Physicochemical and functional properties of starches isolated from different millets

Abstract

The current investigation aimed to investigate the physicochemical, morphological, and functional properties of starches from four millet varieties, namely foxtail millet, finger millet, pearl millet, and sorghum and compared them with rice starch. The morphological characteristics of starch were analysed using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). The study found that the solubility (2.2 ± 0.01 % to 11.30 ± 0.05 %) and swelling power (2.54 ± 0.25 % to 9.63 ± 0.21 %) of starches increased with an increase in temperature. Foxtail millet had the lowest syneresis (3.98 %) over a 5-day cycle compared to other varieties. The pasting properties of all millet varieties, except for finger millet, displayed higher setback values, indicating lower retrogradation properties. The FTIR analysis confirmed the carbohydrate nature of the starch samples, and the microstructure analysis of millet starches revealed symmetrical, round-shaped granules with smooth surfaces. This research is significant in promoting the utilization of millet starches, distinguishing them from other cereals and tubers. The findings are expected to contribute to the evaluation of starch quality for potential applications in various industries, including bio-film production, thereby enhancing the overall value of the product.