Effects of glycerol and PVA on gelatin/Gum Arabic aerogels: Microstructure, mechanical properties, and applications for food monitoring

Smart labels are a hot research topic in the field of food science, but the low sensitivity of film smart labels limits the on-site and visual detection of seafood freshness. To address these challenges, betacyanin (BET) as a response signal and an aerogel smart label based on gelatin/gum arabic (Gel/GA) were designed. The labels produced a visually observable color change in the presence of volatile ammonia (2500 ppm) and displayed an immediate colorimetric response to food spoilage when packaged shrimp was used as an example. The results showed that the smart aerogel labels were better than the film smart labels in the response sensitivity test of volatile ammonia. In addition, the addition of a small amount of plasticizers (glycerol) or hardeners (polyvinyl alcohol, PVA) further enhanced the responsiveness of the aerogel to volatile ammonia. Notably, the addition of a small amount of PVA further increased the hardness of the aerogels. The scanning electron microscopy (SEM), infrared spectroscopy, and X-ray diffraction (XRD) results showed that these results may be caused by the interpenetration of the PVA network and the Gel/GA network to form a new type of interpenetrating polymer network structure. Therefore, the developed smart aerogel labels play an important role in ensuring food quality and reducing food waste and inspire new ideas for the development of additional functional smart labels.