Quantitation of Key Peanut Aroma Compounds in Raw Peanuts and Pan-Roasted Peanut Meal. Aroma Reconstitution and Comparison with Commercial Peanut Products

Abstract

By means of stable isotope dilution assays (SIDA), 26 odor-active compounds, previously characterized by GC-olfactometry (GC-O), were quantitated in raw peanuts, and the concentrations of 38 odorants were determined in pan-roasted peanut meal. On the basis of the quantitative data and odor thresholds determined in vegetable oil, the odor activity values (OAVs) of the most important aroma compounds in raw as well as in pan-roasted peanut meal were calculated. 3-Isopropyl-2-methoxypyrazine, acetic acid, and 3-(methylthio)propanal showed the highest OAVs in raw peanuts, whereas methanethiol, 2,3-pentanedione, 3-(methylthio)propanal, and 2- and 3-methylbutanal as well as the intensely popcorn-like smelling 2-acetyl-1-pyrroline revealed the highest OAV in the pan-roasted peanut meal. Aroma recombination studies confirmed the importance, in particular, of methanethiol and of lipid degradation products in the characteristic aroma of the freshly roasted peanut material. To evaluate additive effects on the overall aroma, the concentrations of eight pyrazines, previously not detected by GC-O among the odor-active volatiles, were additionally quantitated in the pan-roasted peanut meal. A sensory experiment in which the eight pyrazines were added to the recombinate clearly revealed that these volatiles did not show an impact on the overall aroma. Finally, selected odorants were quantitated in commercial peanut products to confirm their important role in peanut aroma.