| In order to study Dioscorea alata resistant starch preparation technology and characteristics, this paper used the add or remove way to study Dioscorea alata resistant starch preparation effect of the main several non-starch compositions in food, and used the autoclaving method to deter the optimal preparation process of resistant starch. In order to improve the yield of resistant starch, it combined the acid hydrolysis to upswing the technology. Then preliminary discuss three characteristics of resistant starch, enzymatic, acid fastness and water absorption. Specifically as follows:1. The technology research of Dioscorea alata resistant starch by autoclaving method Dioscorea alata in Hainan as the research object, using a single factor experiment to invest7conditions of influence factors of the technology by autoclaving method (starch content, pH, autoclaving temperature, autoclaving time, storage time, storage temperature, drying temperature). Designed three factors and two orthogonal rotation combination experiment to the three main influence factors (starch content, pH, autoclaving time), and combined the response surface methodology to result a quadratic polynomial regression model. The results showed:The optimal preparation process of resistant starch by autoclaving methods were, the mass concentration of starch solution33.00%, pH7.6, autoclaving temperature and time121℃,30min, storage temperature and time4℃,24h, and drying time18h at80℃, the yield of resistant starch from Dioscorea alata linn is13.92%.2. The technology research of Dioscorea alata resistant starch by acid hydrolysisIn order to improve the yield of resistant starch, in the optimal preparation process of resistant starch by autoclaving methods, first of Dioscorea alata starch by acid hydrolysis process. Added different kinds of acid to determine which acid has the most significant influence on resistant starch, then worked at three factors and four levels orthogonal experiment for3main influencing factors (acid concentration, acid dosage and acid hydrolysis time). The results showed:acid hydrolysis could effectively improve Dioscorea alata resistant starch yield, effect of citric acid> hydrochloric acid>acetic acid. The optimum technological conditions of acid hydrolysis were:the mass concentration of starch solution33.00%, adding1.42mol/L citric acid, add content was2.42%(percentage of dry weight of starch percentage), then hydrolyses2.39h, regulated pH7.6, pressing heat treatment in121℃ and36min, aging treatment in4℃and24h, drying in80℃and18h, the resistant starch yield would be increased to27.27%.3. Determination of characteristics of Dioscorea alata resistant starchDeterred three characteristics of Dioscorea alata resistant starch, enzymatic determination, acid fastness determination and water absorption determination. The test results show:the enzymatic of Dioscorea alata resistant starch was well, it was without a reducing sugar after4h in amylase. While the original starch under the same conditions was easy enzymatic hydrolyzed. After8h of enzymatic hydrolysis, only0.03%of the reducing sugar was measured in resistant starch. After20h, reducing sugar of two samples almost no longer increased. When pH<2, Dioscorea alata resistant starch(14min) and Dioscorea alata starch(9min) were hydrolyzed in a relatively short time. When pH>3, the acid fastness of resistant starch was significantly better than starch’s, and the edge was increased ceaselessly. The water absorption rate of Dioscorea alata resistant starch (46.2%) was significantly higher than starch’s(10.3%), and was about3.5times higher than the water absorption rate of Dioscorea alate starch.4. The research of non-starch compositions affected Dioscorea alata resistant starch preparationDioscorea alata in Hainan as the research object, using the add or remove way to discussion:added the different kinds and concentrations of soluble sugar、organic acid、metal ions, used pepsin to remove protein in Dioscorea alata, used methanol-petroleum ether solution to remove lipids in Dioscorea alata. Then prepared resistant starch by autoclaving method, determined the yield of resistant starch. To explore the effect of these non-starch compositions to Dioscorea alata resistant starch preparation. The results showed:soluble sugar inhibited the formation of resistant starch, and the inhibition effect was maltose> glucose> sucrose. Low concentration organic acid was helpful to improve the yield of resistant starch, and high concentration organic acid was inhibition of resistant starch yield, effect of citric acid> lactic acid>acetic acid. Metal ions inhibited resistant starch formation, effect of Na+>K+>Ca2+. Endogenous proteins and lipids were inhibition of resistant starch formation.Innovation:the tests researched Hainan agricultural products in high yield of Dioscorea alata, discussed the effect of non-starch compositions to resistant starch preparation, used the response surface methodology to get the preparation technology of Dioscorea alata resistant starch by autoclaving method. On the basis used acid hydrolysis to improve the yield of resistant starch. So it can effectively improve the economic benefits of Dioscorea alata. |
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