Memorias 1er Congreso Vzlno de Cacao_Fundacite Aragua

Memorias del Primer Congreso Venezolano del Cacao y su IndustriaMaracay, febrero 2000

Memorias del Primer Congreso Venezolano del Cacao y su IndustriaISBN 980-620-56-1 2000, FUNDACITE Aragua Hecho el Depsito de Ley Depsito Legal lf11320003386X

Fototografas Edicin, programacin, diseo grfico y produccin

Daniel Pea

Telfs.: 014-3478542, 014-4602941, 014-4441526 E-mail: [email protected]

Instituciones organizadoras

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CAMARA

Comit organizadorEduardo Gonzlez Jimnez FUNDACITE Aragua Franklin Guerra FONCACAO Marietta de Bolvar Gobernacin de Aragua Csar Guevara Cedeo APROCACAO Catalina Ramos CONICIT Kai Rosemberg Productor independiente Guillermo Arrieta FONAIAP Juan Comerma PALMAVEN John Kehoe CAPEC

Presentacin

Estamos presentando a ustedes las memorias del I Congreso Venezolano del Cacao y su Industria, evento que surgi como consecuencia del proceso de la Agenda Cacao promovido por el CONICIT desde el ao 96 y en el cual hemos profundizado ese estilo de hacer las cosas que esa Institucin adelant y cuya principal virtud consiste en crear un espacio comn de discusin en el que todos los actores del circuito cacao aportaron su cuota para construir una visin del problema que pueda ser abordada desde mltiples pticas y que garantiza soluciones integrales y de impacto al mediano y largo plazo.

Esperamos que este evento haya servido de ejemplo, por su estilo y por los productos que de l se han obtenido, a otros sectores o circuitos que requieren de polticas integrales para su desarrollo y consolidacin, en el que todos sus actores se comprometan por igual en implementar las acciones necesarias.

Sin mas, los invitamos a compartir con nosotros la cristalizacin de un sueo que estamos seguros contribuir con el rescate del mejor cacao del mundo

Tabla de Contenido

ConferencistasVingerhoets, Jan La economa mundial del cacao: Perspectivas a nivel mundial ........................................................................................................3 Cros, Emile Factores condicionantes de la calidad del cacao ..................................................................................................................................16 Motamayor, J. C.; Risterucci, A.M.; Laurent, V.; Moreno, A.; Lanaud, C. The genetic diversity of Criollo cacao and its consequence in quality breeding .........................................................................33 Lanaud, C.; Risterucci, A. M.; N'goran, J. K. A.; Kebe, I.; Pieretti, I. The cocoa genetic map, a tool to identify molecular markers for accelerating the breeding steps .........................................57 Gonzlez Rosquel, Ventura Germoplasma vegetal: Un bien comn de uso restringido ..............................................................................................................74 Butler, David The Cocoa Research Unit, Trinidad and its relevance to the regional cocoa industry...............................................................92 Pereira, J. L. Perspectivas para el control de las enfermedades del cacao ............................................................................................................93 Capriles de Reyes, Lilian Reacciones de cultivares de cacao a los principales patgenos presentes en Venezuela ....................................................... 110 Lpez Baez, O.; Evans, M. H.; Esponda Galvez, M.; Ortiz Ochoa, M. A.; Hernndez Velasco, B.; Fontanel, A.; Fraire Vazquez, G. Progresos recientes en la propagacin vegetativa............................................................................................................................ 124

PanelistasCartay, Rafael La economa del cacao en Venezuela .................................................................................................................................................. 129 Reyes Capriles, Silvino Fermentacin y secado del cacao como factores condicionantes de la calidad ........................................................................ 147 Goita, William Insectos asociados al cacao: situacin actual de la investigacin .................................................................................................. 148 Girn, Cirilo Las malezas en el cacaotal: Recuento histrico y situacin actual ................................................................................................ 149 Ramos C., Gladys Situacin actual de la investigacin venezolana en germoplasma de cacao ............................................................................. 155 Moreno, Argelio La investigacin venezolana en cacao: Situacin actual del mejoramiento gentico .............................................................. 164 Portillo, Elvis; Segnini, L.; Parra, R Importancia en la calidad y la denominacin de origen en la produccin de cacao en Venezuela .................................... 179 Pinto, Jos Calidad y certificacin del cacao venezolano .................................................................................................................................... 189 Graziani de Farias., Lucia Calidad del cacao ...................................................................................................................................................................................... 198 de Meja, Mara; Alfonzo, Alfredo Denominacin de origen y control de calidad del cacao (Theobroma cacao L.).......................................................................... 200 Battaglini, Carlos La transferencia de tecnologa y productividad en cacao .............................................................................................................. 206 Lira, Jos Experiencias del proyecto de investigacin desarrollo Buen Cacao en la recuperacin agrcola de Cuyagua, Estado Aragua 1994-1997 .............................................................................................................................. 211

PostersGirn, Cirilo; Tortolero, Juan Evaluacin preliminar de lombricompuesto de cacao en el crecimiento de plantas de cacao en vivero ........................................................................................................................................................................................................... 215 Carrasquero A.; Adams M Determinacin de los procesos asociados a la contaminacin con Cadmio en cacao en Ocumare de la Costa, Estado Aragua ......................................................................................................................................................... 220 Ramrez, Ricardo; Izquierdo, Alexis Estudio de las posibles fuentes de Cadmio en el cultivo de cacao en el estado Miranda ...................................................... 232 Jaimez, Ramn; Franco, Wilfredo Aportes de macronutrientes y descomposicin de la materia orgnica en agroecosistemas de cacao (Theobroma cacao) con frutales en la regin de Tucan ......................................................................................................... 234 Moreira, Mercedes Insectos Plaga de granos y productos de cacao (Theobroma cacao L) almacenado en Venezuela ........................................ 242 Subero, Luis J.; Parra, Dercy Especies de Phytophthora que afectan al cacao (Theobroma cacao L.) en la regin de Barlovento, Estado Miranda ................................................................................................................................................................................... 243 Salas, P.; Prez, O. Incidencia de plagas y enfermedades en la pennsula de Paria.................................................................................................... 245 Goita, William Incidencia de insectos plaga sobre diferentes clones de cacao y su relacin con la presencia de hormigas ..................................................................................................................................................................................................... 247 Galavis Jos D. Metodologa prctica para estimacin de cosecha en el cultivo del cacao (Theobroma cacao) ............................................... 251 Izquierdo, Alexis; Gonzlez, Ramn Caracterizacin edafoclimtica de las zonas cacaoteras de los estados Aragua y Miranda.................................................. 253

Leal, Freddy; Aviln, Luis; Valderrama, Emilia Areas potenciales para el desarrollo del cacao en Venezuela ....................................................................................................... 255 Parra G., Pablo Origen del cacao en Venezuela ............................................................................................................................................................. 257 Leal, Freddy; Snchez, Pedro; Valderrama, Emilia El Gnero Theobroma en estado silvestre en Venezuela .................................................................................................................. 262 Leal, Freddy; Serra, Angele; Valderrama, Emilia El Copoas (Theobroma grandiflorum) Sterculiaceae, pariente del cacao .................................................................................... 268 Salazar, Ysolanda; Crescente, Oscar Aprovechamiento de la cscara de cacao en la elaboracin de jabones ..................................................................................... 275 Guevara, Miguel; Acosta, Mercedes; Crescente, Oscar Anlisis de los indicadores qumicos y fsicos de granos de cacao (Theobroma cacao L.) de la Pennsula de Paria (Estado Sucre) fermentados y sometidos a dos procesos de secado ....................................................... 276 Guevara, Miguel; Acosta, Mercedes; Crescente, Oscar; Hurtado, Pura; De Mejia, Mara Evaluacin de la sucesin microbiana y compuestos qumicos involucrados en el proceso de fermentacin de granos de cacao (Theobroma cacao L.) del Estado Sucre Venezuela .............................................................. 278 Gonzlez, Flavio; Ortiz de Bertorelli, Ligia Influencia del punto de cosecha de la mazorca sobre algunas caractersticas de la grasa de dos cultivares de cacao (Theobroma cacao L.) ............................................................................................................................................. 280 Pinto, Jos; Alvarez, C.; Prez, E.; Canchica, H.; Alfaro, M. Comparacin de parmetros fsico qumicos de granos tostados de cacao (Theobroma cacao L.) de dos zonas del Estado Aragua..................................................................................................................................................... 282 Liendo, R.; Carrillo de Padilla, F.; Quintana, A. Caracterizacin de la manteca de cacao de cultivares criollos e hbridos de (Theobroma cacao L.) de la coleccin del banco de germoplasma del FONAIAP...................................................................................................... 290

Alvarez, C.; Pinto, Jos; Prez, E. Caracterizacin fsico qumica de granos (tostados) y muclago de cacao (Theobroma cacao L.) de la regin de Cumboto .................................................................................................................................................................. 301 Chirino, J. C.; Viloria, C.H.; Esparza, D.; Portillo, E.; Arroyo, N.; Chacn, Y. Evaluacin del mtodo de fermentacin en cacao (Theobroma cacao L.) en la zona sur del Lago de Maracaibo ............................................................................................................................................................................................. 311 Graziani de Farias, Lucia; Alvarez, Yolimar; Trujillo de Leal, Amrica. Efecto del tiempo transcurrido entre la cosecha y el desgrane sobre algunas caractersticas del cacao Criollo (Theobroma cacao L.) seleccin Ocumare 61 durante el proceso de fermentacin utilizando el sistema Trinitario.............................................................................................................................................................. 313 Adams, Estela Programa de extensin agrcola del municipio Mario Briceo Iragorry del Estado Aragua................................................ 315 Pachano, Leonardo; Gmez, Orlando; Sobill, Betsy; Rivas, Alberto; Troncoso, Jess Crnicas de una experiencia exitosa en rehabilitacin de los cacaotales sucrenses................................................................. 317 Rodrguez de Sindoni, Nilda Morfologa y efectividad de la injertacin en patrones jvenes de cacao (Theobroma cacao L.) aplicando el mtodo "chip budding" ................................................................................................................................................... 321 Salazar, Doris; Bravo, Jos; Camejo, Cesar; Velsquez, Lelis; Hurtado, Pura Coleccin, caracterizacin y establecimiento de un Banco de Germoplasma Superior de cacao en la Pennsula de Paria. Estado Sucre - Venezuela ........................................................................................................................ 322 Bravo, Jos; Mayz, Saul; Ruiz, Fidel Produccin asexual de cacao (Theobroma cacao L.). Establecimiento de dos jardines clonales de cacao en las localidades de Agua Blanca, Municipio Andrs Eloy Blanco y Guaraunos, Municipio Bentez, Estado Sucre, Venezuela............................................................................................................................................... 324 Snchez, Pedro A.; Tortolero, Juan Caracterizacin y establecimiento de un banco de germoplasma de cacao criollo en el litoral aragueo ..................................................................................................................................................................................................... 326

