CN104893007A - Starch-based film with antibacterial microcapsules and method for manufacturing starch-based film - Google Patents

Abstract

The invention discloses a starch-based film containing antibacterial microcapsules (see the accompanying drawings) and a preparation method thereof. The material uses starch as the film-forming substrate, adds microcapsules with antibacterial properties, and additives such as gelatin, glycerin, and CaCl ₂ , and is made by casting in a mold. Firstly, clove essential oil and β-cyclodextrin are made into microcapsules by molecular embedding method; secondly, the starch is stirred and gelatinized at a certain temperature, a certain amount of gelatin is heated and dissolved, and a certain amount of glycerin is weighed, and CaCl ₂ is set aside ; thirdly, add gelatin, microcapsules, glycerin, _CaCl2 , etc. into the gelatinized starch solution in proportion and stir for 20 minutes; fourthly, after cooling the mixed solution to room temperature, pour it into a self-made mold for casting, and put it in a drying oven to dry To constant weight; the fifth film and test performance. The starch-based film containing antibacterial microcapsules prepared by the invention has the advantages of wide source of raw materials, safety and sanitation, green and degradable, etc., and has good inhibitory effect on microorganisms in food. It can be used for antibacterial packaging of fresh food and has broad development prospects.

Description

A kind of starch-based film containing antibacterial microcapsules and preparation method thereof

technical field

The invention relates to a starch-based antibacterial film containing microcapsules and a preparation method thereof.

Background technique

Starch is considered to be one of the most promising biodegradable packaging materials. The starch film made of starch after gelatinization, retrogradation and drying has the advantages of good tensile properties and high transparency, but it still has the disadvantage of poor antibacterial properties when used for packaging. A number of studies have shown that the antibacterial properties of starch films can be improved by compounding. Clove essential oil has a strong antibacterial effect, but it is difficult to dissolve in water, has poor stability, and is easy to oxidize and volatilize, which limits its antibacterial effect to a certain extent. Microcapsule technology is a technology that uses film-forming materials to coat solids or liquids to form tiny particles. The clove essential oil can be wrapped in the wall material through the microcapsule technology, which can not only maintain the antibacterial property of the clove essential oil, but also prolong its validity period.

There are some bibliographical reports about the preparation method of antibacterial starch-based film:

studied the antimicrobial activity (AM) of starch-based films coated with linalool, carvacrol, or thymol against Staphylococcus aureus in vitro or inoculated on the surface of cheddar cheese. Studies have shown that within a certain concentration range, the order of sensitivity of Staphylococcus aureus to antibacterial agents is: thymol>carvacrol>linalool.

Zhao Guohua et al. added garlic essential oil to tapioca starch to make an edible film of antibacterial starch. The results showed that when garlic essential oil was added to 1.5% of the mass of cassava starch, the edible film of antibacterial starch had the best antibacterial effect on Escherichia coli and Staphylococcus aureus. Effect.

Zhao Dan added cinnamon essential oil, chitosan and lysozyme to corn starch film to make antibacterial starch film, and studied its inhibitory effect on Escherichia coli and Staphylococcus aureus. The results showed that the corn starch film added with chitosan had the best inhibitory effect on Escherichia coli, and the corn starch film added with cinnamon essential oil had the best inhibitory effect on Staphylococcus aureus.

To sum up, the current domestic and foreign scholars' research on the preparation of antibacterial starch-based films mainly focuses on adding natural or artificial antibacterial agents to starch films. Plant essential oil is a natural antibacterial agent with good performance, but its main compounding method is to add it to the film-forming substrate or coat it on the surface of the film. Due to the volatility of essential oils, this limits their antibacterial effect to some extent. The clove essential oil is wrapped in the wall material to make antibacterial microcapsules, and the antibacterial microcapsules are added to the starch film liquid, which can make the starch-based film obtain good antibacterial properties and prolong its antibacterial validity period. An important development direction of starch-based film preparation.

Contents of the invention

The patent of the present invention mainly aims at the problems existing in the preparation of the existing domestic and foreign antibacterial starch-based films, and provides a starch-based film containing antibacterial microcapsules with good antibacterial effect and long validity period and a preparation method thereof.

In order to achieve the above object, the present invention is achieved through the following technical solutions.

The mass percent prepared by the starch-based film containing antibacterial microcapsules of the present invention:

According to the percentage provided by the technical scheme, the preparation method of the starch-based film containing antibacterial microcapsules of the present invention is as follows:

1) Dissolve 6g of β-cyclodextrin in 36ml of distilled water and set aside.

2) Dissolve 1 g of clove essential oil in 20 ml of ethanol with a volume fraction of 60%, and add dropwise to the aqueous solution of β-cyclodextrin.

3) Take it out after stirring at 60°C for 2.5 hours, and put the solution in a refrigerator at 4°C for 24 hours after cooling to room temperature.

4) Suction filter the solution after standing, and wash the filter residue with absolute ethanol and distilled water respectively.

