The impact of furanoid fatty acids and 3-methylnonane-2,4-dione on the flavor of oxidized soybean oil

• Published in: Journal of the American Oil Chemists' Society 1998-07, Vol.75 (7), p.831-835
• Main Authors: Kao, J.W, Wu, X, Hammond, E.G, White, P.J
• Format: Article
• Language: English
• Subjects: 3‐methylnonane‐2,4‐dione; ACEITE DE SOJA; ACIDE GRAS; ACIDOS GRASOS; Biological and medical sciences; Fat industries; FATTY ACIDS; FLAVEUR; Flavor threshold; FLAVOUR; Food industries; Fundamental and applied biological sciences. Psychology; gas chromatography; HUILE DE SOJA; OXIDACION; OXIDATION; OXYDATION; peroxide value; reversion flavor; SABOR; sensory evaluation; SOYBEAN OIL
• ISSN: 0003-021X; 1558-9331
• DOI: 10.1007/s11746-998-0233-2

Oils from soybeans with high or low contents of furanoid fatty acids were evaluated during storage for flavor intensity of soybean oil (SBO) off‐flavor, but no significant differences were found. In addition, the compound 3‐methylnonane‐2,4‐dione (MND), a breakdown product of furanoid fatty acids suggested by other researchers to contribute to reversion flavor of SBO, was evaluated for its contribution to off‐flavor. The compound was synthesized in the laboratory and purified by gas chromatography (GC) on a Silar 10 C column. GC analysis of the purified MND on a nonpolar SPB‐1 column showed two well‐separated main peaks that have been suggested to represent keto and enol forms. Between these two peaks, a bridge of poorly resolved compounds may have represented various possible enol forms or an equilibration among these forms during the GC separation. MND had an intense straw‐like and frulty odor when evaluated at the outlet of a gas chromatograph. Sensory evaluation of MND in a mineral oil/water emulsion system showed that its flavor intensity increased almost imperceptibly with increased concentration (from 0.09 to 2.56 ppm). An explanation for this unusual flavor response may be that, when molecularly dispersed in air, MND has an intense odor, but when placed in a mineral oil or soybean oil emulsion, MND may exist in a form with relatively low flavor intensity, or it may be bound by the media. The concentrations of MND in SBO at various peroxide values were measured at 0 to 0.804 ppb, which were far less than concentrations tested in mineral oil/water emulsions during sensory evaluation and below published odor threshold values for MND in oil. Therefore, these results do not support the theory that furanoid fatty acids or MND contribute strongly to the reversion flavor of SBO.