From firm to soft: Maturity-driven mechanical damage behavior of apples

Understanding the mechanical damage behavior of apples at different maturity stages is crucial for reducing postharvest losses and maintaining quality during transportation. In this study, a combined approach of compression experiment and finite element simulation was employed to investigate the damage characteristics of Fuji apples under compressive loading across four maturity levels. Controlled compression experiments were conducted using a universal testing machine to quantify the force-deformation response and determine critical damage thresholds. The experimentally derived mechanical parameters were used to calibrate a finite element model developed through reverse engineering. This model effectively simulated the internal stress distribution and deformation behavior of apples during compression. Results indicated a linear positive correlation between storage time and damage volume. Less mature apples exhibited higher fracture resistance and lower stress localization, while more mature apples, with reduced stiffness, were more prone to internal damage and higher stress concentration. The deviation between simulated and measured damage volumes ranged from 3.25 % to 16.8 %, confirming the validity of the developed model in replicating realistic compression scenarios. These findings provide valuable insights for designing harvesting, grading, and packaging equipment tailored to apples at varying maturity stages, ultimately enhancing product quality and reducing losses across the supply chain.