Detection of Firmness in Intact Pumpkins and Sakurajima Radishes by Impact Forces

Abstract

The impact forces of the sample struck by hammer of a rigid sphere were studied as means for nondestructive determination of firmness. Impact forces were predicted with a simple elasticity model. Model results showed that the shape characteristic k (peak force/impulsion^6/5) of the impact force solutions can be used to predict firmness. Because it was sensitive to changes in elasticity of sample and completely insensitive to the speed at contact and variations in size of samples.
On experimental apparatus with intact pumpkins and Sakurajima radishes, the correlation coefficients between the impact characteristic K, and flesh firmness of pumpkins and Sakurajima radishes measured by a penetrometer were 0.93, and 0.92 respectively and hence, these results showed that the method was suitable for determining firmness of pumpkins and Sakurajima radishes.