Navas P. B.; Ascanio C. Propagacin in vitro de cacao (Theobroma cacao L.) por embriognesis somtica.................................................................... 337 Vidal, Ramn; Coelho, Teresa; Navarro, Rafael; Donado, Guillermo; Velzquez, Denny Caracterizacin, seleccin, mantenimiento, evaluacin y difusin del germoplasma de cacao Criollo .......................................................................................................................................................................................................... 338 Prez, O.; Reyes, H. Evaluacin de hbridos biclonales de cacao bajo diferentes condiciones edafoclimticas en Barlovento, Estado Miranda ................................................................................................................................................................. 340 Ramos G.; Vivas J.; Azcar A.; Lacruz C.; Marcano M. Rescate y caracterizacin de una poblacin de cacaos Criollos procedentes de la regin del Guasare, Estado Zulia.............................................................................................................................................................................. 342 Leal, Freddy; Valderrama, Emilia La Coleccin del 45................................................................................................................................................................................... 348 Leal, Freddy; Hernndez, Soraya; Valderrama, Emilia; Trocel, Luz M. Enraizamiento de estacas de cacao ...................................................................................................................................................... 353 Rodrguez, Pedro; Jimnez, Bernardo; Ruz, Fidel; Pachano, Leonardo El Dinero til...Programa de financiamiento para pequeos y medianos productores de cacao del estado Sucre......................................................................................................................................................................................... 361 Romero, Liccia; Monasterio, Maximina El cacao Porcelana, un lujoso componente de la diversidad agroecolgica del sur del Lago de Maracaibo. Interrogantes que rodean su rescate y recuperacin ................................................................................................. 363 Trujillo, L. Valentina; Vidal, Ramn; Bolvar, Angela; Requena, Hctor Evaluacin de niveles de adopcin de tecnologas en el sistema de produccin cacaotero de Cumboto Estado Aragua ........................................................................................................................................................................ 365 Trujillo, L. Valentina; Bolvar, Angela; Oviedo, Nelson; Gmez, Nohelia El Cacao arageo en el contexto nacional e internacional, algunos indicadores.................................................................... 373

Memorias del Primer Congreso Venezolano del Cacao y su Industria

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THE WORLD COCOA ECONOMY: PERSPECTIVES ON A GLOBAL LEVELDr. Jan Vingerhoets, Head of Economics and Statistics Division International Cocoa Organization IntroductionCocoa is very important to the agricultural sectors of a number of producer countries (Cte dIvoire, Ghana, Cameroon, Grenada and the Dominican Republic). In others, including some newly industrialized countries in Latin America and South East Asia (Brazil, Ecuador, Colombia, Malaysia, Indonesia), cocoa is of regional importance, providing a major source of employment in agriculture in certain areas. Before the discovery of oil, cocoa cultivation was very important in Venezuela, when cocoa was a major cash crop for the farmers. And cocoa beans from Venezuela are nowadays still highly regarded for their unique aroma and flavour by manufacturers of quality chocolate throughout the world. It is therefore very encouraging to see the current revival of interest in cocoa in your country, which has culminated in the organization of this conference. For these reasons, I feel honoured by the invitation to address this Conference on the subject of "the world cocoa economy: Perspectives on a global level. And the first perspective on a global level is, of course, Mr.Chairman, the perspective of cooperation in the framework of the International Cocoa Organization. International Cocoa Organization Cocoa is an agricultural commodity, which lends itself most readily to international cooperation. Production of cocoa is concentrated in a few regions of the globe, with the 10 leading producers accounting for over 95% of exports. Although cocoa is consumed more widely, mainly in the middle- and high- income countries of the temperate zones, the top 10 countries represent around 75% of world imports. This has prompted closer cooperation between producer and

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I Congreso Venezolano del Cacao y su Industria

consumer countries, with the objective to reduce fluctuations in prices; to improve the transparency of the world market; to stimulate cocoa development all over the world; and, in general, to work together in all aspects of the world cocoa economy. The first International Cocoa Agreement was concluded in 1972, establishing the International Cocoa Organization (ICCO) to administer it. Since then, succeeding Agreements have been successfully negotiated and at present we are in the fifth Agreement. ICCO will thus be celebrating its 25th anniversary next year, an excellent opportunity to reflect upon past experiences and to look ahead towards challenges in the future. In my presentation, Mr. Chairman, I would like to summarize the key characteristics of the world cocoa market and review some of the economic and policy variables that have influenced trends in cocoa production and consumption since the 1970s. This will be followed by a consideration of the probable evolution of the world cocoa market in the future, which could provide a basis for discussions.

CHARACTERISTICS OF THE WORLD COCOA ECONOMY Bulk and fine or flavour cocoaThe world cocoa market distinguishes between two broad categories of cocoa beans : fine or flavour cocoa beans, and bulk or ordinary cocoa beans. As a generalization, fine or flavour cocoa beans are produced from Criollo or Trinitario cocoa-tree varieties, while bulk cocoa beans come from Forastero trees. Bulk cocoa accounts for over 95% of world production and dominates international trade and world markets. In contrast, the market for fine or flavour cocoa is small, representing only 5% of global production.

Cyclical fluctuationsAnother basic characteristic of the world cocoa market is, Mr. Chairman, that the market is one of the most volatile markets for tropical commodities, exhibiting cyclical fluctuations in prices resulting from changes in stock levels, and this can be said for both bulk and fine or flavour co-

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coa. Historically, cocoa supplies have shown considerable variations. These variations are partly due to the long delay between planting and the harvesting of commercially significant production (three to seven years). This has often been enhanced by the impact on production of vagaries of the weather and the incidence of diseases and pests. In contrast, cocoa consumption is relatively inelastic, especially in the short-term; this means that consumption does not react strongly to changes in production and prices. These characteristics of the cocoa market have resulted in a boom-bust cycle with periods of very high prices followed by periods of very low prices; periods of deficits, followed by periods of oversupply.

TRENDS IN THE WORLD COCOA ECONOMYAfter these few words on the characteristics of the world cocoa market, I come to the important subject of trends in the world cocoa economy since about 1970. Overview Over the past thirty years, the world cocoa market has, as just indicated, gone through a number of cyclical phases, of periods with shortages of supply and with surpluses, and periods with very high prices and with very low prices. Changes have also taken place in the geographical location of production, processing and consumption, in marketing systems and policies affecting the cocoa sector. One can identify three distinct phases of evolution in the world cocoa market, roughly coinciding with the past three decades. The 1970s were characterized by tight supplies and high prices. Cocoa production averaged 1.5 million tonnes and consumption was just below this level, constrained by prices which were at historically high levels, averaging almost US$ 5,000 per tonne in constant (1995/96) terms. And average prices reached their highest level of almost US$ 10,000 per tonne in constant (1995/96) terms, in the 1976/77 cocoa year. Higher prices stimulated production and, combined with government policies aimed at expansion of cocoa cultivation, resulted in a period of sustained increases in cocoa production in the

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1980s. By the end of that decade, cocoa production reached 2.4 million tonnes. Cocoa consumption also increased, responding to higher incomes and lower cocoa prices, but failed to match the very high growth rate in production. This resulted in a build-up of stocks and a steady collapse in cocoa bean prices. By 1990/91 world cocoa bean stocks had increased to a record level of 1.5 million tonnes, and average prices declined to just under US$ 1,400 per tonne in real terms. During the first half of the 1990s, cocoa production remained around 2.4 million tonnes, while consumption continued along a strong upward trend. An upward trend in cocoa production could only be identified since 1995/96, as world production reached a record level of 2.9 million tonnes. Meanwhile, cocoa consumption continued to rise, reaching an all time high of 2.8 million tonnes in the 1996/97 cocoa year. As a result of these developments, supply deficits have characterized the world cocoa market in the 1990s. However, the expected recovery in prices has been disappointing and cocoa bean prices only increased from a low point of US$ 1,300 per tonne five years ago, to US$ 1,500 per tonne on average during the past cocoa year [in constant 1996 terms].

Trends in cocoa productionAfter this brief general overview, I would like to first highlight a few developments in cocoa production, before turning to consumption. World cocoa production was just over 1 million tonnes in 1960 and at present it is approaching the 3 million tonnes mark. This is a very strong increase. But this growth in production was not evenly spread over the world. As a result, Africa is currently the worlds leading cocoa-growing region, producing 65% of world output, with the rest almost equally shared between Asia and the Americas. Cte dIvoire, with over 40% of world production, is the worlds foremost cocoa producer, followed by Ghana and Indonesia, each accounting for about 12% of the world crop.

