From the Long-Established Nihon Maruten Shoyu, Boasting Over 200 Years of History, Comes a Refreshing New Sensation Mentsuyu 'Aomikan Mentsuyu Straight,' Born from Thinned, Unused Green Mandarin Oranges – Now Launched
Nihon Maruten Shoyu, a historic soy sauce manufacturer with over two centuries of experience, has launched 'Aomikan Mentsuyu Straight.' This innovative mentsuyu is crafted from thinned green mandarin oranges, offering a refreshing citrus flavor harmonized with bonito and iriko dashi, representing a significant three-year development effort to revive and enhance a beloved past product.
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- 📰 Published: April 8, 2026 at 20:00
- 🔍 Collected: April 8, 2026 at 11:30
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Nihon Maruten Shoyu Co., Ltd. (Tatsuno City, Hyogo Prefecture, President: Kaito Nobuoka), a long-established soy sauce manufacturer with over 200 years of history, will launch a new product, 'Aomikan Mentsuyu Straight,' which uses thinned, unused green mandarin oranges from Mikajiri, offering a refreshing citrus flavor and a harmonious blend of bonito and iriko dashi.
This product is a straight-type mentsuyu using 'thinned green mandarin oranges' from Mikajiri, Shizuoka Prefecture. It achieves a new flavor where the refreshing aroma and gentle sweetness of citrus harmonize with the umami of bonito and iriko dashi. The background of product development includes thoughts about the 'Setouchi Citrus Mentsuyu,' which was discontinued due to raw material shortages in the past, and a development story spanning three years of conception, involving over 100 prototype trials. It is an unprecedented item that combines history and new challenges, completed by Nihon Maruten Shoyu's long-cultivated technology and creativity in developing seasonings that can express any flavor.
■ 'The Lost Setouchi Citrus Mentsuyu,' Once More. The Thoughts Behind the Development
This product is not just a new item; it was born from the challenge of 'reviving a taste that once disappeared, further evolved.' The development team faced the seemingly simple yet highly difficult theme of citrus and mentsuyu, with a backstory of thoroughly confronting every aspect from material selection to taste design and manufacturing processes. Why did Nihon Maruten Shoyu take on this challenge again? And how did they arrive at the ideal taste? We unravel the behind-the-scenes story through an interview with the development representative.
Development Department, Product Development Division, Chief Kazuki Onishi
The current 'Aomikan Mentsuyu Straight' originated from 'Setouchi Citrus Mentsuyu,' developed in 2022. At that time, we used 'Setoka' citrus from Ehime Prefecture, but due to a poor harvest of Setoka, securing raw materials became difficult, and we could not continue the product. As it was a product we had put out into the world, it bothered us as developers to let it end there. We felt there was potential in the citrus mentsuyu genre itself, so we thought, 'Can we make it again with different ingredients?' and continued searching for alternative citrus fruits. Through that process, we encountered 'thinned green mandarin oranges' cultivated in Mikajiri, Shizuoka Prefecture.
Thinned green mandarin oranges are immature fruits thinned out during the mandarin cultivation process and are generally not utilized much. However, when we prototyped using thinned green mandarin oranges, we felt that the balance of acidity and sweetness was good, and it had potential as a seasoning. We thought that by using this generally unutilized material, we could contribute to upcycling while once again challenging ourselves with 'Setouchi Citrus Mentsuyu,' and proceeded with development.
**The Wall We Faced. Over 100 Prototypes Made Under the Constraint of High-Temperature Sterilization**
Developing mentsuyu using citrus is not easy. Straight-type products require high-temperature sterilization to maintain quality. However, citrus flavors are easily lost when heated, with the aroma dissipating or bitterness emerging. Even if a good balance was achieved, the taste could break down in the final process, which was a major challenge. Therefore, we procured and tested various citrus fruits to pair with thinned green mandarin oranges, and by repeatedly prototyping while changing the combination and ratio of fruit juices, the number of prototypes reached over 100 patterns.
