Gas chromatography-mass spectrometry-based metabolomics analysis of metabolites in commercial and inoculated pickle
Liu Yun， Bingyong mao, Shumao Cui, et al.
J Sci Food Agric.2020 Aug 24. doi: 10.1002/jsfa. 10757
Abstract
Background: Now starter cultures are more and more used to make the inoculated pickles (IPs), but it remains unclear whether there are differences in flavors between IPs and naturally fermented pickles. In this study sixteen commercial pickles (CPs) produced by spontaneous fermentation method were purchased from markets in Sichuan province and Chongqing. Ten strains of three lactic acid bacteria (LAB) species -Lactobacillus plantarum, Leuconostoc mesenteroides and Pediococcus ethanolidurans- were selected as single starter cultures to produce IPs.
Results: Differences in flavor components between the CPs and IPs were monitored using a combination of gas chromatography-mass spectrometry (GC-MS) and multivariate statistical methods. Higher levels of non-volatile substances such as glucose, fructose, tagatose, sucrose, lactic acid and mannitol were detected in most IPs than in the CPs. The values of flavor characteristics such as sweetness, umami and astringency, which were correlated positively with consumers' overall preferences for pickles, were higher in the IPs than in the CPs. Volatile compounds such as geranyl acetate, dimethyl trisulfide, eucalyptol and linalool were distinguished as the main compounds that contributed to the flavor characteristics of the CPs. Except dimethyl trisulfide, dimethyl disulphide was also an odor contributor to the IPs.
Conclusion: The CPs and IPs had different flavor characteristics, especially in the composition and content of volatile components, and the inoculation method reflected some fermentation advantages, which could reduce the bitterness and increase umami and obtain a higher score of sensory preference. This will be helpful for industrial production. This article is protected by copyright. All rights reserved.
Keywords: GC-MS; Pickle; fermentation; lactic acid bacteria; metabolomics