Milling is an important process in the post-harvest handling of red lentils. The effect of milling moisture content, milling speed and milling time on the dehulling characteristics of two varieties of red lentils, CDC Impact and CDC Redberry, was investigated. Response surface methodology with a central composite design was used to determine optimum milling conditions. Optimum milling conditions included: milling moisture content of 12.5%, milling speed of 1,100 RPM and dehulling time of 38 s. Milling with these parameters resulted in dehulling efficiencies of ≥ 85%. Various treatments (high heat drying, near ambient drying, and successive freezing and thawing cycles) were employed to simulate different storage conditions. Dehulling efficiency of both red lentil varieties was negatively affected by drying yet dehulling quality was not adversely affected by freezing and thawing. This work provides information necessary to establish post-harvest techniques that maximise the dehulling efficiency of red lentils.
Keywords: red lentils, storage conditions, moisture content, milling speed, milling time, optimisation, dehulling quality, postharvest technology, response surface methodology, RSM, central composite design, CCD, freezing, thawing