Sichuan pepper and others (Zanthoxylum piperitum, simulans, bungeanum, rhetsa, acanthopodium)

Dried fruits. The aroma and, if present, also the pungency reside in the mostly brown fruit wall (pericarp, shell), not in the deep black seeds. Often, the seeds are omitted. I have repeatedly read that the seeds have bitter taste, but was never able to find that for myself. A better reason to remove them is their unpleasant, gritty texture that almost feels like sand between the teeth.

The Korean species Z. schinifolium has aromatic seeds which are preferred for usage, although the pericarp could also be used, as the flavours are the same.

The spice as commercially available very often contains significant amounts of stem material, mostly the very tough and pointed thorns, which can be harmful if swallowed; it’s best to remove them before usage.

In Japan, young leaves of the Sichuan pepper tree are used fresh, both as flavouring and decoration (kinome or konome [木の芽, きのめ, このめ]).

Rutaceae (citrus family).

The dried fruits of Sichuan pepper and its relatives have an aromatic odour that, for most species, can be described as lemon-like, with more or less pronounced warm and woodsy overtones. Some of the species have deviating flavour, e. g., Z. alatum (spicy) and Z. avicennae and Z. schinifolium both of which have an anise aroma.

The taste of most species is pungent and biting; it may take some time to develop, but in the end produces a strangly numbing, almost anaesthetic feeling on the tongue. Again, Z. schinifolium is an exception because it has only small pungent quality.

Sichuan pepper (Z. piperitum) leaves have a fresh flavour somewhat in between of mint and lime.

Most Zanthoxylum species produce pungent alkamides derived prom polyunsaturated carboxylic acids, which are stored in the pericarp (fruit wall, shell) but not in the seeds. The exact nature of these alkamides may vary from species to species, but common examples are amides of 2E,6Z,8E,10E dodecatetraenoic acid, 2E,6E,8E,10E dodecatetraenoic acid, and 2E,4E,8Z,10E,12Z tetradecapentaenoic acid with isobutyl amin (known as α, β and γ sanshool, respectively) and 2-hydroxy isobutyl amin (hydroxy sanshools), which have been found in several different species of the genus. Total amide content can be as high as 3% (reported in Z. piperitum). Similar alkamides were found in a herb from South America called paracress.

Four types of culinary Sichuan pepper: Upper left Nepali timur (Zanthoxylum alatum), upper right Indonesian andaliman (Z. acanthopodium), lower left Indian tirphal (Z. rhetsa), lower right Chinese jiao (Z. piperitum/simulans) (200 dpi scan).

Zanthoxylum species from Nagaland

Within the ge­nus, a be­wildering collection of further, potentially interesting nonvolatile con­stituents has been identi­fied: flavonoids, terpene alka­loids, benzo­phenthridine alka­loids, pyrano­quinoline alka­loids, quar­ternary iso­quinoline alka­loids, aporphy­rine alka­loids and several types of lignanes.

The typical flavour of Sichuan peppers is due to es­sential oils which are, as a rule, mostly com­posed from terpenoids, but the exact composition varies considerably among the species, and sometimes even within the species. The following accounts on Zanthoxylum essential oils can only give a coarse overview on that matter.

Zanthoxylum species from Nagaland

The essential oil (up to 4%) of Chinese Si­chuan pepper (labelled as Z. piperi­tum, but could also be Z. simu­lans or other) as sold in Euro­pe con­sists mostly of terpenes: Geraniol, linalool, cineol, citronellal; also di­pentene was found. (Deutsch. Apoth-Zeit., 46, 2381, 1987)

The fruits of the Taiwanese species, Z. simulans, yielded mainly β-myrcene, limonene, 1,8-cineol and (Z)-β-ocimene. The total content of essential oil was reported to be 1.7% (steam distillation) and 6.4% (carbon dioxide extraction). (Journal of Agricultural and Food Chemistry, 44, 1096, 1996)

