Enzymolysis-ultrasonic assisted extraction, chemical characteristics and bioactivities of polysaccharides from corn silk

An enzymolysis-ultrasonic assisted extraction (EUAE) procedure of corn silk polysaccharides (CSPS) was established and the physicochemical properties, antioxidant and anticancer activities of CSPS were studied. Orthogonal test and response surface methodology were applied to optimize the extraction parameters. The optimum enzymolysis and ultrasonic conditions were cellulase content of 7.5% for 150 min at 55 degrees C and liquid-solid ratio of 31.8 for 34.2 min at 66.3 degrees C, respectively. Under these conditions, the yield of CSPS increased from 4.56% to 7.10%. CSPS obtained by hot water and EUAE were composed of rhamnose, arabinose, xylose, mannose, galactose and glucose with molecular ratios of 4.17:17.33:5.59:18.65:19.11:35.14 and 8.83:15.77:7.92:12.39:11.15:43.94, respectively. Their molecular weight distributions were 10.52 x 10(4) and 6.88 x 10(4) Da, respectively. CSPS obtained by EUAE showed morphological and conformation changes and higher antioxidant and anticancer activities compared with CSPS extracted by hot water. (C) 2013 Elsevier Ltd. All rights reserved.