阅读说明：本技术 一种花色苷智能活性食品保鲜膜及其制备方法 (Anthocyanin intelligent active food preservative film and preparation method thereof ) 是由 费鹏 张美清 叶妍琦 曾繁森 于 2019-10-24 设计创作，主要内容包括：本发明属于高分子包装材料领域,具体涉及到一种改性花色苷智能活性食品保鲜膜。酰胺化苯丙氨酸修饰的花色苷10-20份,低甲氧基果胶(甲酯化度为20-30%)15-30份,壳聚糖15-30份,甘油5-15份,乙酸3-5份。其中,酰胺化苯丙氨酸修饰的花色苷由以下重量份数的原料制备而成：天然花色苷8-16份,苯丙氨酸8-16份,乙酸酐10-20份,氯化亚砜10-20份,吡啶1-2份。本发明针对天然花色苷在自然环境中易氧化、易分解的问题,以乙酸酐对苯丙氨酸进行酰胺化改性,然后以酰胺化苯丙氨酸对天然花色苷进行酰化修饰,以增强花色苷的稳定性。并以改性花色苷为颜色指示剂,混合低甲氧基果胶、壳聚糖及甘油,制备一种酰化。该保鲜膜能够延长食品货架期,同时通过颜色变化指示食品的新鲜度。(The invention belongs to the field of polymer packaging materials, and particularly relates to a modified anthocyanin intelligent active food preservative film. 10-20 parts of amidated phenylalanine modified anthocyanin, 15-30 parts of low methoxyl pectin (with the methyl esterification degree of 20-30%), 15-30 parts of chitosan, 5-15 parts of glycerol and 3-5 parts of acetic acid. Wherein, the amidated phenylalanine modified anthocyanin is prepared from the following raw materials in parts by weight: 8-16 parts of natural anthocyanin, 8-16 parts of phenylalanine, 10-20 parts of acetic anhydride, 10-20 parts of thionyl chloride and 1-2 parts of pyridine. Aiming at the problems that natural anthocyanin is easy to oxidize and decompose in natural environment, acetic anhydride is used for carrying out amidation modification on phenylalanine, and then amidated phenylalanine is used for carrying out acylation modification on the natural anthocyanin so as to enhance the stability of the anthocyanin. And mixing low methoxyl pectin, chitosan and glycerol with modified anthocyanin as color indicator to prepare acylation. The preservative film can prolong the shelf life of food, and simultaneously indicates the freshness of the food through color change.)

1. The invention relates to an anthocyanin intelligent active food preservative film and a preparation method thereof, which are characterized in that acetic anhydride is used for carrying out amidation modification on phenylalanine, and then amidated phenylalanine is used for carrying out acylation modification on natural anthocyanin, so that the stability of anthocyanin is obviously enhanced, and the effective use time of the anthocyanin in the preservative film is greatly prolonged.

2. The anthocyanin intelligent active food preservative film as claimed in claim 1, which is prepared from the following raw materials in parts by weight: 10-20 parts of amidated phenylalanine modified anthocyanin, 15-30 parts of low methoxyl pectin (with the methyl esterification degree of 20-30%), 15-30 parts of chitosan, 5-15 parts of glycerol and 3-5 parts of acetic acid; wherein, the amidated phenylalanine modified anthocyanin is prepared from the following raw materials in parts by weight: 8-16 parts of natural anthocyanin, 8-16 parts of phenylalanine, 10-20 parts of acetic anhydride, 10-20 parts of thionyl chloride and 1-2 parts of pyridine.

3. The preparation method of the anthocyanin intelligent active food preservative film as claimed in claim 1, is characterized in that: which comprises the following steps:

1) mixing 8-16 parts of phenylalanine, 10-20 parts of acetic anhydride and 0.5-1 part of pyridine, and stirring to react at 25 ℃ for 8-12 h;

2) after the reaction is finished, adding 200 parts of deionized water, adjusting the pH value to 1-4 by using HCl solution, standing for 8-12 h at 4 ℃, filtering, collecting precipitate, and freeze-drying the precipitate to obtain powdery amidated phenylalanine;

3) dispersing the amidated phenylalanine in the step 2) into 200 parts of dioxane solution, adding 10-20 parts of thionyl chloride, carrying out water bath stirring reflux reaction at 70-90 ℃ for 2-4 h, carrying out rotary evaporation at 40-60 ℃ for 0.5-1 h after the reaction is finished, removing redundant thionyl chloride, and collecting the residual solution;

