Qualidade de alface crespa orgânica sob diferentes temperaturas de resfriamento na colheita

Abstract

Lettuce is a vegetable with the highest consumption and economic importance worldwide, however its high perishability requires specific harvesting procedures. In this context, aiming to increase the postharvest conservation of vegetables, the removal of field heat at harvest and pre-cooling can be efficient options for maintaining quality and extending the lettuce postharvest shelf life. Therefore, the objective of this work was to evaluate the quality and shelf life of organic crisp lettuce submitted to different cooling conditions at harvest. The design was completely randomized in a 3 x 5 factorial scheme, with two pre cooling in water at 20 and 4 °C, and a control (no pre-cooling) and five evaluation periods (0, 4, 8, 12, and 16 days), with three replications, consisting of a head of lettuce. Storage was carried out at 12 ± 0.5 ºC/75% ± 2 RH and physical, physicochemical and sensorial evaluations were carried out. The data were submitted to analysis of variance and means compared by Tukey's test up to 5% probability. Lettuces without cooling after 4 days of storage at 12 ± 0.5 ºC/75% ± 2 RH had already lost about 40% of the leaves, completely losing commercial viability on the 6th day of storage. Lettuces cooled to 20°C at harvest maintained acceptable appearance during 8 days of storage at 12 ± 0.5°C/75% ± 2 RH. Lettuces cooled to 4ºC at harvest maintained ascorbic acid levels, chlorophyll content and maintained acceptable appearance during 12 days of storage. Together, cooling crisp lettuce at 4 oC maintained quality and increased postharvest shelf life by 8 days compared to lettuce without cooling at harvest. However, considering the effective cost of refrigeration, cooling lettuce at harvest with water at 20°C is a viable alternative to increase the postharvest conservation of organic lettuce from family farming.