Non-linear coupled ordinary differential equations modelling of thermophysical and kinetic degradation: a study of Broccoli post-harvest quality along the highlands (Okuk) highway

Abstract

Equation (ODE) based predictive model that describes the degradation of broccoli in transportation within Okuk, PNG. While previous studies in PNG have been purely observable, this study addresses a significant research gap by providing a mechanistic, predictive tool that accounts for the dynamic, time-varying temperature shifts T(t) from the cool highlands to the warm tropical coast. The model couples the thermophysical heat transfer with kinetic quality degradation Q(t), and employs numerical simulations using MATLAB’s ODE45 solver to simulate the impact of ambient highway heat and internal respiration or chlorophyll loss. The findings reveal that standard handling results in a 27% quality loss, while pre-cooling intervention of 4◦C acts as a thermal battery maintaining 95% freshness upon arrival. The primary contribution of the study is to demonstrate that degradation is an exponentially accelerating process, providing a data-driven explanation for the establishment of off-grid solar powered cooling (pre-cooling) hubs to protect highlands farmers’ livelihoods and National Food Security.