Preparation, Modification And Application Of Porous Pueraria Starch

The main component of dry kudzu root is starch, cellulose and isoflavones, the pueraria starch extracted from pueraria is a kind of green health food with unique nutrition and is both excellent in food and medicine. The products of pueraria starch on the market currently have instant arrowroot, arrowroot jelly, arrowroot candy, health arrowroot noodles and so on. The products of kudzu starch is more and more popular in the international market in recent years, so the development of new kudzu starch products has an important significance. In this study, we use kudzu starch as raw material, through enzymolysis, crosslinking, and esterification, at last obtained the crosslinked esterifiable porous pueraria starch with more stable structure and properties; then use it as wall material to absorb the PSO, the result proved that the oxidation resistance of PSO was enhanced after being embedded by the porous starch.We use kudzu starch as raw material, prepare porous pueraria stach by enzymatic hydrolysis with a-amylase and glucoamylase’s synergy, and at last obtained the best technology by single factors and orthogonal experiments. Through the observation of SEM, we know the porous starch has uniform pore size distribution; the oil absorption rate of native starch is only about34%, but the porous starch close to60%, the water absorption rate also rose from50%to90%, therefore, compared to native starch, the absorption performance of porous starch is significantly improved.Use epichlorohydrin as cross-linked agents, modified the porous pueraria starch with cross-linking reaction. This cross-linking method is divided to alkalization and cross-linking step. Determined the suitable alkalization and cross-linking conditions by experiments, the absorption performance of cross-linked porous pueraria starch which is obtained under the conditions is improved compared to native starch and porous starch, Which the oil absorption rate of60%, water absorption is about105%.Use octenyl succinic anhydride as the esterifying agent to prepare cross-linked esterified porous pueraria starch, through single factors and orthogonal experiments, we obtained the best esterifiable conditions. The dual modified porous starch show higher absorption performance than single cross-linked starch, it’s oil absorption rate close to65%, water absorption up to110%.Compare the physical properties of native kudzu starch, porous starch, cross-linked porous starch and cross-linked esterified porous starch, we found that the dual modified porous starch has a higher absorption efficiency than the single cross-linked modified starch, and the paste transparency, freeze-thaw stability and retrogradation stability has improved significantly. The paste light transmission rate rose from10.8%which is of single cross-linking modification to21.5%; the freeze-thaw number is from one to two, and the water precipitation rate is only half; the double modified porous starch paste without any stratification after24hours, analyse these starch by SEM, XRD and DSC, it shows that the modified staches maintain the original porous structure, and the structure is more firm. It can be seen from the XRD patterns that the enzymatic hydrolysis of starch, cross-linking and esterification occurred mainly in the amorphous region, so the starch keep the original C-type structure; DSC results show that the enzymatic hydrolysis and crosslinking rose the starch phase transition peak temperature from96℃up to103℃, and the enthalpy also increased, but dropped to about97℃after esterification, and the enthalpy from171J/g down to58J/g, which indicates that the esterifiable starch is more easily gelatinized.Use the obtained modified porous starch as wall material, perilla seed oil as core material, the powder PSO can be made by just physical adsorption, the product has both healthy nature of kudzu starch and PSO. By single-factor experiments and orthogonal test, we can get the powder oil with more than30%embedding rate; do accelerated oxidation test on the raw PSO and powder oil, the test results show that the oxidation resistance of the powder oil is significantly enhanced.