Enzymatic Modification Of Hardwood And Grain Xylan And Its Antioxidant Activity And Application Research

XOS is a functional prebiotic carbohydrate oligomers with antioxidant effects;The different sources and different preparation methods of the same source XOS its antioxidant capacity is different.This paper studied the modification on the grain and hardwood xylan with different enzymes and enzymatic times,then study the antioxidant activity and applications of the hydrolyzate.The results are as follows:It was different that the polymerization degree and each monosaccharide of XOS which obtained from beech hardwood under XynB and XynB+AguA enzyme system.In double enzyme digestion system the free glucuronic acid concentration was 1.1?2.21 mg/ml while in single enzyme system it was 0.13?0.20mg/ml.And the concentration of xylobiose and xylotriose of XOS in double enzyme digestion system was higher than single enzyme system.The polymerization degree of XOS of 1 to 6 hours single and double enzyme digestion was 2.1?1.8?2.8?2.44,respectively.With the extension of the hydrolysis time,the polymerization degree getting lower and the polymerization degree in a single enzyme digestion system was relatively high.The antioxidant activity of XOS under different enzyme systems and different hydrolysis time of different enzyme systems were all different.In all,the activity of XOS in double enzyme digestion system was much higher than single enzyme digestion system,and the clearing DPPH · radicals and total antioxidant capacity in double enzyme digestion system was obvious,what's more,the activity of XOS at 4h was the highest.It was different that the polymerization degree and each monosaccharide of AXOS which obtained from grain under XynB and XynB+Ara enzyme system.The free arabinose concentration of 1 to 6 hours single and double enzyme digestion was 0.10?0.16mg/ml,0.66?0.78mg/ml,respectively.The xylobiose concentration of XOS under double enzyme digestion system was much higher than under single enzyme digestion system at the same time,while xylotriose concentration was much lower.The polymerization degree of XOS under double enzyme digestion system was lower than single enzyme digestion system.,the clearing DPPH · radicals and total antioxidant capacity in double enzyme digestion system was much higher than in single enzyme digestion system,but clearing· OH radicals ability was not significantly different.Alkaline extract of wheat bran arabinoxylan(AX)and hydrolyzate(AXOS)had great ifluence on bread texture and the ability to clear ABTS · + radical,it decreased the hardness of making bread and at the same time the gumminess,cohesiveness and chewiness increased.The influence of AXOS was more obvious than AX on steamed bread.Double enzymatic hydrolysis bread of AXOS obtained lower elasticity than single enzymatic hydrolysis bread,but its gumminess,cohesiveness and chewiness were much higher;The order of different clearing ABTS ·+ radical capacity of bread with different components are:bread flour<bread flour + AX + Ara<bread flour + AX + XynB<bread flour + AX + Ara + XynB..The results showed that the reactivity of free type of arabinose in AXOS with protein in flour is much higher than bound arabinose.