Study On The Preparation, Properties And Hypolipidemic Of Cross-linked Octenyl Succinic Anhydride Modified Sweet Potato Starch

Preparing cross-linked octenyl succinic anhydride sweet-potato modified starch(CLOSA-SPS) were used sweet-potato starch as material, sodium trimetaphosphate(STMP) as cross-linking agent, octenyl succinic anhydride(OSA) as esterifying agent in this paper. First of all, preparation technology, physical-chemical properties were investigated. Then the toxicological safety assessment and regulatory effect on blood lipid level of CLOSA-SPS in hyperlipidemia rats were studied. It was in order to get having the good properties and functionality of the sweet-potato modified starch, widen the application of CLOSA-SPS in the food field and provide abundant theory for the sweet-potato modified starch of practice.1.The bound phosphours were concerned, the optimum conditions of preparing the cross-linked sweet potato starch by orthogonal experiment optimization were:the mount of STMP 10%, cross-linking reaction pH 11.5, cross-linking reaction time 2.5h,cross-linking reaction temperature 50℃. The order of factors which influenced on the bound phosphours was:the mount of STMP> time>cross-linking reaction pH> temperature. Finally, the content of STMP was 0.2%.Then degree of substitution (DS) as indexes, Use Design-expert7.0 response surface design and analysis method to study the influence on DS of starch slurry mass fraction, esterifying reaction pH, esterifying reaction temperature. The regression equation of DS is: DS=0.014+(1.875E-004)*Xi+(9.375E-004)*X2+(3.750E-004)*X3-(6.000E-004)*X1X2+ (7.750E-004)*X1X3+(6.750E-004)*X2X3-(6.500E-004)*X12-(1.800E-003)*X22-(3.750E-004)*X32. The order of each factors which influenced on DS is:esterifying reaction pH> esterifying reaction temperature> starch slurry mass fraction. The optimum conditions of preparing the CLOSA-SPS by response surface analysis method:starch slurry mass fraction 40%,esterifying reaction pH 8.28, esterifying reaction temperature40℃.At last, degree of substitution was 0.015.2.The physical-chemical properties of CLOSA-SPS were investigated. The results showed that:①FTIR spectra showed that cross-linking and OSA esterification dual modified sweet-potato starch obtained new chemical group, which appeared new characteristic peaks at 1723.97cm-1 and 1599.01cm-1. This peak of at 1723.97cm-1 corresponded to the characteristic IR stretching vibration of C= O, which suggested the formation of ester carbonyl groups. Another new peak appeared at 1599.01cm,which was ascribed to the asymmetric stretching vibration of carboxylate (RCOO-);②Compared with the unmodified sweet-potato starch and cross-linking sweet-potato starch, the peak viscocity, thermal paste viscosity and final viscosity of CLOSA-SPS were increased, gelatinization temperature were advanced, paste properties has a better solution stability;③Compared with the unmodified sweet-potato starch and cross-linking sweet-potato starch,dual modified sweet-potato starch improved transmittancy, retrogradation stability, emulsifying stability, freeze-thaw stability;④ross-linking and esterification dual modification can decrease the digestibility of sweet-potato starch and increase the content of SDS and RS. Gelatinized starch measured in vitro digestibility of raw potato starch, RDS was 94%, SDS was 2%, RS was 4%, The certain conditions of CLOSA-SPS, RDS was 76%, SDS was 4%, RS was20%.3.The the toxicological safety assessment and regulation of blood lipids function of CLOSA-SPS were studied, the results showed that the CLOSA-SPS was safe and nontoxic, and it had lower cholesterol (TC), triglyceride (TG) and low Density lipoprotein cholesterol (LDL-C), increase high-density lipoprotein cholesterol (HDL-C) in hyperlipidemia rats and improve the function of liver steatosis.