Optimization of ultrasound-assisted compound enzymatic extraction and characterization of polysaccharides from blackcurrant

In the present study, an efficient procedure for ultrasound-assisted compound enzymatic extraction of polysaccharides from blackcurrant fruits was investigated using response surface methodology (RSM). The Box-Behnken design was applied to optimize the effects of enzyme concentration (X-1), pH (X-2) and ultrasonic time (X-3). The statistical analysis indicated that the independent variables (X-1)) and the quadratic terms (X-1(2) and XD had significant effects on the yield of blackcurrant polysaccharides (BCP). The optimal conditions were: enzyme concentration 1.575%, pH 5.3, and ultrasonic time 25.6 mm. The experimental yield of BCP was 14.28 +/- 0.06%, which was closely matched with the predicted yield of 14.31%. After preliminary purification, BCP I was obtained and characterized by GC, HPLC, and IR. BCP I comprised rhamnose, arabinose, xylose, mannose, glucose, and galactose in a molar ratio of 1.818:1.362:0.377:0.501:1.581:1.722 and its molecular weight was 8146 kDa. BCP I showed notable a-amylase inhibitory activity. (C) 2014 Elsevier Ltd. All rights reserved.