Gelling and bile acid binding properties of gelatin-alginate gels with interpenetrating polymer networks by double cross-linking.

Interpenetrating polymer network (IPN) is an effective method to improve functional properties of hydrogels by forming cross-linking networks. In this study, the gelatin-alginate gels formed by the combination of enzymatic and ionic cross-linking were called IPN gels. Meanwhile, the gels with the treatment of only transglutaminase (TG) or Ca2+ were named as G-semi-IPN and A-semi-IPN, respectively. The formation of semi-IPN and IPN was confirmed by studies on rheology, thermodynamics and micro-morphology. The results showed that the IPN gels had improved gelling properties and structural stability. The functional properties of different gelatin-alginate gels were also investigated. It was firstly found that the IPN gels could enhance mechanical properties, decrease swelling capacity and had better bile acid binding capacity. These results of gelatin-alginate gels provide references and novel prospects of IPN for the application in the field of food industry.