Preparation Of Resistant OSA Starch And Its Application In Complex Coacervation Microcapsule

This article provides a new way for the development and utilization of indica rice starch.By preparing indica rice OSA starch,it can be used as a thickener,emulsifier and other additives in the food industry.Then through the heat-moist treatment to increase its resistance to digestion,It can be used as a surface active agent,thickening stabilizer,anti-digestive health care,and food-based wall material at one time.Finally,use resistant OSA starch and whey protein isolate to Complex Coacervation to prepare probiotic microcapsules.Stability experiments have proved that the resistant OSA starch as the wall material of the microcapsule can well protect the activity of Lactobacillus plantarum and can be used as a new type of wall material of the microcapsule.Below are key research findings:(1)Using indica rice starch as raw material,rice starch octenyl succinate(rice OSA)was prepared by aqueous phase method.The effects of reaction temperature,acid anhydride dropping time,pH,and starch concentration on the reaction substitution degree DS and reaction efficiency RE were studied through single factor experiments.Taking DS as the inspection index,the preparation process of rice OSA was determined by the orthogonal test method.The process conditions are as follows: reaction temperature is 40?,reaction pH is9.0,acid anhydride dripping time is 4h,starch concentration is 30%,OSA starch DS=1.3915% and RE=78.2% obtained under these conditions.Compared with native starch,the change of physical and chemical properties of OSA starch increases with the increase of DS.After esterification,the solubility and swelling power of starch are improved to a certain extent.Fourier infrared spectroscopy shows that the OSA group is introduced.The crystallinity is reduced but the crystal form is unchanged.The thermogravimetric analysis results show that the thermal stability and gelatinization temperature of OSA starch were reduced,it is easier to gelatinize,and the viscosity of the paste increases significantly.The particle size of the emulsion prepared with DS=1.3915% rice OSA is only 426 nm and has good emulsification stability.(2)Heat-moist treatment of rice OSA starch to make it have good digestion resistance.After 18 hours of treatment at 30% moisture content and 120?,the resistant starch content increased from 25.2% to 42.2%,the starch gelatinization temperature increased,viscosity decreased.Digestion experiments showed that the digestion and hydrolysis rate of resistant OSA starch in the simulated gastrointestinal tract was 58.8%,and both fast-digested starch and slow-digested starch were reduced.(3)Explored the application ways of using resistant OSA starch to embed Lactobacillus plantarum.Using OSA starch and whey protein isolate to carry out Complex Coacervation experiments,the optimal complex agglomeration conditions were R-OSA/WPI ratio=1:2,pH=4.10.The obtained complex aggregates form a network structure,which has a good embedding effect on Lactobacillus plantarum.The entrapment rate of live bacteria in the microcapsules made by spray drying is 84.65%.(4)Stability experiments have proved that the number of viable cells of the resistant OSA starch/WPI microcapsules is 5.66 Log CFU/m L after being treated in the gastrointestinal tract for 3 hours.After being pasteurized at 85? for 15 s,the number of viable bacteria is 6.27 Log CFU/m L,and after 12 weeks of storage under high temperature and humidity conditions,some Lactobacillus plantarum bacteria still survived.Experiments have proved that the resistant OSA starch has a good application effect as a microcapsule wall material.