Soybeans fermented products

Figure 9.8 describes a batch process for the production of Japanese soy sauce (koikuchi). Soybeans and defatted soybean meals are cooked in continuous pressure-cookers and mixed with roasted and coarsely broken wheat. The mass is inoculated with Aspergillus spores and incubated in shallow vats with perforated bottoms that allow air to be forced through the mass. After three days of incubation at around 30°C, mould growth covers the entire mass. This mass is called koji. Koji is the essential ingredient of most fermented products of East Asia. It is a concentrated source of enzymes necessary for breaking up the large molecules of the carbohydrates and proteins. 

The Chinese counterpart for the word koji is qu, meaning bloom of mold. Made by growing molds on rice, barley, wheat, soybeans, or a combination, koji contains a great variety of enzymes that digest the starch, protein, and lipid components in raw materials. It is an intermediate product for making various fermented products such as fermented soy paste, soy sauce, soy nu ets, and Japanese sake. 

Fermentation of soybean has also yielded peptides with antioxidant properties in two soy-fermented products, natto and tempeh (Wang et al., 2008). Also, natto fermented by B. subtilis has been shown to exhibit radical scavenging activity and inhibitory effect on the oxidation of rat plasma LDL in vitro (Iwai, Nakaya, Kawasaki, Matsue, 2002). A low-molecular-weight viscous substance (molecular weight < 100 kilo Daltons) had... 

Huang, Y., Lai, Y., Chou, C. (2011). Fermentation temperature affects the antioxidant activity of the enzyme-ripened sufu, an oriental traditional fermented product of soybean. Journal ofBiosdence and Bioengineering, 112,49-53. 

Rozman, D., Pertot, E., Belie, I. and Komel, R. (1985) Soybean peptones as nutrients in the fermentative production of clavine ergot alkaloids with Claviceps fusiformis. Biotechnol. Lett., 7, 563-566. 

Protein preparations and milk-like products are processed from soybeans and peanuts. Alone or together with cereals, soybeans are processed into a large number of fermented products in Asia. The following products are made from soybeans. 

Similar to soybeans, a number of beans are processed into fermented products in Asia. 

Isoflavones, such as genistein (see Fig. 1) and daidzein, are found in Just a few botanical families, e.g., soy. Up to 3 mg/g of genistein and daidzein and their (1 glycosides are present in soybeans. Information on isofiavone content in soy products, such as soy milk, tofu, and fermented products such as miso, soy sauce, and tempeh, is given by Coward [92] and Wang [93]. 

Cells of microorganisms have constituted a portion of human food siace ancient times. Yeast-leavened baked products contain the residual nutrients from the yeast cells destroyed duriag bakiag (see Bakery processes and leavening agents). Cultured dairy products, such as yogurt, buttermilk, and sour cream, contain up to lO cells of lactic acid bacteria per gram (19) (see Milk and milkproducts). Other examples of fermented foods consumed siace early times iaclude fermented meats, fish, and soybean products. 

Tempeh. DehuUed cooked soybeans are inoculated with the mold, Thi pus oligosporus packed in perforated plastic bags, and allowed to ferment for 18 h. The mold mycelium overgrows the soybean cotyledons and forms a compact cake. When sHced and deep-fried in oil, a crisp and golden brown product is obtained. Although native to Indonesia, tempeh has become popular with vegetarians in the United States and other Western countries (93). 

Soybean-Based Cheese. In tofu cheese manufacture, the soybeans are cooked to give soy milk, then formed into a curd using calcium sulfate, and pressed to give tofu. The tofu is inoculated y ctinomucor elegans fermented, salted, and aged to form sufu (soft cheese) (17). This product is widely used ia the Orient and is gaining acceptance ia the United States. 

A subsequent patent, U.S. Patent 2,828,246 described a commercial process for bacitracin production. A 1,230 gallon portion of a medium containing 10% soybean oil meal, 2.50% starch and 0.50% calcium carbonate having a pH of 7.0 was inoculated with a culture of bacitracin-producing bacteria of the Bacillus subtilis group and the inoculated medium incubated for a period of 24 hours with aeration such that the superficial air velocity was 12.1. An assay of the nutrient medium following the fermentation revealed a yield of bacitracin amounting to 323 units/ml. This was more than twice the yields previously obtained. 

Microbial insecticides are very complex materials in their final formulation, because they are produced by fermentation of a variety of natural products. For growth, the bacteria must be provided with a source of carbon, nitrogen, and mineral salts. Sufficient nutrient is provided to take the strain of choice through its life cycle to complete sporulation with concomitant parasporal body formation. Certain crystalliferous bacilli require sources of preformed vitamins and/or amino acids for growth. Media for growing these bacilli may vary from completely soluble, defined formulations, usable for bench scale work, to rich media containing insoluble constituents for production situations (10,27). Complex natural materials such as cottonseed, soybean, and fish meal are commonly used. In fact, one such commercial production method (25) is based on use of a semisolid medium, a bran, which becomes part of the final product. 

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