Response Surface Methodology (RSM) was employed to optimize the hydrolysis conditions of ginkgo cloudy juice using enzymatic hydrolysis. The independent variables were hydrolysis time (20-100 min), alpha-Amylase dosage (2.60-8.18 U/g kernel) and Alcalase protease dosage (0.87-8.94 U/g kernel). The coefficient of determination, R 2 values for suspension stability, browning indexes and juice yield were greater than 0.900. The combined effect of these variables on suspension stability, browning indexes and juice yield were investigated. The results showed suspension stability and juice yield varied curvilinearly with increase of a-Amylase dosage, Alcalase dosage and hydrolysis time and browning indexes increased linearly. Based on response surface and contour plots, the optimum conditions for the enzymatic treatment for ginkgo cloudy juice were: hydrolysis time 73 min, alpha-amylase dosage 7.39 U/g kernel and Alcalase dosage 6.43 U/g kernel. (c) 2006 Elsevier Ltd. All rights reserved.