Relationship between Sensory and Instrumental Analysis for Tomato Flavor

The major components of flavor in tomato ( Lycopersicon esculentum Mill.) and other fruit are thought to be sugars, acids, and flavor volatiles. Tomato overall acceptability, tomato-like flavor, sweetness, and sourness for six to nine tomato cultivars were analyzed by experienced panels using a nine-point scale and by trained descriptive analysis panels using a 15-cm line scale for sweetness, sourness, three to five aroma and three to seven taste descriptors in three seasons. Relationships between sensory data and instrumental analyses, including flavor volatiles, soluble solids (SS), individual sugars converted to sucrose equivalents (SE), titratable acidity (TA), pH, SS/TA, and SE/TA, were established using correlation and multiple linear regression. For instrumental data, SS/TA, SE/TA, TA, and cis -3-hexenol correlated with overall acceptability ( P = 0.05); SE, SE/TA ( P ≤0.03), geranylacetone, 2+3-methylbutanol and 6-methyl-5-hepten-2-one ( P = 0.11) with tomato-like flavor; SE, pH, cis -3-hexenal, trans -2-hexenal, hexanal, cis -3-hexenol, geranylacetone, 2+3-methylbutanol, trans -2 heptenal, 6-methyl-5-hepten-2-one, and 1-nitro-2-phenylethane ( P ≤0.11) with sweetness; and SS, pH, acetaldehyde, aceton, 2-isobutylthiazole, geranlyacetone, β-ionone, ethanol, hexanal and cis -3-hexenal with sourness ( P ≤0.15) for experienced or trained panel data. Measurements for SS/TA correlated with overall taste ( P =0.09) and SS with astringency, bitter aftertaste, and saltiness ( P ≤0.07) for trained panel data. In addition to the above mentioned flavor volatiles, methanol and 1-penten-3-one significantly affected sensory responses ( P = 0.13) for certain aroma descriptors. Levels of aroma compounds affected perception of sweetness and sourness and measurements of SS showed a closer relationship to sourness, astringency, and bitterness than to sweetness.