Chicle (FAO, NWFP 6)

← Asafoetida and Galbanum

Coppen, Gums, resins and latexes of plant origin, 1995

Jelutong →

• Extract from : NWFP 6. Coppen J.J.W., 1995. Gums, resins and latexes of plant origin. FAO, Rome. 142 p. (Non-Wood Forest Products, 6). on line

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6 — LATEXES

CHICLE

DESCRIPTION AND USES

Chicle is the coagulated latex obtained from Manilkara zapota, and is produced on a commercial scale in Mexico and certain parts of Central America. Chicle is to be distinguished from sapote gum, the hard, gummy material which forms slowly over the wound made in the tree to obtain the latex, after the latter has ceased to flow. Sapote gum was once used in Peru as a sizing agent for cloth, and as a glue, but it does not enter world trade and is not considered further here.

Although it has had miscellaneous minor uses as a gutta percha substitute, chicle's economic importance has arisen from its use in the manufacture of chewing gum, where it imparts the "chewing" properties to the product. An inferior, little-used "chicle"-type of gum is crown gum.

WORLD SUPPLY AND DEMAND TRENDS

Markets

At one time, chewing gum base consisted almost entirely of natural "gums", of which the principal one was chicle. The most important of the other natural gums was jelutong, although smaller quantities of sorva and maçaranduba have also been used. Nowadays, with the advent of cheaper, synthetic resins with suitable properties, demand for the natural gums for use in chewing gum has declined.

The United States chewing gum industry was traditionally the major consumer of chicle but as they have moved towards using a greater proportion of synthetic gums, imports of chicle have fallen, and the Far East has become the major market, particularly Japan. In 1930, at the peak of production, over 6 000 tonnes of chicle were imported into the United States. In the period 1963-66, American imports of chicle from Mexico, the leading producer, averaged just over 1 000 tonnes/year. In the three years 1988-90, exports of chicle to the United States from Mexico (Table 30) averaged 10 tonnes.

Imports of chicle, balata, gutta percha and guayule are recorded as a single group in Japanese trade statistics. However, they have been separated, here, into the component gums as judged by the country origins, and data for the period 1988-94 are given in Table 32. Total imports of chicle into Japan are estimated to have been around 800-1 000 tonnes annually in recent years.

In Europe, at least as far as Mexican exports of chicle are concerned (Table 30), Italy has been the major importer. Total annual imports into Italy may amount to 100-200 tonnes.

Supply sources

Mexico is believed to be the biggest producer of chicle, although if the disaggregation of imported chicle and gutta-type products into Japan - and shown in Table 32 - is correct,

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Guatemala, which has been a significant producer in the past, may recently have surpassed Mexico: estimated imports from the two countries for the period 1988-94 averaged approximately 400 tonnes (Guatemala) and 370 tonnes (Mexico) each year. Exports of chicle from Mexico for 1988-90 are shown in Table 30.

Other, minor producers include Belize (see Table 31 for exports in 1989 and 1990), Honduras, Venezuela and Colombia.

Quality and prices

Recent quality and price information on chicle is not available. General requirements of natural masticatory substances, including chicle, are specified in the Food Chemicals Codex of the United States and these detail limits on arsenic, lead and heavy metals.

PLANT SOURCES

Botanical/common names

Family Sapotaceae:

• Manilkara zapota van Royen (syn. Manilkara achras Mill., Manilkara zapotilla Gilly, Achras sapota L., Achras zapote L., Sapota achras Mill.) - Chicle (gum), sapodilla, chico, zapote
• Manilkara chicle Pittier - Crown gum
• Manilkara williamsii Standley (Accepted name : Manilkara bidentata) - Venezuelan chicle

Description and distribution

Manilkara zapota is a tree which reaches a height of 20-25 m in the wild, with a dense rounded or conical crown and a hard timber. It is indigenous to Central America in the region extending from southern Mexico to northern Colombia, but grows best in the Yucatan peninsula, embracing the southern states of Mexico and the northern parts of Belize and Guatemala - these form the principal chicle-producing areas.

However, it is also widely cultivated for its fruit, both in tropical America and further afield in India, Sri Lanka, Malaysia, Thailand and the Philippines. MORTON (1987) states that in Mexico, 1500 ha are devoted to fruit production, while 4000 ha are grown primarily for chicle.

A larger member of the genus, Manilkara chicle, has been exploited in Belize in a minor way as a source of crown gum, an inferior form of chicle.

COLLECTION/PRIMARY PROCESSING

Details of tapping methods used on plantation-grown trees are not known, but in the wild, methods have probably changed little from the early days of production. Contemporary descriptions given by BOLT (1961) are essentially the same as earlier ones by EGLER (1947).

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Starting about 1 m from the base of the tree, the chiclero makes a series of diagonal cuts up the trunk (climbing to a height of up to 10 m with the aid of ropes), each cut alternating in direction to the previous one so as to form an ascending zig-zag line, down which the latex flows. A common fault in earlier days was to extend the cuts to two-thirds or more round the trunk, which eventually led to the death of the tree. A bag is attached to the tree at its base and the chiclero returns to collect the accumulated latex either later the same day or the following morning.

The tree can only be tapped again when the laticiferous vessels in the bark have been renewed and this may take up to five years or more. Up to three tappings can be carried out.

