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During handling operations, many problems that reduce the quality of vegetables may occur. Mechanical injuries are the leading cause of postharvest losses for the pumpkin, and can take place at any point of the production chain. This study aimed at evaluating the pumpkin fruits behavior, during their ripening stages, on the values of maximum compression force for fixed deformations, and determining the proportional deformability modulus of the fruits under compression at the repose position. Fruits were harvested at 15, 30, 40, 50 and 60 days after flowering and uniaxially compressed between two parallel plates. The results allowed to conclude that both the required compression force and the proportional deformability modulus increased during the maturation course, reaching a maximum force of 1,778 N and a maximum deformation modulus of 164 MPa, after 30 days. After this period, both the maximum force and the modulus values decreased, reaching 1,514.8 N of maximum force and a modulus of 132.09 MPa, after 60 days of ripening. Over the course of a longer maturation time, the fruit firmness increased, therefore requiring an increase in the maximum load to achieve greater deformation. The ideal period for harvest and transport of 'Jacarezinho' pumpkin fruits was set from 30 to 40 days after anthesis.

The objectives of this work were to verify the moisture content influence on the maximum compression force values, to determine the Proportional Modulus of Deformation, the Maximum Tangent and Secant for acerola seeds under compression on its natural repose position and for fixed deformations. Acerola seeds with moisture content varying from 0.12 to 0.46 (d.b.) compressed uniaxially between two parallel rigid plates. It can be concluded that the compression needed for deforming the acerola seeds decreases as its moisture content increases when the deformation values were within 19.2 and 548.8 N. The Proportional Modulus of Deformation increases with the reduction of the moisture content, where values found were within 5.2 to 72.1 × 10 7 Pa. The sigmoidal model represented resistance to the compression of the acerola seeds adequately for different moisture content.