INSTRUMENTAL AND SENSORY ANALYSIS OF THE FLAVOR OF FRENCH BEANS (PHASEOLUS-VULGARIS) AFTER DIFFERENT REHYDRATION CONDITIONS

The influence of rehydration conditions on the flavour of French beans (Phaseolus vulgaris) was evaluated. Dried French beans were rehydrate d in closed and open flasks at 100 degrees C for 0, 5, 10, 15, 30, 45 and 60 min. The odour active volatile compounds were released in a mou th model system and determined by gas chromatography/sniffing port ana lysis (GC/SP) and GC/nass spectrometry. Texture characteristics were a nalysed by Kramer shear press measurements. Moreover, the flavour of t he beans was evaluated by descriptive sensory analysis. In GC/SP, exte nded rehydration resulted in increases in the intensities of 2-butenal , 2-methyl-2-butenal, 1-octen-3-one and one unknown compound. Intensit ies of several attributes, such as ''chemical'', ''mealy'', ''mushroom '' and ''musty'' increased with extended rehydration, while intensitie s decreased for ''grassy'' and ''citrus'' attributes. Instrumental and sensory analysis of the texture of the beans revealed a gradual decre ase with extended rehydration. In general, rehydration in open versus closed flasks decreased the odour intensities of volatile compounds as assessed by GC/SP, as well as the intensities of attributes as measur ed by sensory analysis. Correlation of sensory attributes and volatile compounds showed that these compounds made a major contribution to th e difference in flavour of French beans resulting from rehydration con ditions.