Rocket (Eruca sativa Mill.) and corn salad (Valerianella olitoria L.): production and shelf-life of two leafy vegetables grown in a soilless culture system.

摘要

Fresh-cut products are fresh vegetables and fruits, previously washed and cut, packaged and sealed in bags or containers, and marketed as ready-to-eat or ready-to-cook products. Consequently, the products present a high added-value and, therefore, are highly appreciated by the consumers. Recently, Italy is experiencing a booming interest in high quality and tasty ready-to-eat vegetables. Therefore, studies on postharvest shelf-life and quality of typical Italian salads are necessary. Using soilless culture system (SCS) avoids soil contamination of the leaves, facilitating the production of clean material at harvest, and consequently the reduction of many washing treatments. Plants of rocket (Eruca sativa [E. vesicaria]) and corn salad (Valerianella olitoria [V. locusta]) were grown for Leafy Vegetable Production (LVP) in different containerized cell-trays (40 or 160 cells), using different growing media (rockwool or peat and perlite), and different nitrogen concentrations in the nutrient solution (30 and 120 mmol litre-1). At sampling, leaves were cut and weighed, assigned a Quality Index (QI: 100, 75, 50, 25 and 0%), according to marketable values, packaged in commercial plastic boxes, and stored in a cool chamber at 4 degrees C for the postharvest shelf-life phase. Evaluation of postharvest quality was assessed by variations of fresh and dry weight over time (0, 2, 4 and 6 days after storage) and values of QI (at 0, 2, 4 and 6 days of storage). Fresh mass and QI decreased over time for both species, as expected. However, the values decreased less in plants that were grown in 40-cell trays filled with peat and perlite and treated with N at 30 mmol litre-1 than in plants that were grown under the other experimented conditions. The QI indicated that rocket and corn salad can be grown with the tested SCS system to obtain high quality ready-to-eat salads.