Quantitative determination of macronutrients (NPK) in leafy vegetables in marketed in free trade fairs
ADVANCES IN HORTICULTURE - REVIEW | Dos Santos Viana, J.; Nascimento Gomes, A. M.; Nahuz Lourenço, M. S.; Chagas Filho, E.
The search for good quality hardwood vegetables has grown, and consumers are becoming increasingly demanding as to the appearance, color and size of these products. Chemical quality is one of the main programs used in food control. The objective of this paper was to determine the macronutrient contents in leafy vegetables marketed in open fairs in the city of São Luís. The experiment was carried out in the laboratory of mineral nutrition of plants of the engineering nucleus of the State University of Maranhão. From a universe of 14 hardwood vegetables, six of the highest consumption in five free fairs through the application of questionnaires, were selected. Sulfuric digestion/ hydrogen peroxide and P and K determined the N contents by nitroperchloric digestion. The six leafy vegetables selected were: Lactuca sativa, Allium schoenoprasum, Coriandrum sativum, Brassica oleracea var. capitata, Talinum triangulare and Hibiscus sabdariffa. It was verified that the regional vegetables are the most consumed by the population, with emphasis on the non conventional vegetables Hibiscus sabdariffa and Talinum triangulare. The results obtained in the chemical analyses showed potassium and phosphorus deficiency for the samples of Lactuca sativa and Brassica oleraceacapitata in the five fairs studied, indicating inadequate mineral fertilization (excess or deficiency) of these vegetables. While for other unconventional vegetables, more studies are necessary because literature is deficient in information about them.