Kimchi fermentation research
The World Institute of Kimchi (WiKim) has identified the origin source of lactic acid bacteria involved in the fermentation of kimchi and the characteristics of the fermentation process, depending on the strains of lactic acid bacteria. Kimchi, a traditional Korean fermented vegetable food, is fermented by lactic acid bacteria derived from raw ingredients, such as kimchi cabbage, garlic, ginger, and red pepper. Lactic acid bacteria produce various metabolites during fermentation, in response to the type of ingredients and storage temperature. The metabolites determine the flavour and quality of kimchi.
Controlling the fermentation processes involving microorganisms present in kimchi is a scientific and industrial challenge. While the raw ingredients for kimchi are recognised as one of the factors that influence the fermentation of kimchi, only a few studies have been conducted regarding the origin source of lactic acid bacteria responsible for kimchi fermentation, and the different fermentation characteristics depending on the species of lactic acid bacteria.
The Microbiology and Functionality Research Group at WiKim analysed the origin source of lactic acid bacteria that affected the fermentation of kimchi through multi-omics analysis, after selectively sterilising four ingredients (kimchi cabbage, garlic, ginger and red pepper) for kimchi. The analysis revealed that the fermentation was carried out by lactic acid bacteria indigenous to kimchi cabbage and garlic, not by microorganisms derived from ginger and red pepper, among the raw materials for kimchi. Findings from the study were published in the online edition of Food Chemistry.
“We’ve successfully figured out scientific grounds for the fermentation of kimchi by tracing the origin source of lactic acid bacteria involved in the fermentation. This will surely give us an opportunity to strengthen the status of South Korea as the origin of kimchi,” said Dr Choi, Hak-Jong, Acting Director of WiKim.
Kimchi fermented by kimchi cabbage-derived microorganisms showed that the strains in the genus Leuconostoc, Weissella and Lactobacillus formed dominant communities. However, strains of Leuconostoc and Weissella were dominant in kimchi fermented by microorganisms from garlic. These lactic acid bacteria were also confirmed to produce metabolites, such as mannitol and lactic acid.
Researchers also succeeded in isolating three major fermentative microbes involved in kimchi fermentation, which are specific to the ingredients: Leuconostoc gelidum, Weissella koreensis and Lactobacillus sakei. The study confirmed that kimchi is fermented differently depending on the species of lactic acid bacteria aforementioned, by introducing them into sterilised kimchi.
The study identified the origin source of lactic acid bacteria, the determinants of the fermentation of kimchi and the fermentation characteristics by bacteria derived from each ingredient. The findings will be used as scientific data for the production of standardised kimchi.
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