Sudachi (''Citrus sudachi''; Japanese: スダチ or 酢橘) is a small, round, green

citrus ''Citrus'' is a genus of flowering trees and shrubs in the family Rutaceae. Plants in the genus produce citrus fruits, including important crops such as oranges, mandarins, lemons, grapefruits, pomelos, and limes. ''Citrus'' is nativ ...

fruit of Japanese origin that is a specialty of Tokushima Prefecture in

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

. Harvested before it fully ripens to yellow, it is tart and not eaten as a table fruit but used to flavor sauces and marinades, desserts, and drinks in place of

lemon The lemon (''Citrus'' × ''limon'') is a species of small evergreen tree in the ''Citrus'' genus of the flowering plant family Rutaceae. A true lemon is a hybrid of the citron and the bitter orange. Its origins are uncertain, but some ...

or lime. Genetic analysis shows it to be the product of a cross between a

yuzu Yuzu (''Citrus'' × ''junos'', from Japanese language, Japanese or ; ) is a citrus fruit and plant in the family Rutaceae of China, Chinese origin. Yuzu has been cultivated mainly in East Asia, though it has also recently been grown in New Z ...

and another citrus fruit akin to the koji and tachibana orange.

General

The ''sudachi'' has been cultivated for centuries in parts of

, and is perhaps nearly as well known as the

in the country. The fruit is the specialty and symbol of the prefecture of

Tokushima is a Prefectures of Japan, prefecture of Japan located on the island of Shikoku. Tokushima Prefecture has a population of 682,439 (1 February 2025) and has a geographic area of 4,146 Square kilometre, km2 (1,601 sq mi). Tokushima Prefecture b ...

, which produces 98% of all the fruit grown in Japan., citing 2011 Ministry of Agriculture figures for Tokushima's 98% share and 2008 data from ''Tokushima no Engei'' for shares within the Prefecture. The top producing communities are the township of Kamiyama-cho and the village of Sanagouchi-son; combined, they accounted for almost half of the prefecture's annual production in 2008. The plant has white flowers which bloom in May and June. The fruits form in bunches and are harvested in the fall. Though ''sudachi'' fruits will eventually develop a yellow-orange rind color, they are normally harvested and used while still green. They contain large smooth seeds, containing a green polyembryo. The ''Sudachi'' is sour and not consumed whole, but normally squeezed like a lemon or lime to flavor food. A half-slice of the fruit is served as garnish with many traditional Japanese dishes which include fish, soba,

udon Udon ( or ) is a thick noodle made from wheat flour, used in Japanese cuisine. There are a variety of ways it is prepared and served. Its simplest form is in a soup as with a mild broth called made from dashi, soy sauce, and mirin. It is usual ...

, nabe, and even some

alcoholic beverage Drinks containing alcohol (drug), alcohol are typically divided into three classes—beers, wines, and Distilled beverage, spirits—with alcohol content typically between 3% and 50%. Drinks with less than 0.5% are sometimes considered Non-al ...

s. It has also been considered an "indispensable companion" to eating matsutake mushrooms. , a citrus-based sauce used in Japanese cuisine, often includes ''sudachi'' along with other bitter oranges ('' kabosu'' or

juices, and '' daidai'') as an ingredient. ''Sudachi''-flavored products (such as

ice cream Ice cream is a frozen dessert typically made from milk or cream that has been flavoured with a sweetener, either sugar or an alternative, and a spice, such as Chocolate, cocoa or vanilla, or with fruit, such as strawberries or peaches. Food ...

vodka Vodka ( ; is a clear distilled beverage, distilled alcoholic beverage. Its varieties originated in Poland and Russia. Vodka is composed mainly of water and ethanol but sometimes with traces of impurities and flavourings. Traditionally, it is ...

coolers, ice pops, and

soft drink A soft drink (see #Terminology, § Terminology for other names) is a class of non-alcoholic drink, usually (but not necessarily) Carbonated water, carbonated, and typically including added Sweetness, sweetener. Flavors used to be Natural flav ...

s) can also be found in Japan, particularly in Tokushima Prefecture, where the fruit is sold cheaply. In other parts of Japan, the fruit is considered a delicacy and is often expensive. ''Sudachi'' are considered to have a zestier flavor and aroma compared to

s or limes, and have a higher

calcium Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to it ...

and

ascorbic acid Ascorbic acid is an organic compound with formula , originally called hexuronic acid. It is a white solid, but impure samples can appear yellowish. It dissolves freely in water to give mildly acidic solutions. It is a mild reducing agent. Asco ...

