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Post-harvest food loss significantly threatens global food security, and solar drying offers a sustainable preservation solution. The effectiveness of solar drying depends on consumer acceptance, in which color is a critical quality attribute. This study investigated how solar irradiance and temperature affect color degradation during the drying of pineapple (Ananas comosus), orange (Citrus × sinensis), and beet (Beta vulgaris L.). Experiments conducted in Zacatecas, Mexico, compared a Solar Dryer with Dynamic Irradiation Control (SDIC), which limited irradiance to 700 W/m2, against an uncontrolled Cylindrical Solar Dryer (CSD). The results indicate that the controlled SDIC environment promotes gradual and uniform color preservation by minimizing rapid thermal stress. In contrast, the fluctuating high irradiance and temperature of the CSD caused faster, less uniform color changes. Statistical analyses confirmed that both irradiance and temperature significantly impacted color parameters (p < 0.05). The SDIC method reduced the total color change (ΔE) by 30–47% in pineapple and beet compared to the CSD. Regression models identified temperature as the primary driver of redness (a*) degradation, while irradiance was strongly correlated with changes in yellowness (b*). This research highlights the necessity of optimizing solar drying conditions to enhance the quality of dried produce. By improving visual appeal, this optimized green technology can help reduce food waste and support the transition to more sustainable fod processing systems. This controlled approach reduced the total color change (ΔE) by 30–47% in pineapple and beet compared to the CSD, demonstrating its significant potential for quality preservation.
García-Moreira et al. (Tue,) studied this question.