Determination and gustatory properties of taste-active compounds in tomato juice

The water-soluble compounds of a tomato juice selected for its high taste intensity and quality, have been investigated by both physico-chemical and sensory analyses. The physico-chemical assessment of the crude juice led to the construction of a synthetic model juice. Although 97% of the material contained in the crude juice has been identified and quantified, significant sensory differences between the crude and model juice have been found concerning bitterness and sharpness, showing that the components responsible for these gustatory descriptors have not yet been identified in the juice. For the other descriptors: sweetness, saltiness, sourness, umami and astringency, no significant differences were found between these two solutions. Using the model juice, omission tests were performed to explain the three main tastes of the juice: saltiness, sweetness and sourness. Sweetness was mainly attributable to sugars while the non-dissociated and dissociated forms of the organic acids, with potassium as counterion, seemed mainly responsible for sourness and saltiness. Moreover, several masking effects were observed between taste-active components. The contribution of the taste-active compounds to the main tastes were quantified by stepwise multiple linear regressions. The model explained up to 95, 89.9 and 85.8% of sourness, saltiness and sweetness, respectively.