“Kōji”: The Secret Behind Japanese Cuisine’s Flavors

Maehashi Kenjiwrote . . . . . . . . .

What Are Fermented Foods?

Around the world, a range of fermented foods and fermenting traditions have been developed, closely related to each particular culture. Fermented foods are traditional foods whose taste and health benefits are underpinned by years of eating experience.

They are processed foods, prepared through metabolism by microorganisms and using enzymes. Microorganisms existed on the Earth long before humans, and thus, fermented products have occurred naturally since prehistory. Humans encountered the phenomenon of fermentation in the process of preserving food supplies. After discovering these tastes, humans learned to harness the power of fermentation to deliberately produce these items. In this way, fermented products were developed around the world utilizing the major foodstuffs of each locale.

Fermentation-Based Flavors in Japanese Food

Japan has a wide variety of fermented foods that can be divided into four broad categories: condiments, side dishes, alcoholic drinks, and nonalcoholic beverages. Fermented side dishes include tsukemono (pickles), shiokara (salted seafood) and natto; alcoholic beverages include sake and shōchū; and nonalcoholic beverages include amazake.

But the greatest abundance is in the variety of fermented condiments, such as soy sauce, miso, mirin, vinegar, and shio-kōji. The range of condiments produced through fermentation techniques is a special feature of Japanese cuisine. Fermentation is used extensively in Japan to create flavors for food: This is what makes Japanese food so tasty.

In 2013, the United Nations Educational, Scientific, and Cultural Organization inscribed washoku, the “traditional dietary cultures of the Japanese,” on its Representative List of the Intangible Cultural Heritage of Humanity. It noted that washoku utilizes a variety of fresh ingredients and a range of flavors, and recognized the role of its good nutritional balance in supporting a healthy lifestyle. This is without a doubt partly due to fermentation.

What is Kōji?

Kōji refers to cereals inoculated with spores of kōji mold (Aspergillus oryzae). When rice is used, it produces rice kōji, soy beans are used to create soy kōji, and so on. Kōji is indispensable for brewing Japanese sake and traditional condiments. In the brewing world, there is a saying, “First, kōji,” followed by the kai, the paddle used to mix ingredients, and third by the flame used to heat the mixture. Brewers are particular about kōji above all else.

The kanji generally used to write kōji (麹) originated in China. Two components make up the character: the left part is 麦 (barley), and the right part refers to wrapping of cereal grains, 匊. There is another kanji for kōji (糀) invented in Japan during the Meiji era (1868–1912), comprised of a rice grain and a flower, depicting the fluffy mold growing on rice.

Kōji mold secretes digestive enzymes, dissolving the host grains as the fungal filaments grow. Consequently, kōji contains a large range of accumulated digestive enzymes, some of which, for example, decompose starch, and others that break down proteins.

The former decompose starch in the cereal to make it soluble. In addition, they even break down glucose, producing sweetness. Other enzymes decompose proteins in soybeans, creating peptides in which amino acids are linked in a chain. If the peptides decompose further, it produces 20 types of amino acids. Among them, glutamic acid​ is an umami component: the more amino acids, the tastier.

Among microorganisms, kōji mold is a particularly powerful at producing enzymes. Our ancestors employed fermentation extensively, using the enzymes from kōji mold to create sweeteners and umami enhancers from rice and soybeans. In this way, they developed fermented foods with an abundance of tastes and aromas.

Through the action of kōji mold on rice, they also created sake, an alcoholic beverage known for its mellow aromas. In addition, they developed condiments with an intense umami: miso and soy sauce.

The sugars and amino acids produced through enzymatic degradation becomes nutritious lactic acid bacteria and yeasts while creating complex flavors and aromas. Thus, kōji mold is the foundation for fermentation. Kōji mold is also the key to producing rice vinegar, mirin, shōchū and shio-kōji. You cannot discuss Japanese cuisine without mentioning it.

Japan’s “National Mold” is Domesticated

In 2006, the Brewing Society of Japan designated kōji as Japan’s “national mold.” Kōji mold is a term used to refer to Aspergillus oryzae, which has the greatest range of applications, used to make everything from salty miso to sweet amazake. It is also a generic term for the class of molds used as “seed kōji” for soy sauce and alcoholic beverages like shōchū and awamori.

Seed kōji describes the starter culture used to produce the mold. For centuries, seed kōji merchants have cultivated and preserved the purity of strains of seed kōji to sell to brewers.