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One of the important factors in the almost three-fold increase in world cocoa production since 1960, was the introduction of early-bearing and higher-yielding hybrid varieties of cocoa trees. Whereas hybrid trees represented no more than 2% of the total tree-stock in the eight largest producer countries in the early 1970s, this percentage has increased considerably and is now approaching 50% of the cocoa tree stocks in the world. Government policies reinforced the expansion of cocoa cultivation in some countries in the late 1970s and early 1980s. In Brazil and Cte dIvoire, for example, officially-sponsored cocoadevelopment and rehabilitation programmes were responsible for an increase in area under cocoa cultivation, most of which used modern hybrid planting material. Expansion of cocoa production into new areas in Indonesia was also promoted, as a means of economic growth and development in rural areas. Independent and uncoordinated expansion policies pursued by these countries, resulted in a sharp rise in world cocoa supplies, as the newly planted trees reached maturity by the 1980s. The growth in world demand for cocoa failed to take up these additional supplies, resulting in a period of structural surpluses and declining prices. Perversely, individual countries could only maintain export revenues from cocoa through higher production levels, as the potential for additional gains in productivity and reductions in costs was limited. However, the global implications of these policies were a further increase in the level of world production and thus further declines in prices. One of the factors, Mr. Chairman, which has a direct impact on the rate of increase in production, and which can readily be influenced by Governments, are the prices received by the cocoa farmers. Broadly speaking, there are two types of farmer price systems. A free-market system has since long been prevalent in the cocoa producing regions of the Americas and Asia, while a marketing board system, with price heavily influenced by Governments, was more common in Africa. Farm gate cocoa-bean prices in Brazil, Indonesia and Malaysia, for example, followed the trend in world prices, generally maintaining their share at between 60% and 80% in most years. Over-

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all, producer prices in these countries peaked in the mid-1970s and thereafter declined in the 1980s and early 1990s, following the trends in the international price of cocoa beans. As noted earlier, lower prices in Malaysia resulted in abandonment of cocoa farms, especially in the estate sector, in favour of more lucrative crops such as oil palm. In West Africa, on the other hand, farmgate prices followed a more stable trend compared to international market prices, increasing only gradually during the 1970s and 1980s, before declining during the early 1990s. However, overvalued exchange rates and high domestic inflation rates meant that, in real terms, producer prices generally declined throughout the period. The farmers often received less than 50% of the world price, as increases in marketing costs and taxation took a larger proportion of the revenues. In the meantime, Mr. Chairman, the situation has been changing in Africa. Structural economic adjustment programmes have included reforms in the agricultural sector. Liberalization and privatization of the marketing systems for cocoa, often required by international lending institutions, have resulted in higher prices for farmers. Unfortunately, hurried reforms have often resulted in a deterioration in the quality of exported cocoa; in problems with financing of the trade; in a lack of market information for the operators in the sector; and, last but not least, in the emergence of several types of new risks in the cocoa trade. To remedy these problems, ICCO has developed a pilot project which will, starting next year, be implemented in Nigeria, Cameroon and Cte-dIvoire. This is a very interesting and innovative project that also would seem to be relevant for Latin America and the Caribbean.

ConsumptionTurning now to the trends in consumption, Mr. Chairman, I should first like to observe that the processing of cocoa, the grinding of the beans, is still mainly concentrated near centres of consumption in the cocoa importing countries. The Netherlands, the United States, Germany and the United Kingdom are the top four cocoa-processing countries, followed by Brazil in fifth place. The share of origin grindings has only increased marginally during the past decades, but recent investments in cocoa-processing capacity at origin, suggest that grindings in producing

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countries will increase more rapidly in the years to come. Cocoa producing countries, including Cote dIvoire, Ghana and Nigeria, have recently embarked on a policy of processing a larger proportion of their crop domestically, in order to export products with a higher value added. During the 1990s there has also been an increasing concentration of ownership of the worlds cocoa-processing industry in cocoa importing countries. There are now just four large, independent cocoa processing and five major chocolate manufacturing companies, which account for 70% of global processing capacity. This should enable them to reduce costs through economies of scale. Moreover, this gives the nine multinational companies considerable influence in terms of the supply and demand of cocoa beans and cocoa products. These recent developments - increasing grindings capacity in origin countries, and concentration in the industry - could lead to a significant increase in total grindings capacity at the global level, resulting in further rationalization in the industry in the near future. With respect to final consumption of cocoa, I should like to remind you that the United States (22%) still is by far the worlds largest cocoa consuming country, followed - at a distance - by Germany (9%), the United Kingdom (8%), France (7%), the Russian Federation (6%) and Japan (5.5%). Consumption of cocoa in Brazil has witnessed remarkable growth recently and it is now the seventh largest cocoa consumer in the world, accounting for just under 5% of total final consumption. A recent and important development in cocoa and chocolate consumption, Mr. Chairman, has been the continuing and considerable increase in consumption in the Far East, in spite of the lack of tradition in cocoa and chocolate consumption. The surge in demand for cocoa and chocolate in Japan in the past two years is a highly remarkable development. This rapid increase in consumption - in Japan called the cocoa boom - directly originated from a project on generic promotion of consumption, which was initiated by ICCO and implemented by the Cocoa Association of Japan. Among the cocoa-producing countries, the Latin American region has witnessed a remarkable growth in cocoa consumption during the 1990s. In particular, per caput consumption in Brazil

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has doubled over the past 7 years. Since 1993, both total and per caput chocolate consumption has increased by over 10% per annum, following promotional activities by the industry. These positive developments indicate that there is considerable scope for further expansion in cocoa consumption in new markets. Just imagine the enormous potential of the Chinese market, where consumption has been growing very rapidly in recent years!

Stocks and pricesAfter this brief overview of trends in Production and Consumption, I come to the result of the balance (or imbalance) between the two: Stocks and Prices. The 1970s were, as noted earlier, characterized by supply shortages, and stocks fell to their lowest levels in 1976/77 [just over 2 months of grindings]. As a result, prices went through the roof and reached, in the mid-seventies, a level of almost US$ 10,000 [in real, 1996, terms]. In the 1980s, the opposite happened. A period of structural surpluses resulted in a steady build up of world cocoa-bean stocks to a record high of over 1.5 million tonnes, equivalent to almost eight months of global demand. As a consequence, cocoa prices dropped dramatically, falling to an all-time low in the early 1990s. The current decade is, as said earlier, dominated by supply deficits, but prices have not reacted much to these deficits. Stocks are still quite high (around 1.2 million tonnes) and manufacturers nowadays keep much lower stocks than they used to do, where improvements in transport, communications and information technology (computers) play a major role. These cyclical longer-term movements of prices (ups and downs; boom and bust) are the most negative characteristic of the world cocoa market. For this reason, the current International Cocoa Agreement tackles this major problem head-on, in particular, through the activities of its Production and Consumption Committee. The latter is there to stimulate consumption, which, for example, was successfully done in the project in Japan. The Production Committee, on the other hand, is responsible for a Production Management Plan at the global level, implemented by programmes in individual member countries. The clear objective of this plan is to reduce the

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ups and downs in cocoa prices, as I described earlier. This is not easy; this is ambitious. But I am glad to report that the drawing up and implementation of the Plan is now, after a few years of finding the right approach, really taking shape.

PROSPECTS FOR THE WORLD COCOA ECONOMYWith this I finish my story of the trends in the past, Mr. Chairman, and turn to the prospects in the world cocoa economy. My views on these prospects are based on a model of the world cocoa market, developed and used by the Secretariat of ICCO. Of course, one has to be careful with a model, because it definitely has its limitations. On the other hand, the model is the best available rational guide on which to base ones views. The Secretariats analysis indicates that the world cocoa market in the coming six years will remain in the present phase of supply deficits. Both production and consumption will continue to grow, but at a slower pace than during the past decade, with annual increases in demand tending to exceed supply, but prices, in historical perspective, still remaining at relatively modest levels in real terms. World production is expected to continue to expand over the six-year forecasting period through to the cocoa year 2002/03, and to exceed 3 million tonnes at the end of the period. World consumption is also expected to attain over 3 million tonnes by the cocoa year 2002/03. Over the period as a whole, supply deficits are expected to predominate, although occasional annual surpluses may also appear. Accordingly, the level of cocoa stocks is expected to decline to just below 1.1 million tonnes, equivalent to just over four months of demand at the end of the forecast period. Prices of cocoa are expected to continue their recent rise in response. Nevertheless, the rate of recovery is expected to be moderate, because of the large amount of excess stock currently overhanging the market. The prospects are that world cocoa prices will be around 25 per cent higher in real terms by the year 2002/03.

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The relatively pessimistic outlook for production growth, which is implicit in ICCO forecast, results from the assumption that the rather depressed prices will constrain expansion of cocoa cultivation to new areas. However, production could be increased by policy measures aimed at raising productivity, through, for example, rehabilitation programmes to replace older treestocks. Higher standards of husbandry and better disease management and pest-control systems, may also enable farmers to limit the damage caused by pests and diseases. Moreover, scientific research may provide more effective and environmentally sound solutions to these losses and contribute to the future assurance of cocoa supplies. ICCO is working closely with scientists on these matters and has currently two projects under implementation in the area of scientific research. A project on The use of molecular biology techniques in a search for varieties resistant to witches broom disease of cocoa (involving Brazil, Ecuador and possibly Peru), and one on Conservation and utilization of cocoa germplasm (involving Brazil, Ecuador, Trinidad and Tobago and Venezuela from the Latin American and Caribbean region). Other projects related to cocoa pests and diseases are in the pipeline. Success in the fight against pests and diseases could lead to substantial increases in productivity and new supplies to the market. As regards the prospects for cocoa consumption, Mr. Chairman, our econometric model also seems to be rather pessimistic. It has often been observed that markets in the traditional cocoaconsuming countries would seem to be saturated. But the consumers have surprised us time and again by consumption reaching higher and higher levels. And our model is, of course, not capable of predicting with any accuracy future consumption in new markets: in the Far East (including China), in Latin America and in Eastern Europe, including the former Soviet Union. Personally, I believe that one can be optimistic with respect to consumption growth in these new and emerging cocoa and chocolate markets. But, Mr. Chairman, one should not just be optimistic, sit-back and wait and see what is going to happen. Promotion of consumption is in order, and ICCO wants to be increasingly active in this field. We are very much encouraged by the success of the generic promotion campaign in

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Japan. The consumption of cocoa and chocolate has seen a dramatic increase in Japan, as consumers were made aware of some of the nutritional and health-related beneficial effects of cocoa through promotional campaigns. This project may encourage other countries to adopt similar techniques to boost cocoa consumption. ICCO is looking for partners in such campaigns, and we have already started preparations for a cocoa and chocolate promotion campaign in the Russian Federation.

