Extraction, isolation, physicochemical characterization, phytochemical and proximate evaluation of pearl millet (Pennisetum glaucum) starch

Abstract

Pearl millet (Pennisetum glaucum) is the most widely grown type of millet. Starch was extracted from its seeds and subjected to physicochemical characterization, proximate analysis and phytochemical screening in order to ascertain its properties and adjudge its suitability for use in various industries. Physicochemical characterization of the starch revealed that it had gelatinization temperature of 79 OC, foam and emulsion capacities of 4 and 20% respectively, pH of 6.88, water holding capacity of 28.345 ml, bulk and tapped densities of 0.526 g/cm3 and 0.667 g/cm3 respectively, browning temperature of 224.5 – 265.0 OC and charring temperature of 270.3 – 290.0 OC. The starch percentage solubility at 90 OC was 3.2 with a swelling power of 17.65. Pennisetum glaucum starch was discovered to be made up of 17.66% amylose and 82.34% amylopectin. Phytochemical screening of the starch showed the presence of saponins, terpernoids, carbohydrates and resins. Proximate analysis of the starch showed ash content of 0.18%, moisture content of 6.97%, crude lipid content of 5.99%, crude protein content of 3.46% and carbohydrate content of 83.4%. The various results from the characterization of the starch from Pennisetum glaucum showed that it is a potential source of pharmaceutical / industrial starch as its properties compare favourably with those of starch being used in the pharmaceutical industries.