Fracture mechanics analysis of the texture of potatoes

The generalized fracture mechanics approach (GFM) developed by Andrews (1974) was applied to measure the fracture toughness of potatoes of the cultivar Shepody. Specimens were fashioned from the centre portions of 10 tubers, and were soaked in distilled water overnight to attain full turgor pressure in the cells. Tensile tests were performed on specimens with different initial crack lengths. The function k(1)(W-0) for potatoes was evaluated. This function is an explicit distribution function of input energy in the specimen (work done on unit volume of the specimen). From the form of the function, a simple mathematical model was developed to describe k(1)(W-0) for potatoes. The critical apparent energy release rate defined by GFM theory was found to be constant (T = 2650 J m(-2)) and independent of initial crack length and applied load. The fracture toughness (T-0) of Shepody potato obtained from this value of T was 212 J m(-2), which is in good agreement with the results of other researchers using uniaxial compressive and tensile tests.