Difference between revisions of "Pimenta dioica (PROSEA)"

Latest revision as of 11:52, 13 December 2019

Plant Resources of South-East Asia Introduction

List of species

1, fruiting branch; 2, section through flower; 3, dried unripe fruits; 4, section through fruit

Pimenta dioica (L.) Merrill

Protologue: Contrib. Gray Herb. 165: 37 (1947).

Family: Myrtaceae

Chromosome number: 2n = 22

Synonyms

• Myrtus pimenta L. (1753),
• M. dioica L. (1759),
• Pimenta officinalis Lindley (1821)

Vernacular names

• Pimento, Jamaica pepper (En). Allspice (Am)
• Piment des anglais, toute-épice (Fr).

Origin and geographic distribution

The exact origin of pimento is not known but it is indigenous to the West Indies (Jamaica, Cuba) and Central America (southern Mexico, Guatemala, Honduras). Its use as a spice in the Caribbean Islands was discovered by Spanish explorers in the 16th Century. Most pimento is now cultivated or collected from the wild in the region of its natural distribution, most abundantly in Jamaica, and in surrounding areas where it also has been introduced, e.g. Haiti, Costa Rica, Grenada, Barbados, Trinidad, Puerto Rico, Brazil. Elsewhere in the tropics, e.g. in India, Sri Lanka, Fiji, Malaysia (Pinang), Singapore and Indonesia (Java, Sumatra), cultivation of pimento has been tried but never became successful.

Uses

Pimento, being the dried green-mature fruit, is mainly used as a flavouring and curing agent in processed meats and bakery products, and as a flavouring ingredient for domestic culinary purposes. It is said to combine the flavours of cinnamon, clove and nutmeg, hence the name allspice. It is an important component of pimento dram, a Jamaican drink made with ripe fruits and rum, and of liqueurs like Benedictine and Chartreuse. Whole fruits are used in meat broth, gravies and pickling liquids. In desserts, fruit cakes, pies, relishes, sausages and preserves, ground fruits are preferred. Essential oil and oleoresin obtained from pimento fruits are used in meat products, to flavour other fruits and as a scenting agent in the manufacture of soap and men's perfumes. The maximum permitted level of pimento berry oil in food products is about 0.025%. Essential oil from the leaves is used as a flavouring agent in meat products and confectionery. In the United States the regulatory status "generally recognized as safe” has been accorded to pimento (GRAS 2017), pimento berry oil (GRAS 2018), pimento oleoresin (GRAS 2019) and pimento leaf oil (GRAS 2901).

The powdered fruit is used in traditional medicine to treat flatulence, dyspepsia, diarrhoea and as a remedy for corns, neuralgia and rheumatism. A fruit decoction is reported to cure colds, menorrhagia and stomach-ache. Pimento possesses antioxidant, bactericidal, fungicidal, carminative, stimulant and purgative properties. Young woody shoots of pimento are popularly made into walking sticks and umbrella handles.

Production and international trade

Jamaica is the largest producer and exporter of pimento, accounting for 70% of the world exports; this Jamaican pimento is considered the best quality. The remaining 30% of lesser quality is shared by Honduras, Guatemala, Mexico, Brazil, the Leeward Islands and Belize. The annual world trade of pimento averages 3000-4000 t valued at US$ 5-7 million. The major importing countries are the United States, Germany, United Kingdom, Sweden, Finland and Canada. The end-uses of the total pimento production can roughly be divided as follows: domestic use 5-10%, food industry 65-70%, pimento berry oil 20-25%, and oleoresin 1-2%. The average annual pimento leaf oil production is 30-60 t and is mainly exported to the United States and the United Kingdom.

Properties

Per 100 g ground pimento contains approximately: water 8.5 g, protein 6.1 g, fat 8.7 g, carbohydrates 50.5 g, fibre 21.6 g, ash 4.6 g (Ca 661 mg, Fe 7 mg, Mg 135 mg, P 113 mg, K 1.0 g, Na 77 mg, Zn 1 mg), ascorbic acid 39.2 mg, thiamine 0.10 mg, riboflavin 0.06 mg, niacin 2.9 mg, vitamin A 540 IU, phytosterols 61 mg. The energy value is about 1100 kJ/100 g.