Aspergillus flavus is believed to be the ancestor of kōji mold due to its similar taxonomy. Unlike this strongly toxic strain, though, modern kōji mold poses no danger to health.

In facts, recent genome analysis has revealed that the genes that produce poisons in kōji mold are inactive, providing scientific evidence of its safety. By domesticating dangerous molds for over 1,000 years, Japanese people built a rich food culture.

Furthermore, genome analysis has also shown that kōji mold contains abundant digestive enzyme genes compared with other molds, including over 100 gene varieties of proteolytic (protein decomposing) enzymes alone.

The enzymes in kōji mold are so strong that they remain in product seasonings even after brewing, retaining their vitality, which can be employed effectively in subsequent cooking processes. Examples include the production of amazake and shio-kōji, where enzymes in kōji mold that decompose starch digest the starch in rice, creating glucose, and thus imparting strong sweetness. Both still contain strong active enzymes, and when they are used in cooking ingredients high in starch, the enzymes work to produce greater sweetness. If left longer, the ingredients can dissolve and liquefy.

Amazake and shio-kōji can also be used in cooking animal products, such as fish and meat, that are high in protein, to enhance the umami and to tenderize the ingredients. With leaf vegetables, which contain little starch or protein, the enzymes damage the cell walls, making it easier for flavors to penetrate.

Preparing ingredients for cooking includes cutting and other processes that impart physical damage, destroying cells. Enzymes and other components are liquefied, leading to chemical reactions between them. This is one mechanism for producing tastes and aromas.

Because kōji has more powerful enzymes than regular ingredients, it induces significant changes to components when used in food preparation. Brewed seasonings produced with kōji are rich in flavors and aromas drawn out of the ingredients by its enzymes. In particular, kōji enzymes remain in miso, shio-kōji and amazake. The use of kōji condiments is a means of extracting more umami from ingredients—a key washoku food preparation technique.

Characteristic Washoku Tastes: Simple Yet Complex

Condiments often serve a role in adjusting flavor. This is a simple matter in the case of sugar and salt, which adjust sweetness or saltiness according to the amount added. But kōji condiments not only impart their own complex flavors; the enzymes they contain also act on ingredients to produce sweetness or umami with an impact going beyond what is added.

The sauces and soup stocks developed in Western cooking are concentrates of umami extracted from a variety of ingredients. On the other hand, Japan’s kōji condiments, produced with minimal ingredients, use the power of fermentation to create umami and other complex flavors. Washoku preparation is simple, but we can enjoy these complex tastes thanks to this fermentation.

But kōji enzymes do more than just create good tastes. It has been shown that the components produced when kōji enzymes act on ingredients have health benefits.

Components resulting from decomposing starch include glucose and various oligosaccharides. These help to regulate the intestinal environment, and can therefore relieve constipation and diarrhea, as well as boosting immune function to help prevent infections and control allergies.

The components produced in decomposition of proteins include various peptides. They have diverse structures with a large range of functions: some can help reduce blood pressure, while others are anti-acidic. Foods always contain proteins to some degree, so fermented foods using koji always contain peptides.

Measuring the amount of peptides in ingredients requires complex analysis using specialized equipment. But as noted above, as fermentation progresses and umami becomes more evident, decomposition of proteins also increases, producing more peptides. The greater flavor of foods produced by fermentation with kōji is also an indication of their greater health benefits.

Preserving Kōji Food Culture for the Future

There is a term in Japanese, kinshoku, which roughly translates as “fungal diet.” It refers to a diet high in mushrooms, molds, yeasts, bacteria and other microorganisms: essentially, eating fermented foods. Such foods contain bacterial cell​s of microorganisms or metabolites produced by microorganisms and other components produced by microbial enzymes.

Traditional washoku and Japanese food in general almost always uses condiments produced through fermentation by kōji mold. These condiments provide health benefits via the components produced when kōji enzymes decompose ingredients, and also add rich flavors and aromas. The fact that less processing is required to prepare ingredients further boosts the healthfulness of meals.

Kōji foods underpin the traditional healthy diet of Japanese people, and although Japanese food is changing with the times, I hope we can preserve the culture of kōji foods for the future.

Source: Nippon

 

 

 

 

Peach Afternoon Tea Set of Kichijoji Excel Hotel Tokyu in Japan

 

 

 

 

First-of-its-kind Test Can Predict Dementia Up to Nine Years Before Diagnosis

Researchers from the Centre of Preventive Neurology have developed a new method for predicting dementia with over 80% accuracy and up to nine years before a diagnosis. The new method provides a more accurate way to predict dementia than memory tests or measurements of brain shrinkage, two commonly used methods for diagnosing dementia.

