Caper

Capparis spinosa, the caper bush, also called Flinders rose,^[1] is a perennial winter-deciduous plant that bears rounded, fleshy leaves and large white to pinkish-white flowers. The plant is best known for the edible flower buds (capers), often used as a seasoning, and the fruit (caper berry), both of which are usually consumed pickled. Other species of Capparis are also picked along with C. spinosa for their buds or fruits. Other parts of Capparis plants are used in the manufacture of medicines and cosmetics.

Capparis spinosa is native to the Mediterranean, East Africa, Madagascar, south-western and Central Asia, Himalayas, the Pacific Islands, Indomalaya and Australia.^[2] It is present in almost all the circum-Mediterranean countries, and is included in the floristic composition of most of them, but whether it is indigenous to this region is uncertain. Although the flora of the Mediterranean region has considerable endemism, the caper bush could have originated in the tropics, and later been naturalized to the Mediterranean basin.^[3]

The taxonomic status of the species is controversial and unsettled. Species within the genus Capparis are highly variable, and interspecific hybrids have been common throughout the evolutionary history of the genus. As a result, some authors have considered the C. spinosa to be composed of multiple distinct species ^[4] others that the taxon is a single species with multiple varieties or subspecies,^[5][6] or that the taxon C. spinosa is a hybrid between C. orientalis and C. sicula ^[7]

Plant

The caper bush (Capparis spinosa) has been introduced as a specialized culture in some European countries in the last four decades. The economic importance of the caper plant led to a significant increase in both the area under cultivation and production levels during the late 1980s. The main production areas are in harsh environments found in Morocco, the southeastern Iberian Peninsula, Turkey, and the Italian islands of Pantelleria and Salina. This species has developed special mechanisms to survive in the Mediterranean conditions, and introduction in semiarid lands may help to prevent the disruption of the equilibrium of those fragile ecosystems.^[8]

C. spinosa is highly variable in nature in its native habitats and is found growing near the closely related species C. sicula, C. orientalis, and C. aegyptia. Scientists can use the known distributions of each species to identify the origin of commercially prepared capers.^[9][10]

The shrubby plant is many-branched, with alternate leaves, thick and shiny, round to ovate in shape. The flowers are complete, sweetly fragrant, showy, with four sepals, and four white to pinkish-white petals, many long violet-colored stamens, and a single stigma usually rising well above the stamens.^[11]

Environmental requirements

The caper bush requires a semiarid or arid climate. Mean annual temperatures in areas under cultivation are over 14 °C and rainfall varies from 200  mm/year in Spain to 460 in Pantelleria and 680 in Salina. In Pantelleria, it rains only 35 mm from May through August, and 84 mm in Salina. A rainy spring and a hot dry summer are considered advantageous.^[12] This drought-tolerant perennial plant is used for landscaping and reducing erosion along highways, steep rocky slopes, sand dunes or fragile semiarid ecosystems.

A harvest duration of at least three months is necessary for profitability. Intense daylight and a long growing period are necessary to secure high yields. The caper bush can withstand temperatures over 40 °C in summer, but it is sensitive to frost during its vegetative period. The potential exposure of caper hydraulic architecture to cavitations has recently been proposed as an explanation for its susceptibility to freezing conditions. On the other side, a caper bush is able to survive low temperatures in the form of stump, as happens in the foothills of the Alps. Caper plants are found even 3,500 m above sea level in Ladakh, though they are usually grown at lower altitudes. Some Italian and Argentine plantings can withstand strong winds without problems, due to caper bush decumbent architecture and the coriaceous consistency of the leaves in some populations.

The caper bush is a rupicolous species.^[13] It is widespread on rocky areas and is grown on different soil associations, including alfisols, regosols and lithosols. In different Himalayan locations, C. spinosa tolerates both silty clay and sandy, rocky or gravelly surface soils, with less than 1% organic matter. It grows on bare rocks, crevices, cracks and sand dunes in Pakistan, in dry calcareous escarpments of the Adriatic region, in dry coastal ecosystems of Egypt, Libya and Tunisia, in transitional zones between the littoral salt marsh and the coastal deserts of the Asian Red Sea coast, in the rocky arid bottoms of the Jordan valley, in calcareous sandstone cliffs at Ramat Aviv, Israel, and in central west and northwest coastal dunes of Australia. It grows spontaneously in wall joints of antique Roman fortresses, on the Wailing Wall, and on the ramparts of the castle of Santa Bárbara (Alicante, Spain). Clinging caper plants are dominant on the medieval limestone-made ramparts of Alcudia and the bastions of Palma (Majorca, Spain). This aggressive pioneering has brought about serious problems for the protection of monuments.

The caper bush has developed a series of mechanisms that reduce the impact of high radiation levels, high daily temperature and insufficient soil water during its growing period.^[14][15]

The caper bush has a curious reaction to sudden increases in humidity; it forms wart-like pock marks across the leaf surface. This is apparently harmless, as the plant quickly adjusts to the new conditions and produces unaffected leaves.

