Qualitative analysis of volatile compounds in local landraces of tomato cultivated in South Italy

Long storage tomato (Lycopersicon esculentum Mill.) is traditionally cultivated with no irrigation in the semi-arid Mediterranean areas. It provides a niche product that combines good taste with excellent nutritional properties. The aroma of these tomatoes plays an important role in consumer acceptability. However, there is a lack of information about the volatile compounds affecting the aroma in long storage tomatoes. The aim of this research was to analyze the main volatile compounds in ten landraces of long storage tomatoes cultivated in Sicily (south Italy), and to assess the genetic variability for these compounds in order to identify biochemical markers useful for the traceability of the product. The landraces were grown during summer 2007 in a flat site of eastern Sicily. Fresh tomatoes sampled at harvest were analyzed for volatile compounds in a gas-chromatograph. Thirty-nine components have been fully characterized, and grouped as non terpenoids (24 compounds) or terpenoids, mostly monoterpenes (15 compounds). Only seven compounds, non terpenoids, were common to the ten landraces. 6-methyl- 5-hepten-2-one, a carotenoid-related volatile responsible for the tomato-like flavour, was the main component in all samples ranging between 22 and 46% ca. A distinguishing character could be related to the significant presence, at least in some landraces, of terpenoid compounds. Further studies on other populations of long-term storage tomatoes are in progress. Distinctive organoleptic or biomolecular characters associated to these particular kinds of tomato are under research.