JFS C: Food Chemistry and Toxicology Cellulase-Assisted Extraction of Oligosaccharides

ABSTRACT: Defatted rice bran was subjected to cellulase treatment in order to increase its extractable oligosaccha-rides. Various combinations of enzyme concentration (0%, 0.5%, 1.0%, and 2.0%), temperature (room, 30, 40, and 50 ◦C), and time (1, 3, 5, and 16 h) were tested to identify the optimum extraction conditions. The saccharide content and composition of the extracts were analyzed by high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). Digestibility was assayed in vitro with human salivary and porcine pancre-atic α-amylases. Extraction yield ranged from 13.4 % (without cellulase) to 39.9 % (with 2 % cellulase). Total carbo-hydrates, reducing sugars, and crude protein of the dried extracts ranged from 69.2 % to 87.2%, 18.7 % to 62.3%, and 7.1 % to 22.3%, respectively. Mono- and disaccharides constituted more than 50 % of the total carbohydrates in the extracts. Inherent oligosaccharides and those produced by cellulolysis made up less than 25%. The in vitro di-gestibility of the extracts by α-amylases was lower compared with that of the original rice bran sample and potato dextrin, which could be attributed to the increased concentrations of oligosaccharides and reducing sugars