Health links raise interest in tsukemono as fermented food

The Yomiuri Shimbun

Chiharu Iijima, second from left, shows how to prepare a nukadoko fermented pickling bed using rice bran during a class at Aprile Cooking Studio in Musashino, Tokyo.

The Yomiuri ShimbunThis series discusses the present and future of washoku traditional Japanese cuisine. This installment explores tsukemono pickles, which play a key supporting role in washoku.

Amid growing interest in fermented food and having a healthy gut, the value of tsukemono pickles has been looked at anew.

In late February, a cooking class in Tokyo taught how to make nukadoko, a fermented bed of rice bran used for pickling. Twelve participants, mainly in their 20s to 40s, each used 1.5 kilograms of rice bran. They processed the bran by kneading it, then embedding vegetable scraps dubbed sutezuke to get the fermentation going. As it takes about a month to ferment nukadoko enough to be used for pickling, each participant placed their batch in an airtight container to place in the refrigerator when they get home.

The nukadoko-making class has been held once or twice a month since autumn of 2017 as part of efforts to promote the benefits of traditional and fermented foods. According to organizer Aprile Cooking Studio, each session is filled to capacity.

“I heard tsukemono help improve the stomach’s condition,” said a 28-year-old female company worker who participated in the February session. “I want to make them on my own and eat them as part of my everyday meals.”

Cooking school representative Chiharu Iijima said, “As long as nukadoko is stored in the refrigerator, it’s not difficult to take care of it. So it’s easy to introduce [fermented food] into the lives of contemporary people.”

With research having progressed on the links between intestinal bacteria and health, fermented food is gaining more attention. Many tsukemono pickles contain lactic acid that is produced through the fermentation process.

“Lactic acid is a type of bacteria that is good for the intestines,” said Hiroko Nakazawa, a professor of cookery science at the University of Nagano. “When it increases, a good intestinal environment can be maintained.”

An improved intestinal environment is believed to not just help prevent constipation, but also boost the immune system.

“Of course, you can also enjoy the distinctive acidity, umami and aroma that are brought about by fermentation,” Nakazawa added.

In addition, tsukemono are richer in dietary fiber, vitamins and minerals when compared to fresh vegetables. According to the 2015 version of the government’s Standard Tables of Food Composition, fresh daikon contains 1.4 grams of dietary fiber per 100 grams compared to 3.7 grams for takuan pickled daikon. Fresh daikon has 0.02 milligrams of vitamin B1 per 100 grams, while the figure increases to 0.33 milligrams for daikon pickled in nukadoko.

However, there have recently been major changes in tsukemono.

“Since the high economic growth period, an increasing number of people have regarded pickles as akin to salads,” said Nakako Matsumoto, a professor emeritus at Kagawa Nutrition University. “Even when eating tsukemono, many people eat something that is not actually fermented, such as asazuke lightly pickled items.”

Tsukemono are less frequently served in school meals as well, mainly due to the trend of opting for lower salt intake, which means more and more people of younger generations do not know the tastiness of pickles that comes from fermentation.

“Of course, it’s necessary to pay attention to the amount of salt intake, but tsukemono as a fermented food could disappear if we leave things as they are,” Matsumoto said. “I think it’s time to seriously consider whether we should allow this or not.”

Various processing methods

Various parts of the nation have produced distinctive tsukemono. Many areas use agricultural produce as the main ingredient, while some use seafood. There are a wide variety of processing methods, from salting to pickling ingredients in beds that are made with sake lees and rice bran, among other examples.

Among typical tsukemono using fish is one in Hokkaido where herring is pickled together with daikon and other vegetables. It is an important preserved dish in colder regions.

Nara Prefecture’s traditional pickles and Shizuoka Prefecture’s wasabi preserves use sake lees in their pickling beds. Akita Prefecture’s iburigakko is made by smoking daikon until dry to enhance preservability.

There are many leafy vegetables pickled in salt. Nagano Prefecture’s pickles using nozawana leaves and Kyoto Prefecture’s made of sugukina greens are both known as fermented products rich in lactic acid.

“While some areas still maintain the custom of making tsukemono at home, more than a few traditional pickles are disappearing,” said Megumi Nakata, an editor of a quarterly magazine on traditional Japanese home cuisine published by the Rural Culture Association Japan. “In addition, some tsukemono are produced mostly for sales as souvenirs.”

She added: “Traditional tsukemono cannot be made unless major factors — ingredients, climate and season — are all available. They are an important aspect of the food culture that reflects the natural features of each region.”

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