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MAJOR COLOURANTS AND DYESTUFFS ENTERING INTERNATIONAL TRADE

ANNATTO SEED AND ITS EXTRACTS

Summary of Basic Information


Usage: (a) As ground seed for food colouring or as a condiment in many growing countries;and (b) mainly in the form of soluble extracts for food colouring in developed countries.
Common names for product andbotanical source: Annatto or bixa seed (English); urucum(Portuguese); achiote (Spanish).
Raw material source: Seeds harvested from wild and cultivated trees.
Botanical source: Bixa orellana L. (family: Bixaceae); a small tree, native to tropical Central and South America but now widely distributed throughout the tropics.
Form traded internationally: Seeds and, increasingly, as the added-value extracts.
World production: (estimated) 10,000 tonnes annually.
International trade: (estimated) 7,000 tonnes annually in seed equivalents.
Major exporters: Peru and Kenya.
Major importers: USA, Western Europe and Japan.
Availability of reliable published information: Fair to good.

Description and Colourant Uses

Annatto of commerce is the dried seed of Bixa orellana L., an evergreen shrub or small tree which is indigenous to Central and tropical South America. The tree has been introduced widely throughout the tropics as an ornamental or for commercial production of seed and it has become naturalised in many countries of Africa and Asia.

The seed is valued as a source of pigments which impart a red or orange hue, dependent upon the form of usage. In growing countries, the seed is employed directly as a condiment and as a food colourant, especially for cereals in Latin America, and prior to the introduction of fast, synthetic dyestuffs it was used also as a dye for textiles. Export-oriented production is aimed at developed country markets where annatto extracts are employed as natural colourants by the food industries and to a lesser extent in other products, such as cosmetics.

The pigments occur in the coat of the seed which displays a deep red colour. The principal pigment is bixin, the cis-form of the mono-methyl ether of a carotenoid carboxylic acid. The total pigment content of seeds (expressed as bixin) can vary widely, both between and within production areas; the best quality seeds on the market contain over 3% bixin but supplies from several major sources often have only about 2%.

International trade has historically been conducted with seeds. However, the past decade has seen the successful development of exports in added-value extracts by the two major supply sources, Peru and Kenya.

Forms of Usage in Developed Country Markets

The predominant usage of annatto in developed country markets is in the form of extracts by the food industries. The traditional major colouring applications have been in hard cheeses, butter, other dairy products and in margarine. Fish products, salad dressings, confectionery, bakery products, ice-creams, beverages and snack-foods largely account for the remainder of demand.

The particular type of extract employed is dependent on the food product and the need for the pigment to be oil- or water-soluble.
 
 





Water-soluble extracts are employed in bi-phasic or water-based food products such as hard cheeses, bakery products, soups, sauces, pickles, smoked fish, sugar and flour confectionery. The extracts contain a mixture of the sodium or potassium salts of the cis- and trans-isomers of nor-bixin, transformation products of natural bixin which are created by the extraction procedure (described later). Imports are made of aqueous pastes and of the dried, powdered product; the latter may be spray-dried on to an inert carrier. Sales to end-users are made with spray-dried material on a carrier or, more commonly, as aqueous solutions (of which the weakest contain 0.1% of bixin).

Photographs:

N. 1 : Bixa orellana tree. (Photo: G. Blaak)

N. 2 : Bixa orellana in flower. ( Photo G. Blaak)

N. 3 : Bixa orellana with fruits. ( Photo G. Blaak)

N. 4 : Close up of Bixa orellana fruits with exposed seeds. ( Photo: NRI)
 

Oil-soluble extracts are used in margarine, salad oils and other foodstuffs possessing a high fat content. The oil soluble products may contain bixin or nor-bixin or a combination of both, in the free-acid form. They are sold in the dried state or as ready-to-use solutions or suspensions in edible vegetable oils. Solid products may contain up to 99% bixin while vegetable oil solutions may be as low as 0.1% (described later).

Dosage levels of bixin/nor-bixin in food products usually range between 0.01 to 0.5%. The main competitor for annatto extracts in certain food applications is synthetic beta-carotene.

World Demand and Supply Trends

International Trade

Accurate computation of the scale of world trade is made difficult by the fact that trade is conducted both in seeds and in extracts; the latter being in various forms and possessing differing pigment concentrations. A conservative estimate for total world trade is 7,000 tonnes, calculated in seed equivalents. (Other researchers put the figure as high as 9,000 tonnes.)

Table 4: Major importers of annatto seed and its extracts


 
Annual imports of
seed plus extracts,
expressed as seed
equivalents (tonnes)
Annual imports of
extracts, expressed
as percentage of total seed equivalent usage
USA and Canada 
2,500
10%
Western Europe 
2,500
25%
Japan
1,500
80%

Source: Natural Resources Institute (NRI) estimates (based on published trade statistics and interviews with traders).

The acceptance and growth in imports of extracts produced at source into these three major markets is recent, dating from the early 1980s; previously all imports were of seed. The most important extract traded in terms of volume is the water-soluble (nor-bixin) type, followed by vegetable oil extracts and with solvent-extracted bixin in the last place.

Demand for annatto as a colourant by the food industries in developed countries displayed growth during the 1980s in response to either the banning of certain synthetic pigments or from consumer preference for natural products. Non-traditional uses of annatto have developed recently in many countries; for example, in bakery products.

The Japanese market in particular has grown considerably in recent years since all synthetic or "nature-identical" colourings are banned in food products. Japan mainly sources annatto seed and extracts from Kenya where it has a strong involvement in the industry.

The USA is the largest single market for annatto. It sources over 60% of its requirements from Peru and the bulk of the remainder from the Caribbean region. Penetration of this market by extracts produced at source have been small when compared to those of Western Europe and Japan.

In Western Europe, the UK and the Netherlands are the largest importers of annatto seed and extracts, mainly sourced from Peru, and they jointly took the equivalent of 700 tonnes of seed in 1990. Most of the Dutch imports are re-exported to other countries in the European Community. The major consumers in Western Europe are the UK and France and they account for approximately 40% and 30%, respectively, of the total European Community demand. In both countries, annatto is predominantly used in the water-soluble (nor-bixin) form as a colouring for hard cheeses. Usage in margarine is another important outlet in the UK.

Imports by the rest of the worldare estimated as up to 1,000 tonnes in seed equivalents, of which Eastern Europe accounted for over half prior to 1990. Within Latin America, there is a substantial volume of regional trade where annatto is employed in various food applications, including use as a condiment.

The market trend in developed countries has been for a progressive increase in imports of extracts and for more stringent quality requirements (bixin content) for imported seed. Modest rather than dramatic growth in consumption may be expected in Japan and North America. In Western Europe, however, the future is dependent upon whether or not the European Community's regulatory authorities demand that very costly toxicological testing be undertaken on bixin and nor-bixin.

Production and Exports

Annatto has been traditionally grown in many Latin American and Caribbean countries, and over the past century it has achieved significance as a crop in a large number of African and Asian countries. However, there are only three major producers: Peru and Kenya, which are the major world exporters; and Brazil which is a net importer. Small volume producers and exporters include the Dominican Republic, Colombia, Ecuador, Jamaica, Costa Rica and Guatemala in the Western Hemisphere; Côte d'Ivoire and Angola in Africa; and India, Sri Lanka, Thailand and the Philippines in Asia.

