阅读说明：本技术 一种复合微胶囊果蔬保鲜被膜剂及其制备方法 (Composite microcapsule fruit and vegetable fresh-keeping coating agent and preparation method thereof ) 是由 赵蕾 赵花蕾 申长哲 纪晓杰 刘世轩 于 2021-07-01 设计创作，主要内容包括：本发明属于果蔬保鲜领域,具体是一种复合微胶囊果蔬保鲜被膜剂及其制备方法。按质量百分比,芯材原料0.1～5％VC、0.2％～25％柠檬酸、0.15％～3％丙酸钙或脱氢乙酸钠或醋酸钙、0.1％～3％植酸中一种或多种,内层包材原料0.1％～1.5％蔗糖酯,外层包材原料1.5％～13％PVA、0.2％～0.5％壳聚糖、0.1％～1.0％透明质酸钠、0.1％～0.9％β-环糊精、0.3～1.2％羟甲基纤维素钠、0.2～1.5％海藻酸钠中的一种或多种,辅料0.1～5％甘油、5％～30％吐温中的一种或两种,酸度调节剂0.5％～6％柠檬酸、酒石酸中的一种或两种,其余为水。本发明有效提高果蔬保鲜效果及货架期。(The invention belongs to the field of fruit and vegetable preservation, and particularly relates to a composite microcapsule fruit and vegetable preservation coating agent and a preparation method thereof. According to the mass percentage, the core material comprises one or more of 0.1-5% of VC, 0.2-25% of citric acid, 0.15-3% of calcium propionate or sodium dehydroacetate or calcium acetate and 0.1-3% of phytic acid, the inner layer packaging material comprises 0.1-1.5% of sucrose ester, the outer layer packaging material comprises one or more of 1.5-13% of PVA, 0.2-0.5% of chitosan, 0.1-1.0% of sodium hyaluronate, 0.1-0.9% of beta-cyclodextrin, 0.3-1.2% of sodium hydroxymethyl cellulose and 0.2-1.5% of sodium alginate, one or two of 0.1-5% of glycerol and 5-30% of Tween, the acidity regulator comprises one or two of citric acid and tartaric acid, and the balance of water. The invention effectively improves the fresh-keeping effect and shelf life of the fruits and vegetables.)

1. A composite microcapsule fruit and vegetable fresh-keeping coating agent is characterized by comprising a core material, an inner layer packaging material, an outer layer packaging material, auxiliary materials and an acidity regulator; according to the mass percentage, the core material comprises 0.1-5% of VC, 0.2-25% of citric acid, 0.15-3% of calcium propionate or sodium dehydroacetate or calcium acetate, and 0.1-3% of phytic acid, the inner layer packaging material comprises 0.1-1.5% of sucrose ester, the outer layer packaging material comprises one or more of 1.5-13% of PVA, 0.2-0.5% of chitosan, 0.1-1.0% of sodium hyaluronate, 0.1-0.9% of beta-cyclodextrin, 0.3-1.2% of sodium hydroxymethyl cellulose, and 0.2-1.5% of sodium alginate, the auxiliary material comprises one or two of 0.1-5% of glycerol and 5-30% of Tween, the acidity regulator comprises one or two of 0.5-6% of citric acid and tartaric acid, and the balance is water.

2. The composite microcapsule fruit and vegetable fresh-keeping coating agent as claimed in claim 1, wherein the outer layer coating material is 3% of PVA, the inner layer coating material is 0.8% of sucrose ester, the core material is 0.2% of VC, 0.2% of citric acid, 0.15% of calcium propionate or sodium dehydroacetate or calcium acetate, and the auxiliary materials are 3% of glycerol and 30% of Tween.

