Evaluation of Engineering Properties of Tomato (cv. Cobra 26) Fruit, Necessary for its’ Automated Harvesting and Processing

Abstract

Evaluating the influence of maturation on selected physical characteristics and mechanical properties of tomato (cv. Cobra 26) fruits were carried out in this study. These physical characteristics (mass, length, weight, thickness, volume, surface area, aspect ratio, geometric mean diameter, projected area, sphericity, and density), and mechanical properties (failure force, failure energy, relative deformation, and firmness) of the fruits were determined at two maturity stages (pink and red). All these parameters investigated are key factors in the design, programming, and application of tomato fruits harvesting robots and machines. Results obtained from the study revealed that maturity significantly affected all the parameters investigated, apart from the fruit’s volume, sphericity, and aspect ratio. Furthermore, it was observed that all the physical parameters investigated increased during the maturation of the fruits. Regarding the mechanical properties, the results showed that the failure force, failure energy, and firmness of the fruit decreased significantly (p ≤0.05) from 81.80 N to 50.30 N, 367.55 N.mm to 296.68 N.mm, and 89 N to 56 N respectively, as the fruit matured. But in contrast, the relative deformation of the fruit increased significantly (from 9.60 mm to 19.32 mm) as the maturation of the fruit progressed from the pink stage to the red stage. The findings of this study will be useful in the design, construction, programming, and application of tomato harvesting machines.