Résumé :
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Heads of lettuce (Lactuca sativa L., cv. 'Salinas') were individually wrapped or sealed in nonoriented perforated (22 mµ thickness) or unperforated (25 or 50 mµ thickness) nerv polypropylene (PP) films, and stored for 2 weeks at 2°C plus 2.5 d at 12°C. Vacuum cooling and/or active modification of the atmosphere within the package by flushing a gas mixture were applied. Quality of lettuce by scoring wilting, physiological disorders, bacterial decay and overall visual quality was determined. In naked heads stored in air and by lettuce wrapped in perforated PP, russet spotting and pink rib, the main disorders of lettuce during postharvest, developed. However, in all treatments with sealed PP bags, these disorders practically did not appear Heart leaf injury and brown stain developed on lettuce sealed in PP bags, particularly after transfer to higher temperature. Pink rib and heart leaf injury mainly appeared in vacuum cooled lettuce.
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