Natto fermentation temperature and time

The main raw materials of natto are soybeans and soy beans, which are rich in soy protein. Many people in Japan like to eat natto very much, but the taste and flavor of natto are different from those of ordinary beans, so some people like to eat it, while some people don’t. In addition, soybeans themselves have a natural flavor that makes people feel disgusted. But just like durian, some people like to eat it. What is the fermentation process of natto like?

The fermentation temperature of natto is a constant temperature of 28℃ ~ 32℃. The fermentation temperature of natto is 28

The fermentation of fermented black beans is to use the protease produced in the koji making process to break down the protein in the beans, forming a certain amount of amino acids, sugars and other substances, giving the black beans their inherent flavor.

⑴ Washing fermented black beans: There are many spores and hyphae attached to the surface of fermented black beans, which are rich in protein and enzymes. If the spores and hyphae are not washed off and continue to remain on the surface of the koji, after fermentation and hydrolysis, some of them will be soluble and hydrolyzed, but a large part of them will still be attached to the surface of the koji in the form of spores and hyphae. In particular, the spores have a bitter taste, which will bring bitterness to the fermented black beans and cause a dull color.

⑵ Add alum to turn the beans black and increase their brightness.

⑶ Soaking and stewing: Add 18% salt, 0.02% alum and appropriate amount of water to the finished koji, just enough to make the surface of the koji, and soak and stew for 12 hours.

(4) Fermentation: Put the processed bean koji into the can until it is 80% to 90% full, compact it layer by layer, and place it in a constant temperature room at 28℃ ~ 32℃ for fermentation. The fermentation time is controlled at about 15 days.

Fermented black beans are a Chinese Han specialty fermented bean seasoning. Fermented black beans are made from black beans or soybeans as the main raw materials. The soybean protein is decomposed by the action of Mucor, Aspergillus or bacterial protease. When it reaches a certain level, salt, wine, drying and other methods are added to inhibit the activity of the enzyme and delay the fermentation process. There are many types of fermented black beans. According to the processing materials, they can be divided into black fermented black beans and yellow fermented black beans. According to the taste, they can be divided into salty fermented black beans and light fermented black beans.

Fermented black beans, known as "youshu" or "shi" in ancient times. The earliest record was found in the book "Explanation of Names and Explanation of Food" by Liu Xi of the Han Dynasty, which praised fermented black beans as "the harmony of five flavors, which is the necessary combination". The book "Food Classics" written from the 2nd to 5th century AD also records the "method of making fermented black beans". The ancients not only used fermented black beans for seasoning, but also used it as medicine, and they attached great importance to it. This is recorded in "Han Shu", "Shi Ji", "Qimin Yaoshu", "Compendium of Materia Medica", etc., and its production history can be traced back to the pre-Qin period.

According to records, the production of fermented black beans first spread from Taihe County, Jiangxi Province. After continuous development and improvement, fermented black beans became unique and became a favorite condiment, and it also spread overseas. People in Taiwan call fermented black beans "Yinshi", Japanese call fermented black beans "Nashi", and fermented black beans are also commonly eaten in Southeast Asian countries.