Method of preparing composite preservative film or coating from chitosan and alcohol soluble corn protein

Abstract

The invention relates to a method of preparing a composite preservative film or coating from chitosan and alcohol soluble corn protein. The method mainly comprises the following steps: (1) preparing 2wt% chitosan solution; (2) preparing 1-10wt% ethanol aqueous solution of alcohol soluble corn protein; (3) mixing the solutions prepared in the steps (1) and (2) in a volume ratio of 1:9 to 9:1 (v / v) to obtain a composite film solution; (4) flow casting the composite film solution obtained in step (3) and drying to obtain a film; or sequentially overlaying the solutions prepared in the steps (1) and (2) to obtain a double-layer preservative film. The chitosan-alcohol soluble corn protein composite preservative film or coating prepared in the invention is not only improved in the moisture resistance and ultraviolet resistance of a chitosan film, but also improved in the barrier property, mechanical properties and antibacterial activity of a alcohol soluble corn protein film, and is degradable, edible, etc. When the chitosan-alcohol soluble corn protein composite preservative film or coating prepared in the invention is used to package or wrap foods such as meat, oils and fats, fruits and vegetables, the quality guarantee period thereof can be effectively prolonged. Thus, the method has an extensive application prospect.

Description

technical field [0001] The invention belongs to the technical field of food antibacterial and fresh-keeping, and in particular relates to a preparation method of a composite fresh-keeping film or coating using chitosan zein as a raw material. Background technique [0002] In order to achieve the purpose of prolonging the shelf life of food, people have adopted various physical, chemical and biological preservation techniques to process food. The problem caused by food preservation is that the residual toxic and harmful substances in the packaging materials penetrate into the food, resulting in food deterioration. Secondary pollution. At the same time, dried fruits and vegetables such as dried longan are antiseptic and anti-browning with sulfur fumigation. However, due to sulfur fumigation treatment, some SO2 remaining in the pulp will be harmful to human health. However, how to control semi-dried longan, etc. There are few reports on the method of dry browning of fruits and ...

AI Technical Summary

Problems solved by technology

[0005] At present, there are chitosan as the preparation method of the preservative film on the market, and there is also a separate preparation method using zein as the preservative film, but there are certain defects in the use of the two alone, and the film formation of the zein protein alone is easy to lose water. The fresh-keeping coating film becomes brittle and has poor mechanical properties, and the zein film material has disadvantages such as high brittleness, poor moisture resistance, poor stability, and uneven film thickness, so the practical application is limited, and cracks appear on the surface, thus affect fresh-keeping effect; using chitosan solution alone as a fresh-keeping film also has certain defects, and chitosan itself has poor moisture resistance and anti-ultraviolet performance, and it plays a certain fresh-keeping effect on the surface of fruits and vegetables, but the effect is poor; Combining them together as a composite film has not found such a substance and its preparation method on the market at present. The experiment of the present invention proves that the freshness preservation ratio of semi-dried fruits and vegetables such as dried longan and dried persimmons when the two are organically combined as a composite film is used separately as a composite film. The effect of plastic wrap is more significant, which can prolong the shelf life of dried longan and other fruits and vegetables

Images