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Title: ENZYMATIC MODIFICATION OF TOMATO HOMOGENATE AND ITS EFFECT ON VOLATILE FLAVOR COMPOUNDS

Author
item YILMAZ, EMIN - UNIV. OF GEORGIA
item Baldwin, Elizabeth - Liz
item SHEWFELT, ROBERT - UNIV. OF GEORGIA

Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/28/2002
Publication Date: 6/1/2002
Citation: YILMAZ, E., BALDWIN, E.A., SHEWFELT, R.L. ENZYMATIC MODIFICATION OF TOMATO HOMOGENATE AND ITS EFFECT ON VOLATILE FLAVOR COMPOUNDS. JOURNAL OF FOOD SCIENCE. 2002. v. 67. p. 2122-2125.

Interpretive Summary: Consumers have not been satisfied with the flavor quality of commercial tomatoes. In an effort to understand the complex mixture of ingredients that comprise tomato flavor with the goal of eventually improving flavor quality, a study was made of the precursors to tomato flavor compounds. These small molecules, which are responsible for the production of important aromas in tomato, were added to tomato puree to see if they would cause an increase in tomato aroma. It was found that adding these compounds changed the tomato aroma profile, but not in a predictable fashion. Therefore manipulating the levels of these compounds using molecular biology would not necessarily result in an improvement of tomato flavor.

Technical Abstract: Enhancement of the concentration of aroma volatiles through genetic modification has been offered as a strategy to improve the flavor of fresh tomato fruit. Important volatiles in tomatoes are produced by the oxylipin and alcohol pathways. The objective of this study was to determine the effect of added enzymes on key aromatic volatile compounds in homogenates prepared from red ripe and mature green tomatoes. Lipoxygenase (LOX), alcohol dehydrogenase (ADH), and a combination of both enzymes were added to homogenates, mixed for various time periods, and denatured with CaCl2. Headspace gas chromatographic analysis was performed to characterize patterns of 15 key volatiles. Hexanal, cis-3- hexenal and trans-2-hexenal increased in untreated red homogenates. LOX treatment led to an initial accumulation followed by degradation of volatiles. ADH treatment resulted in increased levels of methanol and acetaldehyde. Combination treatments degraded volatiles. Modification of a single enzyme is unlikely to have a predictably positive effect on fresh tomato flavor.