Introduction Mechanical damage of seeds due to harvest, handling and other process is an important factor that affects the quality of seeds. Objectives To evaluate the impact damage to navy bean seeds. Methods The study was conducted under laboratory conditions, using an impact damage assessment device. Independent variables were: seed moisture content (10, 12.5, 15, 17.5, 20, and 25% wet basis), impact velocity (5, 7.5, 10, 12.5, and 15 m/s) and seed orientation (side and end). Results Impact velocity, moisture content and seed orientation were all significant at the 1% level on the physical damage in seeds. Increasing the impact velocity from 5 to 15 m/s caused an increase in the mean values of damage from 0.17 to 32.88%. The mean values of physical damage decreased significantly by 1.96 times (from 27.09 to 13.79%), with increase in the moisture content from 10 to 15%. However, by a higher increase in the moisture from 15 to 25%, the mean value of damage showed a non-significant increasing trend. It was found that the relationship between beans mechanical damage with moisture content and velocity of impact was non-linear and the percentage damage to seeds was a quadratic function of moisture content and impact velocity, respectively. Impact to the end of the seeds produced the higher damage (20.61%) than side of the seeds (11.14%). Conclusion To minimize physical damage to navy bean seeds, the impact velocity should be limited to 10 m/s or below. The optimum level of moisture, where impact damage was minimized, was about 15%.

The objective of this experiment was evaluate of the impact damage to pinto bean seeds where seed moisture content (9.25, 12.51, 15.01, 17.52, 20.01% wet basis), impact velocity (5.5, 8, 10, 12.5 and 15m/s) and seed orientation (end and side) were independent variables. The study was conducted under laboratory conditions, using an impact damage assessment device. The results showed that impact velocity, moisture content and seed orientation significantly influenced the physical damages of pinto beans at 1% level. Increasing the impact velocity from 5.5 to 15m/s caused an increase in the mean values of damage from 0.39 to 37.30%. With increase the moisture content from 9.25 to 17.52%, the mean values of percentage of damaged beans decreased significantly from 41.24 to 4.27%. However, by a higher increase in the moisture from 17.52 to 20.01%, the mean values of physically damaged beans showed a nonsignificant increasing trend. There was an optimum moisture level of 17.52% at which seed damage was minimized. The relationship between the percent of physical damage with impact velocity and beans moisture content was expressed mathematically. It was found that the percentage damage to seeds was a quadratic function of moisture content and impact velocity. Impact to the end of the seeds (18.62%) produced the higher damage than side orientation (13.12%).