Postharvest cooling and storage method effects on carotenoid and chlorophyll contents in broccoli

Localization of broccoli (Brassica oleracea L. var. italica) production in the eastern United States will reduce the time between harvesting and consumer availability, and decrease the loss of nutritionally important phytochemicals through respiration. As postharvest cooling and storage conditions alter the rate of respiration, aims of this study were to determine the effects of postharvest cooling and storage methods on the carotenoid and chlorophyll contents of broccoli cultivars grown in the eastern United States. Changes in carotenoid and chlorophyll contents were investigated for two cultivars ('BH053' and 'Emerald Crown'), two temperature treatments (cooled with top icing stored at 5 degrees C, and cooled with an ice slurry and stored at 0 degrees C in ice), and six different days of storage (0, 7, 14, 21, 28, and 35 days). Results from this study indicated that cultivar and storage time significantly influence both carotenoid and chlorophyll contents in broccoli. However, storage temperature did not have a significant impact on carotenoid or chlorophyll contents. Violaxanthin, neoxanthin, antheraxanthin, lutein, beta-carotene, alpha-carotene, chlorophyll a, and chlorophyll b contents were significantly greater for 'BH053' than for 'Emerald Crown.' Similarly, all carotenoid and chlorophyll contents significantly decreased during storage for both cultivars. The interaction of cultivar and storage time significantly affected beta-carotene content alone. beta-carotene content significantly decreased at 7 d for 'Emerald Crown,' but did not significantly decrease until 21 d for 'BH053.' Results from this study indicated that carotenoid and chlorophyll contents are more dependent on cultivar and storage time than storage temperature. These results confirm that both carotenoid and chlorophyll contents in broccoli decrease as the duration of storage increases. Increased carotenoid contents help to prevent oxidative damage and chlorophyll degradation, which prevents the loss of nutritional and sensory quality during storage. Results from this study suggest that the postharvest quality is greater 'BH053' than for 'Emerald Crown' due to its significantly greater carotenoid and chlorophyll contents.