Impact of Tissue Decay on Drying Kinetics, Moisture Diffusivity, and Microstructure of Bell Pepper and Strawberry

This study investigates the potential to transform plant-based waste into a sustainable resource for animal feed through dehydration. Currently, research on the drying performance of decayed plant tissues remains scarce. To address this gap, we explored the use of a thermogravimetric analyzer (TGA) as a precisely controlled convective drying method to evaluate the drying performance of decayed strawberries (ST) and bell peppers (BP), as models for high- and low-porous structures, respectively. Drying curves, moisture diffusivity, yeast and mold load, and microstructure of decayed plant tissues were evaluated. Our results showed that decayed BP and ST tissues dried up to 22% faster than fresh tissues, with a higher effective moisture diffusivity. Significantly higher yeast and mold counts (log CFU/g) were detected in decayed tissues, resulting in softening and deterioration of the plant tissues. Significant differences were found in the effective moisture diffusivity (D_eff) of bell pepper (BP) and strawberry (ST), with ST tissues exhibiting a greater degree of decay. The microstructural changes in the cell wall caused by decay influenced drying performance and mass transport kinetics, indicating that drying decayed plant tissues is less time-consuming than drying fresh food. These findings offer critical insights for designing drying processes that enhance the value of food waste.