Effect of Pre-storage Hot Water Dipping of Broccoli Heads on Shelf Life and Quality during Storage

Harvested broccoli heads became yellow after 2 days storage at 20°C. However, when the harvested heads were dipped in 45°C water for 14 minutes (heat treatment), head yellowing was apparently retarded for 2 to 3 days at the same temperature as compared with non-heat treated samples. Broccoli heads without heat treatment remained fresh after 5 days storage at 4°C. When broccolis were stored at 20°C after 5 days storage at 4°C, non-heat treated samples bcame yellow in 2 days, whereas heat treated ones remained green for 5 days. Heat treated broccoli heads showed decreases in respiration for 3 days and ethylene production for 2 days during storage at 20°C. A decrease in L-ascorbic acid content in hea ttreated samples was retarded during 5 days storage at 20°C. Chlorophyll and soluble protein contents of heat treated samples remained high after 5 days storage at 20°C. The activities of chlorophyllase and lipoxygenase of heat treated broccoli heads were low during 5 days storage at 20°C. The peroxidase activity of broccolis without heat treatment showed a slow increase during storage at 20°C. When broccolis were stored at 20°C after 5 days storage at 4°C, the peroxidase activity of non-heat treated samples showed a rapid increase since.