Vinegar Extract of Fruit Waste from Juice Production Using Tankan (Citrus tankan Hayata) Native to Okinawa, Japan

Almost all processing residue from tankan juice production are wasted; therefore, we developed a vinegar extract derived from this residue. Vinegar extract was produced using the direct pulverizing method, which was characterized by a yellow color and had the highest aroma scale, low bitterness, and various components, such as polyphenols. Vinegar extracts produced by other methods, such as the stirring and soaking methods, were not as yellow as that produced using the direct pulverizing method, yet they included a group of functional components, polymethoxyflavones, such as nobiletin as well as monoterpene alcohols that are classed as sweet floral, such as linalool. However, vinegar extract produced by the soaking method contained few monoterpenes, such as limonene that do not have a unique citrus flavor, and may be more favorable for use in drinks and seasonings. Therefore, depending upon the desired final product, any of these vinegar extracts may be used.