Sudachi

The Sudachi is a Japanese citrus fruit which is noted for its sourness. It has the scientific name of Citrus sudachi Hort. ex Shirai. The fruit is picked green. The juice is a key ingredient of ponzu juice where it is used as an alternative to vinegar.

The aroma constituents of this citrus have been examined (Njoroge et al., 1995). The peel oil was extracted using cold-pressing and the aroma compounds investigated by capillary GC and GC-MS. Eighty-three constituents were identified in  this peel oil (Njoroge et al., 1995).

Some specific glycosides were isolated from the unripe and green peel of Sudachi fruit. These were sudachiins B, C and D. Sudachiins B and C were identified as sudachiin A 6″- (3-hydroxy-3-methyl)glutarateand 7-O-β-D-glucosyl sudachitin 6″-(3-hydroxy-3-methyl)glutarate, respectively. Sudachiin D is a glycoside in which sudachiin A and 7-O-β-D-glucosylsudachitin were esterified at their 6″-positions with 3-hydroxy-3-methylglutaric acid (Horie et al., 1986).

References

Horie, T., Tsukayama, M., Yamada, T., Miura, I., & Nakayama, M. (1986). Three flavone glycosides from Citrus sudachi. Phytochemistry, 25(11), pp. 2621-2624.

Njoroge, S.M., Ukeda, H., Kusunose, H., Sawamura, M. (1995) Japanese sour Citrus fruits. Part III. volatile constituents of sudachi and mochiyuzu oils. Flavour & Fragrance J. (Article)

Nakagawa, H., Duan, H., & Takaishi, Y. (2001). Limonoids from Citrus sudachi. Chemical and Pharmaceutical Bulletin, 49(5), pp. 649-651.

Tomiyama, K., Aoki, H., Oikawa, T., Sakurai, K., Kasahara, Y., & Kawakami, Y. (2012). Characteristic volatile components of Japanese sour citrus fruits: Yuzu, Sudachi and Kabosu. Flavour and Fragrance Journal, 27(5), pp. 341-355. (Article)