Preparation method of chitosan composite preservative film

Abstract

The invention discloses a preparation method of a chitosan composite preservative film. The preparation method comprises the following steps: dissolving chitosan in an acetic acid solution, heating to 50 to 65DEG C, and stirring until the chitosan is completely dissolved, so as to obtain a solution A; dispersing modified nano carbon crystal in the solution A, wherein the adding amount of the modified nano carbon crystal is 1 to 9 percent; then adding a plasticizer which accounts for 0.2 to 1 percent of the volume of the solution A, and carrying out stirring, ultrasonic dispersion, standing and ultrasonic degassing for 10 to 15 minutes to obtain a solution B; casting the solution B to form a film, standing and drying at the drying temperature of 35 to 55DEG C; then putting into 0.01 to 0.02mol/L of NaOH solution, soaking for 0.5 to 1 hour, flushing with distilled water, uncovering the film and drying in the sun to obtain the composite preservative film. The chitosan composite preservative film disclosed by the invention has relatively low water vapor permeability, so that excessive loss of water in fruits and vegetables is avoided; the chitosan composite preservative film has relatively good sterilizing function and strong antibacterial durability, i.e., an obvious sterilizing effect can be realized within one hour, and the antibacterial rates for escherichia coli and staphylococcus aureus after 48 hours still can reach 90 percent or above, so the preservation time of the fruits and the vegetables is prolonged.

Description

technical field [0001] The invention belongs to the technical field of degradable materials, and in particular relates to a preparation method of a chitosan composite fresh-keeping film. Background technique [0002] With the continuous improvement of modern people's living standards, people's demand for food freshness is increasing. In order to maintain a certain degree of freshness of food for a certain period of time, PE, PVC, PVDC and other plastic wraps based on petrochemical plastics have emerged as the times require. It has the advantages of low price and convenient use, and is widely used in the field of food preservation. However, the above materials are all non-degradable plastics, with low safety index, poor air permeability, and easy to form white pollution. , there is a risk of carcinogenicity. [0003] Chitosan is obtained by removing all or part of the acetyl groups of chitin. It has good biocompatibility, degradability and film-forming properties. The degrad...

AI Technical Summary

Problems solved by technology

Combining nanoparticles with chitosan can make up for the defects of chitosan in film formation and practical application, and improve the performance of chitosan, but SiO 2 Improving the antibacterial ability of chitosan plastic wrap is limited. Nano-Ag is an active metal and is prone to redox reactions, which will lead to changes in the properties of chitosan. TiO 2 It is a photocatalytic antibacterial agent, which needs to be stimulated by ultraviolet light or light to stimulate its antibacterial properties, and the use conditions are limited. Moreover, the above-mentioned nanoparticles are easy to agglomerate and difficult to disperse.

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