Occurrence of ochrato xin A (OTA) in ground roasted coffee fro m d ifferent brands and types available in Yaounde and Douala cities was assessed. Based on these data, exposure of the Cameroonian population to OTA through coffee consumption was estimated. Coffee samples were purchased in hypermarkets and supermarkets of the two selected cities of Cameroon. OTA was extracted, cleaned-up by immunoaffin ity columns, and detected by HPLC-fluorescence detection. OTA was found in 64.7% of pure Arab ica coffee, 75% of pure Robusta coffee, and 62% of Arab ica / Robusta mixtu re coffee, with OTA levels ranging fro m 0.3 to 4.9 µg.kg -1 , 0.6 to 18 µg.kg -1 and 0.3 to 7.4 µg.kg -1 respectively. Robusta Coffee brands are the most contaminated, follo w by coffee mixture brands and Arabica coffee brands. The daily intake of OTA is 0.065 ng / kg bw per day. Consumption of OTA fro m coffee in the cities of Douala and Yaounde are then very lo w compared to that of Europe who is 2-3 ng/kg bw per day. Consumption of OTA fro m coffee in the cities of Douala and Yaounde is very low co mpared to that of Europe, for wh ich the rate is 2-3 ng/kg bw per day.

Ochratoxin-A (OTA) is a mycotoxin that has nephrotoxic, tetragenic, immunotoxic and carcinogenic effects in the human organism. It contaminates several foodstuffs, notably cocoa. The purpose of our study was to compare the incidence of cocoa pod integrity on the fungal microflora and ochratoxin- A production in Cameroon. Irrespective of pod condition, fermented cocoa beans were contaminated by OTA. The maximum mould content was obtained in beans from damaged pod. However, the fungal microflora was more diversified for beans from pod damaged during harvesting than for beans from intact pods, throughout the post-harvest process. The toxigenic strains isolated belonged to the genera Aspergillus. Aspergillus carbonarius isolated from damaged pods, displayed the greatest OTA production which was 110.7 ng.g-1 on cocoa medium and 2772,0 ng.g-1 on official medium. There was a good correlation between OTA presence in the beans and isolated toxigenic strains.

To study the complexation of ochratoxin-A (OTA) by coffee in a real environment (in coffee-drink) and with some coffee constituents able to inter act with the OTA as caffeine, chlorogenic acid and arginine. The cof fee drink was prepared according to the filtermethod. OTA compl exation tests were done at 23°C and at 90-100°C usi ng test tube and filter-paper. OTA was extracted with a met hanol / sodium bicarbonate mixture at 3%, purified on the immunoaffinity column “ochraprep” and quantified by HPLC with a fluorimetric detection. The results gi ve a high rate of OTA complexation by the constituents of the hot coffee-drink was obtained. It depends on the v olume of the coffee drink and the chemical compound. When hot, t he rate of complexation is about 100% with 40 ml of coffeedrinking. After 20 min of heating at 200 ° C, 86.6% of pure OTA were degraded against 12.4% of disappe arance of the OTA due to the complexation by caffeine, 11.6% due to arginine and 6% due to chlorogenic acid. How ever, the products of complexation or degradation are not det ectable by fluorimetry.

L'incidence des procedes post-recoltes sur la contamination du cacao par l'OTA a ete etudiee au cours de 3 campagnes cacaoyeres successives a Kumba au Cameroun. Le type de fermentation (caisse ou tas) n'a pas influence de facon significative la teneur en OTA des feves : la teneur maximale dosee est restee inferieure a 2ng.g [exposant] -1 qui est le seuil tolerable pour les feves de cacao defini par l'Union Europeenne. Par contre, les cabosses abimees et l'ecabossage tardif ont constitue des facteurs aggravants de la contamination du cacao par l'OTA. Une teneur de 75,5 ng.g [exposant] -1 a ete obtenue avant la mise en fermentation et 32.2 ng.g [exposant] -1 apres 4 mois de stockage y est obtenue : ce qui est tres superieure aux doses tolerables pour l'exportation. Suite aux statistiques nationales qui indiquent un niveau d'insecurite alimentaire et de malnutrition important en milieu rural, l'Etat camerounais incite a l'autoconsommation des denrees alimentaires. C'est dans ce cadre que certains cacaoculteurs ont commences a transformer avec des techniques traditionnelles, une partie du cacao produit sous - forme de chocolat en pâte, poudre de cacao et beurre de cacao. A partir des feves contaminees, ni le grillage au feu de bois, ni le decorticage par pilage au mortier n'ont fait baisser de facon significative la teneur en OTA des feves. A l'exception du beurre de cacao, les autres produits de transformation de ces feves ont des teneurs en OTA importantes. Soixante sept pour cent (67%) d'echantillon de chocolat en pâte et de poudre de cacao sont contamines par I'OTA, avec 50% d'echantillon qui ont des teneurs superieures a la norme. A cause de la fragilite de la pellicule des feves du aux cabosses blessees et a l'ecabossage retarde de 10 jours, la contamination par l'OTA n'est plus superficielle et le decorticage ne contribue plus a faire baisser de facon significative la teneur en OTA des feves. Au Cameroun, la consommation journaliere moyenne des derives de cacao est estimee a 0.75 g.j [exposant] -1 chez l'adulte et a 1 g.j [exposant] -1 chez les enfants. L'exposition maximale journaliere a l'OTA pourrait etre de l'ordre de 1.6l ng.kg [exposant] -1 p.c/j chez les jeunes enfants d·environ 20kg. Le cacao est donc une source d'exposition minimale a l'OTA, mais ne tardera pas a devenir un risque si rien n'est fait. (Resume d'auteur)

