Study On The Preparation And Properties Of Acid-acetylated Composite Modified Starch

In order to achieve the purpose of environmental protection and energy saving,it is necessary to improve the preparation technology of modified starch.In this dissertation,dry process with microwave irradiation method was adopted to produce the modified starch,which provided a new and feasible method for industrial production.The preparation technology,structural characterization,and properties of modified starches were further studied using cassava starch as raw materials,and the main conclusions were as followed:1.The best process parameters of acidified starch were: the dosage of hydrochloric acid was 0.8%,moisture content of the system was 18%,the microwave power was 40 W with the radiation time 550 s and radiation temperature75?.In these conditions the viscosity of acid hydrolysis starch was 13 m Pa?s.2.The best process parameters of acetate starch were: the dosage of esterifying agent was 5%,the moisture content of the system was 16%,the microwave power was 400 W with radiation time 700 s and radiation temperature70?,and system p H was 8.The DS of acetate starch which prepared under these conditions were 0.0718.3.The best process parameters of acid-acetylated starch were: the dosage of esterification agent was 5%,the moisture content of the system was 20%,the microwave power was 400 W with radiation time 700 s and radiation temperature65? and the system p H was 8.The viscosity and DS of acid-acetylated starch which prepared under these conditions were 91.4 m Pa?s and DS was 0.0687.4.The results of FT-IR and SEM showed that acidulation reaction and esterification reaction made certain destruction to the morphology on the surface of starch granules,and a new group has been attracted to the starch.5.Compared with the acidified starch,the acetate starch and the cassava starch,the acid-acetylated starch provided improved characteristics in transparency,freeze-thaw stability,retrogradation stability,viscosity and water retention.This dissertation will provide a basis study for the production and the application of acid-acetylated starch in industry area.