4) adding 8-16 parts of natural anthocyanin and 0.5-1 part of pyridine into the residual solution obtained in the step 3), stirring and refluxing the mixture in a water bath at 70-90 ℃ for reaction for 2-4 hours, repeatedly performing rotary evaporation at 60-80 ℃ after the reaction is finished until crystals are separated out, and collecting crystal substances;

5) adding the crystal substance obtained in the step 4) into 100 parts of 90 ℃ acetone solution, stirring to dissolve the crystal substance, then cooling the acetone solution to 0 ℃, standing for 1-3 h, collecting the precipitate after the precipitate is separated out, and freeze-drying to remove the acetone, thus obtaining the amidated phenylalanine modified anthocyanin;

6) adding 15-30 parts of chitosan into 400 parts of deionized water, adding 3-5 parts of acetic acid, mixing, stirring for 60min to obtain a clear and light yellow solution, performing ultrasonic treatment for 5 min to degas, and stirring for 5 min at normal temperature;

7) dispersing 10-20 parts of amidated phenylalanine modified anthocyanin prepared in the step 5) into 200 parts of deionized water, adding 10-20 parts of glycerol, carrying out ultrasonic oscillation for 30 min, then adding 15-30 parts of low methoxyl pectin, and continuing stirring for 60 min;

8) mixing the chitosan solution prepared in the step 6) with the amidated phenylalanine modified anthocyanin/pectin solution prepared in the step 7), and stirring for 60min to obtain a mixed membrane solution;

9) and pouring the mixed film solution on a glass flat plate which is inclined at 15-20 degrees, uniformly coating the film solution on a ground glass flat plate, and then placing the ground glass flat plate in a blast oven for drying for 12-18 h to obtain the amidated phenylalanine modified anthocyanin active intelligent food preservative film.

Technical Field

The invention belongs to the field of polymer packaging materials, and particularly relates to a modified anthocyanin intelligent active food preservative film.

Background

Anthocyanin is one of the most important water-soluble pigments in the nature, is a flavonoid compound which connects anthocyanin and glucoside through glycosidic bond, widely exists in roots, stems, leaves, flowers and fruits of plants, has various biological activities of resisting oxidation, removing in-vivo free radicals, resisting inflammation, resisting tumors, inhibiting obesity, regulating blood lipid balance, inhibiting cholesterol and the like, and is an ideal antioxidant and bacteriostatic additive. As natural antioxidant additives, they are not called into question as synthetic antioxidants. When the preservative is added into a food preservative film, the preservative film can slowly diffuse to the surface or even the interior of the wrapped food from the preservative film, so that the oxidation of nutrient substances in the food is prevented, and the shelf life of the food is prolonged.

In addition, the natural plant has many kinds of anthocyanins, and the shapes, the properties and the like of the anthocyanins are different, but most of the anthocyanins can form different configurations according to the acid-base conditions in the environment, so that different color development reactions can be generated. The deterioration of food due to spoilage is accompanied by the generation of volatile nitrogen compounds such as amines and ammonia, which causes the pH environment to change. Therefore, according to the characteristic that the anthocyanin color changes along with the change of the environmental pH value, the anthocyanin can be used as a gas-sensitive material of a food preservative film to reflect the freshness of food.

Scholars at home and abroad add anthocyanin to a food packaging film to prepare the food packaging film with the characteristic of indicating food freshness by utilizing the pH-color response characteristic of the anthocyanin, for example, a preparation process of an anthocyanin active intelligent packaging film is published by Mingke packaging technology, Inc. of Touling city (application No. 201810667474. X). However, natural anthocyanin is easy to oxidize and is easy to degrade in natural environment, so that the active intelligent preservative film has poor stability and short shelf life, and therefore, the active intelligent preservative film needs to be modified to improve the stability.

Disclosure of Invention

Aiming at the problems that natural anthocyanin is easy to oxidize and decompose in natural environment, the citric acid is grafted to natural anthocyanin molecules so as to enhance the stability of the natural anthocyanin molecules. And mixing low methoxyl pectin, chitosan and glycerol with modified anthocyanin as color indicator to prepare acylation. As the food can release volatile nitrogen compounds such as amine, ammonia and the like in the storage process and change the pH environment, the color of the preservative film can also change along with the change, thereby playing the role of monitoring the freshness of the food.

