| In this study,fresh ginkgo was used as raw material to extract ginkgo starch by alkali method.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 ginkgo starch.Properties,structure and applications in noodles were also researched.The results of this study may provide an new technical way for application of ginkgo and ginkgo starch.Firstly,gingko starch is subgelatinized.Then starch sodium octenyl succinate was prepared by the maximum amorphization of starch as a 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 starch concentration,subgelatinization temperature,subgelatinization time,quantity of lipase,quantity of OSA,reaction pH,reaction temperature and time.Based on those,the orthogonal experiments were used to optimize the technology.The process conditions were as follows:30%starch concentration,75? subgelatinization temperature,30min subgelatinization time,1%and 4%quantity of lipase(10000u/g)and OSA respectively,30 min reaction time,30? reaction temperature,8.0 reaction pH.Under the conditions,the starch sodium octenyl succinate with DS 0.0169 and RE 0.55 was obtained.The granules morphology,structure of functional group,thermodynamic properties of starch sodium octenyl succinate 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.The results of scanning electron microscopy showed that the surface morphology of starch granules could be changed by esterification,and the reaction occurred mainly on the surface of starch.The analysis of differential scanning calorimetry showed that the starch was more easily gelatinized after esterification.The analysis of X-ray diffraction showed that the amorphous region of starch increases after esterification,which may be caused by subgelatinization.The physicochemical properties of starch sodium octenyl succinate were changed.Compared with the ginkgo starch,the solubility,viscosity,retrogradation,transparency and emulsifying capacity were increased significantly(P<0.05).The water holding capacity was also increased.And these properties were increased with the increase of degree of substitution.But transparency were not better than ginkgo.At the same time,the content of SDS and RS of starch sodium octenyl succinite was obviously increased((P<0.05).indicating that the esterified starch had some anti-enzymatic properties.The applications of starch sodium octenyl succinate in noodles were investigated at last.Compared with no starch,adding gingko SSOS in a certain range can improve the quality of noodles,enhance water holding capacity,reduce the turbidity of small noodle soup(p<0.05)and boil loss rate.The hardness,elasticity,stickiness and chewing strength of noodles were also significant increased(p<0.05),especially when the addition amount was 9%.Compared with the addition of ginkgo starch,when the addition amount was 9%,the hardness,elasticity,stickiness and chewiness of the ginkgo SSOS noodles were significantly better than that of the ginkgo starch(p<0.05).At the same time,sensory evaluation showed that when the ginkgo SSOS was added to 9%,the total score of sensory evaluation was the highest. |
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