Odate Tonburi

Odate Tonburi is a processed field-grown food native to Odate, Akita Prefecture, Japan. It is made from the ripe fruit of the annual kochia herb, which is heat-treated. Tonburi is also known as "field caviar" due to its appearance and texture, and its production and consumption in this region has a tradition dating back to the Edo period. It was registered as a Geographical Indication (CI) in 2017.

Tonburi is the fruit of the kochia plant, which was once used to make brooms in various regions of Japan. With the decline in broom production, kochia cultivation also declined. However, in the Odate region, the tradition of eating kochia fruit as a food has persisted since the Edo period, with farmers cultivating it for personal consumption. The nationwide recognition of Odate Tonburi and the increase in its cultivation and processing occurred with the establishment of a factory in Odate City in 1973.

Production of Odate Tonburi is limited to Odate City, Akita Prefecture. Due to the difficulties in growing and processing tonburi, it has not spread to other parts of Japan. The Hinai district of Odate City is an area surrounded by mountains and has little wind. Furthermore, the Sumitani River basin in this region provides spring water, which is essential for processing tonburi.

Odate Tonburi has a grainy structure, approximately 1 to 2 mm in diameter. It is used as an odorless and tasteless food ingredient. The processing process begins with harvesting ripe kochia fruit with a combine harvester and drying it in the sun or in a dryer for about a week. The dried fruit is then thoroughly boiled in a pot, followed by soaking in hot water for 24 hours. In the final stage, the fruit is scrubbed, peeled, and dried again, making it ready for consumption.