The many seaside and mountainous geographic locations from the south to the north of Japan and the influence of seasonal changes have resulted in regional development of many different traditional food. In addition, there are many fermented foods in Japan. Miso and shoyu, major seasoning substances, and sake, shochu, and awamori are widely consumed throughout Japan. There are also minor fermented foods in different local areas that are eaten in the areas where they are produced. In these featured papers we present information on several traditional fermented foods and explain the basis of their processing and associated chemistry.

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Sunki has traditionally been produced in the Kiso area in the southwestern part of Nagano Prefecture, Japan. The raw material of Sunki is red turnip, a traditional vegetable unique to the Kiso area. Sunki is made using fermentation without salt. Following removal of the leaves, turnips are cut in pieces, heated in boiling water for about one minute, and then pack in containers that retain the heat at about 38°C for 24 hours of fermentation. Four kinds of lactic acid bacteria participate in the fermentation process: Lactobacillus fermentum, Lactobacillus delbrueckii, Lactobacillus plantarum, Lactobacillus parabuchneri. Since Sunki is not salted, it has a sour taste. People living in the Kiso area eat miso soup or buckwheat noddle soup topped with Sunki. Soups topped with Sunki are very delicious because of succinic acid, an umami component, that is contained in the fermented liquid. Among the four kinds of lactic acid bacteria, L. fermentum and L. parabuchneri produce succinic acid during the fermentation process for preparation of Sunki. Therefore, not only sourness but also succinic acid, an umami component , is present in the fermented liquid of Sunki.

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Sendango is a traditional processed food item that is characteristic of Tsushima, Nagasaki prefecture. It is prepared by fermenting sweet potatoes. Rokubee is a type of noodle made from Sendango, and its texture is unique in comparison to other types of noodles. Here, the processing of Sendango and the characteristic texture of Rokubee are introduced. We found that Sendango is composed of approximately 90% starch that is bound with approximately 6% fiber to form aggregates. In addition, the starch granules are roughsurfaced and have some holes, confirming that they are degraded by fermentation. The amylose ratio of Sendango starch is high, suggesting that amylopectin is mostly degraded. In addition, Sendango starch properties of gelatinization and retrogradation occur either with difficulty or easily, respectively, and the starch gel may have hard, elastic or viscous characteristics. These properties were shown to be caused by specific degradation of the short chains (A and B1 chains) present in the outmost shell of the amylopectin chain-length. In addition, we searched for the microbe related to the texture. The results suggest that the unique texture of Rokubee is attributable to the action of specific strains of P. echinulatum and P. expansum.

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There are two kinds of Japanese traditional sweet kuzu-mochi. Kuzu-mochi in the Kansai region is made of kuzu-ko (kuzu starch) which is very transparent and has a very soft texture. Another kuzu-mochi is made from fermented starch refined from wheat flour and fermented, and has been eaten in the Kanto region from as early as the Edo period. Kuzu-mochi in Kanto is milky white and has a characteristic non-adhesive elasticity texture. In this review, we present our studies of the texture of kuzu-mochi made of fermented wheat starch (FWS) and detail the changes of starch properties during fermentation.
The raw materials of the kuzu-mochi are FWS, which is a by-product of the gluten manufacturing process. The main microbes in this fermentation are lactic acid and amylase producing bacteria. PCR-denaturing-gradientgel-electrophoresis profiles indicated that the microflora remains stable from the pre-fermentation period to about 6 months post-fermentation. These results suggested that the bacterial community present at the pre-fermentation period can serve as a starter culture for the traditional processing of FWS.
The elastic but non-sticky texture of kuzu-mochi is attributable to the properties of FWS. To elucidate those characteristic properties of FWS, the comparative physicochemical and pasting properties of starch with/without fermentation treatment were examined.
The amylose content in FWS is lower than that in unfermented WS. The λ_max of the iodine absorption spectrum of FWS is blue-shifted relative to that of WS. The maximum and final viscosities of FWS, and its consistency in the rapid visco analyzer viscogram are lower than those of WS. These results reveal that fermentation endows starch with low viscosity and the ability to retard retrogradation.
To clarify the texture characteristics of kuzu-mochi, the physical properties of kuzu-mochi were compared with that of various gelatinous foods such as dango, warabi-mochi, and yokan. Kuzu-mochi was softer than yokan, but it was as hard as dango. The stickiness of kuzu-mochi was lower than that of dango. Kuzu-mochi had an elastic non-sticky texture. Many starch granules were observed within the gel matrix of kuzu-mochi. It is suggested that the gelatinous state of starch in kuzu-mochi contributes to the texture and the internal structure of kuzu-mochi.
The properties of FWS, particularly the pasting and physical properties of the gel, change during the fermentation process. Moreover, it is suggested that microbes contribute to the properties of the wheat starch.