The characteristic scent of pimento is attributed to the presence of a yellow to brownish essential oil (3.3-4.5%, known as pimento berry oil) found mainly in the pericarp. The oil is warm-spicy with a peculiar fresh and sweet top note. Some 50 constituents of the oil have been identified, the major ones being: eugenol 50-80%, methyl eugenol 3-28%, myrcene 1-9%, β-caryophyllene 4-6%, 1,8-cineole 1-3% and humulene 1-2%. Essential oil from Jamaica pimento is considered to be of the highest quality, having the highest eugenol content.

Dried pimento leaves yield 0.7-2.9%, and fresh leaves 0.3-1.3% of a brownish-yellow essential oil (pimento leaf oil). Its major component is also eugenol, but the concentration is somewhat higher (65-96%) than in the berry oil, and its taste is quite different. Pimento oleoresin is a brownish to dark green oily liquid, obtained by solvent extraction of the crushed spice. Its quality and strength are more consistent than the essential oil and its application presents a smaller risk of bacterial contamination. Eugenol is toxic in large amounts and can cause contact dermatitis, whereas the spice itself is also a skin irritant.

Monographs on the physiological properties of pimento berry oil and pimento leaf oil have been published by the Research Institute for Fragrance Materials (RIFM).

Composition

Pimento berry oil (Source: Lawrence, 1979.)

Pimento berry oil (from Cuba) (Source: Pino et al., 1989.)

Pimento leaf oil (from Cuba) (Source: Pino & Rosado, 1996.)

Adulteration and substitutes

Ground pimento is sometimes adulterated with clove stems and starchy products. A mixture of pimento leaf oil and clove stem and leaf oils can serve as a relatively inexpensive substitute for the berry oil. Pimento berry oil is sometimes adulterated with eugenol from cheaper sources.

Description

• Small dioecious evergreen tree, 7-10(-15) m tall, profusely branched, young shoots four-angled; bark smooth and shiny, pale silvery brown, shedding in long strips; wood hard, close-grained, heavy, strong, durable, pink.
• Leaves borne in clusters at the end of branches, opposite, simple, thinly coriaceous, punctate with pellucid glands, aromatic when crushed; petiole 1-1.5 cm long; blade elliptical to elliptical-oblong, 6-15 cm × 3-6 cm, base tapering, margin entire, apex rounded, above dark green, beneath pale green, venation pinnate.
• Inflorescence axillary, compound, paniculate, repeatedly branched, 5-15 cm long, composed of many-flowered cymes.
• Flowers structurally bisexual but functionally male or female, 8-10 mm in diameter, white, aromatic; pedicel about 1 cm long, pale green, pubescent; calyx tubular, tube shortly prolonged above the ovary, lobes 4, rounded, 1.5-2 mm long, creamy-white, wide-spreading at anthesis, persistent in fruit; petals 4, reflexed, rounded, 3-4 mm long, white, falling early; stamens free, numerous, 80-100 in functionally male trees, 40-50 in functionally female ones, about 5 mm long, filaments white, slender, anthers cream-coloured, basifixed, bilocular, dehiscing by longitudinal slits; ovary inferior, 2-celled, usually with one ovule in each cell, style about 5 mm long, white, pubescent, stigma yellow.
• Fruit a subglobose berry, 4-6 mm in diameter, green when unripe, turning glossy purple to black on ripening, with sweet pulpy flesh; dried unripe fruits are dark brown, rough.
• Seeds usually 2, with spirally coiled embryo.

