Abstract:

The volatile compounds of soymilk samples subjected to different pretreatments including blank control,
microwave irradiation, freezing and ultrasonic irradiation were extracted by simultaneous distillation extraction (SDE) and
then analyzed by gas chromatography-mass spectrometry (GC-MS). The separated peaks were identified by mass spectral
library search combined with retention index comparison. The area normalization method was used for quantitative analysis
employing benzyl alcohol as the internal standard. The results indicated that a total of 48 volatile compounds were identified
including 28, 26, 30 and 33 compounds detected in non-pretreated, microwave-treated, frozen and ultrasonic-treated soymilk,
respectively. The main flavor compounds of all four soymilk samples were aldehydes, alcohols, ketones, and furans, among
which, the aldehydes were the most predominant compounds. These results together with sensory evaluation indicated
that frozen soymilk had the best flavor.

Key words: soymilk, different pretreatments, volatile flavor compound, simultaneous distillation extraction-gas chromatography-mass spectrometry (SDE-GC-MS), retention index