Effect of Lactobacillus plantarum fermentation on the volatile flavors of mung beans

The effects of fermentation with Lactobacillus plantarum on the volatile flavors of mung beans were studied using a gas chromatograph-ion mobility spectrometer, electronic nose, relative odor activity values and sensory evaluation. The main volatile compounds in unfermented mung beans were aldehydes such as nonanal, octanal and butanal, and esters such as ethyl hexanoate and ethyl acetate. The relative contents of the beany flavor components (1-octen-3-ol, hexanal and hexanol) were relatively high in the unfermented samples. The main volatile compounds of fermented mung beans (FMB) were acetic acid, ethyl hexanoate and ethyl acetate. The relative content of the beany flavor components in FMB decreased significantly, with hexanal changing the most. L. plantarum 23169 was most effective at removing the beany flavor. The electronic nose results showed that the flavor of L. plantarum 23169 FMB and L. plantarum 22699 FMB changed most and were similar, but the flavors from the three FMB samples could still be clearly distinguished. According to relative odor activity values, the special smell of FMB were fruity and grassy with no beany flavor, and sensory evaluation showed that L. plantarum YI-Y2013 provided a good “deodorization” effect, with the most obvious aromatic flavor and a high overall flavor coordination.