Freeze-thaw stability of konjac glucomannan hydrogels supplemented with natural tapioca/corn starch

The poor freeze-thaw stability of konjac glucomannan (KG) hydrogel will greatly affect its application in the frozen prepared foods. In this study, the filling effects of natural tapioca starch (TS) and corn starch (CS) on the properties of freeze-thaw KG hydrogel were evaluated. The addition of starches significantly improved the gel strength and water holding capacity and inhibited the freeze-induced syneresis of composite hydrogels, where CS is superior to TS. These beneficial effects could be the results of concurrent effects of the decrease of frequency dependence/freezing point, the formation of dense microstructure and the reinforced hydrogen bonds and hydrophobic interactions of composite hydrogels. The foregoing results suggested the potential feasibility of low-cost natural starches to improve the textural properties and freeze-thaw stability of KG hydrogels.