3. The composite microcapsule fruit and vegetable fresh-keeping coating agent as claimed in claim 1, wherein the outer layer coating material is 0.1% of sodium hyaluronate, the inner layer coating material is 0.8% of sucrose ester, the core material is 0.2% of VC, 0.2% of citric acid, 0.15% of calcium propionate or sodium dehydroacetate or calcium acetate, and the auxiliary materials are 3% of glycerol and 30% of tween.

4. The composite microcapsule fruit and vegetable fresh-keeping coating agent as claimed in claim 1, wherein the outer layer coating material comprises 0.5% of chitosan, the inner layer coating material comprises 0.8% of sucrose ester, the core material comprises 0.2% of VC, 0.2% of citric acid, 0.15% of calcium propionate or sodium dehydroacetate or calcium acetate, and the auxiliary materials comprise 3% of glycerol and 30% of tween.

5. The composite microcapsule fruit and vegetable fresh-keeping coating agent as claimed in any one of claims 1 to 4, wherein the pH value of the composite microcapsule fruit and vegetable fresh-keeping coating agent is 2 to 4.

6. A preparation method of a composite microcapsule fruit and vegetable fresh-keeping coating agent is characterized by comprising the following steps:

(1) mixing and dissolving sucrose ester and auxiliary materials at 50-70 ℃ according to a proportion to obtain a first solution;

(2) dissolving the core material in water according to a certain proportion, slowly adding the core material into the first solution, stirring at 40-60 ℃, and rotating at 500-600rpm to obtain a second solution;

(3) completely dissolving the outer layer packaging material to obtain a third solution for later use;

(4) adding the second solution into the third solution, and adjusting the pH value to 2-4 by using an acidity regulator;

(5) standing and defoaming after emulsification to form the microcapsule.

7. The preparation method of the composite microcapsule fruit and vegetable fresh-keeping coating agent according to claim 6, wherein when the outer layer packaging material is PVA, the PVA is dissolved at 95-98 ℃, and then is cooled to 50 ℃ for later use.

8. A use method of a composite microcapsule fruit and vegetable fresh-keeping coating agent is characterized in that the composite microcapsule fruit and vegetable fresh-keeping coating agent is diluted with water according to a mass ratio of 1: 11-15 and then used.

Technical Field

The invention belongs to the field of fruit and vegetable preservation, and particularly relates to a composite microcapsule fruit and vegetable preservation coating agent and a preparation method thereof.

Background

Fruits and vegetables are important components of human food, contain carbohydrates, vitamins, minerals, proteins and edible fibers required by human bodies, have important nutritive value for human health, and have important significance for enriching the types of human food, meeting various food preferences and the like. After being harvested, the fruits and vegetables leave the original living environment and parent bodies but are still living organisms, and the fruits and vegetables have high water content, vigorous life activities and are easy to deteriorate and rot. Therefore, the development of the field of fruit and vegetable postharvest preservation is urgent.

The preservation methods commonly used at present are classified into 3 types, namely physical preservation methods, chemical preservation methods and biological preservation methods. Although the chemical preservation method has obvious effect, the use of chemical reagents easily causes medicine residues, which causes danger to human health; the biological preservation method has strict conditions and high cost, is not suitable for large-scale implementation and has certain limitation; the physical preservation method has the advantages of easy control of treatment conditions, good preservation effect and high safety, so more and more people tend to use the physical method to preserve the fruits and vegetables. Due to the characteristics and convenience of fruits and vegetables, more and more researchers tend to pack the fruits and vegetables, and common packing methods include modified atmosphere packing, film packing, carton packing and the like. However, the gas type and proportion are difficult to master in modified atmosphere packaging, the requirements on equipment are strict, and the investment cost is high, so that the research difficulty is high; the carton package has poor air permeability and water resistance and is not suitable for long-distance transportation. The use and development of film packaging materials provides an effective method and means for solving these problems. Common film materials can be divided into nanofilms, edible films and functional films. The film materials can act on the surfaces of fruits and vegetables in the forms of spraying, dipping, film coating and the like, and the purposes of keeping the product quality and prolonging the storage period are achieved by controlling enzyme activity, regulating physiological metabolism, inhibiting respiration and harmful bacteria growth and the like. Researches show that the nano-film has the advantages of antibiosis, low oxygen permeability, carbon dioxide resistance and the like; the edible film has better selective air permeability and water resistance, and has the advantages of no color, no taste and no toxicity, thereby meeting the requirements of people on food quality and safety; the functional film can better meet the requirement of a commodity aiming at a specific function and has better use effect.

