Dissertation > Agricultural Sciences > Crop > Tuber Crops > Sweet potato ( sweet potato )

Study on the Characterization and Molecular Sulfate Modification of Sweet Potato Vines Polysaccharide

Author YangZuo
Tutor LvFeng
School Fujian Agriculture and Forestry University
Course Agricultural Products Processing and Storage
Keywords sweet potato vines polysaccharide(PSPV) uhrasonic extraction decoloration molecular characterization sulfamic modification antioxidation
CLC S531
Type Master's thesis
Year 2010
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Sweet potato (Ipomoea batatas(L.)Lam.),is a special economical resource in Fujian,which has rich nutrition and special health value.Ultrasonic-assisted technology,decoloration technology,purified technology,sulfate modification and the anti-oxidantive effect of sulfated derivatives of sweet potato vines polysaccharide (PSPV) were studied.Therefore,basic data for development of biological activity and the appliaction of Biopharmaceutical of PSPV were offered.(1) In this study,combined with traditional hot-water extraction,we have disscussed the main affect factors involved in the ultrasonic-assisted extraction procession of the PSPV.The four factors,solid-liquid ratio、extraction temperature、extraction time and uhrasonic power,which were affected the extraction procession were optimized by L16(45) orthogonal test.The obtained results indicated that the optimized parameters were as follows:the solid-liquid ratio 1:50,ultrasonic power 500W and extraction temperature at 75℃for 90 minutes.At this optimization scheme,the method was repeated for twice under neutral pH and the extraction ratio of PSPV was about 3.86%.(2) Under the EDTA subsidiary conditions , H2O2 was used as the decolorant,which was carried on the decoloration to the PSPV.Through the [L9(33)] orthogonal test,we took the content of PSPV,the hydroxy free radical percentage clearance as the weight target.The result indicated that the best technological parameter combination was:Under the condition that the content of EDTA was 5‰of the polysaccharide dissolution fluid and the pH of solution was 8.8,the amount of H2O2 was 1.5% of the polysaccharide dissolution fluid,the temperature was 50℃,the time was 1h,and the pH value is 8.8.Under this condition,the survival rate of PSPV was 70.3% and its hydroxy free radical percentage clearance was 85.4% of original PSPV after the decolorization.(3) The crude PSPV was removed proteins by Sevag’s methods,and was isolated and purified by SephadexG-75.Light brown powder State objects was obtained after freeze-drying and was soluble in water.The PSPV was thermal stability at 0℃100℃among the food processing pH value.The specific rotatory power of PSPV [α]D20=+78°(0.071,H2O)and inherent viscosity [η]= 10.421.The results of color reaction indicated:Reacting with phenol-sulfuric acid reagent,anthrone reagent ,PSPV turned into blown and blind green respectively.However,it turned out to be colorless while reacting with I -KIFeCl2 3 carbazole- sulfuric acid reagent and fehling reagent.It was positive while reacting wih Coomassie BrilliantG-250 reagentthe.The pure PSPV was identified by HPGPC and UV and was a bioactive glycoprotein which contained protein 35.4%.HPLC showed that PSPV had a molecular weight of 1824736,the polydispersity of 1.027394.According to the analysis of IR fingerprint characteristics absorption,the result showed that the PSPV was an acidic polysaccharide containing a carboxyl.In addition, the results of 954.81cm-1 department absorption peak and 1H-NMR showed that the configuration of polysaccharide wasβ– glycosidic.(4) The method of using sulfamic acid as the agent and formamide as solvent was adopted to for sulfamic modification on the polysaccharides from sweet potato vines (PSPV) in this paper..Basing on the rotating perpendicular combination experiments, the dynamic equation of sulfamic modification on PSPV was established,the dynamic equation: Y=1.41000+0.02750X1+0.02500X2+0.01250X3+0.01083X4-0.09521X12-0.08146X22-0.08646X32-0.08646X42 -0.03500X1X2-0.01500X3X4The result indicated that the optimum technological parameters of sulfamic modification on PSPV were to add the amount of sulfamic acid 30mg;formamide volume 8 mL;and esterification time 3 hours;esterification temperature 90℃;the DS of the derivatives on PSPV was 1.42.Moreover,the scavenging ability of sulfated derivatives of PSPV on·OH was positively related with the degree of substitution (DS), and which antioxidant activity was the largest,the SA was 81.29%,treble than the natural PSPV,when the DS was 1.42.

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