**Optimal Balance Achieved with 'Thinned Green Mandarin Juice' and 'Sudachi Juice'**
What we finally arrived at was the method of combining 'green mandarin juice' and 'sudachi juice.' By adding the aroma of sudachi to the gentle sweetness of green mandarins, we achieved a balance that maintains the citrus flavor even after high-temperature sterilization. While sudachi alone can be prone to degradation, combining it with green mandarins stabilizes the overall taste, resulting in a mellow finish. I believe that solving the challenge through the combination of citrus fruits, rather than a single ingredient, was a major point of this development.
**Creating a Taste that 'Establishes Mentsuyu as Mentsuyu.' Whether it Establishes Itself as a 'Meal,' Not Just a 'Seasoning.'**
In taste creation, we focused on ensuring it firmly establishes itself as mentsuyu. If the citrus flavor is too strong, it can feel lacking when paired with noodles. Therefore, we developed it with the flow in mind: first, you perceive the aroma and acidity of citrus, then in the middle, sweetness adds depth, and finally, the umami of the dashi gently spreads. Regarding the dashi, we adjusted it so that it doesn't interfere with the citrus flavor by basing it on iriko rather than overly emphasizing bonito. We also emphasized the depth of flavor so that it would be satisfying not only with somen but also with udon. We are always conscious of whether it 'establishes itself as a meal, not just a seasoning' when actually eaten.
The development itself took about half a year until the quality direction was decided. Since we had the experience of developing the predecessor product that was the origin of the concept, we could proceed with a certain image of the goal in mind, but to approach that image, repeated prototyping was necessary.
While taking hints from taste impressions felt in everyday meals and dining out, we repeatedly prototyped, considering 'What kind of presence will this product have on the dining table?'
**Recipes We Can Confidently Recommend as Development Staff**
As for recommended ways to eat it, I think the simplest is to use it as a bukkake udon. Just pour it over chilled udon noodles and add tempura crisps and chopped green onions, and you can strongly feel the refreshingness of the citrus. It's also recommended to dilute it with water and use it for kake soba, or to arrange it with sudachi on the side. A slightly unexpected use is to season pasta with it, creating a Japanese-style dish with the tang of citrus. We hope it becomes a product that can be used in various ways on the everyday dining table.
Through this development, we felt that there is still new potential depending on the combination of ingredients. Nihon Maruten Shoyu's development is not confined to fixed frameworks; each development representative creates products based on daily food experiences and trends. We believe that even themes that were once perceived as difficult, like this one, can be transformed into new forms by confronting them again.
We want to continue working on creating seasonings that are one step beyond the standard.
■ 'Aomikan Mentsuyu Straight 300ml' Product Overview
**A Straight Mentsuyu with a Refreshing Flavor, Fusing the Taste of Thinned Green Mandarin and Dashi**
This is a new mentsuyu that achieves upcycling without wasting resources, using the juice of 'thinned green mandarin oranges' which are thinned out and unused during the cultivation of mandarins in Mikajiri, Shizuoka. It balances the citrus notes of 'Mikajiri mandarin and sudachi' with the flavors of bonito and iriko dashi, creating a deep taste with a clean finish. You can enjoy udon and somen noodles refreshingly and deliciously.
[Sales Channels]
◾️Official Online Shop
https://www.maruten-shop.com/item_list/016/
◾️Supermarkets nationwide: As of 3/23, planned store information
Kinki
・Life (some stores)
Kanto
・Co-op Deli (some stores)
Hyogo Prefecture
・Co-op Kobe (some stores)
・Aeon Coop Kinki
・MaxValu West Japan (some stores)
・Ginbiru Store (some stores)
・Kawabé (some stores)
Osaka Prefecture
・Aeon Coop Kinki
・Izumi Shimin Seikyo
Tottori Prefecture
・Sunmart
Ehime Prefecture
・Co-op Ehime (some stores)
Akita Prefecture
・Benny Mart
Aomori Prefecture
・Benny Mart
■Company Overview
【Company Name】Nihon Maruten Shoyu Co., Ltd.