Table 5: Approximate volumes of recent annual world exports
 


  tonnes, in seed equivalents
Peru
4,000
Kenya 
1,500
All others
1,500

Source: Natural Resources Institute (NRI) estimates.

In Peru, production of annatto is export-oriented and is very heavily dependent upon the harvesting of wild trees. Annual crop levels vary considerably, partly because the annatto harvest overlaps with that of coffee and also from price responsiveness. Extraction prior to export commenced on a small scale around 1980 and had developed by the early 1990s to take in over half the annual crop. Several multinational companies, based in the USA and Western Europe -Peru's traditional major markets- have established processing factories in Lima and the production and marketing are closely integrated.

Annatto is a low input, cultivated crop in some of the coastal districts of Kenya. All seed is purchased by a parastatal and the bulk is then resold to the sole extractor firm which exports to Japan under long-term contract arrangements. Owing to low farm-gate prices in recent years, seed production has fallen below the processing requirement.

By contrast, the large production of Brazil is to meet the local market demand which consumes several thousand tonnes annually. Supplies are mainly dependent upon small farmers; many large farmers were encouraged to enter into production in the mid- to late 1980s on the expectation of a major growth in world demand but withdrew upon failing to reach price expectations.

Qualities and Prices

There are no published standard specifications for annatto seed or its extract, other than the cleanliness requirements of the American Spice Trade Association (ASTA). Quality, therefore, is defined by the purchaser against in-house standards.

For seed, the content of moisture (maximum acceptable, 10%) and of extraneous matter is a quality consideration. However, the most important quality criterion is the content of bixin and the price fetched is broadly related to this pigment figure. A typical figure for "total bixinoids", expressed as bixin, is 2% on an "as received" basis ? anything greater than this is regarded as better than average and anything less as being inferior quality. Values of 2.5 to 3.5% probably represent the upper range of bixin content in traded seed. Where purchases of seed are made on a spot basis there is usually no adjustment in price made to take account of differences between sample and consignment values for bixin content. If a producer can show the ability to offer consistently good seed in terms of bixin content, then this will undoubtedly work in his favour in negotiating a price.

While some intrinsic differences in bixin content according to the origin of the seed are likely, there is an absence of documented data and it is not possible to rank producing countries in terms of the quality of their seed. Trade opinion is contradictory with regard to Peruvian vs Kenyan seed quality. However, the view seems to be shared that Indian seed is of relatively poor quality.

Table 6: Prices of Peruvian annatto seed, together with the export volumes, 1984-90


 
1984
1985
1986
1987
1988
1989
1990
Quantity  (tonnes) 1,500 1,300 1,200 650  1,450 1,650 1,500
Unit value
(US$/tonne, FOB)

750

800

1,900

 2,300

1,300

900

600

Source: Peruvian Government export statistics.

Shortages of Peruvian seed in 1985 and 1986, brought about by a combination of poor harvests and increasing local demand by extract manufacturers, led to sharply increased prices of seed in 1986 and 1987. World prices declined subsequently as supplies of seed improved. There has been an upward movement in seed prices in the more recent period, partly as a result of the poor Kenyan crop. A landed UK price of US$ 800-1,000 per tonne of seed was quoted by one trade source in mid-1992 for a bixin content of 3% (i.e., top quality).

Annatto extracts entering trade consist of crude extracts in the form of water-soluble powders or pastes (of nor-bixin, containing 20-40% pigments), oil solutions, or bixin concentrates or more highly purified forms of bixin. Bixin crystals- essentially pure bixin- are available from Peru. Reliable price data for extracts are not readily available but as a guide to relative values, in 1988, when seed fetched ca US$ 1,500/tonne, bixin powder was valued at ca US$ 1,000/tonne/1% bixin, i.e., US$ 30,000/tonne for a 30% extract. Bixin crystals were valued at US$ 107,000/tonne.

Marketing Structures and Procedures

Annatto seed is mainly purchased direct from source by the major processors in the consumer centres. Very little trade is conducted through intermediate brokers or dealers. Shipments are made in containers packed entirely with the seed; a 6-m container will take about 18 tonnes. Since the pigment content of the seed deteriorates on multiple handling and from prolonged storage, shipments normally are made immediately after the harvest season ends.

Export of annatto extracts is mainly made directly to the major users but there is some trade with smaller companies which make up formulations for further onward sale. In Peru, several multinational companies have bought local processing operations and their exports are shipped to their food factories.

Prospects for New Suppliers

While there is some uncertainty over trends in usage levels of annatto in the European Community, world demand is expected to remain substantial. This, combined with recent supply problems in Kenya, suggests that prospects exist in the medium term for sales of modest quantities of seed by new sources, provided that its quality is consistent and sufficiently high (preferably a minimum of 2.4% bixin content).

In the longer term, the scale of imports by the major consumer countries of annatto seed is expected to decline further in favour of extracts. Seed producers without domestic extraction industries might then be faced with the decision of investment in processing facilities or of export to other growing countries which have established factories and a seed supply problem.

Consumption might increase in the longer term within some of the more populous developing countries which are expanding their processed food industries. If this materialises, it would provide an alternative to the developed country markets.

Cultivation, Harvesting and Primary Processing

Climate and Soil Requirements

Bixa orellana can adapt to a wide range of conditions in the tropics and in the frost-free sub-tropics. It thrives best at temperatures between 20-26-C in areas with an annual rainfall of 1,250-2,000 mm, preferably well distributed but with a dry season for seed ripening. Nutritional requirements are not high and the tree can be grown on a variety of soil types, provided that drainage is good.

Production Systems

In Peru, the bulk of the crop is obtained from harvesting wild trees, while Kenya, the other major export-oriented producer, has an extensive system of informal cultivation. Elsewhere, both mixed cropping (with other cash crops and food staples) and intensive, mono-crop plantation systems are practised. The latter involves spacings of 3 m x 3 m or 4 m x 4 m, the choice being dependent on soil conditions and the intrinsic growth characteristics of the planting stock. Intercropping can be carried out on plantations in the first year and this assists suppression of weeds.

Annatto fits well into an agroforestry system, provided that it is not shaded by other large trees; an open sunny position is necessary for good performance.

Propagation

Cuttings may be employed for propagation and this approach is preferable for initial multiplication if elite material, possessing a good combination of high seed yields and seed pigment contents, is available. Propagation is more commonly undertaken with seed, either sown directly in the field or raised in a nursery, but this can result in high variability between plants.

Husbandry

Artificial fertiliser application is not necessary on soils of medium fertility and, other than weed control in the first year, husbandry requirements are not demanding. The most important operation is pruning in order to produce a canopy which is easy to harvest (some varieties can grow untended to over 5 m in height) and to prevent disease entering broken branches. Shaping is practised at the end of the first year and pruning of branch ends is done after every harvest.

Harvesting

Under favourable conditions, the first harvest is obtained 18 months after field planting. Seed capsules appear 30 days after flowering and ripen over a further 1-2 months; their colour varies from green to deep red. Seed capsule production and harvesting patterns vary according to local climatic conditions. Hot, dry conditions compress the season, while in Kenya harvesting occurs over 7 months with two peak bearing periods.