Fine or flavour cocoa marketThe above analysis has dealt with developments in the market for cocoa in general, and bulk cocoa in particular, while here in Venezuela, you are, of course, specially interested in the prospects for the fine or flavour cocoa market. It should first be noted that there is no single criterion which could be adopted as a basis for determining whether or not cocoa of a given origin is to be classified as fine or flavour cocoa. Apart from the genetic origin of the planting material, morphological characteristics of the plant and agronomic characteristics, other factors determine the flavour, chemical and colour characteristics of the cocoa beans and nibs produced. An ICCO project, initiated by Ecuador and involving Trinidad and Tobago, Venezuela and Papua New Guinea is at present in an advanced stage of preparation, to develop the capacity to differentiate adequately and objectively between fine and bulk cocoa, thus improving the marketing of fine or flavour cocoa. The share of fine or flavour cocoa in the total world production of cocoa beans has fallen dramatically, from between 40% and 50% at the beginning of this century to just under 5% (120 thousand tonnes) per annum now. The Latin American and Caribbean region supplies 80% of the world fine or flavour cocoa, while Asia produces most of the rest (18%) and Africa very little (2%). The decline in the consumption of fine or flavour cocoa has been brought about by a general shift in consumer demand away from solid to filled products, containing other ingredients endowed with stronger flavours (such as nuts, fruits, creams, etc.), thus reducing the dependence

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on the aromatic and flavour characteristics of fine or flavour cocoa. Nowadays, chocolate manufacturers use fine or flavour cocoa to make premium dark chocolate and high-quality couvertures where the special qualities of such cocoas really stand out. A number of factors continue to limit the growth in the market for fine or flavour cocoa. Production of fine or flavour cocoa has remained stagnant over the past three decades: the area under cultivation has remained unchanged and yields remain low compared with hybrid varieties. Variations in premiums and quality have not encouraged a greater use of this type of cocoa by the chocolate industry. And the concentration in the cocoa-processing industry has favoured the use of large processing plants. This has made handling of relatively small quantities difficult and expensive. And, finally, the observed trend in the consumption of filled chocolate products rather than solid chocolate, also reduced the demand for fine or flavour cocoa. This leads me, Mr. Chairman, to my concluding remarks.

Concluding remarksWhen embarking on a policy of expansion, the cocoa industry in Venezuela should examine the characteristics and prospects of the market for its particular type of fine or flavour cocoa. On the supply side, a number of fine or flavour cocoa producing countries are likely to increase production through programmes of re-habilitation and expansion of the areas under cocoa cultivation. Increased supplies and competition could result in loss of price premiums. On the other hand, the revival of demand for dark chocolate and high quality couvertures by manufacturers of premium products, suggests that there is a real scope for further increases in demand. The strategy for cocoa farming in Venezuela should be to breed higher yielding varieties with good levels of nib yield and butter, while maintaining the special flavour characteristics attractive to manufacturers. This should enable the country to continue supplying the niche market for fine or flavour cocoa and to compete with bulk cocoa. The reputation of Venezuelas cocoa and hence the price premiums received, could be further improved by the establishment of an internationally recognized quality certification system that guarantees uniform quality of ex-

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ported cocoa. On the marketing side, cocoa producers should consider long term contracts, incorporating a premium, with selected companies. Mr. Chairman, the future for the world cocoa producers is bright. Demand for cocoa is expected to exceed supply over the next six years; prices should recover further and remain at levels above those of the past ten years. Over the longer term, successful promotional campaigns may result in an even stronger growth in cocoa consumption, while completion of scientific research projects should result in the discovery of new planting material and agronomic practices, raising productivity and hence the profitability of growing cocoa. This will be to the advantage of both producers and consumers alike. London, November 1997

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Factores condicionantes de la calidad del cacaoEmile Cros, CIRAD-CP, Maison de la Technologie, BP 5035, 34032 Montpellier Cedex 1, Francia ResumenProporcionar un cacao con fuerte potencial aromtico y/o que presenta caractersticas aromticas especiales es hoy en da, una oportunidad brindada a los pases productores para diversificar o reorientar sus producciones a fin de consolidar y/o asegurar nuevos mercados. La seleccin y la divulgacin de semejantes cacaos as como la puesta a punto de tecnologas adaptadas es uno de los pasos que permiten enfrentar esta nueva situacin. Por intuicin, resulta evidente que la calidad aromtica de un chocolate esta relacionada con el origen de las almendras, con la fermentacin y secado y con el tostado. No obstante, hasta ahora, se sigue sin conocer bien la influencia respectiva de cada uno de estos factores. Esta ponencia intenta analizar trabajos que conciernen el desarrollo del aroma cacao y su caracterizacin, para proponer un esquema general de su formacin. Globalmente, el aroma cacao est constituido por una fraccin constitutiva (presente en la almendra fresca), de una fraccin desarrollada durante la fermentacin y secado y por ultimo por una fraccin formada durante el tostado. La fermentacin puede considerarse como la etapa clave de la formacin del aroma. En efecto, esta operacin lleva no solamente a una profunda modificacin del contenido de compuestos implicados en el desarrollo del aroma de origen trmico, pero tambin en la formacin de una fraccin aromtica cualitativa y cuantitativamente muy importante. No se forman sino pocos nuevos compuestos en el tostado. Un gran nmero de compuestos son comunes a todos los cacaos, sin embargo numerosos compuestos son especficos a genotipos determinados. El efecto de las condiciones edafoclimticas, aunque poco estudiado, parece ser bajo al compararlo con la influencia del genotipo. En todo

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caso, los distintos tratamientos del cacao slo permiten la manifestacin del potencial aromtico de la almendra, el cual se halla dependiente del genotipo.

IntroduccinEstos ltimos aos, y especialmente en Europa, la demanda industrial de cacao se ha desplazado parcialmente hacia lotes de calidad aromtica superior. Proporcionar un cacao con fuerte potencial aromtico y/o que presenta caractersticas aromticas especiales es por lo tanto, hoy en da, una oportunidad brindada a los pases productores para diversificar o reorientar sus producciones para consolidar y/o asegurar nuevos mercados. La seleccin y la divulgacin de semejantes cacaos as como la puesta a punto de tecnologas adaptadas es uno de los pasos que permiten enfrentar esta nueva situacin. Si es claro que la calidad aromtica de un chocolate est relacionada, entre otros, con el origen de los granos, con el tratamiento post-cosecha (fermentacin y secado) y con el tostado, resulta que, hasta la fecha, no se conoce bien la influencia respectiva de cada uno de estos factores. Sin volver a recordar aqu con todos los detalles los numerosos trabajos referentes al aroma del cacao (Ziegleder y Biehl 1988, Hoskin y Dimick 1988, Baigre 1994), analizaremos la situacin de los que se relacionan con su desarrollo y su caracterizacin, para proponer un esquema general de su formacin. El conjunto de los datos ilustra la complejidad de las reacciones puestas en juego durante las etapas sucesivas de preparacin del cacao, y evidencia el relevante papel del genotipo y de los tratamientos de fermentacin/secado. Esta ponencia vuelve a recordar las directrices del captulo Formacin del aroma y El tostado de la obra CACAO Y CHOCOLATE - Produccin y caractersticas que se debera de publicar (Lavoisiser) a finales de 1997.

1. - Aroma CacaoEn la fecha, se identificaron unos 500 compuestos voltiles, distribuidos en 17 clases qumicas

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distintas, en el cacao tostado. Van Straten (1983) y Flament (1991) realizaron buenas sntesis bibliogrficas referentes a la caracterizacin de estos compuestos. Las pirazinas son los compuestos predominantes (20% del nmero de compuesto identificados en el aroma) vienen despus los esteres (13%), los hidrocarburos (13%) y los cidos (11%). Estos trabajos son esencialmente descriptivos y no permiten ni aclarar el origen de los compuestos voltiles ni conocer su impacto sobre el aroma. Si no fue posible evidenciar con certeza una o varias substancias, caractersticas del aroma cacao (Dimick et Hoskin 1981), ciertas fracciones globales presentan una nota con cacao (Van Praag et al. 1968, Mohr 1974, Beauhaire, 1978).

2. - Factores del Desarrollo del AromaPor lo general, se admite an demasiadas veces que el aroma cacao est relacionado principalmente con el tostado. Ahora bien, recientes trabajos (Ziegleder 1991, Baigrie 1994, Jeanjean et al. 1994, Jeanjean 1995 y Chanliau 1995) mostraron que la fraccin aromtica del cacao comercial desempea un papel determinante en la calidad del aroma final.