The freshly collected latex is boiled in an open vessel, with constant stirring, until it reaches a concentration such that when it is poured into wooden moulds and set aside to cool it solidifies. The blocks of chicle are then transported after sale to the factory for further processing.

Yields

At the first tapping, mature wild trees yield about 1 kg (and up to 2 kg) of latex; the second tapping yields about half this quantity, and the third one less still. However, as would be expected, there is considerable tree-to-tree variation, and the older literature describes methods used by chicleros to test whether it would be profitable to tap individual trees. Yield data for cultivated trees are not available.

VALUE-ADDED PROCESSING

Further processing (before mixing with other ingredients to form a chewing gum base) entails drying, melting and centrifuging to remove extraneous matter.

PRODUCTS OTHER THAN LATEX

The tree is grown widely for its fruit and, where it has been cultivated as an exotic, this is its primary or sole commercial use. Sapodilla wood is strong and durable but felling of the tree is prohibited in Yucatan because of its value as a source of chicle.

DEVELOPMENTAL POTENTIAL

Methods for propagation and cultivation of Manilkara zapota are well established for production of fruit, and a large number of cultivars have been developed. Unlike many of the other latex-producing trees discussed in this report there is, therefore, a firm foundation of knowledge and practical experience on cultural aspects on which to build. Furthermore, in Mexico this experience extends to commercial cultivation for chicle.

The economic viability of chicle production from cultivated sources depends on the continued market for chicle as a natural chewing gum ingredient, as well as production factors such as labour costs. If the market can be maintained and production costs can be held stable, then some increase in the area under cultivation can be justified. Providing the price of "cultivated" chicle remains attractive compared with "wild" chicle, the market always prefers to meet its requirements from renewable, sustainable resources rather than from wild trees which become increasingly less accessible.

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Research needs

Efforts have been made to extract chicle from the leaves and unripe fruits of the tree, but yields have been too poor to make such production economic. Research should focus on ways of increasing yields of latex from the trunk, either by using improved planting stock or through use of better tapping methods:

• Populations of trees throughout the natural range of Manilkara zapota should be screened to determine the intrinsic (genetic) variability in latex yield between and within provenances, with a view to identifying high-yielding trees.
• The development of improved tapping methods should include an investigation of the possible benefits of using chemical stimulants to increase yields of latex; such methods have been used to improve rubber yields in Hevea.

SELECTED BIBLIOGRAPHY

• ANON. (1967) A note on the market for chicle. 3 pp. Unpublished memorandum of the Tropical Products Institute, London [now Natural Resources Institute, Chatham].
• BOLT, A. (1961) Chicle. World Crops, 13, 58-59.
• DUPAIGNE, P. (1979) [Masticatories and tropical fruits] (in French). Fruits, 34(5), 353-358.
• EGLER, F.E. (1947) The role of botanical research in the chicle industry. Economic Botany, 1, 188-209.
• HUGUET, L. (1952) [The chewing gum tree] (in French). Revue Forestière Française, 4(12), 803-812.
• MORTON, J.F. (1987) Sapodilla. pp 393-398. In Fruits of Warm Climates. 505 pp. Miami, USA: JF Morton.
• NAS (1981) Natural masticatory substances. pp 191-192. In Food Chemicals Codex. Third edition, 735 pp. Washington, DC: National Academy Press.
• SMITH, E.H.G. (1940) Chicle, jelutong and allied materials - a review. Bulletin of the Imperial Institute, 38, 299-320.
• TESSIER, A.M., NOLOT, P. and DELAVEAU, P. (1976) [Critical review of the latexes of Apocynaceae, Euphorbiaceae, Moraceae and Sapotaceae used in masticatories] (in French). Plantes Médicinales et Phytothérapie, 10, 203-212.
• TESSIER, A.M., NOLOT, P. and DELAVEAU, P. (1977) [Modern masticatories] (in French). Médecine et Nutrition, 13(3), 171-199.
• WILLIAMS, L. (1962) Laticiferous plants of economic importance. I. Sources of balata, chicle, gutta percha and allied guttas. Economic Botany, 16, 17-24.

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Table 30. Chicle: exports from Mexico, and destinations, 1988-90 (tonnes)

	1988	1989	1990
Total	171	836	685
Of which to:
Japan	118	637	510
Italy	47	184	101
USA	6	14	9
Canada	-	1	1
Korea, Rep. of	-	-	64

Source: National statistics

Table 31. Chicle: exports from Belize, and destinations, 1989-90 (tonnes)

	1989	1990
Total	79	44
Of which to:
Japan	79	44

Source: National statistics

Table 32. Chicle, balata, gutta percha, and guayule: imports into Japan, and sources, 1988-94 (tonnes)

	1988	1989	1990	1991	1992	1993	1994
Total	1684	2258	2592	2837	2834	2286	1706
Of which from:
Chicle
Mexico	329	542	589	294	288	223	300
Guatemala	174	386	365	378	472	533	479
Belize	35	54	114	57	121	151	48
Honduras	3	-	-	-	-	-	-
Balata
Brazil	253	235	153	359	328	214	151
Gutta percha
Indonesia	577	709	1061	1304	1296	891	623
Singapore	306	331	268	362	315	213	103
Thailand	-	-	-	-	-	54	-
Hong Kong	-	-	25	-	-	-	-
Other
USA	-	-	17	63	13	7	-

Source: National statistics