Seed capsules should be harvested when they commence to split open but before there is a risk of rain or sunlight damage to the seeds and loss by natural dispersal. The cluster of ripe capsules at the end of a branch is removed with a knife or secateurs by cutting above the first node.

Seed Yields

Seed yields reach their peak when the trees are 4 to 5 years of age and a decline usually does not become evident until around 12 years. Productivity can continue for up to 20 years.

Considerable variability is encountered in seed yields and this is influenced by spacing, growing conditions, management practices and the variety (which also has a marked effect on the pigment content). Yields of dried seed are reported to range from 500 kg to 2,500 kg/ha/year for established plantations with 900 to 1,500 kg/ha/year being the most common. For individual trees, the dried seed yield may vary between 0.5 to 4 kg per year.

Post-Harvest Treatment of Seeds on Farm

Seed capsules must be dried as quickly as possible to prevent mould formation and seed germination. This should aim at giving a seed moisture content of 7 to 10%; overdrying results in a loss of the pigment. Over-mature, mouldy and insect-damaged capsules are removed prior to commencing the drying operation.

Traditional sun-drying of the capsules takes 3 to 10 days. Mats or concrete barbecues should be used, with frequent turning and protection from dew at night. Artificial driers, either solar or solid fuel types, have been introduced in some producing areas to speed the process and to reduce spoilage at peak harvest or during wet periods. Temperatures of 55-60 C° are recommended for artificial drying and over-drying should be avoided.

The traditional method of obtaining the seed is to beat the dried capsule with a stick on the ground or in a bag. Each capsule may contain, according to the variety, between 10 to 50 seeds which are distributed between two valves. Extraneous matter is therefore removed by sieving and winnowing but care must be taken to avoid abrasion and loss of the valuable pigmented seed coat.

Various designs of machines have been developed to achieve capsule breaking, sieving and winnowing in large-scale operations.

Immediately on completion of the cleaning step, seeds must be bagged to prevent inadvertent contamination and pigment degradation by exposure to light. Sale of the crop should be made as soon as possible since the pigments deteriorate on storage.

Exporter Handling of Seeds

Exporter operations with seed involve redrying, when necessary, and mechanical cleaning (sieving and aspiration) and bagging. At all stages care must be taken to avoid abrasion damage to the seed and the period between purchase and shipment is kept as short as possible to prevent deterioration in the pigment content.

Clean double jute or hessian bags (50-70 kg capacity) are employed for export, and ocean shipment is carried out in containers which are preferably ventilated types.

Added-Value Processing to Extracts

Water-Soluble Products

The most commonly employed process for the production of water-soluble products involves direct extraction of the seed with aqueous alkali (usually sodium or potassium hydroxide) as the first step. Typically, seed is soaked or stirred in dilute aqueous alkali in a stainless steel vessel for about 10 minutes at a temperature not greater than 70?C. This operation transforms the natural bixin in the seed coat to a simple water-soluble derivative, the salt of nor-bixin. The extract is run off from the vessel and the extraction process may be repeated on the seeds to ensure maximum pigment recovery. The alkaline extract(s) is filtered and then acidified with dilute mineral acid (usually sulphuric or hydrochloric acids) to precipitate free nor-bixin. The precipitate is partially de-watered in a filter press to obtain a weak paste. This may be concentrated by evaporation of water for sale as a paste or be subjected to full dehydration, followed by milling to obtain a dried, powdered product. The latter is expected to possess a pigment content of 30% or more.

The alternative process for water-soluble annatto production is the treatment with alkali of bixin obtained by extraction of seeds with vegetable oil or organic solvents (described below). The resulting aqueous solution of nor-bixin salt may be sold directly or be processed further to obtain free nor-bixin.

Oil-Soluble Products

A very crude product, in the form of a water suspension, may be prepared by first steeping seeds in hot water and then filtering and concentrating the extract to a paste.

However, oil-soluble annatto is normally produced by direct extraction of the seed with food-grade vegetable oils. The extraction is carried out below 70?C and is aided by mechanical abrasion ("raspelling"). This initial extract is subjected to blending to give the requisite standardised product which is a suspension of cis- and trans-bixin in vegetable oil. If a colour more yellow than normal is required, the initial extract is either produced at a high temperature (over 100?C) or it is subsequently heat-treated.

Bixin crystals are produced by a process similar to that employed for spice oleoresins. The seeds may be extracted with an organic solvent ? hexane, methylene chloride, acetone or alcohol ? and, after concentration, crude crystals are obtained. There are a number of variants for the production of 99% pure bixin crystals; one uses methylene chloride as the initial extraction solvent and hexane and acetone are employed successively as washes to remove fats and resinous materials. Crude and pure crystals are sold directly or are employed to prepare vegetable oil suspensions or for conversion to the water-soluble nor-bixin salt.

Extraction by supercritical carbon dioxide has been reported in the literature but has not been adopted commercially as yet.

Developmental Potential

Research

The agronomy and processing of annatto has been fairly well researched and published since the late 1970s, notably in Latin America and especially in Brazil. This reported work includes examination of variability in relation to physical form, yields and quality of seed, plus low-technology processing methods.

Further research needs are more country-specific and adaptive, relating to improvement of planting stock through selection and breeding, the economics of seed and extract production for the international market and, where appropriate, the potential for usage within domestic food industries.

Commercial Production

The earlier discussion on markets concluded that scope exists for the export of seeds in modest quantities by new sources and for the development of added-value processing industries by larger-scale producers. It must be stressed, however, that success with both activities will be dependent on production of good quality material. Selection of planting stock with a high intrinsic pigment content in the seed is of critical importance for competitiveness. Also, the adoption of handling methods which avoid post-harvest deterioration must be considered as an integral part of the operation.

Other Uses

The bark of the tree has been employed in the past as a source of fibres for cordage and for the extraction of a water-soluble gum. Neither of these products appear to have any significant future developmental potential owing to the availability of superior alternatives.

SELECTED BIBLIOGRAPHY

Production, Markets and Economics

COLLINS, P. (1991). Annatto legislation in Europe. In: Proceedings of 1st International symposium on Annatto; Campinas, Brazil; 17-21 June 1991; edited by Carvalho, P.R.N. and Yabiku, H.Y. Campinas, Brazil: Instituto de Tecnología de Alimentos.

DIDRIKSEN, C. (1991). Annatto on the European market. In: Proceedings of 1st International Symposium on Annatto (see under Collins, P.).

INTERNATIONAL TRADE CENTRE (1993). Annatto Seeds: Export Opportunities for the Andean Region. Geneva: International Trade Centre.

PEREZ, S.D. (1991). Situación y perspectiva de Mercada Peruana del achiote y sus derivados. (A review of Peruvian trade in annatto and its derivatives.) In: Proceedings of 1st International Symposium on Annatto (see under Collins, P.).

ROCHA, M.B. et al. (1991). Economic viability of growing annatto: a preliminary approach: Agricultura em Sao Paulo, 38(1), 17-45. (In Portuguese).

STILES, D. (1991). Production and marketing of annatto in Kenya. In: Proceedings of 1st International Symposium on Annatto (see under Collins, P.).

Agronomy and Primary Processing

ANON. (1982). Cultivo y comercialización del achiote, Bixa orellana. Managua, Nicaragua: Financiera de Preinversion. 63 pp.