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

an active intelligent food preservative film containing anthocyanin is prepared from the following raw materials in parts by weight:

amidated phenylalanine modified anthocyanin 10-20 parts

15-30 parts of low methoxyl pectin (methyl esterification degree is 20-30 percent)

15-30 parts of chitosan

5-15 parts of glycerol

3-5 parts of acetic acid

Wherein, the amidated phenylalanine modified anthocyanin is prepared from the following raw materials in parts by weight:

8-16 parts of natural anthocyanin

8-16 parts of phenylalanine

10-20 parts of acetic anhydride

10-20 parts of thionyl chloride

1-2 parts of pyridine

The invention also provides a preparation method of the anthocyanin active intelligent food preservative film, which comprises the following steps.

1) 8-16 parts of phenylalanine, 10-20 parts of acetic anhydride and 0.5-1 part of pyridine are mixed and stirred for reaction.

2) And after the reaction is finished, adding 200 parts of deionized water, adjusting the pH value of the mixture by using an HCl solution, standing the mixture at a low temperature, filtering the mixture, collecting precipitates, and freeze-drying the precipitates to obtain powdery amidated phenylalanine.

3) Dispersing the amidated phenylalanine obtained in the step 2) into 200 parts of dioxane solution, adding 10-20 parts of thionyl chloride, and stirring in a water bath for reflux reaction; after the reaction is finished, removing the redundant thionyl chloride by rotary evaporation, and collecting the residual solution.

4) Adding 8-16 parts of natural anthocyanin and 0.5-1 part of pyridine into the residual solution in the step 3), stirring in a water bath, and carrying out reflux reaction; after the reaction is finished, the rotary evaporation is repeated until crystals are separated out, and crystal substances are collected.

5) Adding the crystal substance obtained in the step 4) into 100 parts of hot acetone solution, stirring to dissolve the crystal substance, then cooling the acetone solution, standing for a period of time to precipitate out, collecting the precipitate, and freeze-drying to remove the acetone, thus obtaining the amidated phenylalanine modified anthocyanin.

6) Adding 15-30 parts of chitosan into 400 parts of deionized water, adding 3-5 parts of acetic acid, mixing, stirring for 60min to obtain a clear and light yellow solution, performing ultrasonic treatment for 5 min to degas, and stirring for 5 min at normal temperature.

7) Dispersing 10-20 parts of amidated phenylalanine modified anthocyanin prepared in the step 5) into 200 parts of deionized water, adding 10-20 parts of glycerol, carrying out ultrasonic oscillation for 30 min, then adding 15-30 parts of low methoxyl pectin, and continuing stirring for 60 min.

8) Mixing the chitosan solution prepared in the step 6) with the amidated phenylalanine modified anthocyanin/pectin solution prepared in the step 7), and stirring for 60min to obtain a mixed membrane solution.

9) And pouring the mixed film solution on a glass flat plate which is inclined at 15-20 degrees, uniformly coating the film solution on the glass flat plate, and then placing the glass flat plate in a blast oven for drying to obtain the amidated phenylalanine modified anthocyanin active intelligent food preservative film.

In the step 1), the reaction temperature is 25 ℃, and the reaction time is 8-12 h.

Step 2), adjusting the pH value to 1-4; standing at 4 deg.C for 8-12 h.

Step 3), stirring in a water bath, refluxing and reacting at the temperature of 70-90 ℃ for 2-4 h; the rotary evaporation temperature is 40-60 ℃, and the rotary evaporation time is 0.5-1 h.

Step 4), stirring in a water bath, refluxing and reacting at the temperature of 70-90 ℃ for 2-4 h; the rotary evaporation temperature is 60-80 ℃.

Step 5), the temperature of the acetone solution is 90 ℃; standing for 1-3 h.

And 9) the glass plate is a ground glass plate.

Step 9) drying time is 12-18 h, and drying temperature is 40 ℃.

According to the technical scheme, phenylalanine is amidated and then grafted to natural anthocyanin molecules so as to improve the stability of the natural anthocyanin molecules. Simultaneously mixing low-methoxyl pectin, chitosan and glycerol to prepare the amidated phenylalanine modified anthocyanin active intelligent food preservative film.

The present invention has the following advantages.

