SHELF LIFE EVALUATION OF TOMATOES BY THE HS-SPME METHOD

Flavour, comprised of aroma and taste, is an important food quality attribute. The aroma or odour of a food product is detected when its volatiles enter the nasal passages at the back of the throat and are perceived by receptors of the olfactory system (retro nasal). The flavour of tomatoes can be characterized by nearly the entire set of their constituents. Indeed, the flavour is not only directly reflected by the sum of the volatile and non-volatile components, but it also depends on their interactions. Solid phase micro-extraction (SPME) headspace sampling combined with gas chromatography (GC), can be used as a reference method for flavour analysis. Another significant factor for buyers and consumers quality is tomato's colour. After harvesting, ripening continues and tomatoes can become overriped very quickly. This can result in a loss of quality and a reduced shelf life. Tomatoes (Lycopersicon esculentum Mill.) "loose tomatoes" and "cluster tomatoes" at red ripeness stage were used. During the experiment the shelf life conditions (atmosphere, temperature and relative humidity) were controlled. Attributes such as colour, size, shape and external defects of fruit and vegetables were investigated in our study because they influence the choice made by consumers. Changes in tomato aroma profiles, dry matter, colour, tytrable acidity, sum of sugars and pH have been monitored at different times and a short-term anoxia treatment of 24 h was applied. Many compounds undergo important concentration changes during shelf life of tomatoes. The HS-SMPE method is useful to evaluate the above mentioned tomato's changes.