The Enzymatic Extraction Of Soluble Dietary Fiber From Soybean Dregs And It's Application

Soluble dietary fiber (SDF) was one of Dietary fibe(rDF) that could not be digested by human digestive enzyme but could soluble in warm water or hot water and could be precipitated by quadruple ethanol solution. People were paying more and more attention to SDF because of it′s abundant nutritional value﹑physiological function and widely practical application.With soybean dregs as raw material to extract SDF by cellulase, this paper discussed the extraction process of SDF and four cellulase were screened.The characteristics of SDF and it′s application in the acidity milk beverage and influence on proliferation of Bifidobacterium were also studied.Four cellulase (Viscozyme L,Amano,Jatan,Shang Hai Guo Yao)were screened in experiment and the results obtained showed that the highest yield of extraction for SDF were Viscozyme L.The extraction process of SDF from soybean dregs were identified and optimized through single-factor experiments﹑orthogonal experiments and analysis of variance,among which the parameters of extraction process were material-water ratio of 1:15,enzyme volume of 0.5%,extraction temperature of 45℃,extraction time of 1.5h and pH4.5. Under this condition, the SDF yield were up to 27.27%.The characteristics of SDF were studied by infrared spectrometer﹑viscometer and other methods, the results showed that SDF were polysaccharides and the SDF content were about 91.12%. The SDF were analyzed to be water holding capacity 8.25g·g-1, swelling capacity 9.38ml·g-1,water binding capacity 7.11g·g-1 and cation-exchange capacity 0.73 mmol·g-1.The SDF had a certain degree of adsorption of sodium cholate and the experiments showed that the more the addition of SDF, with the increasing of adsorption,the longer time to be used for adsorption equilibrium.The solution of SDF from soybean dregs were pseudoplastic fluid which viscosity decreased with the increasing of shear rate. The effetcts of the concentration﹑temperature and pH on viscosity and solubility of SDF were also discussed in this paper.The stabilization effects of SDF on protein particles were similar to pectin through the determination of precipitation rate for acidity milk beverage.Under this condition which were stabilizer concentration 0.4%,pH4.0,the stability of acidity milk beverage that adds SDF were similar to pectin and superior to other stabilizers such as arabic gum and CMC ,but it gave the lowest viscosity. In addition, the SDF had the thickening effect through the study of micr- ostructure of set-style yogurt by scanning electron microscopy.The functionality of SDF from soybean dregs for Bifidobacterium were studied.With the typical Bifidobacterium infantis and Bifidobacterium longum in human intestine as experimental bacterial strain,the effects of SDF on promoting the proliferation of Bifidobacterium were investigated and the influence of concentration of SDF on the proliferation of Bifidobacterium were also discussed.