Preparation, and Characterization of Ultrasound Modified Millet Starch and Its Application for The Encapsulation and Controlled Release of Grape Seed Polyphenols

Abstract

Objective: This study was carried to prepare and characterize the ultrasound modified millet starch, and encapsulate Polyphenols in modified millet starch and alginate microspheres. Methodology: Millet starch was modified using ultrasound treatment at power amplitude of 60% for 10-, 20-, 30- and 40- mins to produce starch nanoparticles. The modified composite microspheres were further prepared using different ratios of modified millet starch particles and sodium alginate (0.2/0.8, 0.4/0.6, 0.6/0.4) to polyphenols. Structural, functional and physicochemical characterisation was carried for the modified starch and the microspheres. Results and Conclusions: The nanoparticles showed significantly increased values of water absorption capacity (WAC), oil absorption capacity (OAC), swelling power and solubility. Nanoparticles showed a smaller median diameter (499.2 ± 0.52 nm), higher encapsulation efficiency, higher ζ-potential, and a better poly dispersibility index. XRD and DSC results confirmed changes in the physical state of starch nanoparticles from crystalline to amorphous. These results were confirmed through FTIR also. Also, FTIR results showed strong interactions among starch, alginate, and GSP in modified millet starch microspheres (MMS-Alg) compared to native sample (NMS-Alg) microparticles, contributing to enhanced EE and slower release of MMS-Alg microparticles. Therefore, modified MMS-Alg composite microspheres can be used as potential candidate for the encapsulation and controlled release of GSP