Quality characteristics of leafy vegetables are affected by the duration of exposure, quality and intensity of light. This study was carried out under greenhouse conditions to evaluate the postharvest quality of hydroponic lettuce affect by thermo-reflective screens with different percentages of attenuation of solar radiation. The experiment was arranged in a 2 x 5 factorial randomized block design, with three replicates and treatments consisting of four thermoreflective screens ( 40; 50; 60 and 70% of attenuation of solar radiation) and one control with the black screen 50%. Lettuce (cv. Olinda, Crespa) plants grown in each experimental plot, represented by an individual hydroponic system, were evaluated for quality at harvest and after four days of cold storage (7.6 ± 1ºC and 27 ± 5% UR). The over-shading caused by thermo-reflective 60 and 70% and black screen 50% affected the lettuce appearance. The plants shaded with thermo-reflective 40% showed lower mass loss after four days of storage. The shading provided by the thermoreflective and black screens did not affect the acid content, soluble solids, vitamin C and chlorophyll content of lettuce.
Lactuca sativa L; mesh shading; soilless culture; storage
