Effect of Milling Speed on Grinding Characteristics and Proximate Composition of Maize Grits (Dalia) during Storage

摘要

The grits, commonly known as 'Dalia" in India, is the main product of dry milling process, which is used as porridge by boiling domestically. In the present study the effect of milling speeds on particle size distribution, grinding constant, specificpower consumption and physico-chemical quality parameters of maize grits were studied and the results were compared with the commercially available maize grits. Higher percentage of maize grits (Dalia') fraction (particle size of 2.8 to 0.71 mm) was obtained by milling in a burr mill at 80 rpm (72.45 ± 0.78%) than at 124 rpm (68.50 ± 1.02%). The fineness modulus was found to be highest (3.77) in 80 rpm speed followed by 124 rpm (3.51). The significant difference in SPC (1.54 kWh/kg), grinding constantand (3.81) was observed for grits prepared at 80 and 124 rpm speeds, respectively. The samples milled at both 80 and 124 rpm speed had a protein content of 7.20 and 7.05%, fat 3.6 and 3.73% and moisture content 9.63 and 9.53% respectively. The commercially available sample had 6.9 % protein, 3.9% fat and 13.8% moisture. The maize grits prepared at 80 rpm packed in HDPE packs can be stored upto 50 days without deterioration in quality parameters.