Effect of Konjac Glucomannan on Gelatinization, Retrogradation, and Gelling Properties of Frozen Wheat Starch

Konjac glucomannan (KGM), a neutral hydrocolloid, is an important food additive used in many European and Asian countries. In this study, the effects of KGM on the gelatinization and retrogradation of frozen wheat starch are investigated. The effect of the addition of KGM on the freeze-thaw stability and the textural and rheological properties of the starch gel are also examined. It is found that while KGM significantly reduces the pasting temperature, it increases the pasting viscosity, breakdown value, and setback value of frozen starch. The retrogradation and syneresis of the starch gel are inhibited after the addition of KGM. This dramatically improves the freeze-thaw stability of the starch gel. At the same time, the viscosity and fluidity of the starch gel are increased, and its pseudoplasticity is reduced due to the addition of KGM. After comparing with the control experiment, it is found that the hardness of the KGM added starch gel is reduced and reaches a minimum at 1.5% and 2.5% of KGM addition. Based on the evaluation of these parameters, it is established that KGM is very useful for improving the quality of frozen starch gel.