Effect of tempering conditions and mill type on physicochemical and functional properties of sorghum (Sorghum bicolor [L.] Moench) flour

The objective of this study was to determine the effect of mill type and moisture content of sorghum (Sorghum bicolor [L.] Moench) grains on the flour yield and the physicochemical and functional properties of flour. Three commercial hybrids of sorghum grains were tempered between 8.2% and 15.5% of water content and milled by both roller and pearling-impact processes. The increase in pearling time decreased the milling yield and the ash content of the flour, reaching values between 47.20-78.02% and 0.44-0.76%, respectively, at 180 s of pearling time. A similar effect was shown in flours produced by roller milling with high moisture content; obtaining values between 47.99-55.82% flour yield, and 0.42-0.64% ash content, at 15.5% moisture content. The pasting viscosity and lightness of the flour ranged from 1197.5-2971.5 cP and 65.5-87.0 respectively; both parameters increased with higher pearling times and moisture content. Practical applications In this research, we produce sorghum flours from two hybrids of brown and one white sorghum. The pearling process followed by impact milling, and roller milling are commonly used in the industry, but there is not enough in-depth knowledge about the characteristics of the sorghum flour produced. This work emphasizes the different alternatives for grain conditioning before milling and also evaluates the physicochemical and technological properties of the flours obtained. We consider that the results represent a very important contribution to the sorghum flour industry. These provide relevant information to choose the most suitable milling conditions to obtain flour with the desired characteristics depending on its final use.