Influence of impact velocity and moisture content on mechanical damages of white kidney beans under loadings

Abstract

Kidney beans are more susceptible to breakage under impact loading during harvesting and processing. This problem limited the mechanical harvesting. Mechanical damage decreased the commercial values of seeds. It also decreased the biological values of seeds. Improper harvesting of beans during harvesting may also result in severe seed vigour loss. The objective of this study was to study the effect of impact velocity (at 5, 7.5, 10, and 12 m/s) and beans moisture content (at 5, 10, 15 and 20% wet basis) on percentage of physically damaged beans. The device of assessing the impact damage was used to conduct the tests. All the tests were conducted in laboratory conditions at about 25 oC and 50% relative humidity. The results showed that impact velocity and moisture content significantly influenced the physical damages of kidney beans at 1% and 5% significant level, respectively. Increasing the impact velocity from 5 to 12 m/s caused an increase in the mean percent of physical damages from 3.25 to 37.5%. The corresponding data for beans at the moisture content of 5% were from 3.7% to 45.7%. With increasing the moisture content from 5 to 15%, the mean values of percentage of damaged beans decreased by 1.4 times. However, with higher increase in the moisture content from 15 to 20%, the mean values of physically damaged beans showed a nonsignificant increasing trend. The relationship between the percent of physical damage with impact velocity and beans moisture content was expressed mathematically. It was found that the model has provided satisfactory results over the whole set of values for the dependent variable.