Effect of Forced-Air Solar Drying and Biogas-Assisted Hybrid Solar Drying on the Overall Quality of Dehydrated Andean Berries

This study evaluated the effect of forced-air solar drying and biogas-assisted hybrid solar drying on the overall quality of dehydrated Andean berries. Blueberry (Vaccinium corymbosum) and goldenberry (Physalis peruviana) were analyzed before and after dehydration using two systems: forced-air solar drying (DCFA) and biogas-assisted hybrid solar drying (DCFA-BG). Physicochemical properties, instrumental color, texture, rehydration index, total phenolic content, total flavonoid content, and antioxidant capacity were determined. Drying markedly reduced moisture content and water activity in both fruits. In blueberry, DCFA-BG achieved the lowest moisture content (22.00%) and water activity (0.65), whereas goldenberry showed similar final moisture contents under both systems, with lower water activity under DCFA-BG (0.64). Total soluble solids and titratable acidity increased after drying, indicating solute concentration. Color changes were more pronounced in goldenberry, while blueberry showed moderate chromatic variation. Blueberry firmness increased after drying, whereas goldenberry exhibited treatment-dependent textural responses. Blueberry showed greater retention of bioactive properties, with increased antioxidant capacity after drying, whereas goldenberry exhibited substantial reductions in phenolic content, flavonoid content, and antioxidant capacity. Overall, biogas-assisted hybrid solar drying effectively reduced moisture content and water activity, although its effects on product quality depended on the fruit matrix. These findings support its potential application as a sustainable alternative for processing perishable fruits in high-Andean rural agroindustrial contexts.