A kind of preparation method of chitosan composite fresh-keeping film

Abstract

The invention discloses a preparation method of a chitosan composite fresh-keeping film, which comprises the following steps: dissolving chitosan in an acetic acid solution, heating to 50-65°C, and stirring until the chitosan is completely dissolved to obtain solution A; Nano-carbon crystals are dispersed in solution A, the amount of modified nano-carbon crystals is 1%-9%, and then add 0.2-1% plasticizer of the volume of solution A, stir, ultrasonically disperse, stand still, and ultrasonically degas 10‑15min to obtain solution B; cast solution B into a film, let it stand and dry at 35‑55°C; then soak in 0.01‑0.02mol / L NaOH solution for 0.5‑1h, rinse with distilled water , peel off the film, and dry in the sun to obtain a composite plastic wrap. The chitosan fresh-keeping film of the present invention has a lower water vapor transmission coefficient, avoids excessive loss of water in fruits and vegetables, has better bactericidal function, and has strong antibacterial persistence, and can play an obvious bactericidal effect within 1 hour, and 48 hours Afterwards, the antibacterial rate against Escherichia coli and Staphylococcus aureus can still reach more than 90%, prolonging the preservation time of fruits and vegetables.

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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