Effect of Tea Polysaccharides on Thermal and Pasting Properties of Wheat Starch

The thermal and pasting properties of wheat starch (WS)/tea polysaccharides (TPS) composite system were investigated. Significant increases of transition temperatures (To, Tp, Tc) and the enthalpy of gelatinization (ΔH1) of WS/TPS (2 wet% and 4 wet%) were found as TPS content increased. The lower ΔH2 (endothermic enthalpy under reheating) and R2 (degree of retrogradation of WS) were also detected in WS/TPS in storage of 3,7,14 days when compared with those of WS. The agreements were shown by RVA with the lower total setback and by Texture Analyzer with lower gel firmness. The results of TPS affecting the thermal and pasting properties could be generally explained with Avrami equation of WS/TPS. The Avrami equation exposed that TPS affect the primary nucleation in early stage and the decreased nucleation rate announced by the constant k. The overall results demonstrated that the TPS has an inhibitory effect on the recrystallization of pasting WS in storage.