Natto, a traditional Japanese fermented soybean dish, has a long and intriguing history that dates back centuries. This unique culinary treasure has captivated the hearts and palates of the Japanese people, and its influence has even spread to various parts of the world.
Why Do Soybeans Become Sticky Natto?
The key to natto's fermentation is Bacillus subtilis, a bacterium commonly found in soil, rice straw, and the air. When cooked soybeans were wrapped in rice straw, the bacteria naturally fermented them, creating natto's distinctive sticky texture.
Origin of the Name "Natto"
The name "natto" has several theories of origin:
- Temple Kitchens: Monks in temples made natto in the temple kitchen (nassho), leading to the name nassho-mame, eventually shortened to natto.
- Stored Beans: Soybeans stored in jars were referred to as "stored beans" (osameta mame), which evolved into natto.
- Sacred Offering Beans: In northern Japan, soybeans touched by sacred straw ropes were believed to be a divine gift, hence the name natto.
Types of Natto
Natto can generally be divided into three main types:
- Sweet Natto (Amanatto): A confectionery made by boiling soybeans with sugar.
- Sticky Natto (Itohiki Natto): The most commonly consumed type, with a sticky texture.
-
- Whole Soybean Natto (Marudaizu Natto): Made with whole soybeans.
- Crushed Soybean Natto (Hikiwari Natto): Made with crushed soybeans, resulting in less stickiness.
- Temple Natto (Tera Natto): Made using salt and koji mold, similar to miso, with a salty and umami flavor but no stickiness.
How Natto Is Made
The process of making natto typically involves:
- Steaming Soybeans: Soybeans are steamed until soft.
- Inoculating Natto Bacteria: Natto bacteria are introduced to the beans.
- Fermentation: Beans ferment at around 40°C for about 20 hours.
- Cooling and Maturation: The natto is cooled and aged to stabilize its flavor.
Why Is Natto Sticky?
The stickiness of natto comes from polyglutamic acid, formed by the breakdown of soybean proteins during fermentation. This acid also contributes to natto's umami flavor.
The Smell of Natto
Natto’s distinctive smell comes from volatile compounds like pyrazines (nutty aroma) and short-chain fatty acids (pungent smell).
Nutritional Value of Natto
Natto is highly nutritious, containing:
- Protein, Fat, Calcium, Iron: From soybeans.
- Vitamin B2: Promotes fat metabolism.
- Nattokinase: An enzyme believed to dissolve blood clots.
- Vitamin K2: Enhances calcium absorption and bone health.
Natto Around the World
Similar fermented soybean products exist globally:
- China: Douchi – Salty fermented soybeans.
- Korea: Cheonggukjang – Sticky fermented soybeans.
- Nepal: Kinema – Closest to Japanese natto.
- Thailand: Thua Nao – Fermented soybeans used in seasoning.
- West Africa: Dawadawa – Fermented soybeans with a strong umami taste.
Natto's unique taste, texture, and health benefits have made it a significant part of Japanese cuisine and culture, while similar fermented products continue to thrive globally.
