The addition of red pepper powder results in the production of 75 to 120 times more ornithine

Dr. Jong-Hee Lee and his research team at the Advanced Process Technology and Fermentation Research Group of WiKim unveiled that “ornithine”——a beneficial substance produced in kimchi, is closely associated with the presence of red pepper powder.

What is ornithine?

As a substance that removes nitrogen waste products such as ammonia, ornithine plays an important role in the process of excreting ammonia by producing urea from it, thereby improving motor function and skin condition. Since ornithine facilitates the excretion of ammonia, it is known to help relieve hangovers. High concentrations of ornithine are sometimes used to treat hepatic coma.

Kimchi is made of a variety of ingredients, namely kimchi cabbage, red pepper, garlic, and salted fish. There are numerous organic substances in these ingredients that undergo fermentation by lactic acid bacteria to produce various metabolites. In particular, red pepper powder is an important ingredient and is responsible for the distinctive red color and spicy taste of kimchi, but there are not many studies that investigate how red pepper powder contributes to the nutritional excellence of kimchi.

Therefore, Dr. Jong-Hee Lee’s research team at the Advanced Process Technology and Fermentation Research Group of WiKim analyzed the changes in the microbial community and metabolites in watery kimchi made of sliced radishes (nabbak kimchi) upon the addition of red pepper powder, and confirmed that the distribution of lactic acid bacteria in kimchi varies depending on whether it contains red pepper powder.

In kimchi that contained red pepper powder, there were 10 times more lactic acid bacteria of “Weissella” than in kimchi that did not contain red pepper powder.

The major lactic acid bacteria involved in kimchi fermentation are largely divided into three genera (Lactobacillus, Weissella, and Leuconostoc). Bacteria belonging to the Weissella are superior to other microorganisms in their ability to break down arginine——an amino acid——to produce citrulline and ornithine.

The study confirmed that about 75 to 120 times more ornithine was produced from the microorganisms in Weissella, which were increased by the addition of red pepper powder in the fermentation process for 1 to 2 weeks immediately after the kimchi was made.

This study has scientifically proven that red pepper powder does more than just add a spicy taste to kimchi by revealing that it affects the growth of lactic acid bacteria and ultimately regulates metabolite production.

WiKim will continue to conduct various studies to prove the excellent health benefits of kimchi and consolidate its reputation as a global health food. The results of this study were published in the online edition of the October issue of “LWT-Food Science and Technology”——an international journal in the field of food science and technology.

※ Title of thesis: Red pepper powder is an essential factor for ornithine production in kimchi fermentation
(Corresponding author) Dr. Jong-Hee Lee (First author) Dr. Sera Jung