(

vitamin C Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits, berries and vegetables. It is also a generic prescription medication and in some countries is sold as a non-prescription di ...

) content than lemons. Compared to the related ''kabosu'', ''sudachi'' are much smaller at up to compared to . Some California farms now grow sudachi on a commercial scale, after trees became readily available to nurseries around 2008. The fruit is also being cultivated in Piura,

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

Classification

Its species name was published by Mitsutaro Shirai (1933), but most modern scientists, even while still using this nomenclature by habit or as legacy, do not consider it as a bona fide species, but a cultivar or a hybrid of uncertain parentage. Tyozaburo Tanaka's assumption that the sudachi is a hybrid of

appears to be supported by DNA studies; recent genetic analysis has confirmed its status as a hybrid, with one parent being the yuzu, and the other an unidentified relative of two native-Japanese cultivars, the koji and tachibana orange. The sudachi was classed within the '' Papeda'' subgenus in the Swingle scheme, and in the more complicated Tyozaburo Tanaka scheme within the ''Eusmocitrus'' or true yuzu subgenus, under the ''Osmocitrus'' or yuzu section.

Phytochemistry

The

flavonoid Flavonoids (or bioflavonoids; from the Latin word ''flavus'', meaning yellow, their color in nature) are a class of polyphenolic secondary metabolites found in plants, and thus commonly consumed in the diets of humans. Chemically, flavonoids ...

eriocitrin abundant in lemon and lime juices is present in comparable concentrations in sudachi juice, but is lacking in yuzu or kabosu juices. Also, neoeriocitrin (characteristic in bergamot '' daidai'') is found in sudachi juice and rind. Eriocitrin is an

antioxidant Antioxidants are Chemical compound, compounds that inhibit Redox, oxidation, a chemical reaction that can produce Radical (chemistry), free radicals. Autoxidation leads to degradation of organic compounds, including living matter. Antioxidants ...

reported to combat lipid peroxidation and like neoeriocitrin is said to block the formation of

lipoxygenase Lipoxygenases () (LOX) are a family of (non- heme) iron-containing enzymes, more specifically oxidative enzymes, most of which catalyze the dioxygenation of polyunsaturated fatty acids in lipids containing a cis,cis-1,4- pentadiene into ce ...

s involved in

allergies Allergies, also known as allergic diseases, are various conditions caused by hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include Allergic rhinitis, hay fever, Food allergy, food al ...

and

atherosclerosis Atherosclerosis is a pattern of the disease arteriosclerosis, characterized by development of abnormalities called lesions in walls of arteries. This is a chronic inflammatory disease involving many different cell types and is driven by eleva ...

. Also, the flavonoid narirutin is said to be the active chemical in the Wakayama Prefecture specialty '' citrus jabara''

juice Juice is a drink made from the extraction or Cold-pressed juice, pressing of the natural liquid contained in fruit and vegetables. It can also refer to liquids that are flavored with concentrate or other biological food sources, such as meat ...

that is said to diminish the effects of

pollen Pollen is a powdery substance produced by most types of flowers of seed plants for the purpose of sexual reproduction. It consists of pollen grains (highly reduced Gametophyte#Heterospory, microgametophytes), which produce male gametes (sperm ...

. The ''jabara'' advertises that it contains 6 times the narirutin in yuzu, but ''sudachi'' juice also contains about 3 times as much as yuzu juice (20.1 mg per 100 ml, vs. 6.6 mg). This substance is quite abundant in the rind of yuzu and kabosu. The ability of the ''sudachi'' to promote the body's calcium absorption has been studied as well. In 2006, a Tokushima University research team published a report which suggests that the fruit may be effective in lowering

glucose Glucose is a sugar with the Chemical formula#Molecular formula, molecular formula , which is often abbreviated as Glc. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae d ...

levels in diabetic patients. The team gave rats sudachi zest over a one-year period and found that their glucose levels were lowered, with signs of improved health in the rats.

References

Footnotes

Bibliography

*
Sudachi
at Citrus Variety Collection * * {{Authority control Citrus Citrus hybrids Japanese fruit