Résumé :
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This work was initiated to determine the effects of cold storage duration and storage temperature on the shelf life of wrapped broccoli when subsequently placed into elevated temperatures to simulate retail shelf conditions. In addition, the effect of hydro-cooling prior to wrapping was evaluated. These tests were designed to test the potential for micro-perforated wrap in extending shelf life of broccoli under varied postharvest handling conditions. In the first experiment, broccoli (Brassica oleracea L., Italica Group; cv. Mariner) was harvested and the crop divided into 4 treatments; (1) 'hydro-cooled + no wrap', (2) 'hydro-cooled + wrap', (3) 'non-cooled + no wrap', and (4) 'non-cooled + wrap'. Samples of each of the 4 treatments were removed from storage after 3 days at 1 degrees C and placed into 13 degrees C to simulate shelf conditions. Visual quality, weight loss and respiration were monitored over 5 days at 13 degrees C. This shelf evaluation was repeated with broccoli samples that had been stored for 10 and 17 days at 1 degrees C. In a second experiment, broccoli was harvested and hydro-cooled. Half the crop was wrapped with micro-perforated film and the other half left unwrapped. From these two treatments, half of the heads were stored at 1 degrees C and the other half at 5 degrees C. After 10 days, all the heads were placed at 13 degrees C for 5 days. Measurements at 13 degrees C were taken as in the first experiment. In the first experiment, for broccoli which was stored for only 3 days at 1 degrees C, the use of either hydro-cooling or wrap gave good firmness retention at 13 degrees C shelf conditions. However, for broccoli which had been stored for 10 or 17 days, both hydro-cooling and wrapping were required to achieve the best firmness retention.
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