Abstract: In this study,response surface methodology was used to optimize the composite enzymatic extraction of polyphenols from the fruit of okra (Abelmoschus moschatus).The composition of composite enzyme was optimized and determined to be 2% cellulose,3% mannanase and 1% pectinase by single factor and orthogonal experiments.The extraction conditions,including extraction time,temperature and liquid-to-solid ratio,were further optimized using response surface mothodology.A polynomial regression model equation was fitted by the combined use of a 3-factor Central Composite Design (CCD) and regression analysis.By analyzing the regression model using response surface analysis,the optimal extraction conditions of polyphenols from okra fruit were determined as follows:the extraction temperature was 44.97 ℃,liquid-to-solid ratio was 58.80:1 (mL:g) and the extraction time was 3.99 h.Under the optimal conditions,the estimated and observed values of maximum yield of polyphenols were 29.193 mg/g and 29.156 mg/g,respectively.The confirmatory experiments indicated the good prediction ability of the established model,which would provide a reference for large quantity extraction of polyphenols from the fruit of okra.

Key words: Abelmoschus moschatus, polyphenols, composite enzymatic extraction, response surface analysis