Recovery study on aspergillus oryzae α-amylaseby tea polyphenols and effects on the properties of α-amylase

To assess the effects of tea polyphen ols(TP)on the properties of α-amylase extracted from Aspergillus Oryzae.α-amylase from Aspergillus Oryzae was complexed with TP extracted from green tea.Bernfeild method was adopted to analyze the activities of free α-amylase and TP complexed α-amylase under various temperatures, pH values and substrate concentrations. It was found that TP were haze-active and showed no inhibitory effect on the α-amylase. By complex and sedimentati on, the maximum recovery of the α-amylase activity reached about 71% at 0.3% TP concentrations. The optimum temperatures for the α-amylase were changed from 30～50℃ to 60～70℃, pHvalue from 3.0～8.0 to 5.0～6.0 and the Km value of the α-amylase complexed with TP from 0.18% to 1.03% the substrate concentration of soluble starch. It is concluded that TP recovered the activity of the α-amylase and showed no inhibitory effect by complexation. After complexed with TP, the optimum temperature and pH value fo r the α-amylase were increased and narrowed The Km value was changed higher for soluble starch substrate, indicating the decreased affinity of the α-amylase with the substrate.