Composición de los aceites esenciales de la corteza de diferentes variedades de Citrus medica L. Influencia del grado de maduración ; Composition of the essential oils of the bark of different varieties of Citrus medica L. Influence of the degree of ripeness

[EN] The vast majority of known commercial citrus fruits originated from four ancestral species: the Pummelo (Citrus maxima Merr.), the mandarin (C. reticulata Blanco), the papeda called C. micrantha ‘‘Wester’’ and the Citron (C. medica L.). The Citron is the ancestor of lemons and limes. It has a great tradition in Chinese medicine and cuisine, where it has been known and used for thousands of years, being the first citrus that arrived into Europe in the 4th century BC. In addition to its aesthetic value (already highly appreciated in the Florentine gardens of the Medici in the 15th century), its essential oils are of high sensory quality, which confers them wide and growing possibilities in productive sectors related to cosmetics and gastronomy. These are constituted by the volatile and semi-volatile fractions of the products in the secondary metabolism and are found in different organs of the plant, particularly in the glands located on the surface of the epicarp of the fruits. Despite not being a hybrid and having remained as a pure species, the different varieties of Citron show very different phenotypes, which are especially reflected in the morphology of the fruits. This variability, associated with genetic factors, implies at the same time changes in the secondary metabolism, which lead to a wide rise in chemo diversity. Accordingly, it is worth noting that the presence of oxygenated monoterpenes, even appearing themselves as minority compounds, provide the essential oils with specific notes of their aromas. Regarding the high practical interest of these oils in perfumery, gastronomy and as a possible natural alternative to certain food additives, it is of remarkable interest the analysis of the composition of the essential oil in different Citron varieties, some still little known and studied. Otherwise, a potential factor of variability in such composition is the ripeness degree of the fruit. Knowing its influence can contribute to achieve an optimal composition from the sensory point of view. This ...