Compounds contributing to the 'beany' odor of aqueous solutions of soy protein isolates

Using gas chromatography/olfactometry (GCO), major odors from the headspace of aqueous solutions of soy protein isolates were evaluated. Many corresponding odorants were identified by correlating GCO with GC/mass spectrometry (MS) on two separate stationary phases followed by comparing retention times, mass spectra, odor descriptions and odor intensities with authentic standards. Based on aroma extract dilution analyses, the most powerful odorants (strongest and most volatile first) were (1) dimethyl trisulfide, (2) trans, trans-2,4-decadienal, (3) an unidentified burnt soy sauce-like odor, (4) 2-pentyl pyridine, (5) trans, trans-2,4-nonadienal, (6) hexanal, (7) an unidentified charred sweaty feet-like odor, (8) acetophenone, and (9) 1-octen-3-one. This is the first reported occurrence of dimethyl trisulfide in soy protein isolates.