchased from the market or are commonly used in the art. The methods in the following implementation cases, unless otherwise specified, are conventional methods in the art.

[0025] Example 1: Composite coating preservative 1.1 Experimental Materials Fresh okra was purchased from Chengyang Vegetable Wholesale Market in Qingdao; NaHS was purchased from Shanghai McLean Biochemical Technology Co., Ltd.; polylysine was purchased from Shanghai McLean Biochemical Technology Co., Ltd.; L-cysteine ​​was purchased from Shanghai McLean Biochemical Technology Co., Ltd.

[0026] 1.2 Formula of composite coating preservative The concentration of okra polysaccharide is 0.5-0.8 g / L, the concentration of NaHS is 0.1-0.3 mmol / L, the concentration of polylysine is 0.1-0.4 g / L, and the concentration of L-cysteine ​​is 0.05-0.2 g / L.

[0027] After preliminary experimental screening (such as Figure 1 As shown in the figure), by measuring the chromaticity of Oyster mushroom during storage, it was determined that the optimal treatment was okra polysaccharide concentration of 0.625 g / L, NaHS concentration of 0.16 mmol / L, polylysine concentration of 0.25 g / L, and L-cysteine ​​concentration of 0.1 g / L.

[0028] 1.3 Preparation method of composite coating preservative Wash the fresh okra, chop it into pieces and crush it with a wall breaking machine. Then filter, decolorize, rotary evaporate and freeze-dry it into powder for later use.

[0029] The okra polysaccharide prepared above was prepared with NaHS, polylysine and L-cysteine ​​in volume ratios of 2:1:1:1, 1:2:1:1, 1:1:2:1, 1:1:1:2, 1:1:1:1, 2:2:1:1, 1:2:2:1, 1:1:2:2, 1:2:2:2 and 2:2:2:1, and stirred evenly.

[0030] After preliminary experimental screening (such as Figure 2 As shown in the figure, the optimal volume ratio was determined to be okra polysaccharide: NaHS: polylysine: L-cysteine ​​= 1:1:1:1. After stirring evenly, it was used as a composite coating preservative.

[0031] Example 2: Application of composite coating preservative in preserving Root Oyster Mushroom 2.1 How to use the composite coating preservative Soak fresh Root Oyster Mushroom in the prepared coating preservative aqueous solution for 3 minutes, take out to dry the water, and store at 4°C after natural air drying.

[0032] 2.2 Experimental design and test indicators Fresh long root mushrooms of the same species were divided into two groups, a control group and an experimental group. The experimental group soaked the long root mushrooms in a composite coating preservative for 3 minutes, fished out and dried, and then stored at 4°C after natural air drying; the control group used distilled water instead of the composite coating preservative, and the rest of the treatments were the same. Three or more repeated experiments were set up.

[0033] On the 0th, 3rd, 6th, 9th and 12th day after treatment, the following indicators of the long root mushroom were tested and analyzed: weight, color, soluble protein content, reducing sugar content, H2O2 content, O 2- Production rate, malondialdehyde (MDA), lipoxygenase (LOX), superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL), glutathione reductase (GR).

[0034] 2.3 Experimental data analysis 2.3.1 Weight of Oyster Mushroom The weight of the long root mushroom was tested on the 0th, 3rd, 6th, 9th and 12th day and the weight loss rate was calculated. The results are as follows: Figure 3 As shown. Figure 3 It can be seen that during the storage period, the weight loss rate of Oyster mushroom increased with time, but the weight loss rate after coating preservation was lower than that of the control group, and the preservation effect was good.

[0035] 2.3.2 Chromatography of Oyster mushroom The color of the long root mushroom was tested on the 0th, 3rd, 6th, 9th and 12th day. The results are as follows: Figure 4 As shown. Figure 4 It can be seen that the chromaticity decreased with the increase of time during storage, but the chromaticity of the treatment group was still higher than that of the control group during storage, which slowed down the decrease of chromaticity, indicating that the treatment with the composite coating preservative is beneficial to maintaining the appearance of Oyster mushroom.

[0036] 2.3.3 Soluble protein and reducing sugars Samples of O. Root were taken on days 0, 3, 6, 9, and 12 to detect their physiological and biochemical indices. Figure 5The figure shows the changes of the composite coating preservative on the soluble protein (A) and reducing sugar (B) content of Oyster mushroom at different time points. Figure 5 It can be seen that during the storage period, soluble protein and reducing sugar showed an upward trend, and after being treated with the composite coating preservative, both substances were higher than those in the control group. This shows that after being treated with the composite coating preservative, the long root mushroom still maintained good nutrients and showed a good preservation effect.

[0037] 2.3.4 H2O2 content and O2- production rate Figure 6 The figure shows the effect of the composite coating preservative on the H2O2 content (A) and O2- production rate (B) of Oyster mushroom at different time points. Figure 6 It can be seen that the composite coating preservative reduces the H2O2 content, slows down the rate of O2- production, and is significantly lower than the control group, which is beneficial to reduce the accumulation of active oxygen and improve the preservation effect.

[0038] 2.3.5 Malondialdehyde (MDA) and lipoxygenase (LOX) Figure 7 The figure shows the effect of the composite coating preservative on the changes of malondialdehyde (MDA) (A) and lipoxygenase (LOX) (B) of Oyster mushroom at different time points. Figure 7 It can be seen that during storage, the LOX activity of Oyster mushroom decreased and the MDA content increased. However, after the composite coating preservative treatment, the MDA accumulation was lower than that of the control group. At the same time, under the treatment of the composite coating preservative, the LOX activity decreased more than the control group and finally remained at a low level. This shows that under the treatment of the composite coating preservative, the integrity of the cell membrane can be effectively protected, the cell membrane damage caused by aging can be prevented and treated, and the quality of Oyster mushroom during storage can be effectively improved.

