Modelling the kinetics of physicochemical changes in Terung Asam (Solanum lasiocarpum Dunal.) during storage

Abstract

This research studied the structural changes and physicochemical quality and in Terung Asam (Solanum Lasiocarpum Dunal) during a 28-day ambient storage period at Day 0, Day 7, Day 14, Day 21 and Day 28. Colour values (L*, C*, h*), soluble solid content (SSC), fresh weight loss (FWL), fruit firmness, total chlorophyll content (TCC) and pH were the parameters assessed. The peel’s ultrastructural and microstructural image characteristics were also examined. Significant (p < 0.05) physicochemical deterioration was observed, particularly in firmness, FWL, and TCC, which followed zero-order kinetic behaviour with high model fits, recording R² values of 0.986, 0.988, and 0.998 and RMSE values of 0.089, 0.731, and 0.062, respectively. In contrast, h* followed first-order kinetics, with R² = 0.829 and RMSE = 4.519, indicating that the colour shift during storage was more dependent on the remaining pigment intensity. In agreement with senescence-related changes, based on cell wall loosening, mitochondrial and chloroplast disintegration, and stomatal deformation identified through microscopic image analysis, it can be concluded that progressive cellular degradation took place. Through the established kinetic models, it was possible to obtain insights into the rate of quality degradation, that provided a predictive framework for postharvest behaviour. These results yielded in improved shelf-life estimation and storage management strategies for Terung Asam, to support its marketability, postharvest handling, and sustainable utilisation.