Functional and antioxidant properties of ready-to-eat flakes from various cereals including sorghum and millets

Abstract

Introduction Nowadays, ready to eat snacks are gaining much importance, as they are convenient to use, easy to handle compared with ready-to-cook snacks. Objectives To study the effects of cereal flaking and blistering process on the properties of the starch and nutraceutical content. Methods Ready-to-eat flakes from cereals such as maize grits, pearled barley, hulled oats, wheat, pearl millet and sorghum  were prepared by hydration, hydrothermal treatment, flaking and blistering in a fluidized bed roaster. Commercial rice flakes were also considered. Results Grains hydrated slowly but flakes hydrated rapidly, indicating the effect of hydrothermal treatment where parboiling was imparted. Equilibrium moisture content on soaking was very high in barley (46%, wet basis) and lowest in maize grits and sorghum (approximately 30%). Swelling power in grains was 11–17% and solubility was 8–29%. On flaking, the swelling power of different flakes remained almost the same. However, the solubility increased significantly. Maize showed the highest amylose content (~29%) and wheat had the lowest. Soluble amylose was lowest in wheat and highest in oats. Gelatinization temperature was highest in pearl millet (77.4 °C) and lowest in barley (59.5 °C). Peak viscosity was high in all the grains, except pearl millet. On flaking and blistering, the gelatinization temperature values and peak viscosity reduced to different extents. Conclusion These blistered cereal flakes are excellent ready-to-eat snacks, as they are rich in total polyphenols (16-58mg gallic acid equivalents/100 g) and exhibit high anti-oxidant activity and possess
good functional properties.