Physical properties and in vitro digestibility of whole grain extrudates of pearl millet and maize
Nutri-Cereals, Single screw extruder, Amylose-lipid complex, Digestibility of carbohydrates.
Pearl millet, currently called “Nutri-Cereal”, has attracted the attention by the Food and Agriculture Organization for human consumption, as health and gluten-free cereal. In contrast to pearl millet, maize is a commercially established gluten-free cereal used in the production of diverse foods, including expanded extrudates. Therewith, the pearl millet (ADRg9070 hybrid) and commercial maize were separately extruded, with the aim to 19 compare physical properties, and the in vitro carbohydrate digestibility. The extrudates were analyzed for the following physical properties: expansion index, texture measurement, proximate composition, total starch, morphology, x-ray diffraction, relative crystallinity, thermal properties, paste profile, water absorption and solubility index. The effects of moisture on pearl millet extrusion was investigated obtaining extruded with smaller sectional expansion index and water solubility index, and highest protein, fiber and fat content. The millet extrudates presented about 20% less digestibility of carbohydrates measured by the total reducing sugar when compared to maize. The maintenance of birefringence and thermal properties mainly in the extruded millet (14%) sample demonstrates a probable thermal resistance of millet starch. Thus, pearl millet extrudates showed distinct properties which may contribute to providing healthier gluten-free products to the food industry.