BECERRA, J.A. (1985). Manual de Cultivo de Achiote. Lima, Peru: FOPEX. 34 pp. (In Spanish.)

BELFORT, A.J.L. et al. (1992). Practical method for drying annatto seeds for seedling production. Belem, Brazil: CPATU Technical Circular No. 67; 14 pp. (In Portuguese.)

BRUCKNER, C.H. et al. (1991). Propagation of annatto by means of fine grafting methods. Revista-Ceres, 38(218), 340-344. (In Portugese.)

GASPARI, R.R. and GASPARI, R.D. (1991). Evaluación del rendimiento y algunos de sus componentes en cinco cultivares de onoto, Bixa orellana L. (Yield and components in five annatto cultivars). Agronomia Tropical, 41(3/4), 191-200. (In Portuguese).

INGRAM, J.S. and FRANCIS, B.J. (1969). The annatto tree (Bixa orellana L.) - a guide to its occurrence, cultivation, preparation and uses. Tropical Science, 11, 97-102.

RAMOS DE SOLORZANO, G. (1991). Annatto cultivation in Venezuela. (FONAIAP - Divulga), 9(36), 15-17. (In Spanish).

SAO JOSE, A.R. and REBOUCAS, T.N.H. (eds.) (1990). A. cultura do urucum no Brasil. Vitoria de Conquista, Brazil: Universidade Estudual do Suoeste da Bahia. 98 pp.

SOCIEDADE BRASILEIRA DO URUCO (1989). Urucu-uma alternativa viavel. (Annatto a viable alternative crop). Fortaleza, Brazil: Departamento Nacional de Obras Contra as Secas. 44 pp. (In Portuguese).

TERRONES, T.A.H. (ed.) (1988). Sistemas de producción de achiote en la Amazonia Peruana. Tingo Maria, Peru: UNDP/Corde-Huanuco. 84 pp. (In Spanish).

Agroforestry and Farming Systems

AMO, R.S. et al. (1993). Use and management of secondary vegetation in humid-tropical area. Agroforestry Systems, 21(1), 27-42.

JOHNSTON, T.D. (1976). Achiote, a promising alternative for inclusion in small farming systems. Turrialba, Costa Rica: CATIE.

KUSHALAPA, K.A. (1988). Silvicultural systems in the tropical rain forests of Karnataka. Indian Forester, 114(7), 372-378.

NOGUEIRA, O.L. et al. (1991). Recommendations for the cultivation of perennial species in mixed systems. Belem, Brazil: CPATU document No. 56, 61 pp. (In Portuguese).

Added-Value Processing and Quality Control

ANON. (1991). Small-scale annatto processing. Food Chain, 3, 6-7.

APPROPRIATE TECHNOLOGY INTERNATIONAL (1991). Annatto processing in Peru. Washington DC: ATI Bulletin No. 21 (February), 6 pp.

BAHL, C.P. et al. (1971). Preparation of bixin and methyl bixin from Indian seeds of Bixa orellana. Current Science, 2, 27-28.

CHAO, R.R. et al. (1991). Supercritical carbon dioxide extraction of annatto pigments and some characteristics of the colour extracts. J. Food Sci., 56(1), 80-83.

ELBE, J.H.V., et al. (1991). Extraction of annatto seed pigment by supercritical carbon-dioxide. J. Food Sci., 56(6), 1655-1659.

HYMAN, E.L. et al. (1990). Reorienting export production to benefit rural producers: annatto processing in Peru. Journal of Rural Studies, 6, 85-101.

PENNY, C. (1991). Questions in colour. Food Ingredients and Processing Int., Aug., 18-20.

PRESTON, H.D. and RICKARD, M.D. (1980). Extraction and chemistry of annatto. Food Chemistry, 5, 47-56.

VENTER, M.W. (1981). The cultivation of Bixa orellana (L.). Crop Production (South Africa), 5(10), 87-89.

WOOD, A.B. et al. (1991). Bixinoid assay in annatto seed and its extracts: an evaluation of methods and recommendations for sample handling. Paper presented by Natural Resources Institute at the 1st Int. Symposium on Annatto, Campinas Brazil, June 1991.

Usage in Foods

ANON. (1992). Annatto use levels. British Industrial Biological Research Association, Carshalton: BIBRA Bulletin.

COLLINS, P. (1992). The role of annatto in food colouring. Food Ingredients and Processing Int., Feb., 23-27.

ENGELHARDT, J. et al. (1988). Annatto: the natural colour of choice in the modern food industry. Natcol Quarterly Information Bulletin, 2, 4-10. Natural Food Colours Association, Basle, Switzerland.

HENRY, B.S. (1992). In: Natural Food Colourants, edited by G.A.F. Hendry and J.D. Houghton. Glasgow: Blackie.

HENNA

Summary of Basic Information


Usage: Principally as aqueous extracts for hair and skin dyeing.
Raw material source: Leaf of cultivated plants.
Botanical source:  Lawsonia inermis L. (syn. L. spinosa L.; L. alba Lamk) a shrub or small tree which is indigenous across a tract from Iran to Western India but now widely introduced throughout the tropics and sub-tropics.
Form traded internationally: Dried, whole or powdered leaves.
World production: Data unavailable but substantially greater than international trade.
World trade: At least 9,000 tonnes annually.
Major exporters: India, Pakistan, Iran, Sudan and Egypt.
Major importers: Middle East and North Africa, Western Europe and North America.
Availability of reliable published information: Poor.

Description and Dyestuff Uses

Henna of commerce is the dried leaf of Lawsonia inermis L., a shrub or small tree which is indigenous to the area between Iran and northern India. The plant has been introduced widely throughout the tropics and sub-tropics as an ornamental (frequently as a fragrant hedge), for home use as a dyestuff and elsewhere as a commercial crop, notably in several North African countries.

Aqueous extraction of the dried leaf provides a dye which can range in colour from black, to red through to blonde (neutral). From ancient times, henna has been employed as a cosmetic dye for hair, skin and nails and it has acquired a particular significance in Islamic culture. More recently, there has been an increase in its usage as a hair dye in Western Europe and North America.

Prior to the widespread availability of synthetic dyestuffs, henna was employed also as a dye for textiles and leather.

The major pigment in henna leaf is lawsone (2-hydroxy-1,4-napthaquinone). This fixes strongly to protein and, consequently, it has fast-dyeing properties. Considerable variability can exist between lots of dried henna leaf in the pigment content (which normally ranges between 1 and 2%) and, more importantly in cosmetic applications, in the colour tone.

International trade is conducted in whole or powdered leaf.

World Demand and Supply Trends

International Trade

Henna is included within a general category for imports/exports in many countries and it is not possible to make a precise estimate of the scale of world trade. However, examination of both import and export statistics suggests an annual trade of at least 9,000 tonnes of dried leaf between the major exporters and the major markets.

The major importers are the Islamic countries of the Middle East and North Africa. Europe and North America are significant but much smaller markets.

Many countries in the Middle East and North Africa have a domestic production of henna but require supplementation by imports. The largest individual importer in this region is Saudi Arabia (approximately 3,000 tonnes), with Algeria, Syria and Turkey as other substantial outlets. Dubai acts as entrepot in the Gulf with annual imports of approximately 900 tonnes. The main suppliers to the Middle East market are India and Pakistan with Sudan, Iran and Egypt in the second rank. Some smaller producers have traditional links; for example, Yemen with Saudi Arabia and Niger with Algeria. Black henna for skin dyeing has the greatest demand in these markets but there is a substantial consumption also of red henna for hair dyeing. Retail sales are virtually all of whole or powdered leaf in these countries.