The team, led by Professor Charles Marshall and published today in Nature Mental Health, developed the predictive test by analysing functional MRI (fMRI) scans to detect changes in the brain’s ‘default mode network’ (DMN). The DMN connects regions of the brain to perform specific cognitive functions and is the first neural network to be affected by Alzheimer’s disease.

The researchers used fMRI scans from over 1,100 volunteers from UK Biobank, a large-scale biomedical database and research resource containing genetic and health information from half a million UK participants, to estimate the effective connectivity between ten regions of the brain that constitute the default mode network.

The researchers assigned each patient with a probability of dementia value based on the extent to which their effective connectivity pattern conforms to a pattern that indicates dementia or a control-like pattern.

They compared these predictions to the medical data of each patient, on record with the UK Biobank. The findings showed that the model had accurately predicted onset of dementia up to nine years before an official diagnosis was made, and with greater than 80% accuracy. In the cases where the volunteers had gone on to develop dementia, it was also found that the model could predict within a two-year margin of error exactly how long it would take that diagnosis to be made.

The researchers also examined whether changes to the DMN might be caused by known risk factors for dementia. Their analysis showed that genetic risk for Alzheimer’s disease was strongly associated with connectivity changes in the DMN, supporting the idea that these changes are specific to Alzheimer’s disease. They also found that social isolation was likely to increase risk of dementia through its effect on connectivity in the DMN.

Charles Marshall, Professor and Honorary Consultant Neurologist, led the research team within the Centre for Preventive Neurology at the Wolfson Institute of Population Health. He said: “Predicting who is going to get dementia in the future will be vital for developing treatments that can prevent the irreversible loss of brain cells that causes the symptoms of dementia. Although we are getting better at detecting the proteins in the brain that can cause Alzheimer’s disease, many people live for decades with these proteins in their brain without developing symptoms of dementia. We hope that the measure of brain function that we have developed will allow us to be much more precise about whether someone is actually going to develop dementia, and how soon, so that we can identify whether they might benefit from future treatments.”

Samuel Ereira, lead author and Academic Foundation Programme Doctor at the Centre for Preventive Neurology, Wolfson Institute of Population Health, said: “Using these analysis techniques with large datasets we can identify those at high dementia risk, and also learn which environmental risk factors pushed these people into a high-risk zone. Enormous potential exists to apply these methods to different brain networks and populations, to help us better understand the interplays between environment, neurobiology and illness, both in dementia and possibly other neurodegenerative diseases. fMRI is a non-invasive medical imaging tool, and it takes about 6 minutes to collect the necessary data on an MRI scanner, so it could be integrated into existing diagnostic pathways, particularly where MRI is already used.”

Source: Queen Mary University of London

 

 

 

 

Stuffed Portobello Mushrooms with Shaved Parmesan

Ingredients

12 large portobello mushrooms, wiped over and stems removed
2 tbsp corn oil, plus extra for oiling
1 fennel bulb, stalks removed, finely chopped
scant 1/2 cup sun-dried tomatoes, finely chopped
2 garlic cloves, crushed
generous 1 cup grated fontina cheese
scant 1/2 cup freshly grated Parmesan cheese
3 tbsp chopped fresh basil
salt and pepper
1 tbsp olive oil

TO SERVE

fresh Parmesan cheese shavings
1 tbsp chopped fresh parsley

Method

1. Preheat the oven to 350°F/180°C.
2. Lightly oil a large ovenproof dish. Place 8 of the mushrooms, cup-side up, in the dish and chop the remaining 4 mushrooms finely.
3. Heat the corn oil in a nonstick skillet, add the chopped mushrooms, fennel, sun- dried tomatoes, and garlic and cook over low heat until the vegetables are soft but not browned. Remove from the heat and let cool.
4. When cool, add the cheeses, basil, and salt and pepper to taste. Mix well. Brush the mushrooms lightly with the olive oil and fill each cavity with a spoonful of the vegetable filling.
5. Bake for 20-25 minutes, or until the mushrooms are tender and the filling is heated through.
6. Top with Parmesan shavings and parsley and serve at once, allowing 2 mushrooms for each person.

Makes 4 servings.

Source: Brunch

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