The leaves of Z. sansho (Japan, allegedly identical to Z. piperitum) contain mostly monoterpene derivatives (citronellal, citronellol) and unsaturated C6 compounds (e. g., Z-3-hexenal), which contribute to a grassy odour. (Bioscience, Biotechnology and Biochemistry, 61, 491, 1997) In the unripe fruits, the content of essential oil is reported to 0.6%, with β-phellandrene (42%), d-limonene (23%) and β-pinene (11%) being the main components. Terpene alcohols (geranyl acetate, citronellol, α-terpineol) were found in the 1 to 5% range. The young leaves (0.12%) yielded mostly terpene hydrocarbons. (Nippon Nogeikakaku Kaishi, 70,1001, 1996)

The most abundant constituent in the essential oil of Z. acanthopodium (Indonesia) is geranyl acetate (35%); the flavour is, however, dominated by the citrus-scented compounds limonene and citronellal. Further components are β-myrcene, β-ocimene, linalool and E-1-decenal. (H. Wijaya, personal communication) (Food Science and Biotechnology, 11, 680, 2002)

Two Zanthoxylum species used in Korean cooking: left chopi (Z. piperitum), right sancho (Z. schinifolium) (200 dpi scan).

The Korean species Z. schini­folium is parti­cularly inter­esting because it is almost non-pungent, and the essential oil distri­butes evenly between peri­carp and seeds. The essential oil was shown to consist mainly of terpenoids (geraniol, limonene, geranyl acetate, β‑phellandrene, phellandral, myrcene, linalool, α‑pinene), but also nonterpenoid volatiles (p‑isopropyl-2‑cyclohexenone, caproic acid, caprylic acid) and especially phenyl­propanoids (anethole, eugenol, methyl chavicol) have been found. (Han’guk Sikp’um Yongyang Hakhoechi, 11, 493, 1998) (Han’guk Sikp’um Yongyang Hakhoechi, 12, 119, 1999) (Zhongguo Zhongyao Zazhi, 16, 359, 1991)

Z. alatum, a species growing in the Himalayas and figuring prominent in Tibetan and Nepali cooking, is reported to contain mostly linalool (more than 50%), further limonene, methyl cinnamate and cineol. (Flavour and Fragrance Journal, 16, 408, 2001) (Journal of Essential Oil Research, 10, 127, 1998)

Also in the Indian species, Z. rhetsa (syn. Z. limonella), the essential oil (3.7%) has been shown to consist mainly of monoterpene derivatives: Sabinene, limonene, pinenes, para-cymene and terpinenes, furthermore the monoterpene alcohols 4-terpineol and α-terpineol. (Zeitschrift f. Lebensmitteluntersuchung und -forschung A, 206, 228, 1998)

Sichuan pepper trunk with strong thorns

Another work on com­position of the leaf oil found caryo­phyllene oxide (13%), caryo­phyllene (10%), β-copaene (5%) and spathulenol (3%); the same authors report sabinene (66%), α- and β-pinene (each 6%) and terpinen-4-ol (4%) in the seed oil. Al­though the authors actually write seed oil, I suspect that the work refers to the es­sential oil obtained from the pericarp. (Journal of essential oil research, 12, 179, 2000)

Sichuan pepper stem with fruits and prickles © Laila Kolberg

Sichuan pepper trunk with strong thorns

The term Sichuan pepper refers to a spice obtained form a group of closely related plants of genus Zantho­xylum. In Asia, most represen­tatives of this genus are found in the Himalaya region, furthermore in Central, South, South East and East Asia. American and African Zanthoxylum species have not yet been put to culinary use.

