Abstract:

The goal of this study was to examine and compare the changes and differences in volatile substances of
fermented grass carp with Lactobacillus plantarum based on two different growth media at different times and consequently
to provide a reference for the research of flavor compounds of fermented grass carp. Electronic nose and headspace solidphase
microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) were used to detect and analyze the
changes of volatile substances. The relative odor activity value (ROAV) combined with odor threshold was applied to
confirm the key odor compounds of fermented grass carp. Electronic nose could sensitively detect the changes in volatile
substances of fermented grass carp during the fermentation process, and the LDA results revealed that there were obvious
differences among these samples. GC-MS analysis indicated that a total of 90 and 70 volatile components were found to
be present respectively in fermented grass carp with L. plantarum in MRS broth medium and 12% skimmed milk medium,
consisting mainly of hydrocarbons, aldehydes, alcohols, ketones, esters, amines and aromatic compounds. The principal
flavor components common to both samples were D-limonene, 1-octene-3-ol, heptanal, octanal, decanal and acetoin.
The unique flavor components of fermented grass carp produced using MRS broth medium were 2,3-butanedione and
(E)-2-nonenal, while the unique flavor components of fermented grass carp produced using 12% skimmed milk medium
were hexanal, nonanal and butyric acid ethyl ester.

Key words: Lactobacillus plantarum, MRS broth, 12% skimmed milk medium, electronic nose, gas chromatography-mass spectrometry (GC-MS), key flavor compounds