【Founded】Kansei 7 (1795)
【Representative Director】President Kaito Nobuoka
【Location】672 Handa, Ibo River Town, Tatsuno City, Hyogo Prefecture
【Maruten Shoyu Official Website】https://www.marten-fi.co.jp/
【Official Online Shop】https://www.maruten-shop.com/
【YASASHIKU Gelato Brand Site】https://www.yasashiku-gelato.jp/
This product is a straight-type mentsuyu using 'thinned green mandarin oranges' from Mikajiri, Shizuoka Prefecture. It achieves a new flavor where the refreshing aroma and gentle sweetness of citrus harmonize with the umami of bonito and iriko dashi. The background of product development includes thoughts about the 'Setouchi Citrus Mentsuyu,' which was discontinued due to raw material shortages in the past, and a development story spanning three years of conception, involving over 100 prototype trials. It is an unprecedented item that combines history and new challenges, completed by Nihon Maruten Shoyu's long-cultivated technology and creativity in developing seasonings that can express any flavor.
■ 'The Lost Setouchi Citrus Mentsuyu,' Once More. The Thoughts Behind the Development
This product is not just a new item; it was born from the challenge of 'reviving a taste that once disappeared, further evolved.' The development team faced the seemingly simple yet highly difficult theme of citrus and mentsuyu, with a backstory of thoroughly confronting every aspect from material selection to taste design and manufacturing processes. Why did Nihon Maruten Shoyu take on this challenge again? And how did they arrive at the ideal taste? We unravel the behind-the-scenes story through an interview with the development representative.
Development Department, Product Development Division, Chief Kazuki Onishi
The current 'Aomikan Mentsuyu Straight' originated from 'Setouchi Citrus Mentsuyu,' developed in 2022. At that time, we used 'Setoka' citrus from Ehime Prefecture, but due to a poor harvest of Setoka, securing raw materials became difficult, and we could not continue the product. As it was a product we had put out into the world, it bothered us as developers to let it end there. We felt there was potential in the citrus mentsuyu genre itself, so we thought, 'Can we make it again with different ingredients?' and continued searching for alternative citrus fruits. Through that process, we encountered 'thinned green mandarin oranges' cultivated in Mikajiri, Shizuoka Prefecture.
Thinned green mandarin oranges are immature fruits thinned out during the mandarin cultivation process and are generally not utilized much. However, when we prototyped using thinned green mandarin oranges, we felt that the balance of acidity and sweetness was good, and it had potential as a seasoning. We thought that by using this generally unutilized material, we could contribute to upcycling while once again challenging ourselves with 'Setouchi Citrus Mentsuyu,' and proceeded with development.
**The Wall We Faced. Over 100 Prototypes Made Under the Constraint of High-Temperature Sterilization**
Developing mentsuyu using citrus is not easy. Straight-type products require high-temperature sterilization to maintain quality. However, citrus flavors are easily lost when heated, with the aroma dissipating or bitterness emerging. Even if a good balance was achieved, the taste could break down in the final process, which was a major challenge. Therefore, we procured and tested various citrus fruits to pair with thinned green mandarin oranges, and by repeatedly prototyping while changing the combination and ratio of fruit juices, the number of prototypes reached over 100 patterns.
**Optimal Balance Achieved with 'Thinned Green Mandarin Juice' and 'Sudachi Juice'**
What we finally arrived at was the method of combining 'green mandarin juice' and 'sudachi juice.' By adding the aroma of sudachi to the gentle sweetness of green mandarins, we achieved a balance that maintains the citrus flavor even after high-temperature sterilization. While sudachi alone can be prone to degradation, combining it with green mandarins stabilizes the overall taste, resulting in a mellow finish. I believe that solving the challenge through the combination of citrus fruits, rather than a single ingredient, was a major point of this development.