In Western Europe, France is the biggest importer (250 tonnes) and it engages in re-exports. The United Kingdom and Germany import approximately 100 tonnes annually, while demand in other Western European countries appears to be at a smaller level.

Imports by the USA are less clearly quantified from import statistics but are of the order of several hundred tonnes annually.

Usage in Western Europe and North America lies predominantly in hair dyeing. End-users purchase both compounded formulations for immediate use and the powdered leaf for home formulation.

Eastern European imports were substantial during the 1970s and 1980s and at around 500 tonnes per annum.

Singapore acts as an entrepot, serving many markets worldwide.

The overall international market trend appears to be a plateauing of demand or at best a very modest long-term growth. In the major Middle East market, consumption is expected to remain substantial but with usage in some countries, notably Saudi Arabia, being mainly confined to the older generation and rural populations; the young and middle-class favour more modern cosmetics. In Western Europe and the USA, a growth in usage was experienced over the 1970s and 1980s along with a trend towards natural products, but this now appears to have stabilised and any future changes in demand are likely to be at the margin, following fashion trends with cosmetics. Eastern Europe may offer a potential for increased sales in the longer term, following economic recovery, but equally the greater availability of Western-type cosmetics may act as a counterbalance.

Any future major growth in global consumption is likely to occur in Asian countries with a strong Islamic culture and growing populations. This new demand could be met in several cases by increased domestic production.
 


Production and Exports

World production of henna is substantially greater than the volume of international trade, owing to the high level of domestic usage in many growing countries. No reliable figures are available on the scale of world production.

The major exporters are in approximate order of importance: India, Pakistan, Iran, Sudan and Egypt. Other smaller-scale exporters include Niger and Yemen. India's exports fluctuated between 4,500 and 7,600 tonnes annually over 1988-93, while Sudan's exports declined from just over 1,000 tonnes to 750 tonnes between 1990 and 1993.

Production in India and Pakistan is extensive rather than intensive and there is a high demand for henna on the domestic markets. The situation in Iran is similar. In several North African countries, intensive production systems are practised.

Although fluctuations in global supply levels have occurred on occasion, there has been no extended period of shortages to the international market.

Qualities and Prices

Apart from India, there are no published standard specifications for henna. Although a method exists for the quantitative assay of the major pigment (lawsone) content, this is rarely used even in developed country markets. In all markets, the colour tone (black, red or neutral) is of greater importance than the pigment strength. Colour quality assessments are made by buyers on a qualitative basis and this can involve a hair or a wool dyeing test against a set of in-house reference standards.

Consignments are offered on the basis of recognized trade categories or grades, and samples are evaluated by buyers for quality within the expectations for the type.

In developed country markets, additional quality tests may be made for the presence of adulterants, such as castor bean leaf, and for the microbial load, especially the presence of Salmonella.

Prices for henna reflect international supply levels and differentials between grades. In the Gulf market, black henna generally commands twice the price of red henna and during 1992 prices ranged from approximately US$ 700/tonne for top grades of Indian and Pakistani black henna to US$ 250/tonne for the lowest grades. During this period Iranian powdered henna fetched approximately US$ 300/tonne and the best Sudanese henna was regarded as too highly priced by comparison with Indian material. Over the period 1987-91, the unit value of henna imports to the Gulf fell by 20-30%.

The unit value of Sudanese exports fell in line with the overall market price movement from US$ 1,500/tonne to US$ 500/tonne between 1990 and 1993.
 

Marketing Structures and Procedures

In the Middle East market, most imports are made direct from source but Dubai and Singapore play a significant role as entrepots for some countries. Trading is undertaken by numerous, often small companies in the region. In recent years there has been a marked move towards import of pre-packaged material (100 to 500 g sachets in 25-50 kg cartons) for direct retail sale.

Western Europe predominantly imports leaf in packages of 50 kg. The minimum shipment size is 5 tonnes but 10 to 20 tonne lots in containers are more usual. Some of the larger users import direct but trade is more commonly conducted by a number of specialist dealers and broker firms.
 

Prospects for New Suppliers

While no rapid growth is expected in demand for henna, the market is sufficiently large for the entry on a modest scale of new suppliers. However, success will be dependent upon the ability to supply regularly a consistently good quality product at competitive prices. Additionally, attention would have to be devoted to gaining a sound understanding of the different requirements for quality and packaging in each of the major geographical markets and of their trading structures.
 

Cultivation, Harvesting and Primary Processing

The published literature on henna is scanty, with the majority of articles pre-dating 1950. However, it is unlikely that agricultural practices and productivity in most countries have changed radically from the summary given below since it is predominantly a small-holder crop which has not ranked high in the priority lists for agricultural programmes.

Climate and Soil Requirements

The henna plant has proven to be adaptable to a wide range of conditions in the tropics and the frost-free sub-tropics. It is tolerant of drought and sandy-stony soils but thrives best in fertile, water-retentive soils. Under ideal conditions for rain-fed cultivation, the rainfall should be well-distributed but with two dry periods a year in order to facilitate post-harvest leaf-drying.

Production Systems

Henna is normally planted in rows with individuals as close as 15 cm within a row, which takes on the appearance of a low hedge when mature. The distance between rows varies greatly according to the producing area, from a dense monoculture (up to 200,000 plants per ha) to a mixed system with annual food crops. (Although not normally considered within the context of agroforestry systems, henna fits the requirements provided that overshadowing by large trees is avoided.)

Input levels similarly vary enormously from one producing area to another from no irrigation to irrigation with heavy applications of fertilizer or farmyard manure (in order to replace the soil nutrient depletion arising from frequent leaf harvesting).

The economic lifetime of plants is between 4 to 6 years with intensive cultivation but many producers do not replace their crop for 12 years or more.

Propagation and Field Establishment

Seed and cuttings are employed for multiplication in nurseries. Presoaking in water or chitting assists germination of seeds which possess a tough outer coat. Prior to field establishment, the young plants are clipped back to around 20 cm in order to promote bushy growth. The planting site should be prepared by ploughing and ideally have compost or manure incorporated.

Husbandry

Weed control is necessary in the first year of field growths and following harvesting in subsequent years. When established as a monoculture with moderate row spacing, annual food crops may be grown in the first year and this assists weed control; legume crops are particularly useful.

Application of fertilizer or manure, if available, over the lifetime of the plot promotes vigorous growth/regeneration after harvesting. Similarly, irrigation is of benefit in low rainfall areas.

Harvesting

The first harvest is taken 12 months after field planting by cutting the plant about 10-15 cm above ground level. Subsequently, two harvests are taken a year under rainfed conditions (spring and autumn in the sub-tropics) and three harvests may be possible with irrigation.

Harvesting should be carried out in a rain-free period and, preferably, under low humidity conditions in order to aid rapid leaf drying and to avoid spoilage.

