eng Enviro Research Publishers Current Research in Nutrition and Food Science Journal 2347-467X 2322-0007 2026-04-10 14 1 371 382 10.12944/CRNFSJ.14.1.25 25721 article Edward Torres-Cruz 1 Saire Roenfi Guerra Lima 1 Fred Torres-Cruz 2 Wenceslao Teddy Medina Espinoza 1 Nury Yaneth Mayta-Barrios 1 Academic Department of Agroindustrial Engineering, Universidad Nacional del Altiplano de Puno, Puno, Peru Academic Department of Statistics and Informatics Engineering, Universidad Nacional del Altiplano de Puno, Puno, Peru Oca (Oxalis tuberosa L.) is an Andean tuber traditionally sun-cured to enhance sweetness and sensory quality; however, quantitative evidence linking changes in total soluble solids (°Brix) with physical and colorimetric modifications remains limited. This study evaluated the effect of a 10-hour sun-curing process on four oca varieties by monitoring total soluble solids (°Brix), fractal dimension, and color attributes. Measurements were recorded every two hours during the sun-curing period and analyzed both individually and within a consolidated dataset. Results showed a consistent increase in total soluble solids (°Brix) across all varieties, with a strong positive correlation between °Brix values and sun-curing time (r = 0.88–0.94). Total soluble solids were strongly associated with fractal dimension and exhibited moderate-to-strong, variety-dependent correlations with color variation (r = 0.76–0.85), indicating that microstructural and chromatic changes accompany increases in °Brix during solar exposure. In contrast, tuber size parameters showed weak, non-significant correlations with °Brix (r < 0.30), suggesting that physical dimensions have limited influence on soluble solid accumulation. Overall, the consolidated analysis confirmed comparably consistent trends among varieties. These findings demonstrate that integrating physicochemical, fractal, and color-based indicators provides a robust approach for evaluating sun-curing effectiveness and postharvest quality in oca. https://www.foodandnutritionjournal.org/volume14number1/evaluation-of-the-impact-of-solar-exposure-on-soluble-solids-fractal-dimension-and-colorimetry-in-oca-oxalis-tuberosa-l-under-high-altitude-conditions/ Brix Colorimetric Analysis Df Fractal Dimension Image Processing Oxalis Tuberosa L. Sun-Curing