Study On The Preparation Technology And Physicochemical Properties Of Resistant Starch

Resistant starch (RS) is defined as the starch that can not be digested in small intestine of human body. There are four categories of RS: physically trapped starch (RS1); resistant starch granules RS₂; retrograded starch(RS3); chemically modified starch(RS4). RS performs better than dietary fibre in physiological function, playing a key role in protecting gut function and reducing glycemic concentration after meal. To make clear of the forming mechanism and the characteristics of RS and to study its preparation technology are important for food industry to select raw material and technology, for improving RS concentration in products and the nutrition value of food, and for the deep processing of corn andpotato resources in our nation.In this study, the common corn starch was used for the purpose of investigating the RS preparation technologies, which included autoclaving treatment and enzymes process. Furthermore, this project first tried to combine these two technologies as autoclaving-enzymes treatment, for searching the better technical condition. A series of tests on improving the productive of RS had been done. The factors under research that influencing the production efficiency of RS consisted of autoclaving temperature and time, starch concentration, incubation temperature and time, cooling speed, enzymes dosage, action temperature and time of enzymes and so on. The better technology parameters and conditions were obtained: the concentration of the starch is 20%, pH value is 5, the pullulana of 2.4PUN/g starch is added, the reaction temperature is 60 ℃ for 12 h, then autoclaving temperature is 121 ℃ for 30 min, and incubating 24 h under 4℃, the productive of RS can reach above 31% through this condition, a little more than the summation of autoclaving treatment and enzymes process.The sample products obtained from this technology were analysed and identified by the absorption curve of RS with iodine, RVA, SEM, and X-ray diffraction. And the results confirmed these samples were RS, which proved the analysis of RS-TSA to be reliable.