Ultrasonic‐assisted extraction and purification of xylo‐oligosaccharides from wheat bran

Abstract

AbstractThis study was to produce functional xylo‐oligosaccharides (XOS) from wheat bran via ultrasonic‐assisted extraction, enzymatic hydrolysis, and purification. Optimal extraction conditions were ultrasonic frequency of 72 kHz, sonication time of 20 min, solid/liquid ratio of 1:21(w/v), 100°C, and extraction time of 2.25 h. Under these conditions, XOS extraction rate of 60.27% was obtained. Optimal enzymatic hydrolysis conditions were 10% for substrate concentration, 800 U/g for enzyme concentration, 55°C, and 4 h for hydrolysis time. Under these conditions, a hydrolysate with 25.52% of XOS content, DP = 2.68. In addition, the hydrolysate solution was decolorized using anion‐exchange resin D392 and the highest decolorization rate (89.26%) was obtained at elution volume of 1 ml/min and 50°C. Decolorized XOS hydrolysate was purified using cation‐exchange resin under optimized conditions of 1.5 ml/min elution volume, 11 ml injection volume, and 35% concentration at 75°C. The concentration of XOS increased from 64.41% to 75.63% after purification.