SUMMARY
      The tomato taste and aroma is the result of the interactions established, mainly, between its sugars, organic acids, free amino acids, minerals, and volatile compounds, the latest playing a relevant role in the final sensory appreciation.  A part of these volatile compounds are found in free forms, forming the free volatile fraction (FVF), but another part is found in glycosidically bound forms and its constituents can not be perceived by the olfactory receptors, constituting the named volatile glycosidically bound fraction (GBF). The glycosidically bound precursors, therefore, make up a potential source to increase the final aroma if the hydrolysis of the glycosidic linkage and the consequent release of aglycons are achieved. The aim of this work was to determine the composition of both fractions in the tomato to, next, evaluate the ability of certain glycosidic activities to release the volatile compounds from their respective glycosidic precursors. 
      The aromatic profile of five cultivars has been characterised. The results have shown a strong influence of the cultivar on the composition of the FVF event of the GBF of the tomato, establishing the potential of the latest to increase free volatile compounds. The influence of fruits maturation on the aromatic profile of the tomato have been studied, observing that the dominant trend of the FVL and GBF components was, in general, to increase its concentration as the fruit maturation move, although with relevant exceptions. This study supports the possibility, reported by other authors, of using the aroma profile of the tomato as a tool for cultivar identification.  
      Extracts enriched in different glycosidic enzymes of fungal origin have been produced. The incubation of the tomato juice added with these enzymes, individually or in combinations, has demonstrated its ability to release several of the particularly relevant aglycons for the tomato aroma according to the literature. From extracts of the GBF of the tomato and its incubation with glycosidic enzymes or its combinations, the volatile compounds and sugar units released were determined. The results support the hypotheses that the tomato glycosides composition involves the sugars glucose, xilosa, rhamnose, and arabinose, and the volatile aglycons aldehydes, alcohols, and terpenes. The quantity of rhamnose detected and the relevant role of the rhamnosidase in the enhancement of volatile compounds of the tomato juice, suggest the abundance of glycosides of this sugar. These results can be the starting point in order to address the biotechnological improvement of the tomato aroma.