Preparation of konjac glucomannan/xanthan gum/sodium alginate composite gel by freezing combining moisture regulation

Specific foods such as connective tissue analogues are increasingly popular for the growing market demands. Hydrogels are considered to possess the potential to simulate connective tissue, however the relatively low mechanical strength of the conventional hydrogel greatly limited its application prospects. In the present study, we aimed to explore the effects of different freezing time, freezing-thawing (FT) cycles, and moisture content on the mechanical properties of konjac glucomannan/xanthan gum/sodium alginate (KGM/XG/SA) composite gel. After getting the freezing treatment, a noticeable change could be observed in the texture properties of the composite gel. As the FT cycles increased, the gel's network became denser, with its pores getting smaller. According to mechanical testing results, it is advisable to freeze the gel for 46 h at −20 °C, while the mechanical strength of the FT-2 is the best among samples. In addition, as the moisture content decreased from 92% to 60%, gel's elastic modulus, tensile strength and toughness increased significantly, and their maximum values were 27.1-, 12.9- and 10.7-fold of the non-dehydrated samples, respectively. Their porous structure would disappear gradually after undergoing the dehydration treatment, resulting in an extremely dense gel network with a significant increase in its mechanical strength. The present study suggests that both the freezing treatment and moisture regulation could effectively change the texture properties of the KGM/XG/SA composite gel, which provides a facile and efficient strategy for designing hydrogels products with exceptional texture and sensory characteristics.