Preparation and Characterization on the Physicochemical Properties of Liner Dextrin-insulin Inclusion Complexes

Liner Dextrin (LD) was prepared by waxy potato starch debranched with pullulanse, which has attracted immense interest in food, pharmaceutical and cosmetic industries as a versatile ingredient. These LD were separated on the basis of their differential solubility in aqueous/ethanol solutions of different volumetric ratios. Three LD products F-40, F-50, and F-M were obtained with average DP degree of polymerization values of 31.44, 21.84, 16.10. The results of Fourier transform infrared spectroscopy (FT-IR) analysis reveal that the reaction mainly conclude hydrogen bonding and hydrophobic interaction between LD and insulin in the process of inclusion complexes formation. X-ray diffraction (XRD) results indicate that the insulin is dispersed in the linear dextrin in an amorphous state, which proves that insulin is encapsulated in LD. The results of circular dichroism (CD) show that the changes in the secondary structure of insulin were negligible during the release from the inclusion complexes. The order of encapsulation capacity is F-M-INS> LD-INS> F-50-INS> F-40-INS. F-M-INS inclusion complexes show better effect on reducing the release of insulin in gastric juice and promote the release of insulin in intestinal juice and blood plasma than LD-INS.