Color developing hydrogel for detecting freshness of vegetable oil as well as preparation method and application of color developing hydrogel

The invention discloses color developing hydrogel for detecting the freshness of vegetable oil as well as a preparation method and application of the color developing hydrogel, and belongs to the technical field of food freshness detection. The preparation method of the color developing hydrogel for detecting the freshness of the vegetable oil comprises the following steps: performing oxidation treatment on TEMPO to obtain nano-cellulose, dispersing the nano-cellulose, acrylamide, potassium persulfate and tetramethylethylenediamine into an aqueous solution, and standing and crosslinking to obtain nano-cellulose-acrylamide composite hydrogel; ascorbic acid, ferrous sulfate and sulfosalicylic acid are mixed to form a peroxide indicator; the nano cellulose-acrylamide composite hydrogel and a peroxide indicator are subjected to standing adsorption, and color developing hydrogel is obtained; compared with a traditional film indicator, the color-developing hydrogel serving as a vegetable oil freshness indicator has