[0039] 2.3.6 Superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) Figure 8 The figure shows the effect of the composite coating preservative on the changes of superoxide dismutase (SOD) (A), peroxidase (POD) (B) and catalase (CAT) (C) in Oyster mushroom at different time points. Figure 8 A and Figure 8 As shown in Figure C, during the storage period, the activities of SOD and CAT gradually increased, and after the composite coating preservative treatment, the enzyme activity was higher than that of the control group, which indicates that during the storage period, the composite coating preservative treatment can increase the activity of the two enzymes and thus reduce the hydrogen peroxide content and superoxide anion generation rate. Figure 8B shows that during storage, the activity of POD decreased with time. At the same time, the composite coating preservative treatment significantly slowed down the decline of POD and its activity was significantly higher than that of the control group. The above shows that the composite coating preservative has a good preservation effect.

[0040] 2.3.7 Polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL) and glutathione reductase (GR) Fig. 9 The figure shows the effect of the composite coating preservative on the changes of polyphenol oxidase (PPO) (A), phenylalanine ammonia lyase (PAL) (B) and glutathione reductase (GR) (C) of Oyster mushroom at different time points. Fig. 9 A, B and C show that during storage, the activities of the three enzymes increased with time, which indicates that during storage, the three enzymes resisted external stress and improved the anti-aging ability of Oyster mushroom during storage. At the same time, under the treatment of composite coating preservative, the activities of the three enzymes were maintained at a high level and significantly higher than the control group.

[0041] 2.3.8 Browning degree and aerial hyphae of Oyster mushroom Fig.10 and Fig.11 The figure shows the effect of the composite coating preservative on the browning degree of Oyster mushroom at the 0th and 12th day time points. Fig.11 It can be seen that during the storage period, the browning degree of the long root mushroom treated with the composite coating preservative was significantly lower than that of the control group. This shows that during the storage period, the composite coating preservative significantly improved the ability of the long root mushroom to resist aging and browning. Fig.10 and Fig.12 It also shows the effect of the composite coating preservative on the changes in the aerial mycelium of Oyster mushroom. Fig.12 As shown in the figure, during the storage period, the growth degree of aerial mycelium of Oyster mushroom under the composite coating preservative treatment was significantly lower than that of the control group. This indicates that during the storage period, the composite coating preservative significantly inhibited the growth of aerial mycelium of Oyster mushroom.

[0042] 2.3.9 Volcano plot analysis of transcriptional sequencing of Oyster mushroom Fig.13 The figure shows the differential gene volcano map obtained after transcription sequencing of the composite coating preservative and the control group. As shown in the figure, under the conditions of FDR=0.01 and FC=1.5, there are 1752 differential genes in the composite coating preservative compared with the control group, including 800 up-regulated differential genes and 952 down-regulated differential genes.

[0043] 2.3.10 KEGG enrichment pathway bubble diagram analysis of transcriptional sequencing of Oyster mushroom Fig.14The figure shows the results of KEGG pathway enrichment analysis of differentially expressed genes obtained through transcriptional sequencing. As shown in the figure, Oxidative phosphorylation, Citrate cycle (TCA cycle), Sulfur metabolism, and Glycolysis / Gluconeogenesis are significantly enriched pathways, indicating that the composite coating preservative has a significant effect on the transcriptional regulation of these metabolic pathways.

[0044] In summary, the composite coating preservative has a good preservation effect on Oyster mushroom at 4°C. It reduces the weight loss rate of Oyster mushroom, slows down the color change, maintains a good soluble protein and reducing sugar content, reduces the H2O2 content and O2- production rate, increases the activity of SOD, PAL, CAT, GR and PPO, slows down the decrease of POD activity, inhibits the accumulation of malondialdehyde and reduces the activity of LOX, inhibits the growth of aerial hyphae, and has a transcriptional regulatory effect on oxidative phosphorylation and sulfur metabolism. It has great application prospects in the preservation of Oyster mushroom.

[0045] It is understandable that those skilled in the art can make equivalent substitutions or changes based on the technical solution and concept of the present invention, and all these changes or substitutions should fall within the protection scope of the claims attached to the present invention.

Claims

1. A composite coating preservative, characterized in that: The main active ingredients of the preservative include okra polysaccharide, NaHS, polylysine and L-cysteine.

2. A composite coating preservative according to claim 1, characterized in that: The okra polysaccharide concentration is 0.5-0.8 g / L, the NaHS concentration is 0.1-0.3 mmol / L, the polylysine concentration is 0.1-0.4 g / L, and the L-cysteine ​​concentration is 0.05-0.2 g / L.

3. A composite coating preservative according to claim 2, characterized in that: The okra polysaccharide concentration is 0.625 g / L, the NaHS concentration is 0.16 mmol / L, the polylysine concentration is 0.25 g / L, and the L-cysteine ​​concentration is 0.1 g / L.

4. The composite coating preservative according to claim 1, characterized in that: The preparation method of the preservative comprises the following steps: preparing okra polysaccharide, NaHS, polylysine and L-cysteine ​​in a volume ratio of 1:1:1:1, and stirring the mixture evenly.

5. Use of a composite coating preservative as described in any one of claims 1 to 4 in preserving Oyster mushroom.

6. A method for preserving Root Oyster Mushroom, characterized in that: Fresh Root Oyster Mushrooms are soaked in the composite coating preservative as described in any one of claims 1 to 4, and then stored at 4°C.

7. The method for preserving Root Oyster Mushroom according to claim 6, characterized in that: The time for soaking fresh Root Oyster Mushroom in the composite coating preservative is 2-5 minutes.

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