Tea Polysaccharides(TPS) has been acknowledged of one of the most important components with various bioactivities in tea.The extraction of TPS from wide tea sources was the previous and determinant work before further studies done.While the extraction procedures of TPS would be different due to the later utilization.In this work,the extraction conditions of TPS were previously optimized by respond surface methodology.A quadric model was obtained as Y = 3.16 + 0.31X1- 0.55X2- 0.47X3- 0.034X1X2+ 0.022X1X3- 0.041X2X3- 0.90X12-0.40X22- 0.73X32.The model was tested and proved through the ANOVA with F-value and p-value.Furthermore,the optimal condition was achieved as extraction temperature of 82℃,extraction time of 106 min and ratio of water to material of 33∶ 1(mL/g),meanwhile the highest yield of TPS showed 3.39% ± 0.08%.The crude TPS was later refined to be of purity of 81.3%.The refined TPS was incorporated with starch as to state the role of TPS in the starch retrogradation of starch-based food.The results showed that TPS-wheat starch mixture has a relatively low degree of retrogradation,which indicated that TPS has a delayed or resistant effect on wheat starch retrogradation.This work may provide a practical evidence for the promising starch-based food incorporated tea.
