VOLATILE COMPOUNDS OF REHYDRATED FRENCH BEANS, BELL PEPPERS AND LEEKS.2. GAS-CHROMATOGRAPHY SNIFFING PORT ANALYSIS AND SENSORY EVALUATION

The flavours of rehydrated diced French beans, red bell peppers and le eks were characterised by gas chromatography/sniffing port analysis (G C/SP) of volatile compounds released in a mouth model system, and by d escriptive sensory analysis. Volatile compounds were identified by com bined gas chromatography/mass spectrometry. In French beans, bell pepp ers and leeks, respectively, 10, 16 and 22 compounds possessed detecta ble odours. A common odour profile was shown in the three vegetables. It comprised each of the odour active compounds present in French bean s: i.e. 2-methylpropanal (chocolate), 2/3-methylbutanal (chocolate), 2 ,3-butanedione (caramel, fatty), hexanal (grassy, bell pepper), 2-meth yl-2-butenal (chemical), octanal (sweet, sickly/musty, grassy, rancid) , 1-octen-3-one (mushroom), dimethyl trisulphide (rotten, metal), 1-oc ten-3-ol (fatty, sickly/musty, mushroom) and one unknown compound (che mical, rotten, rancid). The three vegetables differed markedly in GC/S P patterns and in scores for sensory attributes. Use of nose-clips dim inished the scores for attributes in sensory analysis. In principal co mponent analysis, correlation of rehydrated vegetables with sensory at tributes and volatile compounds showed considerable contribution of vo latile compounds to the flavour of rehydrated vegetables.