Comparison of volatile profiles in Fagopyrum esculentum (buckwheat) soksungjang prepared with different starter cultures during fermentation.

This study investigated the differences and changes in the volatile profiles of buckwheat soksungjang (BS) inoculated with multiple microbial starters (Lactobacillus brevis + Aspergillus oryzae, BS-LA vs. Lactobacillus brevis + Bacillus amyloliquefaciens, BS-LB) during fermentation using SPME coupled with GC-MS and partial least square-discriminant analysis. BS samples fermented for 5 weeks could be differentiated from other BS samples with shorter fermentation periods, and the BS-LA and BS-LB samples fermented for 5 weeks were separated. Acids, benzenes, and esters were main volatile compounds in both BS samples, however, their differences and changes were varied. The increase of 3-methylbutanoic acid was bigger in BS-LB than BS-LA, while the contents of 2- and 3-methylbutanal were relatively higher in BS-LA than BS-LB. Furthermore, the contents of esters of BS-LA significantly increased during fermentation. These results indicate that the volatile profiles of BS samples depend on the fermentation periods and the combination of microbial starters.

Change in profiles of volatile compounds from two types of Fagopyrum esculentum (buckwheat) soksungjang during fermentation.

Fagopyrum esculentum (buckwheat) soksungjang is one of the traditional soybean pastes in Korea. This study profiled and compared volatile compounds between traditionally manufactured (TBS) and commercially modified buckwheat soksungjang (CBS) according to their fermentation periods. More volatile compounds were generated and non-uniform increases or decreases in volatiles were more common during TBS fermentation. In addition, the changes in and differences between the volatiles from TBS and CBS during the fermentation process (after 0, 1, 2, and 5 weeks) were investigated in partial least squares-discriminant analysis models. The changes were accelerated during CBS fermentation in comparison with TBS fermentation. Several major volatile compounds, such as methyl decanoate, 3-hydroxy-2,6-dimethylpyran-4-one, and methyl heptanoate were found in the final stage of fermentation in TBS, in contrary, tridecane, (Z)-hex-3-en-1-ol, furan-2-carbaldehyde, and ethyl tetradecanoate were contributed to the latest of fermentation in CBS.