Effect of gelatin modification by sodium alginate and genipin cross-linking on gel properties and textural...

Gelatin hydrogels possess favorable biocompatibility, biodegradability, and non-toxicity. Overcoming the weak mechanical properties will expand gelatin's application in the biological field. The purpose of this work was to enhance the mechanical characteristics of gelatin hydrogels through covalent and non-covalent crosslinking with genipin and sodium alginate (SA), and to investigate the gelation mechanism via interaction forces. The formation of the composite network was confirmed by rheological, thermogravimetric, infrared spectroscopic, and micro-morphological analyzes. The effects of different SA concentrations on the capabilities of gelatin were investigated, revealing that adding SA could enhance its mechanical, rheological, and thermal stability, as well as its swelling capacity. Among them, the gelatin hydrogel with 0.5% SA added achieved a hardness of 145.56 g and a storage modulus exceeding 1500 Pa, significantly outperforming the unmodified gelatin. The results of gelatin-SA-genipin gels provide important new insights into the potential uses of a composite network hydrogel in the food sector.