Study And Application On Digestibility And Group Distribution Of OSA Starch

The octenyl succinate anhydride(OSA)starch is widely used in food.The introduction of OSA group enhances the anti-digestibility of starch leading to reduction in the glycemic index of starchy food.Additionally,the strong anti-digestible nature of OSA starch offers it the potential to act as a carrier for drug sustained-release.Consequently,corn starches with different crystallization and amylose content were modified by OSA.Firstly,the influence of OSA modification on the physicochemical properties and structural characteristics of starch was analyzed.The relationship between the distribution mechanism of OSA groups on starch granules and starch chains as well as the digestibility of the modified starches were further investigated.In order to investigate its sustained-release ability,OSA starch was applied as the drug sustained-release carrier.This paper intended to provided theoretical basis for OSA starch application in anti-digestible food and drug sustained-release carrier systems.The main research contents and results are as follows:To investigate the effects of OSA modification on its physicochemical properties and structural characteristics,OSA starches with DS of 0.02 and 0.05 were prepared by using waxy starch(WS),normal starch(NS)and high-amylose starch(HS).The results showed that the reaction efficiency of the different starches modified by OSA was in the order of HS>WS>NS.Functionally,the swelling power of the modified starches was increased,and the degree of increase of A-type starch(WS and NS)was higher than that in B-type starch(HS).Morphological investigations revealed that the degree of starch surface damage increased with the elevation of DS.Fourier transform infrared spectroscope(FTIR)and X-ray diffraction(XRD)analysis showed that the modification decreased the degree of the short-range and longrange ordered of A-type starch.The analysis of the distribution of chain length showed that while the content of A chains increased,the content of B chain decreased in A-type starch.However,the change of chain length in B-type starch showed the opposite trend.The analysis of starch molecular weight showed that OSA modification not only reduced the molecular weight but also caused the loose of molecular structure due to OSA group introduction.Secondly,the distribution of OSA groups on starch granules as well as starch chains were further examined.And the relationship between OSA groups distribution and starch digestibility of raw and cooked starch was established,respectively.The distribution of OSA groups on starch granules was studied by confocal laser scanning microscopy(CLSM)and Raman spectroscopy.The results showed that the distribution pattern of OSA groups in B-type modified starch decreased in turn from surface to inner with respect to the content of OSA groups.The order of intensity in the distribution of OSA groups in A-type modified starch was surface > center > intermediate transition position.However,the distribution intensity of NS-OSA was center > surface > intermediate transition position at high DS.The distribution of OSA groups on starch granules caused an elevation of RS content in raw WS,NS and HS increasing from 53.26%,73.61% and 86.85% to 65.42%,82.69% and 88.65%(DS 0.02);71.19%,81.58% and 93.05%(DS 0.05)with the increase of DS respectively.The distribution of OSA groups on the starch chains was studied by pullulanase and ?-amylase.The results showed that OSA groups distributed mainly in the inner chains of modified starches with some OSA groups also distributed in the branches of long chain of A-type modified starch.The distribution of OSA groups on the starch chains caused the RS content in cooked WS and NS to increase by 11.6%,8.19%(DS 0.02)and 21.39%,17.98%(0.05)with the increase of DS,while the RS content of HS-OSA decreased by 1.51%(0.02)and 6.14%(0.02).Finally,WS-OSA,NS-OSA and HS-OSA with different DS were used to replace 50% of hydroxy propyl methyl cellulose(HPMC)to prepare drug sustained-release carriers,and compared the sustained-release effects of different OSA starches and the influence factors were analyzed.The results showed that the sustained release effect of the tablets prepared by WSOSA and HS-OSA was enhanced with the increase of DS.In comparison among tablets with the different carriers,0.02 NS-OSA had the best sustained-release effect are relatively low cost.The correlation analysis showed that the drug release rate was positively correlated with the extent of digestion of OSA starch and negatively correlated with its swelling properties.