Preparation method for edible enzyme-modified chitosan/walnut protein composite film

Abstract

The invention discloses a preparation method for an edible enzyme-modified chitosan / walnut protein composite film, and belongs to the technical field of food packaging. The method comprises the following steps: preparing a 5-7% walnut protein solution, performing full stirring, adding 3-5% of chitosan, performing uniform mixing, adding 2-3% of glycerol, performing mixing, adding 0.08-0.10% of glutaraldehyde, performing mixing, adding transglutaminase with 5 U / g protein-25 U / g protein, adjusting the pH to be 7-9, performing heating in a water bath under the temperature condition of 40-60 DEG Cfor 1-5 h, after the reaction is completed, performing enzyme deactivation under the temperature condition of 85 DEG C, performing cooling, performing ultrasonic treatment at power of 200 W for 15 min, and performing filtration to remove air bubbles; and pouring the filtered film solution into a flatly-placed container, performing air blast drying in a drying oven at the temperature of 60 DEG C for 3 h, after drying is finished, putting the dried material in an environment with relative humidity of 50% and temperature of 25 DEG C, performing equilibration for 48 h, and after equilibration is completed, taking the film. The composite film obtained by the method provided by the invention has a tensile strength of about 19 MPa, an elongation at break of 80% or more, a water vapor transmissioncoefficient of 4.245 g*mm / (m<2>*d*kPa), and a certain antibacterial effect.

Description

technical field [0001] The invention relates to a preparation method of an edible enzyme-modified chitosan / walnut protein composite film, which belongs to the technical field of food packaging. Background technique [0002] Although ordinary polyolefin-based cling film has the advantages of light weight and good mechanical properties, it has problems such as poor biodegradability and limited production raw material (petroleum) resources, which can easily cause "white pollution". With the continuous improvement of people's awareness of environmental protection and food safety, edible packaging materials are sought after for their advantages such as edible, biodegradable, wide source of raw materials, and low price. Chitosan is non-toxic and tasteless, and has excellent natural antibacterial properties, film-forming properties and biocompatibility. The edible film prepared with it as a substrate can meet the requirements of antibacterial packaging materials, and has broad appl...

AI Technical Summary

Problems solved by technology

[0003] The mechanical properties and barrier properties of ordinary protein films are poor, and the single films with chitosan as the film-forming matrix have poor mechanical properties, brittle and fragile films, which limit their commercial applications

At present, researchers at home and abroad have tried to prepare composite films by blending chitosan and protein, mainly studying the compatibility between chitosan and protein, the mechanical properties and film-forming conditions of the composite film, but the effect is not obvious at present. And there are still relatively few studies on chitosan / walnut protein composite membranes.

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