Preparation Of Sea Buckthorn Soluble Dietary Fiber By Solid State Fermentation

Soluble dietary fiber(SDF)was part of dietary fiber, that can not be digested by human digestive enzymes, and dissolved in hot water, and can be deposited by four times ethanol. Soluble dietary fiber with important physiological functions has increasingly been given attention by scholars and public. In order to improve extraction rate of sea buckthorn soluble dietary fiber, sea buckthorn meal was modified by Trichoderma reesei fermentation, and in this study the decolorization of seabuckthorn soluble dietary fiber was researched. Finally, the properties of sea buckthorn soluble dietary fiber were determined.Through the strains selection,Trichoderma reesei strain was suitable for solid state fermentation of sea buckthorn meal. Through Single factor experiments and orthogonal test, the order of factors, which affected sea buckthorn soluble dietary fiber preparation by the fermentation was inoculated-pathogen quantities > fermentation period > fermentation temperature > water content. The conditions for the solid fermentation were optimized as follows: 5mL·100mg^-1 inoculated-pathogen quantities of Trichoderma reesei , fermentation temperature at 28℃, 6 d fermentation and 2 mL·g^-1 addition amount of water. The extraction rate of soluble dietary fiber is 9.65 %.Through the choice test of decolorants , the activated carbon was suitable for decolorization of sea buckthorn soluble dietary fiber ,which was prepared by fermentation. The optimized conditions for the decolorization as follows: solution pH 5, addition of activated carbon 0.5 %, temperature of 40℃. After decolorization, sea buckthorn soluble dietary fiber was pale yellow.By analysis of the characteristics, sea buckthorn soluble dietary fiber was a typical polysaccharide, and the molar ratio of monosaccharides was rhamnose : arabinose : xylose : mannose : glucose : galactose = 2.93 : 4.06 : 4.58 : 6.13 : 6.63 : 28.06. The fermentation can improve the water holding capacity (6.4 g/g)and swelling force(5.3 mL/g)of sea buckthorn soluble dietary fiber. With concentration of sea buckthorn SDF increasing, the viscosity of solution increased Straight. With temperature increasing, the viscosity decreased. The influence of pH value was largest. In addition, sea buckthorn SDF solution viscosity less affected by salt concentration, but greatly influenced by the sucrose concentration. Sea buckthorn SDF had scavenging activity on O2- and·OH ,but DPPH (1,1-diphenyl-2-picrylhydrazyl radical 2,2-diphenyl)smaller.