Profiling of fermentative metabolites in kimchi: Volatile and non-volatile organic acids

Abstract

Gas chromatograph/mass spectrometry (GC/MS) analysis was carried out to determine both the volatile and nonvolatile organic acids in kimchi during 60 days of fermentation at 10 o C. Principal component analysis (PCA) was applied to differentiate the pre-defined organic acids and lactic acid bacteria (LAB) during fermentation. Acetic acid was observed as dominant, which was vigorously produced until the middle of fermentation. Lactic acid was the major non-volatile organic acid in the kimchi and was produced throughout fermentation. In contrast, malic acid content decreased sharply at the initial stage of fermentation. Colony forming units of LAB in the kimchi, such as Leuconostoc, Lactobacilli, Pediococci, and Streptococci, were measured on selective media. Populations of Leuconostoc and Lactobacilli increased exponentially over 7 days of fermentation, indicating acetic acid and lactic acid were mainly produced by Leuconostoc and Lactobacilli. PCA demonstrated that acetic acid, propionic acid, lactic acid, butanoic acid, malic acid, Leuconostoc, and Lactobacilli were major components that differentiated the kimchi according to fermentation time.Keywords gas chromatography-mass spectrometry • kimchi • lactic acid bacteria • organic acid • principal component analysis S.-M. Shim and J. Y. Kim contributed equally.

Microbial Community Dynamics and Metabolome Changes During Spontaneous Fermentation of Northeast Sauerkraut From Different Households

“…The content of butanoic acid in #1 sauerkraut (13.04 ng/L) was higher than that in #3 sauerkraut (1.62 ng/L), whereas no butanoic acid was detected in #2 sauerkraut. The result was in accordance with that reported by Shim et al (2012). Butanoic acid was the most interesting short-chain fatty acid, which could in vivo suppress inflammation to improve nonalcoholic steatohepatitis, and its sodium compound was reported to have influence on the brain metabolism and have potential to modulate sleep (Ye et al, 2018;Szentirmai et al, 2019).…”

Preparation and properties of sodium bicarbonate‐incorporated LDPE films with deodorizing function for kimchi packaging

“…Kimchi is a Korean fermented vegetable food that has a sour, hot, salty, and characteristically carbonic taste owing to acetic acid fermentation of brined vegetable . Kimchi ripens rapidly due to the formation of excessive organic acids, such as lactic acid and acetic acid, resulting in sourness and texture softening, which affects consumer acceptance, flavor, and quality of this food product . After kimchi reaches a well‐aged stage, microbiological and enzymatic activities continue and result in a sour and bitter taste, off‐odor, softening, and deterioration …”

Microbial Succession and Metabolite Changes during Long‐Term Storage of Kimchi

“…It is well known that metabolites such as organic acids (lactic and acetic acids) and other flavoring compounds (mannitol and amino acids) are important components in kimchi tastes and flavors and metabolite profiles represent a collective phenotypic view that reflects the kimchi microbial community. The identification and quantification of the kimchi metabolites have been primarily achieved using traditional instruments such as high‐performance liquid chromatography (HPLC) and gas chromatography (GC) (Shim and others ), but it is almost impossible to analyze all kimchi metabolites simultaneously using the traditional instruments, especially over a long period of time because a wide variety of metabolites, having different chemical properties, are produced during kimchi fermentation. Proton nuclear magnetic resonance ( 1 H‐NMR) is one of the most powerful tools for simultaneously monitoring several metabolites present in 1 sample (Figueiredo and others ).…”