Characterization and evaluation of volatile compounds of three grape varieties (Vitis labrusca) from the region of Bento Gonalves RS

In grape must, the aroma is an indication of adequate conservation status. It is able to indicate losses due to thermal degradation, besides representing a great contribution in the properties of the sensorial quality of the grape juices most appreciated by consumers. This study identified the volatile compounds in different must cultivars of Vitis labrusca grapes. The volatile composition was evaluated by the solid phase microextraction method (SPME), using the polydimethylsiloxane/divinylbenzene fiber (PDMS/DVB). The separation and identification of the volatile compounds were carried out through gas chromatography by mass spectrometry (GC-MS). The results showed the identification of forty-four compounds belonging to the following chemical classes: carboxylic acids, alcohol, aldehydes, ketones, furans esters and terpenes. The class of esters was the most numerous compounds identified and is largely responsible for the fresh and fruity aroma of the tested musts. Solid-phase microextraction proved to be a reproducible, sensitive and fast-response technique for the identification of chemical biomarkers in musts of different grape cultivars.   Key words: Aroma, gas chromatography by mass spectrometry (GC-MS), headspace, solid phase microextraction method (SPME).