Leaf Yields

The yield of dried leaf is highly variable and is dependent upon a number of factors: the germplasm characteristics, the soil nutrition level, water availability and the age of the plantation. The first year's crop is low and maximum productivity is achieved in the second and third years. Performance thereafter is highly dependent upon soil nutrition. Under rainfed conditions, the yield from the first (spring) harvest is about 30% of the annual total for the two crops.

Published information on crop yields suggests that under rainfed conditions for dense planting the dried leaf yield in the first year may be around 200 kg/ha while over the second, third and fourth years the yields normally range between 1,000-1,500 kg/ha. With irrigation and heavy fertilizer treatment, plus three croppings a year, yields in excess of 2,000 kg/ha can be obtained in the peak productivity years.

Post-Harvest Operations on Farm

After cutting, the leaf is allowed to dry while still attached to the stem and this may be done by leaving the crop in the field. Retention of a desirable attractive green colour is assisted by drying in the shade but this can be impractical with very large crops and in the absence of suitable facilities.

Most of the dried leaf can be simply detached by beating the stem on the ground. This should be done on a clean surface to avoid soil contamination and the inclusion of extraneous matter. Sale in clean bags should be made as soon as possible after the harvest to avoid deterioration during storage.

Exporter Operations

Material entering the exporter's premises should be checked for moisture content and, if necessary, be redried in the sun to 10%. Lots should then be graded on the basis of visual appearance and testing for colour tone of aqueous extracts.

For export of leaf, packaging of the graded material should be made in jute or hessian sacks which hold 50 kg. Ocean shipment is now predominantly by means of container vessels and ventilated containers should be selected when available.

Added-Value Processing

For general trade, added-value processing options are restricted to preparation of the powder by simple mechanical comminution and for certain Middle East and Asian markets the powder may be packaged in plastic bags (containing 100-500 g) for retail sale. Precise requirements for the size and labelling of retail packs must be determined from the buyer.

Developmental Potential and Research Needs

Considerable scope exists for improvement of henna productivity and product quality/value in the majority of growing countries. Germplasm selection for both biomass and pigment content enhancement would be a useful area for research.

Re-examination is merited also of field management systems, particularly for mixed cropping and of means of maintaining post-harvest quality; the latter should include the potential for the use of simple, inexpensive driers in humid climates. However, the most important immediate need is a thorough study of the future market demand, particularly in the Middle East and the more populous Asian countries, in order that national agricultural planning bodies can formulate an appropriate strategy on production.

Other Uses

The wood of the henna plant is employed as fuel and for carpentry products in some countries.

Leaf and bark have been used in traditional medicine in several countries for various ailments, including treatment of jaundice. The antifungal, antibacterial and nemacidal properties of extracts have received some scientific examination in recent years but their effectiveness and economic competitiveness have not yet been established.

The flowers possess a pleasant aroma and crude perfumes are produced in some major growing areas by preparing a suspension of comminuted flowers in vegetable oil. There is no recorded international trade in henna flower essential oil.
 

SELECTED BIBLIOGRAPHY

Production, Markets and Economics

ANAND, N. (1983). The market for annatto and other natural colouring materials, with special reference to the United Kingdom. Tropical Development and Research Institute (UK): report No. G174.

AUBAILE-SALLENAVE, F. (1982). Les voyages du henné. J. d'Agriculture Traditionnelle et de Botanique Appliquée, 29, 123-178.

Agronomy

KOLARKAR, A.S. et al. (1981). Note on Mehendi (Lawsonia inermis L.) cultivation in normal and degraded lands of western Rajastan. Indian J. Soil Conservation, 9, 71-74.

KOSHCHEEV, A.V. and BUNKIN, V.P. (1988). The effects of soil salinity on the productivity of henna. Agrokhimicheskoe i Pochvenue Issledovanie v Botanicheskikh Sadak, 68-72. (In Russian.)

RASULOVA, M.R. et al. (1986). Prospects for Lawsonia inermis, Indigofera tinctoria and I. articulata introduction in Tajik SSR. Rastitel'nye-Resursy, 22(2), 227-233.

SCARONE, F. (1939). La henna dans le monde musulman. L'Agronomie Coloniale, 28(May), 129-140.

SASTRI, B.N. (1962). The Wealth of India: Raw Materials. Vol. 6, pp. 47-50. New Delhi: Council for Scientific and Industrial Research.
 

Quality Control

CHOURASIA, L.O. et al. (1989). Study of the quality characteristics of henna. Indian Perfumer, 33(1), 54-59.

INDIAN STANDARDS INSTITUTE. (1984). Specification of henna powder: I.S. 11142. New Delhi: Indian Standards Institute.

LEMORANT, D and FORRESTIER, J.P. (1983). Commerce et henné. Identification, contrôle, fraudes, additifs. J. d'Agriculture Traditionnelle et de Botanique Appliquée, 30, 283-310.
 

Non-Dyestuff Applications


ANAND, K.K. et al. (1992). An evaluation of Lawsonia alba extract as a heptoprotective agent. Planta Medica, 58(1), 22-25.

BAJRANG SINGH et al. (1984). Qualitative analysis of some firewood shrubs. Biomass, 5(4), 317-320.

KUMARI, R. et al. (1987). Screening of aerial parts of Datura, Ipomoea, Tagetes and Lawsonia for their nemacidal activity on Meloidogyne javanica. Agric. Sci. Digest, India, 7(4), 213-216.

LEMORDANT, D. and FORESTIER, J.P. (1983). Usages medicineaux traditionnels et propriétés pharmacologiques de Lawsonia inermis L. J. d'Agriculture Traditionnelle et Botanique Appliquée, 30(1), 69-89.

OUMMACHAN, M. et al. (1990). Observations on certain plants used in the treatment of jaundice. Indian J. Applied and Pure Biology, 5(2), 99-102.
 
 

LOGWOOD AND ITS EXTRACTS

Summary of Basic Information


Synonyms: (a) Wood: campeachy wood (English); bois bleu (French). 
(b) Extracts: haematoxylin; haematein.
Usage: (a) Principally as the haematin extract for dyeing textiles black and blue shades; and 
(b) limited usage of the haematoxylin extract in histology.
Botanical source: Haematoxylum campechianum L. (family Leguminosae); a small tree indigenous to Central and tropical South America but now widely distributed in the tropics.
Raw material source: Harvesting of the trunkwood of wild and cultivated trees.
Form traded internationally: Mainly as powdered extracts, known as crystals.
World production and international trade: Estimated at 600 tonnes annually.
Major exporters: Jamaica, Haiti and Dominican Republic.
Major importers: Western Europe, USA and Japan.
Availability of reliable published information: Very limited and mostly outdated.

Description and Dyestuff Uses

Logwood (Haematoxylum campechianum L.) is a small tree (up to 12 m tall) which is native to Central America and the northern tropical region of South America. Its dyestuff value was recognised at an early stage by the Conquistadors who then promoted cultivation on the major Caribbean islands. During the nineteenth century, logwood was introduced to South and Southeast Asia but this region did not develop as a significant commercial source.

The heartwood contains about 10% of a colourless compound, haematoxylin, which on oxidation transforms to a violet-blue substance, haematoxein (commercial synonym, haematein). Young trunkwood is white to pale yellow while older trees display pigmented streaks arising from the natural oxidation of haematoxylin. The pigment can be produced by deliberate oxidation in the commercial aqueous extraction process of young trunkwood.

