Mechanical properties of tomatoes as related to puncture injury susceptibility

The relation between mechanical properties of tomato (Lycopersicon esculentum Mill.) and puncture injury susceptibility was investigated using two cultivars: Tradiro, which is moderately resistant and Blitz, which is very susceptible. Mechanical properties were determined using a universal testing machine and an acoustic firmness sensor. The susceptibility to puncture injury was measured by a pendulum test. By means of Partial Least Squares analysis (PLS), a relationship with a coefficient of determination (R-2) of 0.78 was found between the mechanical properties and the puncture injury susceptibility of the tomato cultivar. High loadings were found for the force required to puncture the tomato with and without skin, the elasticity of the fruit, the toughness of the skin and the acoustic firmness of the tomato fruit, indicating that these mechanical properties affect the susceptibility to puncture injury. The obtained results directly imply that these mechanical properties should be used to screen for genotypes with lower. susceptibility to puncture injury.