Prediction of the cracking susceptibility of tomato pericarp: Three-point bending simulation using an extended finite element method

Abstract

Fruit cracking is one of the most common physiological disorders that causes fruit loss and reduces tomato fruit marketability and quality. In this study, a three-point bending extended finite element (XFEM) model including five parts: a loading probe, exocarp, mesocarp, pre-crack, and two rigid fixed support points was developed for investigating the cracking susceptibility of pericarp during fruit development and postharvest handling. During pericarp cracking simulation, a displacement load of the probe was applied over a cuboid pericarp sample to replace the increasing turgor pressure of mesocarp cells. The XFEM-based three-point bending model with average tissue mechanical data was found to be able to reproduce the probe loading force-pericarp deflection behavior and the crack propagation length-pericarp deflection behavior in the three-point bending test up to 6 mm tomato pericarp deflection deformation with an average relative error of about 7.8% and 5.2%, respectively. The XFEM model’s crack propagation area and volume were affected by environmental temperature, exocarp and mesocarp thickness. Three multiple linear regression mathematical models were established for quantitatively predicting the tomato pericarp cracking susceptibility. It was found that the factors affecting the cracking susceptibility of pericarp in descending order include exocarp thickness, pericarp deflection, mesocarp thickness, and temperature. This study provides a new approach to quantitatively predict the cracking susceptibility of tomato pericarp, especially in the breeding industry for reversely and quickly locating the fruit anti-cracking gene.