The microcapsule is a microcapsule which can wrap or protect dispersed solid, liquid or even gas and is formed by natural or synthetic polymer materials and has semipermeable or sealed capsule membranes. The selection of the appropriate wrapper is critical to the success of the microencapsulation process and to a large extent determines the properties of the product. Microencapsulation can effectively reduce the reactivity of the core material with pH value, oxygen, humidity, heat, light, other substances and other external environmental factors, and effectively prevent the core material from being damaged by the external environmental factors; the diffusion or evaporation of the core material to the environment is reduced, the volatilization loss of the effective components in the core material is inhibited, the stability of the core material is improved, and the quality is kept for a long time; the release of the core material can be artificially and effectively controlled, so that the original efficiency of the core material is volatilized to the maximum extent; covering up the peculiar smell of the core material, and improving the taste and the sense of the taste of the core material; the physical and chemical properties of the core material are changed to facilitate storage and transportation. The product prepared by the microcapsule technology has good properties and storage stability, so that the product can be used for solving the problems which cannot be solved by the traditional technology, and a plurality of high and new technology products can be further developed by utilizing the microcapsule technology.

Disclosure of Invention

The invention aims to provide a composite microcapsule fruit and vegetable fresh-keeping coating agent and a preparation method thereof.

In order to realize the purpose, the invention adopts the following technical scheme:

the invention provides a composite microcapsule fruit and vegetable fresh-keeping coating agent, which comprises a core material, an inner layer packaging material, an outer layer packaging material, an auxiliary material and an acidity regulator; according to the mass percentage, the core material comprises 0.1-5% of VC, 0.2-25% of citric acid, 0.15-3% of calcium propionate or sodium dehydroacetate or calcium acetate, and 0.1-3% of phytic acid, the inner layer packaging material comprises 0.1-1.5% of sucrose ester, the outer layer packaging material comprises one or more of 1.5-13% of PVA, 0.2-0.5% of chitosan, 0.1-1.0% of sodium hyaluronate, 0.1-0.9% of beta-cyclodextrin, 0.3-1.2% of sodium hydroxymethyl cellulose, and 0.2-1.5% of sodium alginate, the auxiliary material comprises one or two of 0.1-5% of glycerol and 5-30% of Tween, the acidity regulator comprises one or two of 0.5-6% of citric acid and tartaric acid, and the balance is water.

In the technical scheme, further, according to the mass percentage, the outer layer packaging material is 3% of PVA, the inner layer packaging material is 0.8% of sucrose ester, the core material is 0.2% of VC, 0.2% of citric acid, 0.15% of calcium propionate or sodium dehydroacetate or calcium acetate, and the auxiliary materials are 3% of glycerol and 30% of Tween.

In the technical scheme, further, according to the mass percentage, the outer layer packaging material is 0.1% of sodium hyaluronate, the inner layer packaging material is 0.8% of sucrose ester, the core material is 0.2% of VC, 0.2% of citric acid, 0.15% of calcium propionate or sodium dehydroacetate or calcium acetate, and the auxiliary materials are 3% of glycerol and 30% of tween.

In the technical scheme, further, according to the mass percentage, the outer layer packaging material is 0.5% of chitosan, the inner layer packaging material is 0.8% of sucrose ester, the core material is 0.2% of VC, 0.2% of citric acid, 0.15% of calcium propionate or sodium dehydroacetate or calcium acetate, and the auxiliary materials are 3% of glycerol and 30% of tween.