5) Dried at a temperature of 50° C. to make clove essential oil/β-cyclodextrin antibacterial microcapsules for future use.

6) Weigh 44-50% of the total weight of the film to make a starch solution, and gelatinize at 80° C. for 20 minutes.

7) Weigh 9-17% gelatin of the total weight of the film, and continue to stir at 60 degrees Celsius for 20 minutes.

8) Add 26% glycerin, 9-17% antibacterial microcapsules and 4-8% CaCl ₂ and stir for 20 minutes to make a film-forming solution.

9) Defoaming the film-forming solution and cooling. Then pour it into a self-made mold, put it in a 50°C constant temperature drying oven, and dry it to a constant weight before peeling off the film.

The present invention relates to a preparation method of a starch-based film containing antibacterial microcapsules. The preparation method uses microcapsule technology to wrap clove essential oil in β-cyclodextrin, and adds it to the starch-based liquid, and casts it on a self-made mold by solution casting After being cast in medium, dry at constant temperature for a certain period of time and then remove the mold to make a starch-based film containing antibacterial microcapsules. Features of the present invention:

1) The technology of the present invention uses starch and the like as the film-forming substrate, which has the advantages of wide sources, low cost, green and degradable;

2) the clove essential oil that the technology of the present invention adopts is a kind of natural antibacterial agent with excellent antibacterial effect, and is nontoxic and harmless to human body, safe and hygienic;

3) Use microcapsule technology to wrap clove essential oil in β-cyclodextrin, overcome the shortcoming of essential oil being volatile, and prolong the timeliness of antibacterial;

4) The starch-based film containing antibacterial microcapsules prepared by the process of the present invention has good antibacterial performance and hygienic performance, can be used for the packaging of fresh food, and has broad development prospects.

Description of drawings

Fig. 1 is the exterior view of the starch-based film containing antibacterial microcapsules of the present invention.

Example:

1) Dissolve 6g of β-cyclodextrin in 36ml of distilled water with constant stirring at 45°C. Dissolve 1 g of clove essential oil in 20 ml of ethanol with a volume fraction of 60%, and add dropwise to the aqueous solution of β-cyclodextrin. After stirring at a constant temperature of 60°C for 2.5h, the solution was cooled to room temperature and placed in a refrigerator at 4°C for 24h. The solution after standing was filtered with suction, and the filter residue was washed with absolute ethanol and distilled water respectively. Dry at a temperature of 50°C to prepare clove essential oil/β-cyclodextrin antibacterial microcapsules for future use.

2) Weigh 2.5g of starch and 100ml of distilled water to make a solution, and gelatinize at 80°C for 20min. Then weigh 1 g of gelatin and add it to the starch solution after gelatinization, and continue stirring at 60° C. for 20 min.

3) Add 1.5g of glycerin, 0.5g of antibacterial microcapsules and 0.2g of CaCl ₂ into the film solution, and stir for 20 minutes to make a film-forming solution.

4) Defoaming the film-forming solution and cooling to about 50 degrees Celsius. Then pour it into a 200mm*250mm self-made plexiglass mold, put it in a 50°C constant temperature drying oven, dry it to a constant weight, and then peel off the film.

Claims (4)

1. A method for preparing a starch-based film containing antibacterial microcapsules. 2. the raw material mass percent described in claim 1 is: The antibacterial microcapsules are self-made, wherein the quality of clove essential oil as a core material is 1 g, and the mass of β-cyclodextrin as a wall material is 6 g, and the preparation method is a molecular embedding method. 3. The feature of claim 1 is that the film is formed by casting method, and the film is peeled off after drying, and the drying temperature is 50°C. The method for preparing a starch-based film containing antibacterial microcapsules according to claim 1, characterized in that: 6g beta-cyclodextrin is dissolved and stirred in distilled water to form a saturated solution of beta-cyclodextrin, then 1g clove essential oil is dissolved in ethanol and Add dropwise to the aqueous solution of β-cyclodextrin, stir at 60°C for 2.5 hours, take it out, wait for the solution to cool to room temperature, put it in a refrigerator at 4°C for 24 hours, filter it with suction, and use absolute ethanol and distilled water to separate the filter residue Wash and dry at a temperature of 50°C to prepare clove essential oil/β-cyclodextrin antibacterial microcapsules for future use. Then weigh 44-50% of the total weight of the film to make a starch solution, gelatinize at 80°C for 20 minutes, add 9-17% gelatin, continue stirring at 60°C for 20 minutes, then add 26% glycerin, 9-17 % antibacterial microcapsules and 4-8% CaCl ₂ were stirred and reacted for 20 minutes to form a film liquid, the mixed film liquid was defoamed, cooled, then poured into a self-made mold, placed in a 50°C constant temperature drying oven, dried to a constant weight, and then exposed membrane. 4. Its molding described in claim 1 is carried out in self-made special organic glass mould.