Abstract:Micro-pressure heating is a new technique for soymilk processing, but the effect of this heating treatment on soymilk flavor characteristics is not clear. Therefore, traditional heating and micro-pressure heating were respectively applied during the preparation of soymilk, and the heating time was set as 5min, 10min, 15min and 20min, and then sensory evaluation as well as analysis of the changes in the contents of soymilk critical flavor compounds was conducted. The results showed that compared with traditional heating, micro-pressure heating could more significantly decrease the sensory score of beany odor and increase the intensity of cooked beans aroma and sweet aroma, but extending the heating time led to the cooked flavor remarkably enhanced. Furthermore, micro-pressure heating could effectively decrease the content of hexanal, and as the heating time increased (more than or equal to 15min), the contents of other critical beany flavor compounds, including trans-2-hexenal, 1-octene-3-ol and trans,trans-2,4-decadienal, were also significantly decreased, and for the critical non-beany flavor compounds, nonanal and trans-2-octenal suffered great loss, while trans-2-nonanal was thermally stable. According to the odor activity value (OAV) of critical soymilk flavor compounds, although micro-pressure heating could decrease the OAVs of both beany flavor and non-beany flavor, greater decrease occurred in the OAV of beany flavor, thus this heating treatment could effectively adjust the ratio of different flavor compounds and improve the entire flavor quality of soymilk, and soymilk treated with micro-pressure heating for 10min was proved to have the best flavor profile. It can be seen that micro-pressure heating was beneficial to optimize the processing quality of soymilk and had a good prospect of industrialization.