The most important species are: Z. piperitum DC = Z. sansho (Central and Eastern China, Japan, Korea), Z. simulans Hance = Z. bungei (China, Taiwan), Z. bungeanum Max. (China), Z. schinifolium Sieb. et Zucc. (China, Korea), Z. nitidum Roxb (DC) (China, peninsular South East Asia), Z. rhetsa Pierre var. budranga Pier. = Z. limonella (Western North India, peninsular South East Asia), Z. armatum DC = Z. alatum Roxb. (Himalaya, peninsular South East Asia, East Asia), Z. avicennae (Lamk) DC = Z. tidorense (China, peninsular South East Asia, Indonesia) and Z. acanthopodium DC (eastern Himalaya, China, peninsular South East Asia, Sumatra). All species mentioned here have their place in local cuisines and can (excepting Z. schinifolium) mostly be used interchangeably. Literature often gives contradicting information which spice is used where; furthermore, Zanthoxylum is a difficult genus with many different, similar and not well-researched species.

Chinese Sichuan pepper shrub © Laila Kolberg

Zantho­xylum is a dis­simi­lated or probab­ly simply false modi­fication of Greek xanthon xylon [ξανθὸν ξύλον], yellow wood. Cf. German Gelbholz­baum yellow-wood tree and Polish pieprz żółto­drzew yellow-tree pepper (zółty yellow and drzewo tree; see also juniper for the linguistic affiliation of the latter).

Botanical species names of the species mentioned above are derived either by local names (rhetsa, sansho) or are of Latin/Greek origin: piperitus from Latin piper pepper because of the peppery taste; simulans imitating from simulare imitate for the similarity to other species; alatus winged for the leaves’ shape; nitidus shiny, for the bright leaves; armatus armed, from arma weapon for the mighty thorns; further, acanthopodius thistle-footed for similar reasons from Greek akantha [ἄκανθα] thistle, thorn and pous [πούς] foot; lastly schinifolius because the foliage looks like that of Peruvian Pink Pepper (Schinus molle).

The English name prickly ash refers on one side to the numerous thorns of the plant (which are even commonly found in the dried spice), on the other side to the pinnate leaves, which very much resemble those of ash (Fraxinus excelsior). English ash goes back to the Indo–European name of this tree, H₃ES, and is, consequently, found in many Indo–European tongues (Old English æsc, German Esche, Old Norse askr, Lithuanian uosis, Armenian hatseni [հացենի], Russian yasen [ясень]); it must not be confused with its English homonym ash burned material, which derives (via Common Germanic ASKŌ) from an Proto-Indo–European verbal root H₂ES burn and also has relatives in nearly all Indo–European languages: English arid, German Esse chimney, Sanskrit ashani [अशनि] thunderbolt, Latin ara altar (for fire-worshiping), Greek azaleos [ἀζαλέος] dry, inflammable.

Sichuan pepper panicle © Laila Kolberg

The North Ameri­can species, Z. ameri­canum, is known as toot­hache tree. Due to the an­aesthetic power of its alkamide con­stituents, the plant is ef­fective in sup­pressing tooth­ache temporarily if unripe fruits or the wood of young branches are chewed. Another plant rich in alkamides, paracress, has similar names.

The Chinese name of Sichuan pepper is jiao [椒]; to distinguish from other hot spices, the name is often expanded to shan jiao [山椒] mountain pepper, hua jiao [花椒] flower pepper or more rarely qin jiao [秦椒] Chinese pepper and chuan jiao [川椒] Sichuan pepper. While most European tongues name the spice Sichuan-pepper or China-pepper, one sometimes finds loan translations of the first two names, e. g., Hungarian virágbors flower pepper or German Bergpfeffer mountain pepper.

In Western literature, the Chinese name of Sichuan pepper is sometimes given als fagara; in botanical taxonomy, that term denotes a related genus (the name was introduced by Linnaeus in the 17.th century). The word originates from a variant pronunciation of the logographs 花椒; cf. the Cantonese reading fajiu. Possibly, fagara stems from a related South Chinese dialect, or just goes back to an inaccurate transcription of the Cantonese name.

