Synthesis and Characterization of Highly Substituted Acetylated Moth Bean Starch

This study was carried out to understand and establish the changes in physicochemical parameter of moth bean starch (MBS) after acetylation. Highly substituted starch acetate was prepared by reaction with native MBS with acetic anhydride using pyridine as organic solvent. Their formation was confirmed by the titrimetric analysis and Fourier transforms infra red spectroscopy (FT-IR). The presence of absorption band in FT-IR Spectra at 1748 cm(-1) confirmed the carbonyl group attachment. The thermal behavior of native and acetyl substituted MBS was investigated using thermo gravimetric method (TG-DTA). The results reveal that highly substituted starch acetate was more thermally stable as compared to native form. The x-ray diffraction (XRD) patterns showed loss of crystalline nature and its transformation into amorphous form. The scanning electron microscopy (SEM) suggested that the smooth surfaces of starch granules were changed into fibrous form after acetylation.