2.1. - VariedadLa dificultad en estimar la influencia de la variedad sobre el aroma final deriva del hecho de que no se tratan prcticamente nunca los cacaos (fermentacin, secado y tostado) en condiciones idnticas. Recientemente, la aplicacin de un mismo protocolo de preparacin de los cacaos permiti evidenciar destacables diferencias aromticas entre las variedades Forastero, Trinitario y las variedades hbridas (Clapperton 1993). La intensidad aromtica de los Forastero sera ms importante, estos ltimos seran generalmente menos amargos y menos astringentes que las variedades Trinitario. En lo que se refiere a la composicin qumica del cacao comercial, se determinaron los contenidos de precursores de la reaccin de Maillard (aminocidos libres y azucares reductores) en

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unos cacaos de variedades y sobre todo de orgenes diferentes (Rohan 1964, Rohan y Stewart 1965, Maravalhas 1972, Keeney 1972, Reineccius et al. 1972, Jeanjean 1995). No obstante, las diferencias de composicin observadas no pueden atribuirse al slo efecto del genotipo pero proviene de la influencia combinada de la variedad y de los tratamientos post-cosecha. Los contenidos de metilxantinas dependen del genotipo y del nivel de maduracin de los frutos (Timbie 1977, Bastide 1987). Varan fuertemente (Timbie 1977), por ejemplo del 0,6% al 2,3% segn Paiva y Janick (1983), son relativamente constantes segn Chevalley (1992). Cualquiera que sea este contenido, parece que la relacin teobromina / cafena est relacionada con el genotipo. Muy recientemente Jeanjean (1995) estudi la composicin (voltil y no voltil) de 9 clones e hbridos no fermentados y fermentados (Catongo, DR1, UF676, IFC5, UPA402, SCA6, UPA409xPOR, SCA6xICS1, SCA6xIFC2) que provenan de Costa de Marfil. Por ltimo, Jeanjean (1995) y Chanliau (1995) caracterizaron respectivamente la evolucin de la calidad aromtica de un cacao Snchez (Repblica Dominicana) y la de un cacao Trinitario (Madagascar) durante el tratamiento post-cosecha.

2.2 - Madurez del frutoLos granos procedentes de frutos inmaduros fermentan muy difcilmente. Despus de tratamiento, estos granos muchas veces son pizarrosos o son mohosos (MUSA y SAID 1988).

2.3 - Tratamiento post-cosecha 2.3.1. El grano frescoQue sepamos, el primer trabajo de identificacin de la fraccin voltil del grano fresco (origen del cacao no indicado) fue llevado a cabo por GILL et al. (1985). Segn estos autores, los constituyentes mayores son el estireno (68,8% - P/P de la fraccin voltil) y el dimetilformamida (8,5% P/P) acompaados de una baja cantidad de alcoholes, de aldehdos y de cetonas. Jeanjean (1995) mostr que los contenidos de precursores de Maillard de 9 clones e hbridos son poco diferentes. El grano fresco no contiene prcticamente azucares reductores pero del 1 al 1,2%

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de sacarosa, los contenidos de aminocidos libres (AAL) son del orden del 0,2% (pero 0,4% en un lote de Trinitario de Madagascar, Chanliau 1995). Los compuestos fenlicos son principalmente constituidos de flavan-3-oles (epicatequina y procianidinas B2, C1 y B5) y sus contenidos son variables segn el origen de los cacaos. Los contenidos de teobromina son del orden del 1% mientras que los de cafena alcanzan el 0,3%. Segn el genotipo o el origen de las muestras, la composicin en compuestos voltiles de los 9 clones e hbridos presenta importantes diferencias. Desde el punto de vista global, los alcoholes y los esteres son los compuestos mayoritariamente representados (como promedio el 57% y el 23% respectivamente). A la inversa del trabajo de Gill et al. (1985), ninguna presencia de estireno fue detectada en estas muestras, los nicos hidrocarburos identificados son el metilo- y el propilbenceno (Madagascar), el 1,4- dimetilbenceno (Snchez), el mirceno y uno de sus ismeros (en 3 clones). Los compuestos comunes a estos cacaos son 4 alcoholes (2-metilpropanol, 2-metilbutanol, 3metilbutanol, feniletanol), 2 derivados con carbonilo (3-metilbutanal, acetofenona) y 2 esteres (acetato de etilo, acetato de 2-metilpropan-1-ilo).

2.3.2. Fermentacin y secadoBien se sabe que la fermentacin incluye dos fenmenos distintos pero no independientes: Una fermentacin microbiana de la pulpa que contribuye a eliminar la pulpa mucilaginosa presente alrededor de los granos. Un conjunto de reacciones bioqumicas internas a las almendras (Lpez y Quesnel 1971, Ziegleder 1982), que llevan entre otras cosas a una profunda modificacin de la composicin fenlica (Villeneuve et al.1989) y a la formacin de los precursores de aroma que se consumirn en el tostado (Seiki 1973, Reineccius et al. 1972, Voigt y Biehl 1995). La formacin de una fraccin voltil (Gill et al. 1985, Ziegleder 1991).

El anlisis del cacao fermento siendo hasta ahora por motivos tcnicos, realizado en granos seca-

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2112 10 8 3 6 2 4 2 0 0 1 2 3 4 Das 5 6 7 8 1 0 !"#Sacarosa !"#Azcares reducto5 4

dos, las operaciones fermentacin y secado se examinarn por lo tanto conjuntamente sabiendo que siguen siendo difciles de determinar sus influencias respectivas.

2.3.2.1. Compuestos no voltiles (Fig. 1) Azcares reductoresEl contenido de azucares reductores, fructosa y glucosa, no representa despus de fermentacin ms que aproximadamente el 25% del contenido inicial de sacarosa, el contenido de fructosa (0,2%-0,4%) siendo ntidamente superior a aquel de la glucosa (0,07%-0,1%). Los contenidos de fructosa y glucosa son bajos pero equivalentes (0,02%-0,04%) para granos poco o no fermentados (Reineccius et al. 1972). Generalmente, el contenido mximo de azucares reductores se alcanza al 4 da de fermentacin, permanece constante y luego disminuye levemente al terminarse la fermentacin (Bracco et al. 1969). La cintica de evolucin de estos compuestos indica ms precisamente que la sacarosa disminuye muy rpidamente hasta el 4 da de fermentacin y que entre 3 y 5 das de fermentacin, perodo durante el cual la acidez del medio es importante, son mximos los contenidos de precursores (Jeanjean 1995). Sin que se hayan demostrado estos mecanismos an, resulta verosmil que los azucares reductores sean formados por la hidrlisis de los poliholosidos y de la sacarosa (Ziegleder y Biehl 1988).

8 7 6 5 4 3Aminocidos libres

2 1 0 0 1 2 3 4 Das 5 6 7 8

50 40 30 20

!"#Epicatequina !"#Procianidina B2

cidos aminos libresSe triplica globalmente el contenido de cidos aminos libres (AAL), este aumento se debe especialmente a aquel de los AAL hidrfobos (5 a 10 veces). La cuadrilla de Biehl (Biehl et al. 1993, Voigt et al. 1994) demostr que las protenas de reserva se hidrolizan mediante proteasas y producen la formacin de ms de 80 oligopptidos y AAL diferentes. La naturaleza de estos compuestos depende del pH de la reaccin:10 0 0 1 2 3 4 Das 5 6 7 8

Figura 1. Evolucin de algunos compuestos no voltiles del cacao "Snchez" durante la fermentacin (!, !) y el tostado (", ") (Jeanjean 1995).

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Las protenas son en primer lugar hidrolizadas por una endopeptidasa asprtica (pH ptimo 3,5) y producen la formacin de oligopptidas hidrfobas que no son precursores del aroma,

Estos ltimos, bajo la accin de un carboxipeptidasa (pH optimo 5,4-5,8) producen la formacin de oligopptidas hidrfilas y de AAL hidrfobos (alanina, valina, leucina, fenilalanina...). Esta ltima fraccin (pptidas y AAL) calentada en presencia de glucosa produce la formacin de un aroma con cacao.

Compuestos fenlicosLa fraccin polifenlica (Villeneuve et al.1989, Porter et al. 1991, Clapperton et al. 1992) de los granos es esencialmente compuesta de flavan-3-oles (epicatequina y procianidinas B2, C1 et B5) y, con contenidos mucho ms bajos, de antocianos, de flavonoles y de derivados hidroxicinmicos (Bastide 1987). Las procianidinas son taninos condensados y contribuyen a la astringencia del cacao. Durante la fermentacin, se asiste a una fuerte disminucin del contenido de fenoles totales del orden del 70 al 80%. Las procianidinas disminuyen globalmente del 90% en ocho das y sus evoluciones son comparables a las logradas por Villeneuve et al. (1989). Esta disminucin se debe a fenmenos de difusin, de curtido y de polimerizacin oxidativa, ocasiona una reduccin de la astringencia.

PurinasLa difusin de las purinas (teobromina, cafena) hacia fuera de las almendras, produce una disminucin de aproximadamente el 20% (Seiki 1973) al 30% (Jeanjean 1995) del contenido de estos compuestos durante los tratamientos de fermentacin/secado. Debido a esto se produce una reduccin de la amargura de los granos.

2.3.2.2. Compuestos voltilesEl tratamiento de fermentacin y secado lleva al desarrollo de una fraccin voltil (GILL et al.

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1985) en la cual los alcoholes y los esteres constituyen los dos principales grupos de compuestos, entre ellos el feniletanol, el 3-metilbutanol y sus acetatos son los constituyentes mayores. La presencia de alcoholes, de esteres y de tetrametilpirazina indica que una parte de este "aroma de fermentacin" es verosmilmente de origen microbiolgico (Kosuge et al. 1962, Zak et al. 1972, Adamek et al. 1992). Anlisis ms profundizados de la fraccin voltil de granos fermentados muestran que sta se halla constituida globalmente por dos tipos de compuestos (Ziegleder 1991): Los anlogos a compuestos de origen trmico; es el caso, por ejemplo, de los aldehdos de Strecker clsicos del cacao (2-metilpropanal, 3-metilbutanal, fenilacetaldehido), pero tambin de los aldehdos procedentes de las reacciones de aldocondensacin tales como el fenil-2-but-2-en-al, el metilo-5-fenil-2-hex-2-en-al (Ziegleder 1983, Mermet 1989). Los que no parecen provenir ms que de la fermentacin (Gill et al. 1985).