Similar to English, which often uses the word pepper to denote pungent spices even if they are unrelated to pepper, Chinese often forms compound names with the jiao element for such spices. Thus, chile is la jiao [辣椒] hot Sichuan pepper, long pepper is chang jiao [長椒] long Sichuan pepper, paprika is tian jiao [甜椒] sweet Sichuan pepper and allspice can be called gan jiao [甘椒] which also means sweet Sichuan pepper. The most important compound of that type is hu jiao [胡椒] wild pepper, which can also be interpreted as foreign pepper or barbarian’s pepper. which usually means black pepper, but can be applied to Sichuan pepper, too. That compound name may also appear in the name of pepperlike spices, e. g., hundred flavour wild (black) pepper (bi wei hu jiao [百味胡椒], allspice) or wild (black) pepper from the West (ba xi hu jiao [巴西胡椒], pink pepper which is a spice native to America). Tasmanian pepper is called shan hu jiao [山胡椒] wild (black) pepper of the mountain, probably calqued on the English name mountain pepper (a name used predominantly in Australia for Tasmanian pepper).

Ripening fruits of Nepalese Z. alatum

Ripe fruits of Nepalese Z. alatum

The name of the dish dry-fried lamb with three types of jiao (sanjiao bao yangrou [三椒爆羊肉]) is due to that ambiguity: Green bell peppers (qing jiao [青椒] green pepper) and chiles (la jiao) are quickly fried in a wok and sprinkled with toasted Sichuan pepper (hua jiao).

Chinese shan jiao [山椒] is also the source of Korean sancho [산초]; note, however, that this name refers to a related spice with completely different flavour. The spice corresponding to Chinese jiao is known as chopi [초피] in Korean; this name also shows a syllable derived from jiao.

Ripe fruits of Nepalese Z. alatum

Similarly, Japanese sanshō [山椒, さんしょう, サンショウ] is adapted from Chinese shan jiao [山椒] mountain pepper. It is even spelt alike in Chinese and Japanese if the Japanese Kanji writing system is employed. The Kanji sign 山 means mountain also in Japanese, and like most Kanji, it has two distinct readings: Alone and in mostly natively Japanese words it is spoken yama (kun reading), e. g. archaic yama-kujira [山鯨, やまくじら] wild boar (literally mountain whale) or in seiyō-yama-hakka [西洋山薄荷, せいようやまはっか] which is the Japanese name of lemon balm (literally foreign mountain-mint). Yet in words of Chinese origin one has to apply the on-reading which goes san, e. g. san-kei [山径, さんけい] mountain path or the said name of Sichuan pepper, san-sho. Occasionally, the Kanji reading is totally irregular, e. g., in wasabi [山葵, わさび].

The Chinese term ma [麻] basically means hemp fibre (it can also denote hemp seeds or, by extension, sesame seeds); the sign shows plants (lin [林] trees, forest) drying under a shed (chang [厂] factory, workhouse). Apparently, the narcotic properties of hemp motivated its use for the numbing flavour of Sichuan pepper.

The Epicentre: Szechwan Pepper Nature One Health: Prickly Ash chemikalienlexikon.de: Linalool Recipe: Sangsang (saksang) (eng.ohio-state.edu) Rezept von goccus.com: Shichimi tōgarashi [七味 唐辛子] Recipe: Aurey Bendi (Indian Lima Beans) (groups.google.com) Rezept von goccus.com: Shui zhu niu rou [水煮牛肉] (In Wasser gekochtes Rindfleisch) Recipe: Shui zhu niu rou [水煮牛肉] (Sichuan water-boiled beef) (www.juoaa.org) Rezept: Shui zhu niu rou [水煮牛肉] (In Wasser gekochtes Rindfleisch Sichuan-Art) (www.laohu.de) Rezept: Shui zhu niu rou [水煮牛肉] (Rindfleischtopf Sichuan-Art) (chefkoch.de) Recipe: Nepali Meat and Vegetable Momos (groups.google.com) Sichuan Food’s Signature Fire Is Becoming Hard to Find — About the Ban of Sichuan Pepper in the USA Sichuan is hot and spicy; the food too! (gluckman.com) Gewürz-Bazar: Nepalpfeffer (timbur)