In the technical scheme, further, the pH value of the composite microcapsule fruit and vegetable fresh-keeping coating agent is 2-4.

The invention provides a preparation method of a composite microcapsule fruit and vegetable fresh-keeping coating agent, which comprises the following steps:

(1) mixing and dissolving sucrose ester and auxiliary materials at 50-70 ℃ according to a proportion to obtain a first solution;

(2) dissolving the core material in water according to a certain proportion, slowly adding the core material into the first solution, stirring at 40-60 ℃, and rotating at 500-600rpm to obtain a second solution;

(3) completely dissolving the outer layer packaging material to obtain a third solution for later use;

(4) adding the second solution into the third solution, and adjusting the pH value to 2-4 by using an acidity regulator;

(5) standing and defoaming after emulsification to form the microcapsule.

In the technical scheme, further, when the outer-layer packaging material is PVA, the PVA is dissolved at 95-98 ℃, and then is cooled to 50 ℃ for later use.

In the technical scheme, the method is further characterized in that the composite microcapsule fruit and vegetable fresh-keeping coating agent as defined in any one of claims 1-5 is diluted with water according to the mass ratio of 1: 11-15 for use.

The product can soak about 50kg of fruits and vegetables by diluting 1kg of the product with 12-15 times of water, and the varieties are slightly different.

The invention has the beneficial effects that: the composite microcapsule fruit and vegetable fresh-keeping coating agent can effectively improve the fresh-keeping effect of fruits and vegetables stored in a low-temperature refrigeration house and prolong the shelf life. The composite microcapsule of the invention can form a soluble shield film with the functions of water locking, bacteriostasis, antioxidation, nutrient consumption delay and the like on the surface of fruits, and the film is edible and degradable. The raw materials of the invention are all selected from various food additives meeting the national standard, and the invention is green, safe and residue-free.

Drawings

FIG. 1 is a view showing the microscopic observation of example 1 of the present invention;

FIG. 2 is a sustained release profile of example 1 of the present invention;

FIG. 3 is a graph showing the effect of example 1 on antioxidant activity;

FIG. 4 is a graph showing the bacteriostatic effect of example 1 on Penicillium;

FIG. 5 is a graph showing the bacteriostatic effect of example 1 on gray enzyme;

FIG. 6 is a graph showing the bacteriostatic effect of example 1 on Aspergillus niger;

FIG. 7 comparison graph of example 1 applied to the preservation of yellow peaches;

FIG. 8 example 1 is applied to a rose grape freshness-keeping contrast chart;

fig. 9 comparative graph of the application of example 1 to the preservation of kiwifruit.

Detailed Description

The invention is further illustrated but is not in any way limited by the following specific examples.

Example 1

A composite microcapsule fruit and vegetable fresh-keeping coating agent takes 100g as an example, and comprises the following raw materials: 0.8g of sucrose ester, 3g of glycerol and 30g of Tween, 0.2gVC, 0.2g of citric acid, 0.15g of calcium propionate, 3g of PVA.

The preparation method of the fruit and vegetable fresh-keeping coating agent comprises the following steps:

(1) completely dissolving 0.8g of sucrose ester, 3g of glycerol and 30g of tween at the temperature of 50-70 ℃ to obtain a first solution;

(2) adding 0.2gVC, 0.2g citric acid and 0.15g calcium propionate into water, dissolving completely, slowly adding into the first solution, keeping the temperature at about 50 deg.C, and controlling the rotation speed at 600rpm of 500-;

(3) completely dissolving 3g of PVA at 95-98 ℃, and cooling to 50 ℃ for later use to obtain a third solution;

(4) adding the second solution into a third solution, and adjusting the pH value to 2-4 by using citric acid;

(5) standing and defoaming after emulsification to form microcapsules;

(6) and (5) filling, sealing and forming a finished product.