JEANJEAN (1995) caracteriz 24 compuestos comunes que incluyen los 8 comunes del grano fresco (cuadro 3) y 29 compuestos "especiales" en la fraccin voltil de los clones e hbridos fermentados secados. sta se halla esencialmente constituida de alcoholes, de cidos, de esteres y de aldehdos. Acorde al tipo de cacao, se caracterizaron entre 15 y 30 compuestos nuevos que aparecen en la fermentacin. La cintica de evolucin de los compuestos comunes durante la fermentacin es de 3 tipos: Algunos compuestos presentes antes de la fermentacin (por ejemplo: 2-metilpropan-1ol, acetato de 2-metilpropan-1-ilo) ven su contenido permanecer constante o disminuir, Otros, tales como los acetatos de alcoholes sencillos siguen una curva en campana cuyo mximo se sita hacia el 3er o 4 da de fermentacin Por ltimo, los contenidos de aldehdos, cetonas y tetrametilpirazina aumentan regularmente durante la fermentacin. Se lograron resultados anlogos con un lote de cacao Trinitario de Madagascar (fig. 2). El grano

243 2.5 2 1.5 1 0.5 0Alcoholes y cetoalcoholes (Y2) Aldehidos y cetonas (Y1) Acidos (Y1) Esteres (Y1) Pirazinas (Y1)

I Congreso Venezolano del Cacao y su Industria3 2.5 2 1.5 1 0.5 0

no fermentado y secado posee una fraccin voltil en la cual se caracterizaron 36 compuestos, esencialmente alcoholes y esteres. Durante el tratamiento de fermentacin/secado numerosos compuestos nuevos aparecen de los cuales se identificaron 23. Se trata esencialmente de esteres (acetato de heptan-2-ilo, fenilacetato de etilo, 3-fenilprop-2-en-ato de etilo...), de derivados con carbonilo (fenilbut-2-en-al, 4fenilcicloheptanona...), de pirazinas (2,3-dimetilpirazina, la trimetilpirazina, 3-etil-2,5dimetilpirazina, 3,5-dietil-2-metilpirazina...) y de cidos (cido hexanoico, 4-metilpentanoico...). El cido actico es el compuesto que predomina ampliamente esta fraccin voltil. Con excepcin de la clase de las pirazinas cuyos contenidos aumentan en particular al terminarse la fermentacin, las dems clases de compuestos evolucionan acorde a una cintica en campana con contenidos mximos a los 4 das de fermentacin. Existen en la literatura numerosos ejemplos de formacin de estos compuestos por va microbiolgica (Berger 1995) ltimamente, Romanczyk et al. (1995) caracterizaron la formacin de metilo, 2,5-dimetil, trimetil y tetrametilpirazina y de 2-acetilo-1-pirrolina en cultivos, sobre gel de Agar, de cepas de Bacillus cereus aisladas de cajas de fermentacin de cacao. No obstante, otros compuestos tales como los aldehdos (por ejemplo el 3-metilbutanal o el fenilacetaldehido) son tambin susceptibles de provenir ya sea de reacciones de degradacin trmica de los aminocidos libres correspondientes, ya sea de reacciones de oxidacin de los alcoholes correspondientes. Por lo tanto, aparte de los compuestos presentes inicialmente en el grano fresco secado cuyo contenido no aumenta en la fermentacin, que se pueden entonces considerar como constitutivos del grano, el origen de numerosos otros compuestos voltiles sigue siendo hipottico: Formacin exgena y migracin en la almendra (metabolitas producidas por los microorganismos y productos de degradacin de estas metabolitas),

Figura 2. Evolucin de la fraccin voltil durante la fermentacin de un cacao Trinitario de Madagascar.

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Formacin endgena por va bioqumica (metabolismo interno) o qumico (productos de degradacin trmica o de oxidacin).

Durante el secado, la composicin qumica sigue evolucionando, por ejemplo: Reduccin del contenido de cido actico por evaporacin, Oxidacin de los polifenoles (Forsyth y Quesnel 1963), Sntesis de aldehdos verosmilmente por reacciones de tipo Strecker (Ziegleder 1982).

Aromas indeseables ("Off-flavors")La sobre fermentacin lleva a la formacin de compuestos voltiles que perjudican una buena calidad aromtica. stos (amoniaco, cidos orgnicos de cadenas cortas, aminos bigenos) proceden generalmente de la degradacin de cidos aminos (Biehl 1986).

4. - TostadoEl desarrollo del aroma cacao de origen trmico es un fenmeno complejo (Cros y Jeanjean 1997) que depende de los parmetros de tostadura pero tambin de la composicin qumica del grano (Jeanjean 1995). Cualquiera que sea la tcnica del tostado utilizada, los precursores de aroma desarrollados durante la fermentacin y el secado participan en la formacin del aroma cacao tostado (Cros et al. 1993) va la reaccin de Maillard, la caramelizacin de los azucares, la degradacin de las protenas y la sntesis de compuestos azufrados (reacciones menores). El tostado es el toque final del desarrollo del aroma, las operaciones ulteriores de la fabricacin del chocolate no conducen ms que a una eliminacin de una parte de la fraccin voltil. Lleva no solamente a la formacin de compuestos nuevos pero tambin al aumento del contenido de compuestos presentes en el grano de cacao comercial.

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4.1. Compuestos no voltilesEl consumo de los precursores es bien evidentemente funcin del nivel de fermentacin del cacao. En el caso del cacao no fermentado, la tostadura produce un consumo de los azcares reductores de aproximadamente el 50%, un consumo de sacarosa muy variable segn los cacaos y un consumo de AAL del 10 al 30%. El tostado del cacao bien fermentado lleva en cambio a un consumo prcticamente total de los azucares reductores y del 30 al 40% de los AAL. Para un mismo grado de tostado, las cantidades mximas de precursores consumidas corresponden a cacaos fermentados 3 a 4 das en lo que concierne los azucares reductores, y 4 a 5 das en lo que concierne los AAL (Fig. 1) Este perodo de 3 a 5 das de fermentacin es tambin aquel durante el cual los compuestos fenlicos se deterioran. Las metilxantinas se hallan poco afectadas por la tostadura.

4.2. Compuestos voltilesEl examen individual de cada cacao muestra que la tostadura lleva a la formacin de numerosos compuestos voltiles nuevos. No obstante, los compuestos comunes a los clones e hbridos cuyo contenido incrementa en la tostadura son relativamente poco numerosos. Algunos de ellos son presentes ya en el grano fermentado, los dems, y especialmente dos pirroles y cinco pirazinas no se forman ms que en la tostadura. Estos ltimos son por lo tanto de origen nicamente trmico. La comparacin de las fracciones voltiles comunes del cacao no fermentado/tostado y del cacao fermentado/tostado muestra que 6 compuestos son directamente relacionados con la fermentacin, de ellos, cuatro no se forman ms que en la tostadura de cacao fermentado (3hidroxipentan-2-ona, diacetato de butan-2,3-diilo, 3-etilo-2,5-dimetilpirazina, dimetilsulfuro). Como lo haba sealado ya Beauhaire (1978) una parte de la fraccin voltil del cacao comercial

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no evoluciona en la tostadura. Los resultados logrados con cacao "Snchez" indican que sta es principalmente constituida de alcoholes y esteres. Adems, la mayora de los hidrocarburos disminuyen durante este tratamiento. Los compuestos de esta fraccin pueden por lo tanto considerarse como de origen no trmico.

4.3. ConclusinEl conjunto de los resultados anteriores permite realizar un primer enfoque global de la formacin del aroma cacao con arreglo al tratamiento de fermentacin/secado y de la tostadura. El grano fresco secado posee un aroma de constitucin cuantitativamente poco importante, principalmente constituido de esteres y de alcoholes. Algunos de estos compuestos (C1) no evolucionan durante la fermentacin mientras que los dems se desarrollan (c2-->C2). El aroma de origen "de fermentacin" se halla por lo tanto constituido por estos compuestos C2 a los cuales se agregan nuevos compuestos oriundos de la fermentacin y del secado. Asimismo, este aroma "de fermentacin" contiene 2 clases de compuestos diferentes: los que no evolucionan en el tostado (F1) y aquellos cuyo contenido incrementa (f2 -->F2). Por ltimo, nuevos compuestos aparecen nicamente en la tostadura (T). El aroma cacao tostado se deriva por lo tanto de la aadidura de todos estos compuestos. Su complejidad reside en el hecho de que puede establecerse slo el origen de una parte de los compuestos voltiles presentes inicialmente en el grano fresco y aquellos nicamente formados en la tostadura.

5. - GenotipoEs posible poner de relieve la influencia del genotipo al comparar (como estn las cosas por otro lado: misma caja de fermentacin, condiciones de secado idnticas, mismo nivel de tostadura..) las fracciones voltiles de los distintos cacaos. Resulta entonces posible evidenciar diferencias cualitativas y cuantitativas de composicin del aroma y esto en todos los niveles de su desarrollo.

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A ttulo de ejemplo, la comparacin entre clones e hbridos previamente indicados se pormenoriza ampliamente por otro lado (Cros y Jeanjean 1995).Inf uenci delprocesam i l a ento

Es interesante notar que la especificidad aromtica de un cacao dado se encuentra de nuevoTostado

A l endra m f resca

Ferm entaci n y secado

globalmente cualquiera que sea el lugar de cultivo, lo que tendera a confirmar la contribucin gentica en la calidad aromtica y el carcter de herencia del carcter especfico. Esto sugiere igualmente que el factor "terruo" es bajo y que el material vegetal utilizado as como las condiciones de tratamiento post-cosecha son los factores llaves del desarrollo del aroma. Adems, resulta que el carcter especfico depende no solamente del nivel de fermentacin pero igualmente del nivel de tostado. Por ejemplo, la comparacin de las notas con sabor de fruta/ con sabor de flor de los chocolates preparados respectivamente a partir de granos no tostados y tostados de cacao Trinitario de Madagascar fermentados 4 y 6 das, indica que la intensidad de

T c2 C1 C 2 + N uevos com puestos f 2 F1 F2 + T

este carcter disminuye en el tostado (Chanliau 1995).

A RO M A CACAO C 1 + F1 + F2 + T

Conclusin generalTodo este estudio muestra la complejidad de los fenmenos puestos en juego en el desarrollo de la fraccin voltil del cacao y la importancia del aroma de origen de fermentacin.

