Volatile compounds of rehydrated French beans, bell peppers and leeks. Part II. Gas chromatography/sniffing port analysis and sensory evaluation

The flavours of rehydrated diced French beans, red bell peppers and leeks were characterised by gas chromatography/sniffing port analysis (GC/SP) of volatile compounds released in a mouth model system, and by descriptive sensory analysis. Volatile compounds were identified by combined gas chromatography/mass spectrometry. In French beans, bell peppers and leeks, respectively, 10, 16 and 22 compounds possessed detectable odours. A common odour profile was shown in the three vegetables. It comprised each of the odour active compounds present in French beans: i.e. 2-methylpropanal (chocolate), 2/3-methylbutanal (chocolate), 2,3-butanedione (caramel, fatty), hexanal (grassy, bell pepper), 2-methyl-2-butenal (chemical), octanal (sweet, sickly/musty, grassy, rancid), 1-octen-3-one (mushroom), dimethyl trisulphide (rotten, metal), 1-octen-3-ol (fatty, sickly/ musty, mushroom) and one unknown compound (chemical, rotten, rancid). The three vegetables differed markedly in GC/SP patterns and in scores for sensory attributes. Use of nose-clips diminished the scores for attributes in sensory analysis. In principal component analysis, correlation of rehydrated vegetables with sensory attributes and volatile compounds showed considerable contribution of volatile compounds to the flavour of rehydrated vegetables.