**4. Traditional Japanese foods prepared from soybeans**

Soybeans have been cultivated throughout Japan since the Yayoi period (1700–2300 years ago) [27, 28] and have contributed significantly in the preparation of Japanese food consumed nowadays. Currently, soybean is cultivated all over the country, from Hokkaido in the north to Okinawa in the south and there are varieties suitable for the cultivation conditions of each region. In the fiscal year of 2019, soybean demand in Japan was 3,670,000 tons, with food-related use accounting for 28% or 1,019,000 tons, while the remaining 72% accounted for non-food applications such as livestock feed. Currently, ~80% of soybeans intended for consumption are imported from overseas, primarily from the United States, Canada, and Brazil [29]. The main food-based applications of soybeans include the production of miso (soybean paste), soy sauce, tofu, fried bean curd, natto (fermented soybeans), dried bean curd, and soy milk (**Figure 3**). As an essential ingredient in Japanese cuisine, these traditional foods not only contribute to the health and nutrition of the Japanese population, but also in Japanese food culture. In December 2013, the

**Figure 3.** *The strain of Traditional Soybean Products.*

#### *Present and Future Perspective of Soybean Cultivation DOI: http://dx.doi.org/10.5772/intechopen.103024*

"traditional food culture of the Japanese people" was registered as an UNESCO Intangible Cultural Heritage [30], and Japanese food culture is continuously gaining global attention due to the health benefits and taste of tofu, soy sauce, and miso [31].

The original form of miso is considered to have been established in Japan from the Chinese continent during the Nara period (710–794). Over the course of its 1400-year history, fermented soy sauce prepared from soybeans and grains mixed with mold-containing koji and salt has spread throughout the country and has been enhanced to fit each region's preferences. Soy sauce production is thought to have been established independently in each local environment [32]. Currently, various types of miso are available and they can be grouped into four main types: (1) rice miso prepared from soybeans, rice koji (malted rice) and salt; (2) barley miso prepared from soybeans, barley koji and salt; (3) soybean miso prepared from soybean miso balls, koji and salt; and (4) mixed miso prepared by mixing several types of miso. Rice miso is further classified based on different flavors and colors according to the koji ratio and salt concentration used, and is classified into sweet (white, red), sweet (light-colored, red), and dry (light-colored, red) rice miso while barley miso is classified as sweet and dry [33]. Among these, rice miso is the most widely produced miso and is manufactured in many regions of Japan. Rice miso is prepared by adding rice malt and salt to steamed soybeans and fermented. The salt inhibits bacterial growth as well as proteolytic enzymes, saccharolytic enzymes, and lipolytic enzymes produced by koji degradation to its ingredients; the aromatic flavor components that determine the taste of miso and miso-like color are mediated by the action of salt-resistant lactic acid bacteria and salt-resistant yeast during the fermentation and subsequent maturation processes [34]. Aroma extract dilution analysis (AEDA) is conducted to examine the aroma components in fermented soybean foods such as miso [35]. AEDA involves the detection of components eluted from a gas chromatography (GC) column based on the odor and can analyze the aroma of trace amounts of components that cannot be detected by GC [36]. The complex aroma of raw miso is attributed to major components such as 4-hydroxy-2(or 5)-ethyl-5(or 2)-methyl-3(2H)-furanone and 3-hydroxy-4,5-dimethyl-2(5H)-furanone. Furanone and other recently identified substantially low abundant components are considered to be key factors affecting the aroma of miso [37–39]. Moreover, it has been revealed that aroma alterations due to heat treatment during manufacturing and cooking procedures may be triggered by an increase in methional content, a major component, and a decrease in the levels of three components, 1-octen-3-one, (Z)-1,5-octadien-3-one, and trans-4,5-epoxy-(E)-2-decenal. Recently discovered trace components are important factors affecting soybean characteristics [40]. Miso contains numerous biological regulators, and it has been reported to inhibit melanin production, osteoporosis as well as to reduce cholesterol and blood pressure [41–43]. Miso consumption has considerably affected health maintenance of Japanese population during its long history, and is expected to improve accordingly the diets of the global population.

## **5. Development of new products prepared from soybeans**

Soybeans contain an optimal balance of essential amino acids as suggested by their amino acid score of 100. Milk has the same amino acid score (100) and is an essential component of the human diet since ancient times. Throughout the history of food, consumption of milk can be summarized by the "dairy milk tree," that is characterized by the combination of fermentation and separation of protein-rich and fat-rich milk components [44]. A variety of dairy products ranging from butter and powdered milk to cream, condensed milk, ice cream, cheese, yogurt,

and *Lactobacillus*-based beverages are prepared from milk, and they have become closely intertwined with the food culture of each region. Various studies have examined processing of soybeans to yield water-soluble protein components and oily components such as milk. Nevertheless, protein and fat components in soybeans are strongly associated, and effective classification of the two components represents a major challenge [45, 46].

Fuji Oil organization, which has been investigating soybeans for more than half a century, enhanced the process of separating lipophilic and hydrophilic proteins and developed an approach for separating soy milk into two parts: oily soy cream and low-fat soy milk. This new separation technology has been patented as the world's first Ultra Soy Separation (USS) method (**Figure 4**). The soymilk cream and low-fat soy milk separated using the USS process has been confirmed to contain various tastes and functions not detected in conventional soy milk. Soymilk cream has a deep richness of soybeans and improves the flavor of the ingredients combined with it and confers a delicious creamy texture to food. Low-fat soy milk is a healthy ingredient that although contains very limited oil amounts, it has a significantly strong soybean flavor and can be utilized as a soup stock. The first premium soy milk products developed after the USS manufacturing method were presented in the Japanese Pavilion of the Milan Expo in 2015, where food was the main theme and attracted particular attention as a food material that contains a new plant-based taste (**Figure 5**). A variety of desserts and beverages prepared using soy butter, soy cream, and low-fat soy milk that all benefit from plant-based taste of this novel ingredient, are now available in convenience stores in Japan and attract the attention of "flexitarians" who are interested in plant-based foods. In the near future, "dairy milk tree" based on soymilk cream and low-fat soy milk may further develop with the formation of a variety of new traditional foods. In summary, soybeans are anticipated to contribute in the amelioration of the health of the Japanese and global population.

**Figure 4.** *USS (Ultra Soy Separation) method.*

*Present and Future Perspective of Soybean Cultivation DOI: http://dx.doi.org/10.5772/intechopen.103024*

**Figure 5.** *Cheese-like soy milk products and their applications.*