It also shows characteristics of a plant adapted to poor soils.^[16] This shrub has a high root/shoot ratio and the presence of mycorrhizae serves to maximize the uptake of minerals in poor soils. Different nitrogen-fixing bacterial strains have been isolated from the caper bush rhizosphere, playing a role in maintaining high reserves of that growth-limiting element.^[17]

Propagation

Capers can be grown easily from fresh seeds gathered from ripe fruit and planted into well-drained seed-raising mix. Seedlings will appear in two to four weeks. Old, stored seeds enter a state of dormancy and require cold stratification to germinate. The seed of the genus Capparis is bitegmic. The testa is 0.2–0.3 mm thick, with all its cell walls somewhat lignified, some of them with distinct thickening; its tegmen consists of an outer fibrous, lignified layer four to ten cells thick, with a lignified endotegmen composed of contiguous cuboid cells, with strongly thickened radial walls. Only the mesophyll between exo- and endotegmen is unlignified. Caper seed germination shows a dependence on the integrity of the covering structures. The viable embryos germinate within three to four days after partial removal of the lignified seed coats.^[18] The seed coats and the mucilage surrounding the seeds may be ecological adaptations to avoid water loss and conserve seed viability during the dry season.

Use of stem cuttings avoids high variability in terms of production and quality. Nevertheless, plants grown from cuttings are more susceptible to drought during the first years after planting. The caper bush is a difficult-to-root woody species, and successful propagation requires careful consideration of biotypes and seasonal and environmental parameters. Rooting percentages up to 55 are possible when using one-year-old wood, depending on cutting harvest time and substrate used. Propagation from stem cuttings is the standard method for growing ‘Mallorquina’ and ‘Italiana’ in Spain, and ‘Nocella’ in Salina. Hardwood cuttings vary in length from 15 to 50 cm and diameter of the cuttings may range from 1.0 to 2.5 cm. Another possibility is to collect stems during February through the beginning of March, treat them with captan or captafol and stratify them outdoors or in a chamber at 3–4 °C, covered with sand or plastic. Moisture content and drainage should be carefully monitored and maintained until planting. Using semi-hardwood cuttings, collected and planted during August and September, low survival rates (under 30%) have been achieved. Softwood cuttings are prepared in April from 25- to 30-day shoots. Each cutting should contain at least two nodes and be six to 10 cm long. Basal or subterminal cuttings are more successful than terminal ones. Then, cuttings are planted in a greenhouse under a mist system with bottom heat; 150 to 200 cuttings/m² may be planted.

Orchard establishment

Caper plantings over 25 to 30 years old are still productive.^[19] Thus, physical properties of the soil (texture and depth) are particularly important. Caper bushes can develop extensive root systems and grow best on deep, non-stratified, medium-textured, loamy soils. Mouldboard plowing and harrowing are usual practices prior to caper plant establishment. Soil-profile modification practices, such as deep plowing operating 0.6 to 1 m, can ameliorate some restrictions. In Pantelleria, digging backhoe pits for each shrub was found to be the most effective means of cultivating caper in rocky soils. Two planting designs are used, the square/rectangle and the hedgerow system. Spacing is determined by the vigour of the biotype, fertility of the soil, equipment used and the irrigation method, if any. Bush spacing of 2.5 X 2.5 m or 2.5 X 2 m is common in Pantelleria. In Salina, 3 X 3 m is satisfactory for ‘Nocella’. In Spain, 4 X 4 or 5 X 5 m is satisfactory for ‘Mallorquina’. Spacing of 2.0 to 2.5 m is appropriate if C. spinosa is used to control soil erosion on slopes.

Culinary uses

The salted and pickled caper bud (often called simply capers) is often used as a seasoning or garnish. Capers are a common ingredient in Mediterranean cuisine, especially Cypriot, Italian and Maltese. The mature fruit of the caper shrub are prepared similarly and marketed as caper berries.

The buds, when ready to pick, are a dark olive green and about the size of a fresh kernel of corn. They are picked, then pickled in salt, or a salt and vinegar solution, and drained. Intense flavor is developed as mustard oil (glucocapparin) is released from each caper bud. This enzymatic reaction leads to the formation of rutin often seen as crystallized white spots on the surfaces of individual caper buds.

Capers are a distinctive ingredient in Italian cuisine, especially in Sicilian and southern Italian cooking. They are commonly used in salads, pasta salads, meat dishes and pasta sauces. Examples of uses in Italian cuisine are chicken piccata and spaghetti alla puttanesca.

Capers are known for being one of the ingredients of tartar sauce. They are often served with cold smoked salmon or cured salmon dishes (especially lox and cream cheese). Capers and caper berries are sometimes substituted for olives to garnish a martini.

