Japan is the world’s largest producer of fermented foods. Natto, which is not a favorite of foreigners, is truly a typical Japanese fermented food. Speaking of fermented foods commonly eaten overseas, Chinese people eat Chinese pickles and menma, and Europeans eat cheese, sauerkraut, pickles, anchovies, and so on. Fermented foods are eaten not only in Japan but all over the world. Today, we will talk in depth about “fermentation,” the foundation of fermented foods. Let’s learn about the effects and types of fermentation and try various fermented foods.
What is Fermentation?
The production of something useful by the action of microorganisms is called fermentation. In more detail, it means that microorganisms break down carbon-containing compounds to produce simple compounds. In a more narrow sense, it is the breakdown of sugar to produce alcohol, lactic acid, etc.
In contrast, the production of harmful or unwanted substances by the action of microorganisms is called decomposition. Fallen leaves rotting away on the soil or food left to rot are the same work as fermentation for microorganisms, and it is from the standpoint of humans that we decide whether something is “fermentation” or “decomposition. Humans have been taking advantage of the work of these microorganisms to process foods and produce fermented foods. Behind the many fermented foods in Japan lies the wisdom of observing nature and making use of its workings in human activities.
PicklesBy pickling vegetables in salt and storing them at low temperatures, lactic acid is produced by the action of lactic acid bacteria.
Natto (fermented soybeans)The stickiness of natto is due to a substance called glutamic acid produced by the bacillus natto.
Katsuobushi (dried bonito flakes) The current production method was established in the mid-Edo period. However, it was not until the Showa period (1926-1989) that aggressive molding began to take place. It is also known as the hardest food in the world.
Effects of Fermentation
There are three main effects.
The first is an increase in shelf life. For example, Pickles extend the life of food due to the acidic environment created by microorganisms.
Second, nutritional value is increased. For example, in Natto (fermented soybeans), the enzyme protease produced by the bacillus natto breaks down the soy protein, making it easier to digest and absorb. In addition, vitamins produced by microorganisms are added, making it more nutritious than the original soybean.
Third, it tastes better. For example, Dried bonito flakes are treated with a process called kabi-tsuke, which removes water from the bonito meat and improves its shelf life due to kojic acid produced by the fungus, while the breakdown of proteins increases inosinic acid and amino acids, which are umami ingredients, making it a perfect “Dashi” (soup stock) material. All of these are wisdom and ingenuity to make good food that lasts longer and tastes better than what is found in nature.
Types of Fermentation
Fermented foods that we usually eat can be categorized into eating, drinking, and seasoning. Some fermented foods have been made in Japan since ancient times, while others are of foreign origin.
Fermented foods
Fermented foods include soybean-based fermented foods such as Natto (fermented soybeans), vegetable-based fermented foods such as Pickles, seafood-based fermented foods such as Bonito flakes, meat-based fermented foods such as Cured ham and Salami, Cheese, Yogurt, Bread, and Chocolate.
Fermented beverages
In addition to alcoholic beverages such as Sake, Beer, Wine, Shochu and Awamori, there are fermented teas such as Amazake and Black tea, and lactic acid bacteria beverages such as Calpis.
Fermented Seasonings
In addition to the basic seasonings of “Soy sauce,” “Miso,” “Vinegar,” and “Mirin,” there are fish sauce such as Nampula, koji seasonings such as Shio koji and Soy sauce koji, and Sake kasu.
The Science of Fermentation
Fermentation is a process by which microorganisms obtain energy, which is also closely related to respiration. The three major elements of nutrition are carbohydrates, proteins, and lipids, all of which are “polymers” consisting of many similar small molecules. Thus, when broken down, carbohydrates are converted into sugars, proteins into amino acids, and lipids into fatty acids and glycerol.
These are transformed and many are taken up into metabolic pathways. Ultimately, they are broken down into carbon dioxide and water, and energy is extracted in this process. This is respiration.
Oxygen plays an important role in this process. In mitochondria inside cells, energy is efficiently extracted through respiration using oxygen. Outside of the mitochondria, in what is called the cytoplasmic matrix, “anaerobic respiration” takes place, which does not use oxygen, and energy is obtained at a lower efficiency. The resulting products are lactic acid and alcohol.
In other words, the key to fermentation is the control of microbial metabolism and the creation of a suitable environment for that control.
Reference：https://www.hakko-blend.com/
Book: “More Delicious When You Know. The Official Guidebook of Japanese Food”, National Museum of Nature and Science, Tsuyoshi Hosoya
