Composition Analysis of Enzymatic Hydrolysates of Insoluble Dietary Fiber Black-grained Wheat and Its Effects on Quality of Whole Grain Extruded Products

Objective:To systematically analyze the composition and application characteristics of xylanase enzymatic hydrolysate (BWXH) prepared from black-grained wheat insoluble dietary fiber, and study its effect on the quality of whole grain extruded products. Methods:BWXH was obtained by enzymatic hydrolysis of black-grained wheat insoluble dietary fiber by xylanase. The content of feruloyl oligosaccharides (FOs) in BWXH was determined by dual-wavelength method;the monosaccharide and oligosaccharide composition, infrared spectrum of BWXH were analyzed by ion chromatography and FT-IR;the high temperature and high pressure was simulated to test the stability of BWXH;and then BWXH was added to the whole grain extrusion product, and the expansion rate, sensory score and product brewing characristics of the extruded product were studied. Results:The content of feruloyl oligosaccharides (FOs) and ferulyl group were 0.104 mmol/g and 0.717 mg/g, respectively. BWXH were mainly composed of DP2, DP3 and DP4 by analysis of ion chromatography;and BWXH were mainly composed of arabinose, xylose and glucose, with the molar ratio of 1.70:4.25:1.00 and the degree of branching (A/X) of 0.40. High pressure (121℃, 0.15 MPa) could promote the transformation of high polymerization (DP) of dietary fiber into low DP of FOs. Extrusion experiments showed that a proper addition (7%) of BWXH could prove the quality of extruded products. Conclusion:As a kind of oligosaccharide, BWXH could be used in whole grain extruded products, which provided a theoretical basis for the development of functional food ingredients from black-grained wheat insoluble dietary fiber.