Nattokinase can be enriched in Bacillus subtilis fermented soymilk,but the resulting off flavor has seriously affected its industrial promotion. In order to ascertain the source of peculiar flavor in fermented soymilk,this study traced and identified volatile components of fermented soymilk at different times by electronic nose and gas chromatography mass spectrometry (GC-MS),and analyzed the metabolic changes of protein in fermented soymilk by physicochemical methods. The results of electronic nose reflected the trend of sample's flavor over time. GC3MS detected a total of 60 volatile components during the entire fermentation process,including alkanes,alcohols,aldehydes,ketones,organic acid esters,heterocycles. However,only the heterocyclic compounds dominated by pyrazines showed an increasing trend while the proportions of 2,5-dimethylpyrazine and 2,3,5-trimethylpyrazine in heterocyclic compounds were 76.65% and 16.00%,respectively. Therefore,2,5-dimethylpyrazine is presumed to be a flavor characteristic of fermented soymilk. Moreover,physicochemical analysis showed that the degradation of protein accelerated the production of amino acids,and the catabolism of amino acids might promote the synthesis of 2,5-dimethylpyrazine,which caused the flavor deterioration of fermented soymilk. This study will be expected to provide a base for the flavor improvement and industrial promotion of functional fermented soymilk.
GAO Yaxin
,
NI Nan
,
XU Bin
,
FAN Hairu
,
ZHANG Mengran
,
LU Cong
,
ZHANG Nana
,
FAN Bei
,
WANG Fengzhong
,
LI Shuying
. Exploration on the peculiar flavor of fermented soymilk by Bacillus subtilis BSNK-5[J]. Food and Fermentation Industries, 2020
, 46(15)
: 258
-264
.
DOI: 10.13995/j.cnki.11-1802/ts.023635
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