Enzymatic Preparation And Antioxidant Acivity Of Functional Oligosaccharides From Corn Cob

Functional oligosaccharides have many physiological activities,such as improving intestinal microflora structure,enhancing human immune function,delaying body aging,and so on.The functional oligosaccharides were prepared by enzyme technique.The functional oligosaccharides enzymatic hydrolysis was separated and purified by activated carbon column chromatography.The composition of the purified components was analyzed and detected by ion chromatography,infrared spectroscopy and other chromatographic techniques.The antioxidant activity of the components before and after purification were studied.In order to provide theoretical basis for the comprehensive exploitation and utilization of maize resources.Enzymatic extraction was used for feruloylated oligosaccharides from corn cob.Single factor experiments the parameter changes in the level range,xylanase amount,substrate concentration,enzyme time,pH and enzyme temperature as independent variables to optimize the extraction process parameters for FOs production from corn cob by using central composite design and response surface analysis.The maximun production of FOs of 0.7648 mmol/L was obtianed when the enzymatic extraction was done at 53 ℃ for 16h with the substrate concentration 111g/L,addition amount of enzyme 89.7mg/L.The corncob functional oligosaccharide enzymatic hydrolysate(EH)was separated by activated carbon column chromatography to get water washing oligosaccharides(WO)and different concentrations of alcohol eluent oligosaccharides(EO).The degree of polymerization of WO was mainly DP2～DP4,EO-10 and EO-20 was mainly DP2 and DP3,EO-40,EO-60 and EO-80 have a higher degree of polymerization in addition to DP2-DP4.The monosaccharides of WO and EO are mainly composed of xylose and arabinose.The molar ratio of WO is Ara:xyl:Glc:Gal was 1:12:0.2:0.2,the A/X was 0.083.The molar ratio of EO is Ara:xyl:Glc:Gal was 1:20:0.67:0.33,the A/X was 0.05.The high branching degree of WO is more favorable for conjugated ferulic acid to the arabinose group.UV scanning and HPLC showed that WO with conjugated ferulic acid was feruloylated oligosaccharides,EO was arabinoxylo-oligosaccharies without onjugated ferulic acid.The antioxidant acivity of three functional oligosaccharides before and after purification were studied.The results indicated that three functional oligosaccharides showed certain effects in scavenging free radicals and nitrite,the reduction ability and inhibiting lipid peroxidation were increased the increasing of functional oligosaccharides concentration,which showed that all of them had certain antioxidant activity.Overal,the antioxidant activity of the three oligosaccharides was WO>EH>EO.