Study On The Preparation,Properties Of Rice Starches Octenyl Succinate And Its Application In Nanoemulsion

OSA-modified starch（starch octenyl succinate）is a product obtained by the esterification reaction of octenyl succinic anhydride and starch.Through modification,both hydrophobic and hydrophilic groups can be introduced into starch,thereby changing its functional characteristics.OSA-modified starch can be used as an emulsifier to prepare nanoemulsion,which can carry many nutrients and enhance their stabilities.This article mainly studied the structure,physicochemical and functional properties of OSA-modified derivatives of three Japonica rice starches（NAT-Waxy ST,NAT-Normal ST and NAT-High Amy ST）,and their application effects in the preparation ofβ-carotene emulsion.Three kinds of japonica rice starches were modified by OSA at three OSA concentrations,and the structures of OSA derivatives were characterized.The results showed that as the amount of OSA increased,the degree of substitution of the modified starch increased.When the concentration of OSA is the same,the modified starches prepared by NAT-Waxy ST and NAT-Normal ST have a higher degree of substitution than NAT-High Amy ST.Compared with the three original japonica rice starches,the infrared spectra of the corresponding OSA derivatives showed characteristic absorption peaks at 1725 and 1571 cm^-1,which proved that the starch was successfully esterified by OSA.OSA modification had no significant effect on the morphology and particle size distribution of the three japonica rice starches.After OSA modification,the crystal forms of the three japonica rice starches did not change,but the relative crystallinity decreased slightly.The physicochemical and functional properties of OSA-modified japonica rice starch and native japonica rice starch were compared,and the effect of amylose content on the properties of OSA modified japonica rice starch was studied.The results showed that OSA modification reduced the gelatinization temperature of japonica rice starch and increased its gelatinization viscosity and swelling properties,but the degree of change was related to the amylose content.The paste prepared from OSA modified japonica rice starch has good freeze-thaw stability.The RS content of OSA modified japonica rice starch is higher than that of the original starch.Among the three modified japonica rice starches,the derivative of NAT-High Amy ST has the highest RS content.OSA-modification enhances the emulsifying ability and stability of japonica starch.The emulsifying ability and stability of OSA-Waxy ST is better than OSA-High Amy ST.Three OSA-modified japonica rice starches were used as emulsifiers to prepareβ-carotene nanoemulsions,and the stability of the emulsion and its protective effect onβ-carotene were investigated.The results showed that the emulsion prepared with OSA-High Amy ST as the emulsifier had the largest particle size,and there was no significant difference between the other two emulsions.Temperature is an important factor affecting the stability of the emulsion.Preserving theβ-carotene nanoemulsion at 4°C can more effectively prevent the particle size of the emulsion from becoming larger and the oxidative degradation ofβ-carotene.The light has little effect on the stability of the emulsion.In the measurement of retention rate,it is found that using these three OSA modified starches as emulsifiers to prepareβ-carotene emulsion can effectively storeβ-carotene.In this project,three kinds of japonica rice starches were used as raw materials to prepare three kinds of Japonica rice modified starch（OSA-Waxy ST,OSA-Normal ST and OSA-High Amy ST）with similar substitution degrees,and applied them in the preparation ofβ-carotene nanoemulsion.More applications in the food industry have laid the foundation.