The nutrition quality of five different lettuce cultivars (Mimosa Verde, Mimosa Vermelha, Vera, Regina and Lucy Brown) produced under NFT (Laminar Flow of Solution) system was determined by their centesimal composition and nitrate content. To analyze the experimental treatments it was used a completely randomized design with four replications. The experiment was developed in a greenhouse belonging to the Department of Agricultural Engineering of the Federal University of Santa Catarina, Florianópolis, Santa Catarina State, Brazil, from May to July of 2004 (autumn-winter period). The lettuces were grown in a group of benches (3% declivity) with seven canals (6.0 m length and 1.50 m width) where the nutritional solution would circulate. The space used was 0.25 m between canals and 0.25 m between plants in the canal, thus in each canal 24 plants had been lodged, totalizing 168 per bench. The circulation of the nutritional solution was controlled by a timer, which set in motion the joint motion-bomb in intervals preset in a turn 24-hour. The harvest was effected 54 days after the sowing, having remained per 24 days in the production group of benches. The American type of lettuce 'Lucy Brown', also presented a greater water content in its shoot as well as nitrate content than the others. Mimosa Vermelha and Mimosa Verde cultivars had on average, greater dry mass content theirs of shoots, as well as lipids, protein and caloric value than the others. 'Mimosa Vermelha' presented greater carbohydrates content and 'Mimosa Verde' the greater mineral residue content, but not differing from Regina cultivar. The biggest fiber content was presented by 'Regina'.
hydroponic; Lactuca sativa L.; nitrate and centesimal composition
