Abstract:

The optimization of four technological parameters for the pectinase hydrolysis was carried out using response surface and grey correlation analyses in order to improve juice yield. A regression model with juice yield (Y) as a function of initial pH (x1), hydrolysis temperature (x2), hydrolysis time (x3) and enzyme load (x4) was set up as follows: Y = 89.78333＋0.86250x3＋0.67917x4 ＋ 0.80937x32 － 0.83125x1x2. The analysis of variance for the model showed that hydrolysis time and enzyme load significantly affected juice yield (P＜0.05) and that the others had no significant effect on juice yield (P＞0.05). The multiple regression analysis indicated that the established model had an excellent goodness of fit, suggesting good reliability in predicting the function.

Key words: pectinase, juice yield, quadratic rotary combination design, response surface methodology (RSM), grey correlation analysis