Study on volatile aroma compounds in donkey broths of different stewing time

Donkey broth has a unique aroma and is affected by cooking time. Five donkey broth samples of different stewing time were prepared. The volatile components were extracted by solvent-assisted flavor evaporation (SAFE) and analyzed by gas chromatography-mass spectroscopy (GC-MS). According to the result, a total of 45 volatile aroma compounds were identified in five donkey broths (stewing time of 0 min, 1, 2, 3 and 4 h respectively). In terms of gas chromatography-olfactometry (GC-O) analysis, aroma extraction dilution analysis (AEDA) and calculating odor activity values (OAVs), respective 26 and 15 aroma active compounds were pointed out significantly in five donkey broths. Twelve odorants including 2-methyl pentanal, 3-hydroxyl-2-butanone, hexanal, dimethyl trisulfide, nonanal, 3-(Methylthio)propanal, 2-ethyl-1-hexanol, benzaldehyde, 4-methoxyallylbenzene, (E,E)-2,4-nonadienal, delta-hexalactone and octanoic acid were characterized as the common aroma active compounds existed in donkey broths with different stewing time. Principal component analysis (PCA) and sensory evaluation results characterized the difference of aroma profiles for the five different donkey broths, which showed that the duration of the stewing time had an important effect on the general flavor of donkey broth.