The time of the day to harvest affects the degreening, antioxidant compounds, and protein content during postharvest storage of broccoli

Abstract

Harvesting of broccoli at several moments of the day affects the rate of senescence during storage. In this work, broccoli heads were harvested at several moments and then kept at 20°C in order to analyze protein metabolism and antioxidant compounds. Almost no differences were detected in the contents of total and soluble proteins, and free amino acids. Only an increment in free amino acids was detected by day 3 in samples obtained at 8:00 hr. With reference to antioxidants, the contents of ascorbic acid, carotenoids and xanthophylls, phenols, and flavonoids were similar in samples harvested at different moments. However, an increment was detected in carotenoids, phenols, and flavonoids during storage of samples collected at 18:00 hr on day 3 and samples collected at 13:00 hr on day 5. The combination of delay of senescence and increment in antioxidants suggest harvesting at 12:00 or 18:00 hr. Practical application: Broccoli is a vegetable with an important level of nutrients. However, it is also highly perishable and suffers a high rate of senescence and loss of quality during postharvest. In this work, it is demonstrated that the simple practice of harvests in different moments of the day can affect the postharvest behavior of broccoli, and it is suggested to carry out the harvest toward the end of the day.