Interpenetrating network gels composed of gelatin and soluble dietary fibers from tomato peels

The advantages of interpenetrating polymer network (IPN) included ideal texture and stability, which was able to apply to the field of food gels. In this study, calcium ions and transglutaminase (TG) were used to cross-link soluble dietary fiber (SDF) from tomato peels and gelatin chains to prepare composite gels with semi-interpenetrating (semi-IPN) or interpenetrating network (IPN) structures. Rheological studies proved that semi-IPN or IPN structures could improve the gelation properties of gels. Scanning electron microscopy showed that the IPN gel had a dense, complex microstructure. In addition, the results of texture property, water-holding capacity, swelling ratio and freeze-thaw stability showed that composite gels had potential to supply specific functional gels, which is good for the development of formula products.