Growth and development

The leaves of pimento are shed at intervals of 2-2.5 years. Pimento grown from seed flowers at the age of 7-8 years, trees from grafted material at 3 years. In Jamaica the main flowering period is from March-June. The functionally male trees shed copious pollen which is mainly transported by bees and wind. Pollen of functionally female trees is usually sterile, so some male trees are always necessary in a plantation. Full bearing for seedling trees may be attained in 15-25 years, depending on the care given to the plantation. Fruiting may continue for 100 years or more. Seeds are dispersed by birds.

Other botanical information

Because pimento is functionally dioecious, there are male and female trees. Fruiting trees are functionally female; non-fruiting or barren trees are functionally male. Both tree types are so similar in appearance that they cannot be identified before flowering. In Jamaica and other production areas several cultivars have been developed but collection of the spice from wild stands is still very important.

Pimento is entirely different from "pimiento”, a form of red Capsicum pepper, although it is usually classified with this group in the import statistics of most countries. The fruits of pimento were initially mistaken by the early Spanish explorers for the fruits of pepper (Piper nigrum L.) because of their similarity in shape and flavour. They named the fruits "pimienta” (pepper) which was later corrupted and anglicized into "pimento”.

Ecology

The natural habitat of pimento in Jamaica is limestone forest. Optimum average annual rainfall is 1500-1600 mm, but a range of 1000-2500 mm annual rainfall is acceptable, with only a few months with less than 100 mm rain. Mean annual temperatures range from 18-24°C, with a minimum of 15°C and a maximum of 32°C. Pimento grows best on well-drained loamy limestone soils with pH of 6.3-8.0, from sea-level up to 1000 m altitude, but it does best below 300 m.

Propagation and planting

Pimento is propagated either by seed or vegetatively by bud or approach grafting. Although more cumbersome, approach grafting has been reported to give 95% success as compared with only 30% for budding. Seed should be selected from fresh ripe fruits collected from healthy, regularly bearing trees and sown immediately in seedbeds or boxes to obtain a high germination rate. Seed cannot be stored since it quickly loses viability. Seedbeds should be well-watered before sowing and mulched with dried leaves or straw, paper or damp sacks to promote germination. All coverings must be removed at the initiation of germination, which may begin 9-10 days after sowing and continues irregularly over an extended period. At the 2-leaf stage, seedlings are potted into reasonably large containers, maintained in humid, shady conditions and are ready for field transplanting when 9-10 months old, being about 25-40 cm tall. Planting holes are dug 60 cm wide and deep and filled with a mixture of topsoil, farmyard manure and compost. Three seedlings are planted in each hole in a triangle 30-45 cm apart. Once flowering begins, the best female tree is retained and the other two removed. To ensure adequate pollination, one male tree should be retained for every 10 female trees. For grafted plants, only one plant is planted per hole, provided its sex is known. Final spacing between trees should be about 6 m × 6 m. A much closer spacing together with regular trimming to promote small bushy growth is used if leaf oil rather than berries is desired. Intercropping with banana and other crops is sometimes practised during the first 5 years.

Husbandry

Pimento benefits from regular weeding and mulching, and young trees should be protected from grazing stock. Complete NPK fertilizer, e.g. 15-15-15, 12-10-18 or 10-10-20 may be applied annually at the rate of 0.9 kg/tree in 2 applications, increasing up to 2.5 kg for trees older than 10 years. Trees cultivated for leaf production benefit from regular nitrogen applications.

Diseases and pests

The most serious disease of pimento is leaf rust caused by Puccinia psidii. Favoured by wet weather and low temperatures, it causes severe defoliation of young leaves and may eventually lead to the death of the plant. It may be controlled by spraying with commercial fungicides. Another important disease is dieback, fireblight or canker caused by Ceratocystis fimbriata. The symptoms include formation of bark canker, dark streaking of the wood and drying out of the leaves. Judicious pruning and cutting of infected branches are some ways to control the spread of the disease.

Pimento is not seriously attacked by insect pests but among those reported to cause some damage are scale insects, whitefly, red-banded thrips, bagworm caterpillars, fiddler beetles, several borers, black ants and termites.