**Creating a Taste that 'Establishes Mentsuyu as Mentsuyu.' Whether it Establishes Itself as a 'Meal,' Not Just a 'Seasoning.'**
In taste creation, we focused on ensuring it firmly establishes itself as mentsuyu. If the citrus flavor is too strong, it can feel lacking when paired with noodles. Therefore, we developed it with the flow in mind: first, you perceive the aroma and acidity of citrus, then in the middle, sweetness adds depth, and finally, the umami of the dashi gently spreads. Regarding the dashi, we adjusted it so that it doesn't interfere with the citrus flavor by basing it on iriko rather than overly emphasizing bonito. We also emphasized the depth of flavor so that it would be satisfying not only with somen but also with udon. We are always conscious of whether it 'establishes itself as a meal, not just a seasoning' when actually eaten.
The development itself took about half a year until the quality direction was decided. Since we had the experience of developing the predecessor product that was the origin of the concept, we could proceed with a certain image of the goal in mind, but to approach that image, repeated prototyping was necessary.
While taking hints from taste impressions felt in everyday meals and dining out, we repeatedly prototyped, considering 'What kind of presence will this product have on the dining table?'
**Recipes We Can Confidently Recommend as Development Staff**
As for recommended ways to eat it, I think the simplest is to use it as a bukkake udon. Just pour it over chilled udon noodles and add tempura crisps and chopped green onions, and you can strongly feel the refreshingness of the citrus. It's also recommended to dilute it with water and use it for kake soba, or to arrange it with sudachi on the side. A slightly unexpected use is to season pasta with it, creating a Japanese-style dish with the tang of citrus. We hope it becomes a product that can be used in various ways on the everyday dining table.
Through this development, we felt that there is still new potential depending on the combination of ingredients. Nihon Maruten Shoyu's development is not confined to fixed frameworks; each development representative creates products based on daily food experiences and trends. We believe that even themes that were once perceived as difficult, like this one, can be transformed into new forms by confronting them again.
We want to continue working on creating seasonings that are one step beyond the standard.
■ 'Aomikan Mentsuyu Straight 300ml' Product Overview
**A Straight Mentsuyu with a Refreshing Flavor, Fusing the Taste of Thinned Green Mandarin and Dashi**
This is a new mentsuyu that achieves upcycling without wasting resources, using the juice of 'thinned green mandarin oranges' which are thinned out and unused during the cultivation of mandarins in Mikajiri, Shizuoka. It balances the citrus notes of 'Mikajiri mandarin and sudachi' with the flavors of bonito and iriko dashi, creating a deep taste with a clean finish. You can enjoy udon and somen noodles refreshingly and deliciously.
[Sales Channels]
◾️Official Online Shop
https://www.maruten-shop.com/item_list/016/
◾️Supermarkets nationwide: As of 3/23, planned store information
Kinki
・Life (some stores)
Kanto
・Co-op Deli (some stores)
Hyogo Prefecture
・Co-op Kobe (some stores)
・Aeon Coop Kinki
・MaxValu West Japan (some stores)
・Ginbiru Store (some stores)
・Kawabé (some stores)
Osaka Prefecture
・Aeon Coop Kinki
・Izumi Shimin Seikyo
Tottori Prefecture
・Sunmart
Ehime Prefecture
・Co-op Ehime (some stores)
Akita Prefecture
・Benny Mart
Aomori Prefecture
・Benny Mart
■Company Overview
【Company Name】Nihon Maruten Shoyu Co., Ltd.
【Founded】Kansei 7 (1795)
【Representative Director】President Kaito Nobuoka
【Location】672 Handa, Ibo River Town, Tatsuno City, Hyogo Prefecture
【Maruten Shoyu Official Website】https://www.marten-fi.co.jp/
【Official Online Shop】https://www.maruten-shop.com/
【YASASHIKU Gelato Brand Site】https://www.yasashiku-gelato.jp/