Preparation And Properties Of Amorphous Octenyl Succinic Anhydride Modified Cassava Starch

It was studied in this thesis how to prepare starch sodium octenyl succinate with octenyl succinic anhydride(OSA)as an esterification agent and lipase as a catalyst by using non-crystal granular cassava starch.Properties,structure and applications in frozen dumplings were also researched.The preparation of non-crystal granular starch was firstly studied by ethanol reagent method,and determined the suitable parameters for the preparation:20 min heating time,80? heating temperature and 50%ethanol concentration.Then starch sodium octenyl succinate was prepared by the maximum amorphization of starch as raw material.By single factor experiments,the effects of varieties of factors on the degree of substitute and reaction efficiency of starch sodium octenyl succinate were studied,including the quantity of lipase,the quantity of OSA,the time of reaction,the temperature of reaction and the pH of reaction.Based on those,the perpendicular experiments were used to optimize the technology.The process conditions were as follows:0.8%and 4%quantity of lipase and OSA respectively,30 min reaction time,45? reaction temperature,8.0 reaction pH.Under the conditions,the starch sodium octenyl succinate with DS 0.02456 and RE 0.794 was obtained.The granules morphology,structure of functional group,thermodynamic properties of starch sodium octenyl succinate and the crystal structure of non-crystal granular starch were analyzed by the modern analytical techniques.From Fourier transform infrared results,a new absorption peak appeared at the wavelength of 1722cm-1,which suggested that starch molecules were linked with OSA in the form of ester bond.Canning electron microscope result showed that the surface of starch granules was seriously destroyed after the decrystallization and esterification.Differential scanning calorimeter result proved that the starch was more easily gelatinized after the decrystallization and esterification.The X-ray diffraction result indicated that non-crystal granular starch was more easily esterified due to the increasing of amorphous region.The physicochemical properties of starch sodium octenyl succinate were changed.Compared with the cassave starch,the retrogradation,transparency and viscosity were better.Freeze-thaw stability and emulsifying ability significantly were enhanced.Moreover,Transparency and freeze-thaw stability were increased significantly(p<0.05),and emulsion ability and emulsion stability were enhanced with the degree of substitute increasing.The applications of starch sodium octenyl succinate in frozen dumplings were investigated at last.It could improve the farinograph and texture properties of dough.When the addition was 4%,stability time was increased significantly and the degree of softening was decreased.It could also reduce the dumpling wrapper's cooking loss significantly after repeated freezing and thawing(p<0.05).The result of texture analyzer indicated that the hardness of the dumpling wrapper increased significantly under cycles of freezing and thawing,the elasticity of raw dumpling wrapper and the gumminess of cooked dumpling wrapper were both increased significantly(p<0.05),when starch sodium octenyl succinate was added into dumpling wrapper.The sensory evaluation of cooked dumpling wrapper showed that,starch sodium octenyl succinate could also improve their appearance,hardness,boiling fastness and soup features.