Impacto da cura na qualidade pós-colheita de batata-doce ‘Blesbok’

Abstract

Sweet potato is a globally cultivated vegetable that has gained greater prominence in Brazil in recent years. Simultaneously with the increase in consumption, production, and exportation of this crop in the country, losses during the postharvest stage have also increased. Many countries choose to adopt the curing process, a practice not used for sweet potato in Brazil to reduce these losses. Therefore, in response to the demands of the Brazilian sweet potato production chain, this study aimed to generate information about the sweet potato curing process in Brazil, evaluating its effects on the quality attributes of the cultivar Blesbok. A batch of roots was placed in a curing unit (≈ 29 °C and 90% RH) for seven days, and at the end of this stage, it was stored in a cold chamber (≈ 14 °C and 90% RH) for forty days. Simultaneously, another batch was directly placed into the cold chamber without undergoing the curing unit. Analyses were performed one day after harvest (T0), on the fourth (C4), fifth (C5), sixth (C6), and seventh (C7) days after the beginning of curing, and on the twentieth (A20) and fortieth (A40) days after the end of curing. During the curing period, overall, when compared to non-cured roots, the cured roots showed lower L* and °h values and higher values of total sugars, non-reducing sugars, antioxidant activity (phosphomolybdenum), trans-cinnamic acid, and suberin deposition. Regarding the activity of the enzyme phenylalanine ammonia-lyase, when compared the treatments, cured roots showed higher activity on C6 and lower activity on C7. However, during the seven days of the curing process, no significant changes were observed in weight loss, firmness, C*, reducing sugars, total phenolics and antioxidant activity (ABTS•+). Regarding days of refrigerated storage, the cured roots showed lower L* values (C7 and A20) and mass loss, and higher values of total sugars, non-reducing sugars and suberin deposition, whereas no differences were observed between treatments for firmness, C*, °h, total phenolics, antioxidant activity, and phenylalanine ammonia-lyase enzyme activity. Scanning electron microscopy images enabled the monitoring of the starch degradation process, which aligned with the results obtained in the sugar analyses. Additionally, after twenty days of storage, roots directly placed into the cold room showed signs of microbial infection, whereas the cured roots remained healthy. The application of the curing process preserved the postharvest quality of the ‘Blesbok’ sweet potato, favoring its appearance, shelf life, and quality attributes.