Sandía: Cambios en los atributos de calidad durante su almacenamiento refrigerado

Watermelon [Citrullus lanatus (Thunb.) Matsum. et Nakai] is one of the most commercially traded and demanded fruits during the summer. In 2023, 7,493 tons of watermelon were delivered to the main wholesale market in Montevideo, the Unidad Agroalimentaria Metropolitana (UAM), 6,443 tons of which originated from the department of Rivera, Uruguay's principal production region. This study aimed to evaluate the postharvest quality of watermelon fruits marketed at the UAM under refrigerated conditions (11°C and 98% relative humidity) at the beginning (0 days) and after 7, 14, 21, and 28 days of storage. At each sampling point, the effects of refrigerated storage time on weight loss, external appearance, specific weight, rind and pulp color, pulp appearance, firmness, juiciness, total soluble solids (TSS), juice content, pH, titratable acidity (TA), total carotenoids and lycopene content, total polyphenols (TP), and total antioxidant capacity (TAC) were assessed. The experimental design was completely randomized (CRD) with five treatments (0, 7, 14, 21, and 28 days). Watermelons were randomly stored in a refrigerated chamber (41 fruits), and at each sampling point, 8 randomly selected fruits (replicates) were analyzed, with time (days) as the factor. The results showed that certain physical and chemical attributes, such as dimensions, specific weight, rind color, firmness, TSS, pH, TA, and pulp juice percentage, remained unchanged during the 28-day storage period. However, other attributes, including weight loss and the overall external and pulp appearance, were affected. The pulp color changed from a dark red hue up to 7 days to a lighter, less red tone, indicating overripeness and/or quality deterioration, along with a decrease in total carotenoid and lycopene content. TP content increased by 36% during the last week of storage, while TAC, measured using the DPPH method, decreased by 57%. In contrast, minor changes were observed using the ABTS and FRAP methods. The content of nutritionally significant and bioactive compounds contributing to pulp color and antioxidant capacity maintained pulp quality at acceptable levels up to 14 days. This study characterized, for the first time, the refrigerated storage of watermelons marketed at the UAM, quantifying and evaluating the preservation of physical attributes, nutritional and bioactive compounds, and antioxidant capacity in the fruit pulp.