Enzymatic Modification of Sea Buckthorn Dietary Fiber by Xylanase from Streptomyces rameus L2001: Characterization of its Physicochemical Properties and Physiological Effects on Bifidobacterium

Xylanase from Streptomyces rameus L2001 was used to modify sea buckthorn dietary fiber to enhance the amount of soluble fiber in this study. We then investigated the physicochemical and physiological properties of the resulting dietary fiber. Conventional single factor methods and response surface methods were used to optimize the conditions and the outcomes were as follows: hydrolysis time, 5 h; enzyme content, 46 U/g; temperature, 55.7°C. Under these conditions, the yield of modified soluble dietary fiber was 42.84 mg/g, as compared with 14.04 mg/g for unmodified fiber. We also conducted studies to determine the properties of modified sea buckthorn dietary fiber, including water holding capacity, oil binding capacity and swelling capacity, which were 110.7%, 106.9% and 116.5%, respectively, relative to unmodified fiber. We next cultivated Bifidobacterium with the soluble dietary fiber (derived from modified sea buckthorn) and compared growth with that of bacteria maintained on glucose. Supplying Bifidobacterium longum and B. infantis with the soluble component aided their proliferation, particularly of B. longum. This is the first report on sea buckthorn dietary fiber and its modification with xylanase