Study On Preparation And Application Of Cross-linked Porous Starch

Cross-linked porous starch, a new type of modified starch with hollow, can be produced by hydrolyzing cross-linked starch under the pasting temperature which is made from corn starch through cross-linked. In order to enhance the starch granule structure and improve lipophilicity of the porous starch, it make bridges between molecules and form cross-linked bonds, thereby improving the physical and chemical properties of porous starch and application performance.Cross-linked starch was made from corn starch through mixed acid (citric acid, acetic anhydride) as cross-linked reagent. The single element and orthogonal experiment showed the optimum cross-linked reaction condition as follows:the amount of mixed acid was 5%, mixed acid ratio was 1:50, temperature was 35℃, reaction time was 2.5h. Under this condition, the sedimentation volume of cross-linked starch was 3.93mL.Cross-linked porous starch can be obtained by complex enzyme (a-amylase and Glucoamylase) enzymolysis. Select starch concentration, pH, reaction temperature, reaction time, enzyme addition, enzyme combination as single-factors. The optimum enzyme conditions of cross-linked porous starch were acquired through the single factor and orthogonal experiment as the capacity of absorption water and oil, there were starch concentration was 20%, pH value was 5.0, enzyme addition was 1.75%,, enzyme combination was 1:6, reaction temperature was 45℃, reaction time was 20 hours. Under optimum condition, the capacity of cross-linked porous starch of absorption oil was 89%, the capacity of absorption water was f49%. Using scanning electron microscopy and infrared absorption spectrometer to observe and analyze the cross-linked porous starch, we can see that the particle of granules showed honeycomb hollow structure, and the sites of enzymes and cross-linked role are in-OH and-CO groups of starch grains which is means esterification cross-linked reaction.Lycopene was absorbed by porous starch and cross-linking porous starch so that established method of the porous starch prepared lycopene powder, and studied factors that influence the stability of lycopene include temperature, optical fiber. After 120h in the conditions of light (natural light, fluorescent lamp and darkroom), the residual rates of cross-linking porous lycopene powder, porous starch lycopene powder and lycopene decreased by 44.69%,27.89%,13.49%; 76.68%,47.15%,22.07% and 81.31%,65.15%,31.74%. After 4h in the conditions of thermal (60℃and 90℃), the residual rates of them decreased by 7.36%, 63.28%; 5.58%,74.37% and 19.04%,81.55%.The results show that cross-linked porous starch has good adsorption property. The antioxidant capacity and in natural light (bright light), high temperature environment stability of cross-linked porous starch lycopene powder is better than lycopene. It provides reference for application and storage of lycopene.