Tailoring Assam Magic Rice Starch through Oxidative Modification for Enhanced Pharmaceutical Applications

Abstract

Objective:

To evaluate the physicochemical properties and oxidative modification of starch isolated from Assam Magic Rice (Komal Chawl) and assess its suitability as a pharmaceutical excipient.

Methods:

Native starch was extracted by alkaline deproteination method and oxidized using sodium hypochlorite. Characterization was performed by Fourier-Transform Infrared (FTIR) spectroscopy, Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Rapid Visco Analyzer (RVA). Functional properties were determined through swelling power (SP), water solubility index (WSI), particle size distribution, and micromeritic parameters (Carr’s Index, Hausner’s Ratio).

Results:

FTIR confirmed oxidation by the appearance of carbonyl bands at ~1711 cm⁻¹. DSC showed a reduction in peak gelatinization temperature from ~80 °C (native) to ~65 °C (oxidized). XRD indicated a shift from A-type to Vh-type crystallinity. SEM revealed rougher granule morphology, and dynamic light scattering showed a decrease in particle size from 655 nm to 280 nm. Amylose content decreased from 17.2% to 14.0% and amylopectin from 56.8% to 35.0%. Flow properties improved, with Carr’s Index reduced from 30.35% to 22.93% and Hausner’s Ratio from 1.36 to 1.24. Oxidized starch exhibited greater hydrophilicity, lower swelling power, and enhanced solubility.

Conclusion:

Oxidative modification of Assam Magic Rice starch produced significant structural, thermal, and functional changes. The modified starch demonstrated improved micromeritic properties, reduced particle size, and superior hydrophilicity, supporting its potential application as a direct compression and controlled-release pharmaceutical excipient.