Haematein has resisted total substitution by synthetic dyes owing to its special properties. It has a fair degree of fastness, good penetration and by selection of different mordants subtle colour tones ranging through grey, brown, blue to black can be produced. The black colour is especially important since few synthetic dyes can compare it in tone. Major applications lie in the dyeing of natural and synthetic fabrics and other uses include dyeing of leather, fur, feathers, paper, wood and incorporation in inks.

Haematoxylin is employed in comparatively small quantities as a histological staining agent by pathology laboratories. In this application, it has successfully resisted challenges from alternatives.

Only a minor international trade is conducted in trunkwood. The bulk of the wood is extracted immediately after tree felling and the product is powdered for export.
 
 

World Demand and Supply Trends

International Trade

As is the case with many similar products, the true scale of current world trade is difficult to quantify owing to the shortcomings in classification within import and export statistics. The best possible estimate is 600 tonnes of extracts per year (which corresponds very roughly to 2,500 tonnes of logwood feedstock).

The major importers are Western Europe, North America and Japan. France is the largest individual importer in Western Europe and engages in a substantial re-export trade with other countries in the European Community and further afield.

Periodic supply problems and, consequently, price rises have been encountered over the past twenty years and this has resulted in a trend towards increased substitution by synthetics in major dyeing applications. However, the special qualities of haematin and haematoxylin remain highly regarded and the threat of complete substitution by synthetics is not yet evident.

Production and Exports

Export of logwood played an important role in the economy and development of a number of countries in Central America and the Caribbean, and it was a significant element in the decision to colonize British Honduras (now Belize). The trade peaked in the late nineteenth century at around 100,000 tonnes of wood per annum, with Haiti accounting for 90% at some stages and British Honduras shipping between 4,000-13,000 tonnes.

During the twentieth century, demand progressively declined and also exports moved from logs to extracts.

The major commercial sources of logwood extracts in recent years have been the larger Caribbean islands (Jamaica, Haiti and the Dominican Republic).

Other producers include several Central American countries and Brazil.

Trees are cultivated in Jamaica and some of the other islands but elsewhere in the region the industry is heavily dependent upon wild trees.

Qualities

Dried extracts, often called crystals, are distinguished as haematoxylin or haematein; the latter is graded according to the degree of oxidation of haematoxylin to haematein, typically over the range of 15 to 100%. An 80% grade, for example, contains haematein:haematoxylin in the ratio of 80:20.

Marketing Structures and Procedures

Direct purchases from source are made by a large number of specialist firms, some of which are end-users. In Western Europe, France performs a major function as the principal importer and distributor to other countries.

Prospects for New Suppliers

Demand in the major developed country markets is not expected to grow but the periodic problems of supply shortages offer scope for market entry on a modest scale by new producers.

Any significant prospects for increased global usage probably lies with those countries in South America and Asia which are experiencing population growth and an emergent middle-class with sophisticated tastes in the quality and range of dyed manufactured products.

Cultivation, Harvesting and Processing

Climate and Soil Requirements

The tree is adaptable in the lowland tropics to a range of soils. In Central America, it is frequently found on marshes which are prone to periodic flooding. In Jamaica, the tree thrives best in moist interior valleys and coves at the foot of hills and tolerates chalky soil.

Production Systems

The tree may be established on an intensive (plantation) or extensive basis. While not reported as being used in an agroforestry context, logwood would appear well suited for this purpose. Annuals or short-lived perennial shrubs probably could be cultivated as lower storey crops in the early years of a plantation.

Propagation

Cuttings and seed are both used for propagation.

Husbandry

Apart for weed control during the early phase of establishment, logwood requires minimal attention.

Harvesting

Trees are felled while relatively young since this ensures a high haematoxylin recovery. The age at which this size is attained is dependent upon the variety and the site's soil and climatic characteristics.
 

Extraction

Bark and sapwood are first removed from the trunkwood. The heartwood then is mechanically reduced to chips for extraction which is carried out in hot water, sometimes in an autoclave under pressure. When hot, the extract is orange-red in colour and this changes to yellow on cooling.

Dehydration of the extract under vacuum provides haematoxylin crystals. For the production of haematin, the extract is aerated or treated with an oxidising agent prior to dehydration.
 

Yields of Heartwood and Extracts

No reliable published data are available on heartwood or extract yields.

Developmental Potential and Research Needs

The scope for further development of the logwood industry is dependent on future supply and demand levels. The primary requirement, therefore, is for a thorough market study of both traditional (developed country) and prospective new (Asian and Latin American) areas.

If the findings of the market study were positive, research would be merited on the following topics:

(a) selection of elite germplasm for propagation since there are clearly significant provenance differences amongst the cultivated and wild stock in pigment content, growth performance and eco-climatic adaptation;

(b) utilisation of the species as a component of agroforestry systems; and

(c) the potential for improvement of yields and quality control in the processing operations.



Other Uses

The wood can be employed as building and carpentry timber but has some limitations in the latter application owing to its uneven and brittle characteristics. It is also an acceptable fuelwood.

Extracts have been employed in traditional medicine in the past as an astringent, anti-inflammatory agent and for gastrinal disorders.

The tree produces fragrant flowers and this has led to its use as an ornamental hedge and as a food source for honeybees.
 

SELECTED BIBLIOGRAPHY

Markets

ANAND, N. (1983). The Market for Annatto and Other Natural Colouring Materials, with Special Reference to the United Kingdom. Tropical Development and Research Institute, UK: Report No G174.

Agronomy and Processing

ECHENIQUE-MANRIQUE, R. and DEL AMO, R.S. (1977). Palo de campeche. INIREB, Mexico: Information Bulletin No 17.

KOCHKAR, S.L. (1988). Economic Botany in the Tropics. Delhi, India: MacMillan India Ltd.

LALOR, G.C. (1961). The logwood dye industry, processing in Jamaica and research on constituents: Bull. Sci. Res. Council Jamaica, 2(1), 16-18.

RECORD, S.J. and HESS, R.W. (1943). Timbers of the New World, pp. 276-277. Yale, USA: Yale University Press.

SASTRI, B.N. (1959). The Wealth of India, Vol. 5, pp. 2-3. New Delhi: Council of Scientific and Industrial Research.

Dyestuff Chemistry and Applications

NEWSOME, O. (1950). Logwood and its applications, Part 1 Dyer, 104(13), 625-627.

ROBINSON, R. (1958). Chemistry of brazilin and haematoxylin. Bull. Soc. Chim. France, 1(Jan), 125-134.
 
 

RED SANDALWOOD

Summary of Basic Information


Usage: As a spice and as an orange-red food colourant.
Product synonyms: Santalin; sandalwood extract.
Raw material source: Heartwood of a tree; mainly harvesting of wild resource.
Botanical source: Pterocarpus santalinus L. (Papilionaceae sub-family; Leguminosae).
Common synonyms for botanical source: Red sandalwood; red sanders; sanderswood; lalchandan, errachandan, rakta chandan.
Distribution: Confined to a specific area of India.
Product traded internationally: The powdered heartwood.
World production and trade: Around 50 tonnes a year of heartwood.
Exporter: India.
Major importers: Western Europe, Japan and China (Taiwan province).
Availability of reliable published information: Poor.

