Traditional fermentation engineering

Chinese traditional fermented food has a long history, diverse varieties and rich flavor. The more common fermented food are: fermented dairy products, bean products, meat products, etc. Traditional food fermentation system is usually composed of one or more microorganisms, which are in a special micro ecological environment. The microorganisms produced are directly related to the smell and quality of fermented products!

Traditional fermentation technology generally refers to a technology that directly uses the naturally existing microorganisms in raw materials, or uses the microorganisms in the fermented products such as dough and brine preserved in the previous fermentation to ferment and make food. Traditional fermentation is mainly solid fermentation and semi-solid fermentation of mixed strains, usually family or workshop. Generally speaking, traditional fermentation has a long cycle, is greatly affected by environmental factors, has high labor costs, and has a low level of industrialization.

Microorganisms involved in traditional fermentation technology include:

1) Traditional soybean fermented foods include soy sauce, soy sauce, fermented bean curd and Douchi. Taking soy sauce as an example, the main microorganism of the starter "koji" used in traditional soy sauce brewing in China is mold, of which Aspergillus oryzae is the main one; The lactic acid bacteria related to the formation of soy sauce flavor include Streptococcus halophilus, tetracocci of soy sauce, Lactobacillus plantarum and so on. In addition, yeast with high osmotic pressure resistance and strong salt tolerance, such as Roche yeast and halophile yeast, also have a great impact on the formation of soy sauce aroma and flavor. Natto in Japan is produced with Bacillus natto, which is a special probiotic food

2) Zhenjiang balsamic vinegar and Shanxi aged vinegar are the most famous traditional vinegar. The main functional microorganisms in traditional vinegar include Acetobacter, lactic acid bacteria, mold, yeast and so on. Among them, the main bacteria in Zhenjiang balsamic vinegar are lactic acid bacteria, acetic acid bacteria, glycoacetobacter, Staphylococcus, enterobacter, etc., and there is only one genus of fungi, yeast. In the brewing process of Shanxi aged vinegar, the yeasts include Deke yeast, Jiuxiang yeast and oospore yeast, and the functional bacteria for acid production are Lactobacillus plantarum and Acetobacter Pasteurella.

3) In the traditional Monascus and yellow rice wine fermentation process, the structure of yeast flora has been in a state of dynamic change until the final stable completion.

Fermentation engineering is a new technology that uses modern engineering technology to produce useful products for human beings by using the specific functions of microorganisms, or directly applies microorganisms to industrial production processes. Fermentation engineering includes strain breeding, culture medium preparation, sterilization, expanded culture and inoculation, fermentation process and product separation and purification. Compared with traditional fermentation technology, the application of biotechnology in fermentation engineering has brought new opportunities for food production. With the strong support of biotechnology, traditional fermentation technology is developing in the direction of science and technology, and a systematic fermentation project has been formed.

Fermentation is the core process of making yogurt, and the design of fermentation tank will directly affect the quality of products.