Figura 3. Esquema de formacin del aroma Cacao

El tratamiento de fermentacin/secado y la tostadura permiten la manifestacin del potencial aromtico del cacao, el cual se determina por el genotipo. La fermentacin es el factor llave de esta manifestacin: lleva no solamente al desarrollo de los precursores que se utilizarn en la tostadura, pero tambin a aqul de una fraccin voltil determinante en la calidad final del producto.

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BibliografaAdamek P., Bergstorm B., Borjesson T., Stolmann U. 1992. Determination of volatile compounds for the detection of moulds. In: Modern methods in food mycology. Ed. Sansom R.A., Pitt J.I. Amsterdam, Elsevier, 327-336. Baigrie B. D. 1994. Cocoa flavour. In: Understanding natural flavours. Ed Piggott J. R. et Paterson A. Blackie Academic & Professional, Glasgow 1994, pp 268-282. Bastide P. 1987. Evolution et mtabolisme des composs phnoliques des fves de cacao durant leur dveloppement au cours de la croissance et de la maturation du fruit de Theobroma cacao L. Thse de Doctorat, Physiologie et Biologie des Organismes et des Populations, Universit de Montpellier II, 147 p. Beauhaire J. 1978. Contribution l'tude de l'arme du cacao, influence des conditions de fermentation et de torrfaction sur la formation des composs aromatiques. Thse de Doctorat. Universit de Technologie de Compigne, 104 p. Berger R. G. 1995. Aroma Biotechnology, Springer-Verlag, Berlin, 240 p. Biehl B. 1986. Cocoa fermentation and problem of acidity, over-fermentation and low cocoa flavour. In: Cocoa and coconuts: progress and outlook. (Report of the Int. Conf. on Cocoa and Coconuts, octobre 1984, Kuala Lumpur). Ed: Pushparajah E. and Chew Poh Soong, Incorporated Society of Planters, Kuala Lumpur, pp 561-568. Biehl B., Voigt J., Heinrichs H., Senjuk V., Bytof G. 1993. pH-dependent enzymatic formation of oligopeptides and amino acids, the aroma precursors in raw cocoa beans. 11 me Conf. Int. Rech. Cacaoyre, Yamoussoukro (Cte d'Ivoire), 717-722. Bracco U., Grailhe N., Rostagno W., Egli R.H. 1969. Analytical evaluation of cocoa curing in the ivory coast. J. Sci. Food Agric., 20, 713-715. Chanliau S. 1995. Influence du traitement post-rcolte et de la torrfaction sur le dveloppement de l'arme cacao. Essais prliminaires de caractrisation des composs odorants. Diplome d'Etudes Approfondies, option Sciences des Aliments, Universit de Montpellier II, 38 p. Chevalley J. Travaux cit dans: Influence of genetic factors and agroclimatic conditions on the quality of cocoa. Publication Nestec Ltd, Agricultural Services (Suisse). Clapperton J., Hammerstone Jr. J. F., Romanczyk L. J., Yow S., Chan J., Lim D., Lockwood R. 1992. Polyphenols and cocoa flavour. 16mes Journes Internationales d'Etude du Groupe Polyphnols (J.I.E.P.), Lisbonne (Portugal), 112-116. Clapperton J. 1993. Genetic variation in cocoa flavour. 11me Conf. Inter. Rech. Cacaoyre, Yamoussoukro (Cte d'Ivoire), 749-754. Cros E., Mermet G., Jeanjean N., Georges G. 1993. Relation prcurseurs - dveloppement de l'arme cacao. 11me Confrence Internationale sur la Recherche Cacaoyre, Yamoussoukro (Cte d'Ivoire), 723-726.

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I Congreso Venezolano del Cacao y su IndustriaCros E., Jeanjean N. 1995. Formation de larme cacao. In: Rencontre cacao - Les diffrents aspects de la qualit. Actes du sminaire. Ed. CIRAD, Montpellier (France). Cros E., Jeanjean N. 1997. Formation de larme cacao. In: Cacao et Chocolat - Production et caractristiques. Lavoisier (Paris), paratre. Cros E. 1997. Torrfaction. In: Cacao et Chocolat - Production et caractristiques. Lavoisier (Paris), paratre. Dimick P.S., Hoskin J.M. 1981. Chemico-physical aspects of chocolate processing. A review. Can. Inst. Food Sci. Technol., 14, 269-282. Flament I. 1991. Coffee, Cocoa and Tea. In: Volatile compounds in foods and beverages. Ed: Maarse H., Marcel Decker Inc. New York (1991), pp 617 - 669. Flament I., Willhalm B., Stool M. 1967. Recherche sur les armes. Sur l'arme du cacao. III. Helv. Chim. Acta, 50, 2233-2243. Forsyth W.G.C., Quesnel V.C. 1963. The mechanism of cacao curing. Adv. Enzymol., 25, 457-492. Gill M. S., MacLeod A. J., Moreau M. 1985. Aroma components of cocoa beans. Proceedings of the 4th Weurman Flavour Research Symposium, ADDA J. Ed. Dourdan (France). In: Development in Food Science (1985), Elsevier, Amsterdam, 10, 261-266. Hoskin J.C., Dimick P.S. 1988. Chemistry of flavour development in chocolate. In: Industrial chocolate manufacture and use. Ed: Beckett S.T., Blackie & Son, Glasgow, pp 108-121. Jeanjean N., Cros E., Flori A. 1994. Cocoa flavour: correlation between non-volatile and volatile compounds. Malaysian International Cocoa Conference, Kualalumpur (Malaisie), sous presse. Jeanjean N. 1995. Influence du gnotype, de la fermentation et de la torrfaction sur le dveloppement de l'arme cacao. Rle des prcurseurs d'arme. Thse de Doctorat, Universit de Montpellier II, 200 p. Keeney P.G. 1972. Various interactions in chocolate flavor. J.A.O.C.S., 49, 567-572. Kosuge T., Kamiya H. 1962. Discovery of a pyrazine in a natural product. Nature, 193, 776-779. Lpez A., Quesnel V.C. 1971. An assesment of claims relantry to the production and composition of chocolate aroma. Rev. Int. Choc., 26, 19-24. Maravalhas N. 1972. Acides amins dans les fves de cacao non fermentes et fermentes. Rev. Int. Choc., 27, 23-24. Mermet G. 1989. Cacao: Influence des paramtres de torrfaction sur la consommation des prcurseurs d'arme et la formation de quelques composs volatils. Thse de Doctorat. Universit Montpellier II, 146 p. Mohr W. 1974. Uber die Technologischen Grund lagen der Aromaent wick-lung bei der Schokolade fertigung. 1 Internationaler Kongress ber Kakao-und Schokoladeforshung, Munich, pp 224-236. Musa M. J., Said M. B. 1988. Cocoa beans: aspects, relationships and implications to Malaysian cocoa beans. In: Workshop on processing and grading of cocoa, Serdans ( Malaysia), 1-24.

ConferencistasPaiva M., Janick J. 1983. Variability of alkaloid production in Theobroma cacao L. Revista Theobroma, 13, 249-262. Porter L.J., Ma Z., Chan B.G. 1991. Cocoa procyanidins: major flavonoids and identification of some minor metabolites. Phytochem., 30, 1657-1663. Reineccius G.A., Andersen D.A., Kavanagh T.E. et Keeney P.G. 1972. Identification and quantification of the free sugars in cocoa beans. J. Agric. Food Chem., 20, 199-206. Rohan T.A. 1964. The precursors of chocolate aroma: a comparative study of fermented and unfermented cocoa beans. J. Food Sci., 29, 456-459. Rohan T. A. et Stewart T. 1965. The precursors of chocolate aroma: the distribution of free amino acids in different commercial varieties of cocoa beans. J. Food Sci., 30, 416-419. Romanczyk L., McClelland C. A., Post L. A. Aitken W. M. 1995. Formation of 2- acetyl-1-pyrroline by several Bacillus cereus isolated from cocoa fermentation boxes. J. Agric. Food Chem., 43, 469-475. Seiki K. 1973. Chemical changes during cocoa bean fermentation using the tray method in Nigeria. Rev. Int. Choc., 28, 38-42. Timbie D. J. 1977. Studies on the proteins and purine alkaloids of cocoa beans. Ph. D. Thesis, Pennsylvania State University, 110 p. Van Praag M., Stein H.S., Tibbets M.S. 1968. Steam volatile aroma constituents of roasted cocoa beans. J. Agric. Food Chem., 16, 6, 1005-1008. Van Straten S. 1983. Cocoa. In: Volatile components in food, 5th ed. Division for Nutrition and Food Research, TNO, Zeist, pp 71.1-71.6 Villeneuve F., Cros E., Macheix J. J. 1989. Recherche d'un indice de fermentation du cacao. III. Evolution des flavan-3ols de la fve. Caf, Cacao, Th, 33, 165-170. Voigt J., Heinrichs H., Voigt G., Biehl B. 1994. Cocoa specific aroma precursors are generated by proteolytic digestion of the vincillin-like globulin of cocoa seeds. Food Chem., 50, 177-184. Voigt J., Biehl B. 1995. Precursors of the cocoa-specific aroma components are derived from the vicilin-class (7S) globulin of the cocoa seeds by proteolitic processing. Rev. Bot. Acta, 108, 299-307. Zak D.L., Ostovar K., Keeney P.G. 1972. Implication of Bacillus subtilis in the synthetis of tetramethylpyrazine during fermentation of cocoa beans. J. Food Sci., 37, 967-968. Ziegleder G. 1982. Highly volatile cocoa flavour constituants as indicator during cocoa processing. Review of Chocolate, Confectionnary and Bakery, 7, 17-22. Ziegleder G. 1983. Neue Erkentnisse ber Kakaoaromabildung und Veredehung und ihre um Setzung in Technologische verfahren. Lebensmmittelchem. Gerichtliche. Chem., 37, 63-69.

