Kimchi is a traditional Korean fermented food made by salting vegetables such as napa cabbage and fermenting them with various seasonings (yangnyeom) including red pepper, garlic, and salted shrimp. It’s not just a spicy pickle—through a complex fermentation process, it develops distinctive sourness, umami, and rich nutritional value.
In 2013, kimchi and its culture “kimjang” were registered as UNESCO Intangible Cultural Heritage, recognizing its value worldwide.
In this article, we’ll explore the science of “lactic acid fermentation,” the secret behind why kimchi becomes delicious and why it’s so healthy.
What is Kimchi?
Kimchi represents one of humanity’s oldest preservation techniques, transforming fresh vegetables into a probiotic-rich food through natural fermentation. The process begins with salting vegetables to draw out excess moisture and inhibit harmful bacteria. Then, a mixture of seasonings—yangnyeom—is added, containing ingredients that nourish beneficial lactic acid bacteria.
The result is a food that’s simultaneously fresh, fermented, spicy, sour, and umami-rich—a complex flavor profile that has made kimchi one of the world’s most celebrated fermented foods.
The Kimchi Fermentation Process: A Relay of Lactic Acid Bacteria
Kimchi fermentation, like yogurt fermentation science, is based on “lactic acid fermentation,” but the types and functions of the lactic acid bacteria involved are different. Kimchi fermentation proceeds through a “relay of lactic acid bacteria,” where various bacteria take turns being active.
The Stars of Fermentation: Plant-Based Lactic Acid Bacteria
The fermentation of kimchi is carried out by “plant-based lactic acid bacteria” derived from vegetables. Compared to “animal-based lactic acid bacteria” found in yogurt, these bacteria are more resistant to salt and acid and can survive in harsh environments. As a result, they’re more likely to reach the intestines alive.
Main Lactic Acid Bacteria in Kimchi Fermentation
- Leuconostoc mesenteroides: Actively multiplies in the early stages of fermentation. Produces carbon dioxide, giving kimchi a refreshing sourness and fizzy texture. Also inhibits the growth of other harmful bacteria.
- Lactobacillus plantarum and Lactobacillus brevis: Multiply from the middle to late stages of fermentation. Produce robust sourness (lactic acid), enhancing kimchi’s preservation and creating deep flavor.
The Fermentation Mechanism
Kimchi fermentation proceeds slowly at low temperatures.
- Salting: First, napa cabbage is salted to remove excess water and inhibit harmful bacteria.
- Yangnyeom: Seasonings like red pepper, garlic, ginger, and salted shrimp are rich in sugars and amino acids that serve as food for lactic acid bacteria.
- Early Fermentation: Leuconostoc bacteria consume the vegetables’ sugars and multiply, producing lactic acid, acetic acid, and carbon dioxide. This creates kimchi’s characteristic refreshing flavor.
- Middle and Late Fermentation: As acidity increases, acid-resistant Lactobacillus bacteria become dominant and produce more lactic acid, advancing the aging process. This creates delicious kimchi with a balanced sourness and umami.
Microbial Succession in Fermentation
This lactic acid fermentation process is a wonderful example of how microorganisms enhance food flavor and preservation, also seen in the nukadoko microbial ecosystem.
Health Benefits of Kimchi
Kimchi is counted among the “world’s 5 healthiest foods,” with many scientifically proven health benefits.
1. Improved Gut Health
Plant-based lactic acid bacteria in kimchi reach the intestines alive and work as beneficial bacteria. Additionally, the abundant dietary fiber in vegetables like napa cabbage serves as food for beneficial bacteria, helping them multiply. Kimchi, which provides both “probiotics (lactic acid bacteria)” and “prebiotics (dietary fiber)” simultaneously, is extremely effective for maintaining gut health.
2. Enhanced Immunity
When gut health improves, the intestinal immune system is activated, boosting overall immunity. Components in seasonings like garlic and ginger also support immune function.
3. Skin Health
Capsaicin in red peppers promotes blood circulation and increases metabolism. It’s also rich in antioxidants like vitamin C and β-carotene, which prevent skin aging.
4. Obesity Prevention
Capsaicin promotes fat burning. Recent research has reported that regular kimchi consumption may reduce body fat and blood cholesterol, potentially preventing obesity.
5. Antioxidant and Anti-Cancer Effects
Kimchi ingredients like napa cabbage, garlic, and red pepper are rich in antioxidant components. These components are believed to remove reactive oxygen species that cause cancer and lifestyle-related diseases.
| Health Benefit | Active Component | Mechanism |
|---|---|---|
| Gut Health | Lactic acid bacteria + Dietary fiber | Probiotics and prebiotics work together |
| Immunity | Lactic acid bacteria + Garlic | Intestinal immune system activation |
| Skin Health | Capsaicin + Vitamin C | Blood circulation promotion + Antioxidant |
| Obesity Prevention | Capsaicin | Fat burning promotion |
| Anti-Cancer | Antioxidants | Reactive oxygen species removal |
Types of Kimchi
Beyond napa cabbage kimchi, there are many varieties:
- Kkakdugi: Radish kimchi. Characterized by a crunchy texture.
- Oi-sobagi: Cucumber kimchi. Has a refreshing taste.
- Mul-kimchi (Water Kimchi): Made without red pepper, not spicy. The soup is consumed along with the vegetables.
How to Eat Kimchi Effectively
Since the lactic acid bacteria in kimchi are heat-sensitive, eating it raw without heating is recommended to maximize health benefits. While heated dishes like pork kimchi and kimchi jjigae are delicious, the beneficial effects of lactic acid bacteria are reduced.
Additionally, combining kimchi with natto’s remarkable health benefits in “kimchi natto” makes an optimal gut-health menu. Pairing it with different types of miso is also recommended.
Conclusion
Kimchi is not just a spicy pickle but a scientifically excellent fermented food created through the ingenious fermentation process of a lactic acid bacteria relay. Abundant plant-based lactic acid bacteria, dietary fiber, and nutrients from various seasonings combine to bring us many health benefits.
From improved gut health to enhanced immunity and skin health, its power is immeasurable. Please incorporate kimchi into your daily meals and experience its deliciousness and health benefits for yourself.
References
- Park, K. Y., Jeong, J. K., Lee, Y. E., & Daily, J. W. (2014). “Health benefits of kimchi (Korean fermented vegetables) as a probiotic food.” Journal of Medicinal Food, 17(1), 6-20.
- Jung, J. Y., et al. (2011). “Metagenomic analysis of kimchi, a traditional Korean fermented food.” Applied and Environmental Microbiology, 77(7), 2264-2274.
- Patra, J. K., et al. (2016). “Kimchi and other widely consumed traditional fermented foods of Korea: A review.” Frontiers in Microbiology, 7, 1493.
- Korea Agro-Fisheries & Food Trade Corporation
- Jeonju International Fermented Food Expo
