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Title: AROMA PERCEPTION OF INDIVIDUAL VOLATILE COMPOUNDS IN FRESH TOMATOES (LYCOPERSICON ESCULENTUM) AS AFFECTED BY THE MEDIUM OF EVALUATION

Author
item TANDON, K - UNIV OF GEORGIA, ATHENS
item Baldwin, Elizabeth - Liz
item SHEWFELT, R - UNIV OF GEORGIA, ATHENS

Submitted to: Postharvest Biology and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/10/2000
Publication Date: 11/1/2000
Citation: N/A

Interpretive Summary: Consumers are dissatisfied with fresh tomato flavor which is comprised of sugars, acids and aroma components. In order to improve tomato flavor, it must be determined which of the 400 volatile compounds are important to tomato aroma. To do this water is spiked with an aroma compound at different levels and analyzed by the human nose to see at which level the compound can be detected. It is assumed that if the compound can be detected at the level it is found in the fruit, then it must contribute to the overall flavor. This study shows that the medium in which the aroma compounds is tested affects the concentration at which it can be detected. Deodorized homogenate as well as the dilute alcohols present in the homogenate in solution were found to alter the aroma thresholds of many tomato volatiles.

Technical Abstract: Odor thresholds of volatile compounds in fresh tomato (Lycopersicon esculentum) were estimated and odor units calculated to determine whether the medium of evaluation affects aroma perception. The Ascending Methods of Limits was used to determine odor thresholds of cis-3-hexenal, hexanal, trans-2-hexenal, hexanol, cis-3-hexenol, 2-isobutylthiazole, 6- methyl-5-hepten-2-one, geranylacetone, 2-pentanal, B-ionone, 1-penten-2- one, 3-methylbutanol, 2-methylbutanal, acetone and 2-phenylethanol in deionized water, and ethanol (100ppm)/methanol (500 ppm)/water mixture (simulating levels found in fresh tomato), and a deodorized tomato homogenate. Cis-3-Hexenal exhibited the highest level of odor units in all three media. Odor threshold were lower in deionized water for all compounds than in the ethanol/methanol/water mix. And thresholds were higher in the deodorized tomato homogenate for most compounds. Distinct differences were noted in aroma descriptors depending on the media.