Hydrophobic Modification of Nanometer Starch and Adsorption of Lutein

Objects: In order to improve the application of starch in the field of drug loading, the aim was to prepare the nano hydrophobic modified starch and study its effect on hydrophobic drug loading. Methods: Nanometer starch (SNPs) was prepared using tapioca starch as a raw material by deposition method. On this basis, rosin ester nanometer starch (RENPS) with different degrees of substitution (DS) was synthesized by modifying SNPs in a two-phase system and using lipase as a catalyst. The adsorption effects of SNPs and RENPS on lutein under different conditions were investigated. Results: The results indicated that the esterification did not significantly affect the morphology of SNPs. The size of SNPs ranged from 250 nm to 800 nm, and the main peak was 480 nm. The size of RENPS ranged from 100 nm to 800 nm, and the main peak shifted from 450 nm to 100 nm with the increase of DS. There was a positive correlation between DS and the hydrophobicity of RENPS. The contact angle of RENPS could reach 93.32°±1.15°, while the contact angle of SNPs was only 51.69°±2.15°. As DS increased, the time for RENPS to reach the adsorption equilibrium of lutein decreased gradually, but the amount of adsorption increased gradually. The adsorption of lutein by SNPs was a first-order kinetics, and the adsorption of lutein by RENPS was a second-order kinetics. Conclusion: In this study, a hydrophobic modification method of RENPS was determined, and the loading capacity of modified RENPS on hydrophobic drugs was significantly improved.