WATERMELON SURFACE ABRASION ASSESSMENT METHOD

The resistance to abrasion during handling and transport has been dete rmined for only a few fruit and vegetables under limited conditions. A method was developed to assess surface abrasion of whole watermelon u sing an Instron testing machine and a friction apparatus. Abrasion tes ts were conducted on two cultivars at three normal forces and three sl iding speeds using a single abrasive surface. Segments of the friction force versus displacement curve were classified into types of respons e and associated with removal of different layers of the watermelon su rface. These responses, in turn, were correlated to various degrees of failure of the watermelon's surface. The threshold failure, for examp le, was defined as the beginning of surface abrasion. The magnitude an d start of each type of failure response was affected more by normal f orce than sliding speed. An equation, in terms of the normal force, wa s developed to predict the number of times a surface can be reused and still yield results comparable to a new surface.