Preparation Of Porous Starch Butyrate Ester And Its Application As Pickering Emulsion Stabilizer

Pickering emulsion is a kind of high-quality emulsion system with core protection and controlled release performance and high safety.Natural starch(NS)has the characteristics of environmental protection,green and safety,making it one of the more advantageous solid particle stabilizer in preparing Pickering emulsion.Butyric acid(BA)is a short-chain fatty acid that can prevent the occurrence of colon cancer.It can react as a hydrophobic group with starch particles to improve the emulsification performance of NS.Porous starch(PS)has much higher advantages in specific surface area and porosity than natural starch.As the reaction subject,it can improve the reaction efficiency and make Butyric acid modified porous starch(BA-PS)with higher Degree of substitution(DS).In this study,BA-PS was prepared with the enzyme-modified PS as the main body and BA as the object,and was characterized for its structure and performance,BA-PS as the stabilizer of Pickering emulsion to explore its emulsification;Finally,BA-PS Pickering emulsion was used as the carrier to further explore its application value in the clinical anticancer drug Taxol(Paclitaxel,PTX),in order to provide some theoretical basis for the application of porous starch ester butyrate as Pickering emulsion stabilizer.The study results are mainly as follows:(1)The specific surface area of PS prepared by enzymatic method of 3.91 m~2/g,with an average pore diameter of 11.13 nm,this method retains the original crystalline structure and the honeycomb porous structure of the particles running from the surface to the inside.(2)With the PS as the main body,The BA is the object,BA-PS with DS from0.023 to 0.176 were prepared,FT-IR and NMR indicated the esterification was successfully completed;SEM and XRD showed that BA-PS retained the granular structure and crystallization structure of PS very well,However,the relative crystallinity of BA-PS decreases with increasing DS.The TGA results show that the esterification modification improves the thermal stability of starch.And the thermal stability gradually increases with the increase of DS;DSC results showed that esterification increased the gelatinization resistance of starch.The in vitro digestion results showed that,The BA modification significantly increased the digestive resistance of NS(p<0.05),and the performance is positively correlated with the DS.The content of resistant starch in ba-PS of the largest DS prepared in this study reached 40.79%(3)The application of BA using NS,PS and BA-PS as stabilizer to investigate the effect of BA modification on the emulsification properties of starch.The results showed that the emulsification ability of NS and PS was poor,and the emulsification ability and emulsification stability of starch were greatly improved after BA modification.The emulsification index of BA-PS stable emulsion with three different DS is 42.61%,73.61%and 85.43%,the emulsification capacity of BA-PS increases with DS;the stable emulsion droplet size decreases with DS;the better the uniformity of the emulsion droplet,the better the viscosity of the emulsion system,the smaller the zeta potential value;the tighter the starch layer on the droplet surface;the stable BA-PS shows good storage stability in 50 D.(4)In the application study of BA-PS Pickering emulsion loaded on PTX,the emulsion characterization results showed that the addition of PTX did not affect the emulsification properties and emulsification stability of BA-PS.The maximum encapsulation rate of PTX by the emulsion system was 82.12%,and the maximum retention rate of PTX during 30 D storage was 77.31%.The in vitro release results showed that when the BA-PS Pickering emulsion simulated the human digestive system,PTX was greatly released during the digestion of the small intestine system.After 6 h of the small intestine digestion,the final PTX release rates of the three different DS emulsions were 85.59%,77.46%and 73.53%,respectively.The BA-PS Pickering emulsion greatly improved the bioavailability of PTX.In conclusion,the BA-PS prepared in this study has better resistance to digestion and emulsibility,and the Pickering emulsion prepared as a stabilizer allows a further study on the delivery of drugs or active substances.