Minimally-processed lettuce quality as affected by polymeric films employed as packaging material
A. Chiesa , E. seija, S. Moccia and D. Frezza
Proceedings of 26th International Horticultural Congress. Volume of Abstract . Toronto, Canada, 11-17 August, 2002. Abstract S09-P-98. pp. 249.
2002
บทคัดย่อ
The use of minimally-processed vegetables has continued to increase in salad bars and fast food. Storage life of minimally-processed lettuce (Lactuca sativa L.) is influenced by their continued respiration and the biochemical activity associated with senescence. Enzymatic browning is one of the main causes of quality losses during postharvest storage. The use of modified-atmosphere packaging and low temperature reduce respiration and delay senescence, thus extending storage life. The objective of this work was to assess the suitability of a range of polymeric films for modified atmosphere packaging on butterhead, crisphead, latin and leafy lettuce types minimally-processed during storage at 5 0C for 9 days. Multilayered polyolefin RD-106, PD-900 andPD-961EZ with different gas permeability (oxygen permeability of 3000 to 11500 cm.m-2 4 h-1 (1 atm at 23 0C) carbon dioxide permeability of 9800 to 30000, cm.m-2 .4h-1 (1 atm at 23 0C) were tested. Phenylalanine ammonia lyse (PAL), polyphenol oxidase (PPO) and perxidase (POD) activities, and phenolic compounds content were measured to relate them to overall visual quality, leaf edge browning and leaf surface browning. Wnzymatic activities varibillity was related to lettuce type and packaging material permeability for O2 and CO2 . In general, a low chlorogenic acid concentration and the best organoleptic quality was related to PD 900 packaging material, although leafy lettuce type had the highest chlorogenic acid concentration without quality losses by enzymatic browning. All leafy lettuce treatments packaged with multilayered polyolefins maintained consumer acceptability after 9 days of storage.