Quantification and sensory studies of character impact odorants of different soybean lecithins

Fifty-four potent odorants in standardized, hydrolyzed, and deoiled and hyd rolyzed soybean lecithins were quantified by high-resolution gas chromatogr aphy/mass spectrometry (HRGC/MS). The characterization of their aroma impac t was performed by calculation of nasal (n) and retronasal (r) odor activit y values (OAVs). For this, the nasal and retronasal recognition thresholds of 18 odor-active compounds were determined in vegetable oil. The following compounds showed the highest nOAVs: 2,3-diethyl-5-methylpyrazine, methylpr opanal, acetic acid, pentanoic acid, 2-ethyl-3,5-dimethylpyrazine, pentylpy ridine, (Z)-1,5-octadien-3-one, 2-methylbutanal, and beta-damascenone. In a ddition to the compounds above, 1-octen-3-one, 1-nonen-3-one, and 3-methyl- 2,4-nonandione showed potent rOAVs. The results of quantification and OAV c alculation were confirmed by a model mixture of 25 impact odorants, which y ielded a highly similar sensory profile to that of the original soybean lec ithin. The sensory importance of pyrazines and free acids increased through enzymatic hydrolysis and decreased by the process of deoiling. The impact of unsaturated ketones on the lecithin aroma was not changed by either proc ess.