Characterization of the mechanical properties of the cape gooseberry fruit (Physalis peruviana L.)

Colombia is the world’s leading producer of the cape gooseberry and it is a crop of great importance due to its high demand in the international market. The fruit, the part that is sold, is an ovoid-shaped, juicy berry, and its harvest starts when the fruit is orange-colored and the cap surrounding the fruit is yellow- colored. This labor is done manually. During this phase of collection, subsequent handling and transport to the places of packaging and marketing, the fruit is subjected to multiple loads which may deteriorate it in different ways, resulting in significant product losses. Rheological tests of unidirectional compression, punctures, and cuts at the peduncle were per- formed in order to characterize the mechanical response of the fruit to the type of forces exerted at harvest and post-harvest handling. It was found that the fruit’s firmness in unidirectional compression in the axial direction, with a ripeness grade of four, was 38.6 N, while the force required to separate the fruit from the peduncle was 15.1 N. The mechanical behavior of the cape gooseberry corresponds to a viscoelastic, anisotropic, highly variable material.