Capers are categorized and sold by their size, defined as follows, with the smallest sizes being the most desirable: non-pareil (up to 7 mm), surfines (7–8 mm), capucines (8–9 mm), capotes (9–11 mm), fines (11–13 mm), and grusas (14+ mm). If the caper bud is not picked, it flowers and produces a fruit called a caper berry. The fruit can be pickled and then served as a Greek mezze.

Unripe nasturtium seeds can be substituted for capers; they have a very similar texture and flavour when pickled. Pickled caper berries are very popular as a snack in Menorca.

Caper leaves, which are hard to find outside of Greece, are used particularly in salads and fish dishes. They are pickled or boiled and preserved in jars with brine—like caper buds.

Dried caper leaves are also used as a substitute for rennet in the manufacturing of high-quality cheese.^[20]

Pickled caperberries

Salted capers

Nutrition information

Traditional uses

In Greek popular medicine, a herbal tea made of caper root and young shoots is considered beneficial against rheumatism. Dioscoride (MM 2.204t) also provides instructions on the use of sprouts, roots, leaves and seeds in the treatment of strangury and inflammation.

Different flavonoids were identified in caper bush and capers: rutin (quercetin 3-rutinoside), quercetin 7-rutinoside, quercetin 3-glucoside-7-rhamnoside, kaempferol-3-rutinoside, kaempferol-3-glucoside, and kaempferol-3-rhamnorutinoside. Rutin has no known toxicity.^[21] Capers contain more quercetin per weight than any other plant.^[22]

Caper root bark and leaves may have some anticarcinogenic activity. ^{[citation needed]} In fact, the hydrolysis products of indol-3-ylmethyl glucosinolates have anticarcinogenic effects.^[23] Although the consumption of capers is low in comparison with the intake of other major dietary sources of glucosinolates (white cabbage, broccoli and cauliflower) it may contribute to the daily dose of natural anticarcinogens that reduces cancer risk. ^{[citation needed]} Glucosinolates are known to possess goitrogenic (anti-thyroid) activity. Rutin and quercetin may contribute to cancer prevention.^[24] Selenium, present in capers at high concentrations in comparison with other vegetable products, has been associated with the prevention of some forms of cancer.^[24]

History

The caper was used in ancient Greece as a carminative. It is represented in archaeological levels in the form of carbonised seeds and rarely as flower buds and fruits from archaic and Classical antiquity contexts. Athenaeus in Deipnosophistae pays a lot of attention to the caper, as do Pliny (NH XIX, XLVIII.163) and Theophrastus.^[25]

Etymologically, the caper and its relatives in several European tongues can be traced back to Classical Latin capparis, “caper”, in turn borrowed from the Greek κάππαρις, kápparis, whose origin (as that of the plant) is unknown but is probably Asian. Another theory links kápparis to the name of the island of Cyprus (Κύπρος, Kýpros), where capers grow abundantly.^[26]

In Biblical times, the caper berry was apparently supposed to have aphrodisiac properties;^[27] the Hebrew word abiyyonah (אֲבִיּוֹנָה) for caperberry is closely linked to the Hebrew root אבה, meaning "desire".^[28] The word occurs once in the Bible, in the book of Ecclesiastes, at verse 12:5.

The King James Version translates on the basis of the Hebrew root (and perhaps the metaphorical meaning):^[29]

...the grasshopper shall be a burden,
and desire shall fail. (12:5 KJV)

The medieval Jewish commentator Rashi also gives a similar gloss (12:5 JPR). However, ancient translations, including the Septuagint, Vulgate, Peshitta and Aquila, render the word more concretely as κάππαρις, "caper berry".^[27] Thus in the words of one modern idiomatic translation (2004),

...the grasshopper loses its spring,
and the caper berry has no effect; (12:5 HCSB)

Of other modern versions, the NIV goes for "desire" (12:5 NIV), while the NASB has "caper-berry" (12:5 NASB), as did the 1917 Jewish Publication Society version (12:5 JPS).

The berries (abiyyonot) were eaten, as appears from their liability to tithes and to the restrictions of the 'Orlah. They are carefully distinguished in the Mishnah and the Talmud from the shoots, temarot, and the floral envelopes, ḳapperisin; and declared to be the fruit of the ẓalef or caper plant. But the caper of present-day commerce, the flower bud, which is now eaten pickled, is not mentioned in the Talmud at all.^[27]

Talmud Bavli, Gemara Berachot, page 36 A&B, discusses the eating of caper husks versus caper berries, both inside the land of Israel, outside the land of Israel, and in Syria.

References

External links

Wikimedia Commons has media related to Capparis spinosa.

• Caper factsheet—NewCROP, Purdue University
• Article about the capers of Salina Island
• Capparidaceae (alternative name for Capparaceae) in L. Watson and M.J. Dallwitz (1992 onwards). The families of flowering plants.
• Capparis spinosa at Flowers of Israel website