Aroma impact components in commercial plain sufu.

Volatile components of three commercial plain sufus or fermented soybean (Glycine max) curds (A-C) were extracted by a supercritical fluid extraction apparatus and analyzed by gas chromatography-mass spectrometry. A total of 83 compounds were found, of which 68 compounds were common among the three samples. Samples A, B, and C had 76, 75, and 74 components, respectively. Alcohols (17), acids (15), and esters (16) were the major classes. The rest of the classes were miscellaneous compounds (9), aldehydes (7), alkanes (5), aromatic compounds (5), ketones (3), furans (2), S-containing compounds (2), and other N-containing compounds (2). Gas chromatography-flame ionization detection-olfactometry analyses identified 17 potent odorants with different odor descriptions such as sour, sweet, fruity, coconut-like, and meaty. Fourteen odorants were further pinpointed by omission experiments among the 17 to be critical to the odor of commercial plain sufu. Acetic acid, methional, ethyl (Z,Z)-9,12-octadecadienoate, ethyl (Z)-9-ocatadecenoate, and 3-methylbutanoic acid were some of the potent odorants found.