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Tea is generally divided to three types: non-fermented tea, fermented tea and post fermented tea. The best-known post fermented teas in the world are Myan in Thailand and Pu'er tea in China. We also have post fermented tea Goishi cha in Kochi, Awaban cha in Tokushima, Ishizuchikuro cha in Ehime and Batabata cha in Toyama. In this section, we introduce Goishi cha and Awaban cha.
Goishi cha has two fermenting steps during production. In the first step, mold ferments the tea leaf. Yeast and lactic acid bacteria added in the second step provide the fermented leaf with good original aroma and flavor in addition to it beneficial health properties.
Awaban cha has only one fermentation step after rolling tea leaf, with a yeast and LAB effect to provide aroma and flavor during fermentation. Awaban cha has good flavor with acidity in addition to beneficial health properties.
Post fermented teas have original aroma, flavor, and beneficial health functions.

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The Ministry of Health, Labour and Welfare (MHLW) in Japan introduced a positive listing system for food additives when they implemented the Food Sanitation Law. Currently, all food additives are classified into four groups: designated food additives; existing food additives; natural flavoring; and food/food ingredients used as additives. All designated additives and some existing food additives are currently regulated by the specifications and/or standards. These specifications and standards include those concerning chemical and physical characteristics, manufacturing, storage, and use. These standards, along with specifications for labeling and storage, are published in an official compilation entitled, “Japan's Specifications and Standards for use of Food Additives” (JSSFA), under the Food Sanitation Law. JSSFA has been revised by adding the new specifications and/or standards. The 9th edition of JSSFA was made available in February in 2018 on the MHLW home page. In this review, highlights of revised points in the 9^th edition of Japan's Specifications and Standards for Food Additives are introduced.

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Aroma is one of the important quality factors in food. Aroma compounds are often stored as glycosidically bound volatiles (GBVs) in grapes (Vitis vinifera), tea (Camellia sinensis), sweet potatos (Ipomoea batatas), kiwifruit (Actinidia deliciosa ), tomatos (Solanum lycopersicum) , etc. These GBVs in plants are hydrolyzed by chemical reaction and/or glycosidases during food processing or mastication and aroma compounds are liberated. Tea quality is defined by the appearance of tea products, as well as the color, aroma, and taste of tea infusions. There are over 600 aroma compounds in tea products and fresh tea leaves. The aroma in black and oolong tea in particular contains the aroma compounds of fruit, flower, and sweetness. Vigorous research has recently confirmed that the aroma component of black and oolong tea is derived from GBVs. This research note shows not only when, where and how GBVs in fresh tea are biosynthesized, but also shows a different mechanism of aroma generation between black tea and oolong tea.

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Melting, recrystallization, and complex formation of starch and its effect on food quality control are reviewed. The effect of water content on the melting temperature of starch and the effect of baking temperature on the water evaporation rate were investigated in cookie dough. A stepwise procedure without starch melting during baking was designed. In vitro starch digestibility from stepwise-baked cookies was much lower than that for conventionally baked cookies. Retrogradation (recrystallization of melted starch) of rice starch gel could be prevented by the addition of low-molecular-weight carbohydrates. The browning reaction between the low-molecular-weight carbohydrates and protein in rice could be diminished by adjusting pH and water content. Complex formation between amylose and lipid in gelatinized starch solution was investigated systematically, and lauric and oleic acid samples showed the largest reduction in the hydrolyzed starch content. This result was related to the extent of complex formation and its helical order. In addition, there was a possibility of further complex formation between amylose and unsaturated fatty acid during the hydrolysis of gelatinized starch.

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Japanese people are globally recognized as mycophilic, and the use of wild mushrooms as food in Japan has been described even in old literature. Several hundred mushroom species are reported to be edible in Japan. Based on long traditional wild mushroom consumption, the mushroom cultivation industry developed in Japan after World War Ⅱ. Since many wild mushrooms are known to be poisonous, knowledge of species identification is critical to use them safely. In this article I focus on the culture of mushrooms as food in Japan, and discuss background and future perspectives

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