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Title: THE RELATIONSHIP BETWEEN LIPID PATHWAY ENZYMES AND VOLATILE COMPOUNDS IN FRESH TOMATOES

Author
item YILMAZ, EMIN - UNIV. OF GEORGIA
item TANDON, KAWALJIT - UNIV. OF GEORGIA
item SCOTT, JOHN - UNIV. OF FLORIDA
item Baldwin, Elizabeth - Liz
item SHEWFELT, ROBERT - UNIV. OF GEORGIA

Submitted to: Journal of Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/4/2001
Publication Date: 9/1/2001
Citation: Yilmaz, E., Tandon, K.S., Scott, J.W., Baldwin, E.A., Shewfelt, R.L. Absence of a clear relationship between lipid pathway enzymes and volatile compounds in fresh tomatoes. Journal of Plant Physiology. 2001. v. 158(9). p. 1111-1116.

Interpretive Summary: A major consumer complaint about fresh market tomatoes is the lack of characteristic flavor. Flavor is basically made up of sweetness (sugars), sourness (acids), and aroma (flavor volatiles). To better understand tomato flavor in order to ultimately improve it, a study was undertaken to analyze the protein components responsible for producing important tomato aroma volatiles at different stages of tomato ripening. The proteins and aroma volatiles were measured in green, pink and red tomatoes in 12 varieties. Differences were found between varieties in protein patterns and levels of aroma volatiles, suggesting the potential for altering tomato flavor by selecting varieties with different protein patterns.

Technical Abstract: Specific activities of lipoxygenase (LOX), hydroperoxide (HPL), and alcohol dehydrogenase (ADH) were determined at green, pink, and red stages of ripeness in twelve tomato selections ripened during storage. The interrelationships between lipid-derived volatiles and the activities of these three enzymes in these twelve selections were evaluated. LOX and HPL showed highest activities at the pink stage of ripeness, whereas ADH was most active at the red stage. Variability of enzyme activity among individual fruit and of hue angle within ripeness stage was great. There were differences among the twelve lines for each enzyme activity, suggesting the potential for altering tomato flavor by selecting lines with different enzyme patterns. A wide difference in mean enzyme activities and concentrations of measured volatiles was noted. Predictive models were developed for hexanal, trans-2-heptanal, penetenone, cis-3-hexenal, trans-2-hexenal, cis-3-hexenol, and methanol as a function of one or more of the enzymes studied. Enzyme activity itself was not found to be a good predictor of the amount of volatiles produced suggesting that genetic modification of a single specific enzyme is not likely to produce a beneficial effect on fresh tomato flavor.