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Title: ODOR SIGNIFICANCE OF UNDESIRABLE DEGRADATION COMPOUNDS IN HEATED TRIOLEIN AND TRILINOLEIN

Author
item Neff, William
item Warner, Kathleen
item BYRDWELL, WM - FLORIDA ATLANTIC UNIV

Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/15/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: Frying oils break down under the conditions commonly used for frying. This breakdown is responsible for the dark color and unpleasant odor of used frying oils. We need to understand what compounds are being formed during the breakdown of frying oils to determine what is responsible for the dark color and unpleasant odor. When the compounds responsible are identified, better oils can be designed which minimize the formation of the undesirabl breakdown products. This study sought to identify the compounds produced during the breakdown of simple oils such as triolein and trilinolein. By understanding the products formed by these simple oils, other breakdown products in more complicated oil mixtures such as sunflower and corn oils can be identified by comparison. Then, oils can be produced which will resist formation of these products to the greatest extent possible. This will ultimately lead to consumer products that last longer on the shelf without going bad, and which withstand frying conditions better to give a more healthful, better tasting food product.

Technical Abstract: To better understand production of undesirable or negative odors such as fruity, plastic, and waxy that are characteristic of higher oleic acid containing oils, model heated oil systems of triolein and trilinolein were studied. Identification of the odor significance of volatile compounds produced by fractionated and non-fractionated triolein and trilinolein was done by purge and trap gas chromatography ion trap mass spectrometry olfactometry. The predominate odors of the triolein heated 1, 3, and 6 hours at 190 deg C were fruity and plastic with other negative odors of acrid and grassy. Some of the volatile compounds that produced negative odors (given in parentheses) in heated triolein in order of increasing concentration were hexanal (grassy), octana (fruity), (E)-2-decenal (plastic), nonanal (fruity), and E-2-undecenal (plastic). Some of the negative odor compounds in trilinolein heated at 1, 3, and 6 hours in order rof increasing concentration included E-2-nonenal (plastic), pentanal (grassy), and hexanal (grassy). The amount of volatile compounds produced and intensity levels of the odors were lower in trilinolein than for triolein. Formation of many of volatiles was explained after identification of the volatile precursors, including epoxy, keto, and dimer oxidation products that were produced during heating. This work may lead to better understanding and to the prevention of the formation during frying of nonvolatile compounds, which can decompose to products and cause deterioration of frying oils and fried food quality.