Description and Colourant Uses

"Red sandalwood" or "red sanders" (Pterocarpus santalinus L.) is a deciduous medium-sized tree (up to 11 m), which is indigenous to a restricted area of Andhra Pradesh and Madras States in India. It is a member of the "insoluble redwoods", i.e., red dyestuff sources which are not extractable by water (e.g., Pterocarpus indica of South and Southeast Asia and Pterocarpus species of Africa).

Red sandalwood and some of the other "insoluble redwoods" were employed in the past for dyeing wool, cotton and leather and for wood staining. Today, usage of red sandal appears restricted to foods where it imparts a sweet-spicy flavour and orange-red shades. For the food industries, the extract is normally sold in the alcohol-soluble form, either as liquids or powders but water-soluble forms (salts) are also available. Red sandal has been traditionally used with fish products in Europe and more recent applications include the colouring of seafood sauces, meat products, snackfoods, breadcrumbs and alcoholic drinks. Dosage levels range from 0.1 to 1% (weight for weight).

The principal red pigments in red sandal heartwood are santalin A and B, and these are soluble in organic solvents and alkalis but not in water. A yellow isoflavone pigment, santal is present also. The santalins together with other related pigments are found in some other Pterocarpus and Baphia species.

World Demand and Supply Trends

Exports of red sandalwood from India to Europe commenced in the seventeenth century, primarily for textile dyeing but there was some demand also for the timber. Around 1880, exports averaged 3,000 tonnes per annum with the UK as the major importer. By 1900, exports and usage of red sandal as a textile dye had effectively ceased owing to the competition from synthetics.

In the 1930s, Japan commenced to import Indian red sandalwood for the manufacture of the traditional "shamishen" musical instrument and this market remains important today at a level of several hundred tonnes per annum. Demand by Japan for "wavey grain" quality timber resulted in significant illegal and destructive exploitation of the wild resource in the 1950s and 1960s and controls were imposed on trading.

In Europe, red sandalwood extract has a long history of use as a red colourant for fish processing, e.g., in pickled herrings. More recently, interest has been shown by the food industry to expand the range of applications. In the European Community, red sandalwood extract is presently classified as a "spice extract" and thorough toxicological testing may be demanded by the regulatory authorities before reclassification to food colourant status with an E number.

Exports of red sandal powder from India averaged 50 tonnes annually between 1988-1993. The major importers have been Japan, China (Taiwan province) and Western Europe.

Silviculture and Colourant Processing

Climate and Soil Requirements

The natural habitat of P. santalinus in India is characterised by a hot, dry climate with around 100 mm of rain in each of the two annual monsoons. The trees are found in dry, hill areas, often on rocky ground, and at altitudes ranging from 150-900 m.

Propagation and Management

Natural regeneration occurs by seed. Artificial propagation can be achieved with seeds and cuttings. Saplings are field planted when one year old and at spacings of 3.5 to 4.5 m. Both waterlogged sites and overshading by other trees must be avoided.

The tree regenerates well from coppicing but growth is slow and a 40-year coppice rotation is practised in India.

Colourant Extraction

Only the heartwood is employed for extraction of the colourant. The process involves reduction of the wood to chips or powder and extraction with alcohol.

The extract may be simply concentrated or be stripped of solvent to give a solid product prior to sale. No reliable published information is available on commercial extraction yields.

For sale to end-users, specific formulations (as liquids, dispersed solids or water-soluble forms) are prepared at strengths appropriate for the food product.

Other Uses

Red sandalwood has multipurpose uses. In India, it has played a traditional role in medicine as an astringent and for the treatment of gastric and skin disorders. During the nineteenth century when sustainable exploitation of the natural resource was not accorded a high priority, the wood was employed for railway sleepers and for boiler fuel.

Today, production of "wavey grain" timber for the export market is of some importance and there is usage on the domestic market for carving, furniture and charcoal. The leaves are employed as cattle fodder.

Development and Research Needs

In recent years, attention has been devoted in India to selection of elite germplasm for the production of "wavey grain" timber and to improved means of vegetative propagation. Relatively little systematic work has been reported on the utility of the species as a multipurpose tree or on food colourant aspects. With regard to the latter, the most pressing need is probably a thorough assessment of market demand trends and its relationship to raw material supply.
 

SELECTED BIBLIOGRAPHY

Silviculture

ANON. (1969). Wealth of India, Vol. 8. New Delhi, India: Publications and Information Directorate, CSIR.

REDDY, K.K. and SRIVASUKI, K.P. (1992). Biotechnical approach for tree improvement in red sanders. Indian Forester, 18(1), 15-20.

Colourant Processing and Uses

LABATUT, M.L. (1989). Renewed interest for flavanoids of sandalwood and roselle as natural red colourants for foods. In: Proceedings of Food Ingredients Europe Conference, 1989. Maarssen, the Netherlands: Expoconsult Publishers.

MATHEW, P.T. and GOPAKUMAR, K. (1992). Effect of incorporation of vegetable colour from red sandal (Pterocarpus santalinus) on acceptability, colour development and growth of tilapia (Tilapia mossambica). Fishery Technology, 29(2), 124-126.

REDDY, C.V.K. (1972). Red sanders and its history of utilization. Indian Forester, 98(10), 589-593.

TEWARI, D.N. (1994). Tropical Forest Products. Dehra Dun, India: International Book Distributors.

THEDENS, P. and VERSTRYNGE, L. (1989). Plant extracts used as colourants. Voedingsmiddelentechnologie, 22(18), 32-34.

Colourant Chemistry and Analytical Methods

ARNETH, W. and MARTIN, G. (1987). Extraction of colourants from meat and meat products. Mitteilungsblatt Bundesanstalt Fleischforschung, Kulmbach, 98, 7728-7729.

ARNONE, A. et al. (1975). Structures of the red sandalwood (Pterocarpus santalinus) pigments, santalins A and B. J. Chem. Soc., Perkin Trans. I, 2, 186-194.

EIGGINGER, R. (1987). Identification of natural water-soluble food colourants by TLC. Mitteilungsblatt Bundesanstalt Fleishforschung, Kulbach, 97, 7574-7579.

GURDUTT, K.N. and SESHADRI, T.R. (1974). Constitution of the santalin pigments A and B. Phytochemistry, 13(12), 2845-2847.

Chemistry of Other Constituents of Pterocarpus spp.

ARNONE, A. et al. (1977). Colouring matters of the West African redwoods, Pterocarpus osun and P. soyauxii. Structures of santarubins A and B. J. Chem. Soc., Perkin Trans. I, 19, 2116-2118.

DEAN, F.M. (1963). Naturally Occurring Oxygen Ring Compounds. London: Butterworth.

KUMAR, N. et al. (1974). Terpenoids of Pterocarpus santilinus heartwood. Phytochemistry, 13(3), 633-636.

KUMAR, N. and SESHADRI, T.R. (1975). Triterpenoids of Pterocarpus santalinus. Constitution of a new lupene diol. Phytochemistry, 14(2), 521-523.

KUMAR, N. and SESHADRI, T.R. (1976). Terpenoids of Pterocarpus santilinus leaves. Current Science, 45(14), 516-517.

KUMAR, N. and SESHADRI, T.R. (1976). A new triterpene from Pterocarpus santilinus bark. Phytochemistry, 15(9), 1417-1418.

 
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