Sichuan pepper

Sichuan pepper is a spice made from the dried pericarp of a plant of the genus Zanthoxylum in the family Rutaceae. It is commonly used in Sichuan cuisine of China and in the cuisines of the Himalayas. Despite its name, Sichuan pepper is not closely related to black pepper or chili peppers. Instead, Zanthoxylum plants are in the same family as citrus and rue.
When eaten, Sichuan pepper produces a tingling, numbing effect due to the presence of hydroxy-alpha sanshool. It is used in Sichuan dishes such as mapo doufu and Chongqing hot pot, and is often added to chili peppers to create a flavor known as málà.

Species and cultivars

Sichuan peppers have been used for culinary and medicinal purposes in China for centuries with numerous Zanthoxylum species called huājiāo. Commonly used sichuan peppers in China include:

Species	Species common name in Chinese	Fruit common name in Chinese	Characteristics
Zanthoxylum bungeanum			Red, more pungent
Zanthoxylum schinifolium			Green, less pungent, more numbing
Zanthoxylum armatum		Fresh: Dry:	Green, less pungent, fragrant, more numbing

Less commonly cultivated species found in China include:

Zanthoxylum simulans
For a full list, consult Flora Reipublicae Popularis Sinicae, which lists scientific binomials, accepted common names among Chinese scholars, and local vernacular names.

Over the years, Chinese farmers have cultivated multiple strains of Z. bungeanum and Z. schinifolium.
Zanthoxylum armatum is found throughout the Himalayas, from Kashmir to Bhutan, as well as in Taiwan, Nepal, China, Philippines, Malaysia, Japan, and Pakistan, and is known by a variety of regional names, including timur in Nepali and Hindko, yer ma in Khams Tibetan and thingye in Bhutan.

Other Zanthoxylum spices

Zanthoxylum gilletii is an African species of Zanthoxylum used to produce spice uzazi. Similarly, other Zanthoxylum species are harvested for spice and seasoning production in a number of cultures and culinary traditions. These spices include andaliman, chopi, sancho, sanshō, teppal, and tirphal.
Zanthoxylum oxyphyllum, known as mejenga, is used as a herb in Assam, India.

Culinary uses

Sichuan pepper is an important spice in Chinese, Nepali, Kashmiri, north east Indian, Tibetan, and Bhutanese cookery of the Himalayas. Sichuan pepper has a citrus-like flavor and induces a tingling numbness in the mouth, akin to a 50-hertz vibration, due to the presence of hydroxy-alpha sanshool. Food historian Harold McGee describes the effect of sanshools thus:

Chinese cuisine

Whole, green, freshly picked Sichuan pepper may be used in cooking, but dried Sichuan pepper is more commonly used. Once dried, the shiny black seeds inside the husk are discarded, along with any stems; the husk is what we know as Sichuan pepper or peppercorn.
The peppercorn may be used whole or finely ground, as it is in five-spice powder. Mala sauce, common in Sichuan cooking, is a combination of Sichuan pepper and chili pepper, and it is a key ingredient in Chongqing hot pot.
Sichuan pepper is also available as an oil. Sichuan pepper infused oil can be used in dressing, dipping sauces, or any dish in which the flavor of the peppercorn is desired without the texture of the peppercorns themselves.
Hua jiao yan is a mixture of salt and Sichuan pepper, toasted and browned in a wok, and served as a condiment to accompany chicken, duck, and pork dishes.
The leaves of the sichuan pepper tree are also used in soups and fried foods.

Other regions

One Himalayan specialty is the momo, a dumpling stuffed with vegetables, cottage cheese, or minced yak or beef, and flavored with Sichuan pepper, garlic, ginger, and onion. In Nepal, the mala flavor is known as timur.
In Bhutan, it is used in preparing ezay, to add spiciness to rice porridge, ba-thup and noodle and other snacks. It is extensively used in preparing blood sausages throughout Bhutan and Tibet.
In Korean cuisine, sancho is often used to accompany fish soups such as chueo-tang.
In Indonesian Batak cuisine, andaliman is ground and mixed with chilies and seasonings into a green sambal or chili paste. Arsik is a typical Indonesian dish containing andaliman.

Medicinal uses

In Traditional Chinese medicine, Zanthoxylum bungeanum has been used as a herbal remedy. It is listed in the Pharmacopoeia of the People's Republic of China and is prescribed for ailments as various as abdominal pains, toothache, and eczema. However, Sichuan pepper has no indications or accepted case for use in evidence-based medicine. Research has revealed that Z. bungeanum can have analgesic, anti-inflammatory, antibacterial, and antioxidant effects in model animals and cell cultures. In rabbits, Z. armatum was experimentally investigated for its potential use in treating gastrointestinal, respiratory, and cardiovascular disorders.

Phytochemistry

Important compounds of various Zanthoxylum species include:

Zanthoxylum fagara —alkaloids, coumarins
Zanthoxylum simulans —Mostly beta-myrcene, limonene, 1,8-cineole, Z-beta-ocimene
Zanthoxylum armatum —linalool, limonene, methyl cinnamate, cineole
Zanthoxylum rhetsa —Sabinene, limonene, pinenes, para-cymene, terpinenes, 4-terpineol, alpha-terpineol.
Zanthoxylum piperitum —citronellal, citronellol, Z-3-hexenal
Zanthoxylum acanthopodium —citronellal, limonene
Historical US import ban

From 1968 to 2005, the United States Food and Drug Administration banned the importation of Sichuan peppercorns because they were found to be capable of carrying citrus canker. This bacterial disease, which is very difficult to control, could potentially harm the foliage and fruit of citrus crops in the U.S. The import ban was only loosely enforced until 2002.
In 2005, the USDA and FDA allowed imports, provided the peppercorns were heated for ten minutes to approximately to kill any canker bacteria. Starting in 2007, the USDA no longer required peppercorns to be heated, fully ending the import ban on peppercorns.