Harvesting

Fully mature but still green fruits of pimento are harvested 3-4 months after flowering. In Jamaica, harvesting normally occurs from July to September. In Central America and Mexico harvesting is from June to August and mostly from wild sources. In Jamaica, harvesting is done on contract by families. Small fruiting branches are broken off from the trees and fruits are picked individually. If not done carefully, this often severely damages the trees, which take 3-4 years to recover; it also facilitates disease attacks. Leaves from the broken branches are collected separately and used for distillation of oil.

Yield

Mean annual yields of 1-2.5 kg green pimento per tree have been reported for young trees, but average yields up to 25 kg are possible. Average yields are low because pimento usually has a good crop only once in 3 years. About 52-62 kg of pimento spice can be obtained from 100 kg of fresh green fruits. Mean annual yield for trees of all ages is 1.1 kg dried pimento per tree. Annual leaf yield averages 10-30 t/ha.

Handling after harvest

Before drying, fresh green fruits of pimento may undergo "fermentation” or "sweating” for up to 5 days as done in Jamaica or are simply blanched for 10 minutes in boiling water as practised in Central America and Mexico. These techniques are believed to speed up drying and give a brighter colour to the dried fruits. The fruits are subsequently dried either in the sun or with artificial dryers. They should be regularly turned to obtain uniform colour and to reduce the moisture content to 12%. Sun-drying may take 5-10 days, depending on weather conditions. Well-dried fruits should be brownish-black and rattle when a handful is shaken.

If essential oil is desired, the fruits are crushed and distilled immediately using direct steam for about 10 hours. The crushed spice also yields an oleoresin when a variety of organic solvents is used. The essential oil from the leaves is obtained by steam distillation.

Genetic resources and breeding

The Ministry of Agriculture in Jamaica maintains germplasm collections and has breeding programmes for pimento. Vegetative propagation can be used to develop high-yielding cultivars, but breeding work is still in its initial stage. Other breeding objectives are high essential-oil content, modified tree shape with low branching, and disease resistance.

Prospects

World demand for pimento is relatively static and future plans for expansion of production should be considered with caution. Research and development efforts should focus on novel uses of pimento, coupled with new marketing strategies to promote the spice.

Literature

• Duke, J.A. & duCellier, J.L., 1993. CRC handbook of alternative cash crops. CRC Press, Boca Raton, Florida, United States. pp. 391-393.

• Duke, J.A. & Hurst, S.J., 1975. Ecological amplitudes of herbs, spices and medicinal plants. Lloydia 38(5): 404-410.

• International Trade Centre UNCTAD/GATT, 1982. Spices: a survey of the world market. Vol. 1. Geneva, Switzerland. 326 pp.

• Parry, J.W., 1969. Spices. Vol. 2. Morphology, histology, chemistry. Chemical Publishing Co., New York, United States. pp. 7-11.

• Purseglove, J.W., Brown, E.G., Green, C.L. & Robbins, S.R.J., 1981. Spices. Vol. 1. Longman, Harlow, Essex, United Kingdom. pp. 286-330.

• Rosengarten, F., 1973. The book of spices. Revised edition. Pyramid, New York, United States. pp. 99-110.

• Weiss, E.A., 1997. Essential oil crops. CAB International, Wallingford, Oxon, United Kingdom. pp. 322-333.

Sources of illustrations

Purseglove, J.W., 1968. Tropical Crops. Dicotyledons. Vol. 2. Longman, London, United Kingdom. Fig. 65, p. 411 (section through flower); Rehm, S. & Espig, G., 1991. The cultivated plants of the tropics and subtropics. English translation of 1984 German edition. Technical Centre for Agriculture and Rural Cooperation (CTA). Verlag Josef Margraf, Weikersheim, Germany. Fig. 84, p. 283 (cross-section fruit); Swahn, J.O., 1991. The lore of spices. Their history and uses around the world. AB Nordbok, Gothenburg, Sweden. p. 171 (fruiting branch). Redrawn and adapted by P. Verheij-Hayes.

Authors

• D. Sulistiarini