A new method for measuring impact related bruises in fruits

This paper presents a new method for the direct determination of apple deformation under impact loading conditions that uses a high speed camera. The separately mounted camera was not susceptible to impact oscillations, which allowed for more accurate measurements of displacement. The application of two independent measuring systems, a high speed camera and a force sensor, enabled the quantitative assessment of phenomena occurring during and after the impact of apples against a rigid, flat plate. For the apples with a mass between 170 and 180 g, bruising started at impact velocities of 0.5 m s−1. Permanent deformation and maximum stress were the best parameters determining the damage under impact loading conditions. The experiment confirmed the importance of the critical stress criterion as regards the whole fruit under impact loading conditions.