Physico-Chemical Characteristics of Maize and Sorghum as Affected by Popping

The purpose of the present work was to evaluate the impact of popping on the physical, nutritional and pasting characteristics of maize and sorghum. The bulk and true densities of both the maize and sorghum flour were observed significantly (P < 0.01) higher as compared to popped maize and sorghum flour. The water absorption and solubility index were higher for the popped grain flours due to porous structure. Water absorption index of maize grain increased upon popping from 302.7 ± 8.86 to 418.33 ± 9.77 and from 233.93 ± 4.04 to 397.57 ± 8.55 for sorghum grain. The peak, breakdown, final and setback viscosity values were lower for the popped flours. The lightness value of popped maize flour was significantly (p < 0.01) higher and ‘a’ and ‘b’ values were significantly (p < 0.01) lower than un-popped maize flour. However, in case of sorghum, popping exhibited reverse behaviour in terms of colour characteristics by causing a decrease in lightness and increase in a value, b value and chroma. In vitro protein digestibility of maize and sorghum increased significantly (p < 0.01) from 47.25 to 59.30 and 40.71 to 48.67 %, respectively after popping. Significant (p < 0.01) decrease in carotenoid, moisture content and increase in protein and carbohydrate content was observed upon popping. © 2015, The National Academy of Sciences, India.