Effects of olive, canola, and sunflower oils on the formation of volatilesfrom the Maillard reaction of lysine with xylose and glucose

Some important edible oils (extra virgin olive oil, canola oil, and sunflow er oil) were added to aqueous glucose-lysine or xylose-lysine model systems to investigate their effect on the formation of volatiles from the Maillar d reaction (MR). The volatile compounds were extracted by a Likens-Nickerso n apparatus and quantified. Pyrazines, Maillard reaction products with an i mportant impact on food flavor, appeared to be particularly sensitive to th e presence of the oils in both the xylose-lysine and glucose-lysine model s ystems. The unsubstituted pyrazine was formed more with olive oil, less wit h canola oil, and even less with sunflower oil, whereas 2-methylpyrazine, 2 ,5-methylpyrazine, and 2,3-dimethylpyrazine were formed less with olive oil , more with canola oil, and even more with sunflower. The oxidative states of the oils and their fatty acid fingerprints were determined: the results indicated that the relative amounts of the pyrazines are sensitive to the d egree of unsaturation of the oil. The autoxidation of the volatile compound s generated from the MR, investigated by the addition of free radical modul ators (antioxidants alpha -tocopherol, 2,6-di-tert-butyl-4-methylphenol, an d rosemary extract; or pro-oxidant alpha-alpha'-azobis-isobutyronitrile, a free radical initiator), was limited in respect to aqueous model systems.