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I Congreso Venezolano del Cacao y su IndustriaZiegleder G. 1991. Composition of flavor extracts of raw and roasted cocoas. Z. Lebensm. Unters. Forsch., 192, 521525. Ziegleder G., Biehl B. 1998. Analysis of cocoa flavour components and flavour precursors. In: Analysis of non alcoholic beverages. Ed: Linskens H.F. et Jackson J.F. Modern methods of plant analysis - New series, Springer Verlag, Berlin, pp 321 - 393.

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The genetic diversity of Criollo cacao and its consequence in quality breeding

J.C. Motamayor, A.M. Risterucci, V. Laurent, A. Moreno**, C. Lanaud. AGETROP/CIRAD, BP5035, 34032 Montpellier, France. **Estacin Experimental de Caucagua, FONAIAP, Venezuela. SummaryGenetic diversity analysis of Venezuelan and some Mexican Criollo cacao trees, as well as individuals from the other morphogeographic groups, was performed using RFLP markers. Samples of Criollo trees were collected in ancient Venezuelan plantations without regard to agronomic traits. Also, some samples of Criollo could be taken in the Lacandn rainforest of Mexico, where wild Criollo cacao trees have been reported. In addition to those already mentioned samples of Criollo trees from several germplasm collections in Venezuela, Costa Rica and Mexico were also studied. RFLP analyses revealed a high level of homozygosity in the Criollo clones collected in the ancient Venezuelan plantations and in the Lacandn rainforest, in contrast to Criollo clones sampled in germplasm collections. A significant molecular similarity between all the types of Criollo studied (Pentagona, Porcelana, Criollo Andino, Criollo de la Costa and the one from the Lacandn rainforest) was found, in spite of the dissimilar morphological traits that differentiate them. Criollo from germplasm collections appeared generally, to be more heterozygous and variable, perhaps due to selection for some agronomically important characteristics. This probably corresponds to partial introgressions of Forastero genes, which gave vigour and resistance to ancestral Criollo varieties.

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From data obtained new hypotheses concerning evolution and domestication schemes could be proposed. The low genetic variability encountered among the Criollo varieties, suggests that the Criollo group originated from a reduced ancestral population and that man participated in the spread of individuals of this group in Central America. In addition, consequences for breeding for quality traits can be derived since the poor yield and the pest susceptibility which has characterised the individuals of the Criollo group could be explained partly as a consanguinity depression phenomenon. Thus, for obtaining genetic gain but conserving quality, crosses between Criollo individuals must be avoided. Different breeding strategies for improvement of quality varieties are discussed.

IntroductionTheobroma cacao L. (2n=20) is a tree cultivated in humid tropical regions. Its geographical origin was proposed by Cheesman (1944) as the upper Amazon, according to the great morphological diversity found by Pound (1938) in this region. Cheesman (1944) distinguishes two morphogeographic groups: Criollo and Forastero. The terms Criollo and Forastero employed by Cheesman (1944) came simply from the current language of the Venezuelan cacao producers who utilized these names in order to differentiate the local cultivated cacao (Criollo) from the introduced (Forastero). Forastero trees are native to South America. They are more vigorous and more productive than Criollo trees. Traditionally the Forastero group is subdivided according to its geographical localisation in to Upper Amazon Forastero (UAF) and Lower Amazon Forastero (LAF), but other populations located along the Orinoco river and Guiana region are also included in the latter sub-group. Cheesman (1944) mentioned the Trinitario group as a subgroup of Forastero, however, it is now generally considered as a different morpho-geographic group. Trinitario was proposed to have originated in Trinidad by natural hybridisation between the remaining Criollo individuals (after a natural disaster in 1727) and the Forastero individuals introduced from the east of Venezuela. Criollo trees were the first to be domesticated, and their culture was very important for Maya and Aztec civilisations (Paradis, 1979; Coe and Coe, 1996). However, their origin is not well known. Several hypotheses have been put forward to explain

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the origin of the Criollo group (Cheesman, 1944; Holdridge, 1950; Mora Urpi, 1958; Soria, 1959; Cuatrecasas, 1964; Purseglove, 1968). The most cited of them are those of Cheesman (1944) and Cuatrecasas (1964). Cheesman (1944) proposed participation of man as the cause of cacao (Criollo) arising in Central America but, Cuatrecasas (1964) suggested the independent differentiation of the Criollo and Forastero groups into two subspecies on both sides of the Panama isthmus. More recently, Lanaud (1987) and Laurent et al. (1994) proposed the theory of the refuge zone during the quaternary as a possible cause of differentiation of populations such as Criollo or Guiana populations. Criollo trees produce poor yields, but are of great economic importance because of their higher chocolate qualities. Criollo plantations in Mexico and Venezuela, as in others countries of Latin America, are progressively being replaced by Trinitario genotypes which are more vigorous and productive. Many genetic exchanges occurred between local Criollo and introduced Trinitario trees, giving rise to a population of Criollo more or less introgressed with Forastero genes, thus making it difficult to recognise "pure" Criollo types. Currently, Criollo trees are characterised by the presence of several traits such as plump and white or rosy beans, light green flushes, light colours in the floral piece, pointed and rough pod forms and thin and soft pericarp (Cheesman, 1944; Purseglove, 1968; Soria, 1970; Reyes, 1992). The color of seeds is one of the principal descriptors, but xenia phenomena exist for this character (Enriquez and Soria, 1968). Other characteristics such as flushes and floral pieces colours are influenced by environmental factors and are dependent on developmental stage. Thus, the morphological identification of individuals in the field is very difficult. This implies that for correct identification, materials need to be collected and studied as well as their descendants in germplasm collections. This form of assessment, presents several problems resulting from space restrictions and the requirement for time consuming procedures. However, the use of molecular techniques such as Restriction Fragment Length Polymorphism (RFLP) analysis, allow the correct and rapid identification of individuals, and at the same time as providing a tool to assess their genetic diversity for phylogenetic studies or crop improvement. RFLP markers have been

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used for these purposes in a great number of species like barley (Peterson, et al., 1994), soybean (Keim, et al. 1994) and walnut (Fjellstrom et al. 1994). Several studies concerning the genetic diversity within, and the phylogenetic relationships between the morpho-geographics groups of T. cacao have been published. Engels (1986), using morphological descriptors, found a great genetic diversity in Forastero as well as in the Criollo group, however, the latter could not be distinguished from Trinitario individuals. Lanaud (1987), using isoenzymes, found variability within the UAF group which embraces the global variability of the species. Nevertheless, Laurent et al. (1993b), using heterologous cytoplasmic probes, founds as Engels (1986) obtained, a greater variability in the Criollo and in the Trinitario group. However, those results are in contrast to later findings by Laurent et al. (1993a and 1994), using rDNA and cDNA probes, which confirmed the greater variability in the UAF group found with isoenzyme analysis. Figueira et al. (1994), using Random Amplified Polymorphism DNA (RAPD) markers, found a continuos variability between the three morpho-geographic groups and thus was not able to differentiate them. However, N'Goran et al. (1994), also using the RAPD technique, found a genetic structure closer to the traditional classification, observing an important variability within the Criollo group. Using RAPDs, de la Cruz et al. (1995) studied the genetic differentiation observed between wild cacao (wild Mexican Criollo) from Central America and individuals from the three morpho-geographic groups (Forastero, Trinitario and modern Criollo), and concluded that cultivated cacao originated in South America. Lercetau et al. (1997), using RAPD and RFLP markers reported similar findings to Figueira (1994), namely, a lack of gene differentiation between the accessions studied, with the exception of a few variable and with a low heterozygosity rate group, the group Nacional of Equator. In all these works, some discrepancies between molecular results and morphological grouping were attributed to difficulties encountered in the morphological classification of clones In plant breeding, knowledge about the genetic diversity of the species is very important as it reflects the genetic potential that can be exploited by the breeder. In addition, learning about the origin and the domestication process of a species can contribute to an understanding of how varieties obtained their genetic constitution, and this may be important for the breeder interested

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in recreating characteristics of a particular variety. Some parameters derived from molecular data such as genetic distances among populations or individuals, as well as the heterozygosity rate per individual, may orientate the crossbreeding schemes in a breeding program. In order to contribute to the knowledge about the evolution and the domestication process of Theobroma cacao L., as well as to provide useful information for cacao breeding programs, this work aimed to study, at the molecular level, the diversity of Criollo material prospected in the oldest Venezuelan plantations and in the Mexican Lacandn rainforest. This work placed a particular emphasis on the characterisation of the pure Criollo varieties traditionally cultivated before Forastero introductions and that gene flow occurred between the two groups.

Materials and MethodsPlant Material. A complete list of individuals used in the study and their geographic origin is shown in Table 1. Genotypes are classified as Ancient Criollo, Actual Criollo, Trinitario, Lower Amazon, Guyana and Upper Amazon Forastero. Ancient Criollo individuals were defined as those trees sampled in places where no or very limited gene flow could occur between Criollo and Trinitario trees, since no or rare introduction of Trinitario material was suspected in those places. For the purposes of this work, it was postulated that Trinitario introduction started no more than 70 years ago, thus, if Trinitario introduction was suspected, only the older trees were sampled (trees of more than 70 years). In order to find Ancient Criollo trees, specialists, technicians and agriculturists were consulted. In Venezuela, most samples were taken from trees growing on old or abandoned farms, and in gardens of houses situated in towns difficult to access. Some of the places visited were previously recognised by Reyes (1992). Samples of Ancient Criollo trees from Mexico were collected in the Lacandn rainforest where wild Criollo trees have been reported (Cuatrecasas, 1964). Actual Criollo individuals were defined as those coming from modern farms or from farms where an important introduction of Trinitario or Forastero seedlings or clones was suspected. Also within this class, are included materials from some germplasm collections of Costa Rica, Ivory Coast, Mexico and Venezuela.

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Trinitario and Guyana, Low and Upper Forastero individuals

Memorias 1er Congreso Vzlno de Cacao_Fundacite Aragua

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