Grinding characteristics, physical, and flow specific properties of roasted maize and soybean flour

Grinding characteristics (one and two stage grinding) of roasted maize (RM) and soybean (RS) were conducted in attrition mill to find the effect of feed rate and peripheral speed on average particle size (A(PS)), specific energy consumption (S-EC), size reduction ratio (SRR), and grinding constants. Carr Index (CI), Housner ratio (HR), density, water, and oil absorption capacity of flour were also studied as a function of particle size. The higher SRR, A(PS), and grinding recovery were recorded in the first stage grinding as compared with second one. S-EC was decreasing significantly (p<.05) from 0.00390.0011 to 0.0013 +/- 0.0019 kwh/kg as, feed rate increased from 9 to 15 kg/hr. The grinding constants were significantly increased in the second stage grinding. The flowability of flour such as CI and HR was poor at lower particle size. S-EC and A(PS) analysis revealed that a two-stage segregated grinding would be suitable for RM and RS grinding. Practical applicationsRoasted maize and soybean flour are highly nutritive food and prepared by roasting, grinding and sieving. Flour particle sizes and flow specific properties play an important role in addressing malnutrition and ready-to-eat food formulations. The digestibility and release of bioactive components also depend upon particle size and granular morphology of the food. Though, the present study is also acquainted with energy consumption during processing operation and product quality and which are key parameters for scaling-up and designing the grinding equipment. The information generated regarding the energy consumption and health benefits may be useful for food processors and consumers as well.