1. According to the invention, phenylalanine is amidated and modified by acetic anhydride, and then natural anthocyanin is acylated and modified by the acetic anhydride, so that the stability of anthocyanin is obviously enhanced, and the effective use time of the anthocyanin in the preservative film is greatly prolonged.

2. The anthocyanin modified by amidated phenylalanine is used as the color indicator, and the color of the anthocyanin can be continuously changed along with the extension of the storage time of the food, so that the preservative film can play a role in monitoring the freshness of the food.

3. The modified anthocyanin has stronger oxidation resistance and can play a role in enhancing the fresh-keeping capability of the preservative film.

Drawings

Fig. 1 is a technical schematic diagram of the present invention.

Wherein, (1) phenylalanine, (2) acetic anhydride; (3) amidated phenylalanine; (4) thionyl chloride; (5) amidated phenylalanyl chloride (6) anthocyanin (cyanidin-3-O-glucoside is exemplified); (7) amidation of phenylalanine-modified anthocyanins (molecular modification may also occur at other hydroxyl positions).

Detailed Description

An active intelligent food preservative film containing anthocyanin is prepared from the following raw materials in parts by weight:

amidated phenylalanine modified anthocyanin 10-20 parts

15-30 parts of low methoxyl pectin (methyl esterification degree is 20-30 percent)

15-30 parts of chitosan

5-15 parts of glycerol

3-5 parts of acetic acid

Wherein, the amidated phenylalanine modified anthocyanin is prepared from the following raw materials in parts by weight:

8-16 parts of natural anthocyanin

8-16 parts of phenylalanine

10-20 parts of acetic anhydride

10-20 parts of thionyl chloride

1-2 parts of pyridine

The invention also provides a preparation method of the acylation, which comprises the following steps.

1) Mixing 8-16 parts of phenylalanine, 10-20 parts of acetic anhydride and 0.5-1 part of pyridine, and stirring for reaction at 25 ℃ for 8-12 h.

2) And after the reaction is finished, adding 200 parts of deionized water, adjusting the pH value to 1-4 by using an HCl solution, standing for 8-12 h at 4 ℃, filtering, collecting precipitate, and freeze-drying the precipitate to obtain powdery amidated phenylalanine.

3) Dispersing the amidated phenylalanine in the step 2) into 200 parts of dioxane solution, adding 10-20 parts of thionyl chloride, carrying out water bath stirring reflux reaction at 70-90 ℃ for 2-4 h, carrying out rotary evaporation at 40-60 ℃ for 0.5-1 h after the reaction is finished, removing the redundant thionyl chloride, and collecting the residual solution.

4) Adding 8-16 parts of natural anthocyanin and 0.5-1 part of pyridine into the residual solution in the step 3), stirring and refluxing the mixture in a water bath at 70-90 ℃ for 2-4 h, repeatedly performing rotary evaporation at 60-80 ℃ after the reaction is finished until crystals are separated out, and collecting crystal substances.

5) Adding the crystal substance obtained in the step 4) into 100 parts of 90 ℃ acetone solution, stirring to dissolve the crystal substance, then cooling the acetone solution to 0 ℃, standing for 1-3 h, collecting the precipitate after the precipitate is separated out, and freeze-drying to remove the acetone, thus obtaining the amidated phenylalanine modified anthocyanin.

6) Adding 15-30 parts of chitosan into 400 parts of deionized water, adding 3-5 parts of acetic acid, mixing, stirring for 60min to obtain a clear and light yellow solution, performing ultrasonic treatment for 5 min to degas, and stirring for 5 min at normal temperature.

7) Dispersing 10-20 parts of amidated phenylalanine modified anthocyanin prepared in the step 5) into 200 parts of deionized water, adding 10-20 parts of glycerol, carrying out ultrasonic oscillation for 30 min, then adding 15-30 parts of low methoxyl pectin, and continuing stirring for 60 min.

8) Mixing the chitosan solution prepared in the step 6) with the amidated phenylalanine modified anthocyanin/pectin solution prepared in the step 7), and stirring for 60min to obtain a mixed membrane solution.

9) And pouring the mixed film solution on a glass flat plate which is inclined at 15-20 degrees, uniformly coating the film solution on a ground glass flat plate, and then placing the ground glass flat plate in a blast oven for drying for 12-18 h to obtain the amidated phenylalanine modified anthocyanin active intelligent food preservative film.