As shown in FIG. 1, the microcapsule coating pattern obtained by the above preparation is observed under a microscope, and it can be seen that the preparation method of the present invention gives very good microcapsule particles.

FIG. 2 is a graph of the slow release effect of the product; the observation through a microscope shows that the outer wall of the capsule is thinned to be broken, and the active ingredients in the capsule start to move outwards, which shows that the capsule is opened gradually to release the inner part slowly along with the change of time after the capsule is formed, and the active ingredients in the capsule are released gradually to achieve the effect of slow release.

Example 2

A composite microcapsule fruit and vegetable fresh-keeping coating agent takes 100g as an example, and comprises the following raw materials: 0.8g sucrose ester, 3g glycerol and 30g tween, 0.2gVC, 0.2g citric acid, 0.15g calcium propionate, 0.1g sodium hyaluronate.

The preparation method of the fruit and vegetable fresh-keeping coating agent comprises the following steps:

(1) completely dissolving 0.8g of sucrose ester, 3g of glycerol and 30g of tween at the temperature of 50-70 ℃ to obtain a first solution;

(2) adding 0.2g of VC, 0.2g of citric acid, 0.15g of calcium propionate/sodium dehydroacetate/calcium acetate into water, completely dissolving, slowly adding the solution into the first solution, keeping the temperature at about 50 ℃, and controlling the rotation speed at 600rpm, thereby obtaining a second solution;

(3) completely dissolving 0.1g of sodium hyaluronate to obtain a third solution;

(4) adding the second solution into a third solution, and adjusting the pH value to 2-4 by using citric acid;

(5) standing and defoaming after emulsification to form microcapsules;

(6) and (5) filling, sealing and forming a finished product.

Example 3

A composite microcapsule fruit and vegetable fresh-keeping coating agent takes 100g as an example, and comprises the following raw materials: 0.8g of sucrose ester, 3g of glycerol and 30g of Tween, 0.2gVC, 0.2g of citric acid, 0.15g of calcium propionate, sodium dehydroacetate or calcium acetate, 0.5g of chitosan.

The preparation method of the fruit and vegetable fresh-keeping coating agent comprises the following steps:

(1) completely dissolving 0.8g of sucrose ester, 3g of glycerol and 30g of tween at the temperature of 50-70 ℃ to obtain a first solution;

(2) adding 0.2g of VC, 0.2g of citric acid, 0.15g of calcium propionate/sodium dehydroacetate/calcium acetate into water, completely dissolving, slowly adding the solution into the first solution, keeping the temperature at about 50 ℃, and controlling the rotation speed at 600rpm, thereby obtaining a second solution;

(3) completely dissolving 0.5g of chitosan to obtain a third solution;

(4) adding the second solution into a third solution, and adjusting the pH value to 2-4 by using citric acid;

(5) standing and defoaming after emulsification to form microcapsules;

(6) and (5) filling, sealing and forming a finished product.

Example 4 Oxidation resistance

The determination method comprises the following steps: the DPPH assay was used. The DPPH absolute ethyl alcohol solution is purple, has maximum absorption at 517nm, and the absorbance and the concentration are in a linear relation. The ability to scavenge free radicals can be assessed by adding a free radical scavenger thereto, in combination with or in place of DPPH, to reduce the number of free radicals, decrease the absorbance value, and gradually change the color of the solution towards yellow.

Fig. 3 is a graph illustrating the effect of the core material on antioxidant activity, using example 1 as an example. As can be seen from figure 3, the antioxidant activity of the product is higher than that of a control group, ethanol with the same volume is added into the control group, and the effect of the product diluted by 12 times is similar to that of the original liquid, so that the optimal dilution ratio of the product is 1: 11.

