Studies on puffing of Bengal gram. I.

Preliminary sand roasting of the Bengal gram was carried out at 150 to 200 degree C for 30-135 s followed by equilibration and water-dipping of previously roasted and moisture conditioned grains. Effect of impact was assessed by passing roasted grains through a laboratory model puffing roller coupled with a hot plate and in a centrifugal sheller at different revolutions. Max. puffing was achieved under the following conditions: initial grain moisture content of approx. 7.8%; preliminary roasting of grains with sand at 170 degree C for 75 s; tempering of grains for about 90 min to reach a moisture content of approx. 4.9%; dipping in water for 5 s to absorb 0.8% additional moisture; final puffing of grains by roasting at 230 degree C for 30 s; and impacting between a roller (300 m/min) and a hot plate (rather than a centrifugal sheller) for dehusking and splitting.