Development of multi-cross-linking, rapid curing, and easy cleaning, edible hydrogels for meat preservation

The design and development of a food preservation coating material with rapid curing and stable performance to shorten the coating process time and reduce quality changes caused by temperature fluctuations in cold chain is highly desirable in fresh meat preservation applications. In this study, a series of multi-cross-linked edible hydrogels were designed based on gelatin and k-carrageenan through the self-assembly triple-helix of gelatin and the potassium ion-mediated k-carrageenan double-helix structure. The tannic acid with phenolic hydroxyl groups was employed to enable the dynamic bond cross-linking between two polymers, endowing the composite hydrogel with rapid curing ability at low-temperature and a uniform molecular network structure. The hydrogel with a concentration of gelatin was 16% (GCBG-16) achieved the optimal combination properties, including 73.41% of elongation at break, 71.59 kJ/m² of toughness, 27.73% of swelling ratio, and 50.73% of DPPH· scavenging rate. The hydrogels could be rapidly washed within 30 min at 40 °C by water, as well as possessing a certain self-healing and anti-freezing capabilities. The hydrogel GCBG-16 had a great capacity for protecting meat with a E value of 50.4 and 17.53 N of shear force even placed in a 37 °C environment, which showed no significant difference (p > 0.05) compared to the initial value. Furthermore, the fresh meats with coating showed delayed central temperature increase speed after leaving from the cold chain and placed in a 37 °C environment. The research results demonstrated that the proposed hydrogel has great potential in preserving fresh meat, which can serve as a matrix material combined with other active additives for extending the shelf life of meat products.