EXAMPLE 5 bacteriostatic Properties

The picked fruits and vegetables are mainly infected by fungi (penicillium, grey enzyme and aspergillus niger) to cause spoilage, and the storage and shelf life of the fruits and vegetables are influenced. The product can inhibit growth of fungi by regulating their growth environment. The method is safe, nontoxic and effective. At present, researches prove that the growth of microorganisms can be inhibited under acidic conditions, for example, 0.5 percent of citric acid can effectively inhibit escherichia coli and salmonella in the cleaning process of fresh-cut lettuce.

As shown in FIGS. 4-6, the core material shows the bacteriostatic effects on 3 fungi under different pH conditions, respectively, in example 1.

As shown in FIG. 4, the product has antibacterial effect on Penicillium, wherein the growth of Penicillium under 3 pH conditions is lower than that of the control group, and the control group is not treated; growth was most slow at pH 2 and similar at pH 3 and 4.

As shown in FIG. 5, the product has a lower gray mold growth than the control group under 3 pH conditions, and the gray mold grows most slowly under 3 pH conditions, followed by 3 pH and 4 pH conditions.

As shown in FIG. 6, the product has bacteriostatic effect on Aspergillus niger, wherein the growth of Aspergillus niger is lower under 3 pH conditions than that of the control group, the growth is most slow under the condition of pH 4, and the growth is followed by pH 3 and pH 2 times.

In conclusion, the product has slightly different inhibiting conditions for 3 fungi under 3 different pH conditions. According to the characteristics of the product and the application scene, the pH range of the product is selected to be 3-4. If the pH value is too low, the taste of the fruit and vegetable and the stability of the product are easily affected, and if the pH value is too high, the expected effect of the product cannot be achieved.

Example 6

Taking yellow peach, rose fragrance and kiwi fruit as examples respectively, diluting the stock solution of the fruit and vegetable fresh-keeping coating agent in example 1 with water according to the mass ratio of 1:11, soaking 100 kg of fruits and vegetables in the diluted fresh-keeping solution for 2-3 days, taking out, draining, and refrigerating for storage.

1. Yellow peach group: the yellow nectarine is placed in a refrigerator at 3-5 ℃ for 60 days, the external of the unused yellow nectarine has obvious mildew phenomenon, the internal tissue fiber becomes coarse, the aging is obvious, and the pulp is softened seriously. The yellow peaches in the group were intact on the outside, no obvious fibrous tissue was found inside the fruits and the water was well retained. In taste tasting, the unused yellow peaches are obviously soft; the yellow peaches in the group are still crisp, sweet and delicious, and keep the original flavor.

2. A rose fragrance group: when the muscat grapes are placed in a refrigerator at 3-5 ℃ for 30 days, the grapes in the unused group are obviously mildewed and rotten, and the stems at the front ends of the grapes are obviously browned and dehydrated. The grape particles fall off by touching with hands and are softened severely. The appearance of the grape group is not obviously changed, the grape is still bright and intact, and the grape stalks have no obvious browning phenomenon. The tasting taste is not obviously different from the fresh grape.

3. Kiwi fruit group: the actinidia arguta after using the product is stored under the refrigeration condition of 2-4 ℃, the actinidia arguta is placed at the normal temperature after 30 days, and the contrast effect within 11 days after the actinidia arguta is taken out is observed respectively in aspects of appearance, hardness and section.

Appearance: the peel of the unused group is completely shrunk and dehydrated, the fruit stalks are dry and fall off, the peel of the used group is full and glossy, and the fruit stalks are dry but do not fall off.

Section: the section of the unused group is aged seriously, the tissue is loose and deformed, the color around the peel is darkened completely, the water is discharged seriously, and meanwhile, the fruit core part is aged and darkened; the color of the group is slightly darker, but the tissue is still clearly intact, and the fruit core is still kept.

It will be apparent to those skilled in the art from this disclosure that many changes and modifications can be made, or equivalents modified, in the embodiments of the invention without departing from the scope of the invention. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention shall still fall within the protection scope of the technical solution of the present invention, unless the contents of the technical solution of the present invention are departed.