Susceptibility of Bean Seeds to Thermal and Impact Damage

After convectional drying, bean seeds (Nadwislanski variety) were subjected to impact trials conducted in a specially constructed centrifugal impactor. The influences of rotational speed of 1000-2500 rev/min, seed moisture content of 14-21% w.b., and drying air temperature of 25-55°C on seed damage and germination were examined. To make the results more useful, a theoretical analysis of the mechanical forces acting on the seed was conducted to determine impact velocities. Values of impact velocity, below 4·0m/s and seed moisture contents above 18% w.b. were associated with acceptable seed damage of 5%. The test conditions, within the ranges given above, had little effect on seed germination capacity.