Aqueous extraction of corncob xylan and production of xylooligosaccharides

Xylooligosaccharide, which is usually produced from xylan by enzymatic hydrolysis, is a newly developed functional oligosaccharide having many beneficial biomedical and health effects. In this study, a process for producing xylooligosaccharides from corncob was developed. The procedure consisted of soaking the corncob in 1.0 g/l H2SO4 at 60 °C for 12 h, followed by filtrating and washing with tap water to pH 6 and steaming at 135-140 °C for 0.5 h. The steamed corncob was mashed and hydrolysed by xylanase. The cumulative yield of xylooligosaccharides after enzymatic hydrolysis was close to 67.7 g/100 g by steaming (based on xylan in raw material), and the purity of xylooligosaccharides was over 70 g/100 g (based on the total sugars in the hydrolysate). This study demonstrated that the xylan-lignin complex present in the corncob was affected during steaming at 135 °C for 30 min. Almost all of the xylan was removed from the lignin after steam application and subsequent enzymatic hydrolysis.