Elastic stresses and plastic deformations in 'Santa Clara' tomato fruits caused by package dependent compression

The objective of this work was to study the fruit compression behavior aimi ng to develop new tomato packages. Deformations caused by compression force s were observed inside packages and in individual 'Santa Clara' tomato frui t. The forces applied by a transparent acrylic lever to the fruit surface c aused pericarp deformation and the flattened area was proportional to the f orce magnitude. The deformation was associated to the reduction in the gas volume (Vg), caused by expulsion of the air from the loculus cavity and red uction in the intercellular air volume of the pericarp. As ripening advance d, smaller fractions of the Vg reduced by the compressive force were restor ed after the stress was relieved. The lack of complete Vg restoration was a n indication of permanent plastic deformations of the stressed cells. Vg re generation (elastic recovery) was larger in green fruits than in the red on es. The ratio between the applied force and the flattened area (flattening pressure), which depends on cell turgidity, decreased during ripening. Frui t movements associated with its depth in the container were observed during storage in a transparent glass container (495 x 355 x 220 mm). The downwar d movement of the fruits was larger in the top layers because these movemen ts seem to be driven by a summation of the deformation of many fruits in al l layers.