Evaluación del contenido de minerales en lechuga (Lactuca sativa var. Crispa) crecidas en diferentes soluciones nutritivas de un cultivo hidropónico

Abstract

The main problem in people with kidney disease is the limited amount of minerals that can be ingested in the diet, sodium and potassium being the most restricted minerals. The present study allowed to evaluate the mineral content in lettuce (Lactuca sativa var. crispa) grown in different nutritive solutions of a hydroponic crop. For which, four NFT hydroponic systems were implemented with two nutritive solutions recommended by commercial houses and two nutritive solutions with the absence of potassium. Vegetative development, physicochemical parameters, microbial load and bioactive compounds were evaluated in the lettuces. The results showed that the absence of potassium in the nutritive solution influenced vegetative development, generating smaller plants, fewer leaves and less weight. The soluble solids and the titratable acidity had an increase of 300 and 100 %, respectively, with reductions in potassium of 73,19 % and an increase in sodium of 53,62 %. On the other hand, the microbial load was lower than the maximum limits allowed by Spanish legislation (105 CFU/g for mesophilic aerobes, 104 CFU/g for total coliforms, molds and yeasts). Finally, the total carotenoid content was lower in 85 and 36,2 % in the treatments without potassium, however, Treatment 2 without potassium presented a higher concentration of total phenols, the content of vitamin C in the two seasons showed a range of 10,49 and 13,8 mg/100g in lettuce without potassium. Concluding that hydroponic cultivation helps to obtain food for people with kidney disease.