Preparation method and sensitivity regulation method of pH type food freshness indication label

Abstract

The invention discloses a preparation method and a sensitivity regulation method of a pH type food freshness indication label. The preparation method comprises: extracting a pH sensitive natural dye to obtain a pH sensitive natural dye concentrated solution; dissolving a natural polymer material in a solvent to obtain a film-forming stock solution; sequentially adding a plasticizer, a water absorbent, a phase transfer catalyst and the pH sensitive natural dye concentrated solution into the film-forming stock solution, and fully stirring until the materials are uniformly mixed and dispersed toobtain a film-forming solution; and carrying out ultrasonic deaeration on the film-forming solution, slowly pouring the film-forming solution into a culture dish, and drying the solvent to obtain thefreshness indication label. According to the present invention, the pH value of the film-forming solution in the preparation process of the indication label is adjusted according to the front-back relationship between the freshness indication label color transition point and the food spoilage point, such that the two time points are matched so as to achieve the purpose of precise indication; and the method is simple and easy to implement, and the prepared indication label has high sensitivity, has the sensitivity capable of being regulated based on food spoilage rule, and has wide application.

Description

technical field [0001] The invention relates to the field of food packaging, and more specifically, the invention relates to a method for preparing a pH-type food freshness indicator label and a sensitivity control method thereof. Background technique [0002] With the improvement of people's living standards, consumers have higher and higher requirements for food quality, safety, nutrition and health. The freshness of food is one of the important factors affecting food quality and food safety. The freshness of food not only determines the price of commodities, but also a key indicator that affects consumers' willingness to purchase and the health of eaters. At present, consumers' judgment on the freshness of food is limited to checking the shelf life date on the packaging. This method ignores the deterioration of food caused by adverse changes in the environment (high temperature, high humidity, etc.) during the storage and transportation of food. There is a certain gap i...

AI Technical Summary

Problems solved by technology

[0005] At present, the main problems in the development and application of pH-type food freshness indicator labels are: 1) the purity of synthetic pigments is high, and the color change is too sensitive when the indicator is applied, and the color change is even ahead of the food spoilage point; 2) the natural pigments are not sensitive enough, Indication hysteresis often occurs during application, that is, the color change lags behind the food spoilage point

Instructions ahead of time can cause unnecessary food waste, while instructions lagging behind can pose a threat to human health

In addition, synthetic pigments have safety risks and are not recommended for use in food packaging

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