KINARI and Kanagawa University Launch Joint Research to Scientifically Examine the Skin Benefits of Discarded Yuzu Extraction Residue

KINARI Co., Ltd. (Head office: Shinagawa-ku, Tokyo; President and Director: Masafumi Yamamoto) and Kanagawa University (President: Ryusuke Toda) began joint research on April 1, 2026, with the aim of scientifically clarifying the potential benefits of discarded yuzu extraction residue for the skin. The research is being led by the Laboratory of Food and Cosmetic Science, Department of Applied Biological Science, Faculty of Chemistry and Biochemistry, Kanagawa University, under Professor Yuichi Nodake. The study is part of KINARI’s efforts to create value from plant-derived ingredients and advance research and development. It focuses on unused residue derived from domestically produced yuzu and will scientifically verify and clarify its effects on skin cells and related areas. Background: Yuzu has long been a familiar part of everyday life in Japan. In addition to its pleasant fragrance, the fruit is rich in vitamin C and citric acid, making it a promising ingredient for beauty applications. However, much of the residue generated during the processing of yuzu juice and peel is discarded, creating a challenge around the effective use of unused resources. KINARI has been working to turn discarded yuzu residue into cosmetic ingredients while continuing to examine its functionality. This research aims to deepen those efforts and scientifically reveal the still-unexplored functional properties of yuzu residue. Research overview: The study will examine how yuzu residue affects the skin by conducting experiments on skin cells that make up the epidermis and dermis. It will scientifically verify the effects of useful components contained in yuzu residue on the skin. The team will also evaluate, from multiple perspectives, the functionality of domestically sourced yuzu-derived ingredients containing compounds such as narirutin and hesperidin. Through these efforts, the project aims to uncover new potential in yuzu that has not yet been sufficiently clarified and to create value based on scientific evidence. Professor Yuichi Nodake of Kanagawa University’s Laboratory of Food and Cosmetic Science commented: “Although yuzu is a familiar material, many aspects of its functionality remain unexplained. In this research, we will focus on yuzu residue that has not been sufficiently utilized to date, and will evaluate its potential for beauty applications from multiple angles, particularly its effects on the cells that make up the skin. We hope the findings obtained through this research will lead to the development of new products using unused resources and contribute to environmental conservation.” Masafumi Yamamoto, President and Director of KINARI, commented: “KINARI has long focused on natural materials and has worked to create valuable products that harness the power of plants. Yuzu is one such material. While it is a uniquely Japanese ingredient that has been cherished for generations, we believe the residue generated during juice extraction still holds new value that has not yet been fully utilized. Through this research, we aim to scientifically clarify the functionality of these unused resources, connect that to further value creation, and contribute to a sustainable society.” Future outlook: The findings and results from this research will be applied not only to the development of skincare cosmetics but also to value development for yuzu-derived ingredients and services, with the goal of use across a wide range of fields. By identifying the potential of unused resources, KINARI aims to create new value that combines functionality and sustainability. The company will continue to create value that enables new forms of beauty through research and development that makes use of nature’s benefits. About Soka Mocka: Soka Mocka was launched in 2001 under the concepts of plant-derived ingredients, additive-free formulations designed with skin gentleness in mind, and 100% natural fragrances. The brand uses the vitality of plants such as grasses, flowers, trees, and fruits that have adapted to harsh natural environments, and offers natural cosmetics that emphasize functionality, gentleness to the skin, and carefully selected materials. Company overview: Company name: KINARI Co., Ltd.; Location: 2-2-24 Higashi-Shinagawa, Shinagawa-ku, Tokyo; Representative: President and Director Masafumi Yamamoto; Capital: 10 million yen; Business: Planning, development, and sales of cosmetics; URL: www.sokamocka.com