Effect of Packaging Films on the Quality of Broccoli

Broccoli (Brassica oleracea L., cv. Keirin) is a highly perishable produce and its postharvest life and quality greatly depend on storage conditions, such as temperature, atmosphere composition, relative humidity and packaging films. The effect of modified atmosphere packaging (MAP) on the quality of broccoli heads was investigated in the present study. Broccoli was packaged with four different types of films: polypropylene (PP), micro-perforated polypropylene (PP hole), oriented polypropylene (OPP) and low density polyethylene (LDPE), and then stored at 15°C for 13 days to study the effects of modified atmosphere packaging (MAP) on the maintenance of quality and functional properties by comparison with non-packaged broccoli as a control. Results indicated that deterioration occurred quickly in the control broccoli due to a relatively high rate of metabolism and a consequent high respiration rate and ethylene production, manifested mainly by weight loss, yellowing and chlorophyll degradation. Also, a rapid decrease in ascorbic acid and total phenolic concentration was observed. Conversely, in those broccoli packaged under MAP, especially for LDPE, all changes related with loss of quality were significantly reduced and delayed with time. Moreover, levels of total carotenoids and total phenolic compounds remained during the whole period. Thus, broccoli packaged with LDPE film had prolonged storability up to 10 days at 15°C with high quality, this period being only 4 days in control broccoli.