The Research Of Soluble Dietary Fiber From Momordica Charantia L.Var.abbreviata Ser.

With Momordica charantia L. Var. abbreviate Ser.(MCV) as raw materials, this paper discussed the extraction process of soluble dietary fiber (SDF) and its antidiabetic effects. In this study, the extraction technology of SDF from MCV pomace was investigated. The operating conditions, containing: solid-liquid ratio, extraction temperature, extraction time, enzyme concentration and pH, were optimized using response surface methodology. The results showed that the optimum conditions of SDF extraction were as follows: solid-liquid ratio 1:30 (w:v) , enzyme concentration 1.3%, extraction temperature 54℃, extraction time 1 h and pH 5. The SDF yield was to 31.3%.According to the characteristics of SDF extraction process of MCV, polysulfone hollow fiber membrane module(MWCO30 kDa) is applied in the ultrafiltration of SDF.The optimum process parameters were critical operation pressure of 0.06 MPa, feed rate 160 L/h,operation temperature 25-35℃,and concentration multiple about 10.The SDF purity was up to 89.47% after membrane separation, which reduced the consumption of reagent obviously.Fractionation and chemical composition of SDF from MCV were determined. SDF was fractionated into 3 fractions by anion-exchangechromatography on DEAE-Sepharose CL-6B: WSP1, WSP2 and WSP3. WSP3 was fractionated into 2 fractions on Sepharose CL-6B: WSP31 and WSP32(the main fraction). The high-performance size-exclusion chromatography (HPSEC) showed that both of WSP1 (31,562 Da) and WSP32 (143,239 Da) were homogeneous fraction. WSP1 is a kind of neutral polysaccharide, consisted mainly of glucose and galactose,with low content of rhamnose and mannose;WSP32 is a kind of weak acidic polysaccharide,with 11.9% of uronic acids, consisted mainly of arabinose, xylose, rhamnose and galactose, along with low amount of glucose and mannose.The results of gas chromatography (GC) showed that the monosaccharide in SDF and IDF are composed of both rhamnose, arabinose, xylose, glucose, mannose and galactose. Comparing IDF with SDF, however, the former had more xylose and there was higher amount of galactose, glucose and arabinose in the latter.The rheological property of SDF was studied.The results showed the solution of SDF was rheopectic fluids.Apparent viscosity decreased with the increase of shear rate. Apparent viscosity increased with the increase of concentration,and the addition of salt affected the rheological property of SDF.SDF solution exhibited typical"weak gel"properties.At the same time,the influence of temperature and pH on the SDF solubility was disscussed.The hypoglycemic effects of SDF were studied in alloxan-induced diabetic mice.The results showed that the SDF didn't have significant effect on fast blood glucose(FBG) in normal mice. Treating alloxan-induced diabetic mice for 7 days with SDF at low(400 mg/kg bw) and high(1000 mg/kg bw) dose,respectively,the high dose produced a significant fall(P<0.01) in fast blood glucose (FBG) , but the low dose didn't(P>0.05). The hypoglycemic effect of high dose was further confirmed by oral glucose tolerance test(OGTT).There was some benefitial effects to the symptoms of bodyweight decreasing in diabetic mice.However, the hypoglycemic effects of SDF were weaker than that of peptides and saponins from MCV,significantly.