Cocoa beans from several types of post harvest trea m nts were processed into cocoa butter, cocoa powd er and chocolate spread using traditional processing techn iques. OTA was analyzed in two hundred and sixteen (216) samples of cocoa and cocoa derived products using H PLC with fluorimetric detection. It was found that OTA content in cocoa nibs depended only on the state of cocoa pod and the time duration of cocoa pod-openi ng. Cocoa beans from damaged cocoa pods and pod-opening delay ed by 10 days were the most contaminated by OTA. Ne ither roasting using fire wood, nor shelling by pounding a mortar could reduce significantly the OTA cont ent in cocoa beans. Apart from cocoa butter, the other cocoa der ived products also had high OTA contents. Sixty sev en (67%) of chocolate spread and cocoa powder samples were cont ami ated by OTA, and 50 % had contents superior to the limit defined by the European Union. Because of the fragile pellicle of cocoa beans, due to damaged po s and cocoa pod-opening delayed by 10 days, the contamination b y OTA was no longer superficial and shelling does n ot longer contribute to reduce significantly the OTA content in beans. Like with modern procedures, traditional techniques of cocoa processing do not have significant influence on OTA content of derived products. Only the raw ma teri l (quality and state of cocoa pod) can influence the OTA content of cocoa derived products. Keys words: cocoa, OTA, traditional techniques of cocoa proce ssing, cocoa derived products _________________________________________________________________________

This study set out to assess the relative importance of sound and unsound beans in a batch of coffee with regard to ochratoxin A (OTA) contamination. Initially, unsound beans were found to account for 95% of contamination in a batch of coffee, whatever the methods used for post–harvest processing. It was also found that beans displaying traces of attacks by Colletotrichum kahawae were the greatest contributors to OTA contamination. In a second stage, the study compared the contamination of sound beans with that of beans attacked by Colletotrichum kahawae. On average, beans attacked by Colletotrichum kahawae had a statistically higher OTA content than sound beans (18.0 µg kg−1 as opposed to 1.2 µg kg−1). In addition, the average OTA content in unsound beans varied depending on growing conditions.

Dans le cadre d'un programme d'etude des sources de contamination par l'ochratoxine A et de sa presence dans les feves de cacao, les resultats obtenus en Cote d'Ivoire et au Togo suggerent que la presence d'OTA est liee aux pratiques de travail post-recolte et aux conditions climatiques. Le but de notre etude etait de completer ces travaux en identifiant plus precisement les facteurs qui favorisent l'apparition d'OTA durant la phase post-recolte et plus particulierement durant la recolte, l'ouverture des cabosse, et durant les phases de fermentation et de sechage. Quatre essais ont ete realises dans une exploitation cacaoyere de decembre 2003 methodes de travail utilisees par les petits cacaoculteurs ont fait l'objet d'une etude. Cinq categories de cabosses ont ete etablies pour etudier les facteurs de qualite phytosanitaire de la recolte : Les cabosses saines, Les cabosses pourries (pourriture brune et autres maladies de ce type), Les cabosses laissees a secher sur l'arbre (cabosses momifiees), Les cabosses endommagees par les insectes (mirides et autres), Les cabosses endommagees physiquement de l'exterieur (attaque de rongeurs, secateur ou emondoir) Chaque echantillon etait compose de chaque categorie de cabosses. Apres avoir ete entreposes pendant 7 jours, les echantillons ont ete mis en tas pour la fermentation en utilisant deux methodes : celle des cacaoculteurs et la methode standard. Cette experience a ete repetee quatre fois. Les resultats montraient clairement que la presence d'OTA etait beaucoup plus elevee dans les feves provenant des cabosses endommagees physiquement que dans les feves provenant des autres groupes de cabosses. Les feves provenant des cabosses physiquement endommagees (blessees ou pourries) presentaient le plus grand risque de contamination par l'OTA. Les conditions meteorologiques durant la principale saison seche en Afrique de l'Ouest, et particulierement l'action de l'harmattan en fevrier, ont une incidence significative sur la production d'OTA (fait deja etabli en 2002/2003 et confirme en 2003/2004). Ces resultats permettent de mieux identifier les stades critiques de contamination du cacaoyer par l'OTA au champ. Ils suggerent que des mesures de prevention pourraient etre prises de l'etape du ramassage des cabosses jusqu'aux etapes de fermentation et de sechage. D'autres etudes seront necessaires pour confirmer ces resultats. D'autres possibilites de recherche sont envisagees, notamment sur les conditions liees au developpement et a la toxigenicite de la microflore presente sur les cabosses recoltees durant la phase de contamination. (Resume d'auteur)

On the island of Reunion, a project designed to develop a high added-value coffee brand was launched in 2002. The project focused on Coffea Arabica var. Laurina called 'Bourbon Pointu', and set out to determine growing practices and post-harvest treatments enabling the production of an inimitable coffee. The project involved the development of 106 experimental cultivation plots. The first phase of the project, from 2002 to 2007, was used to establish technical/commercial references for the production and processing of high added-value "grands crus" coffees. Soils were characterized and farms potentially suitable for the production of quality coffee were identified. Over that period more than 1126 samples were collected and analysed in diffuse reflectance from 1100 nm to 2500 nm using a NIRSystem FOSS 5000 spectrometer (Port Matilda, USA). In that way, a Near Infrared (NIR) spectral database specific to Bourbon Pointu (BP) coffees was compiled. A principal components analysis was performed on the spectral database in order to calculate Mahalanobis distances from the average spectrum for each spectrum and then fix boundaries for the population. Based on these results, samples differing from pure BP, such as "Bourbon rond", were removed from the database. The database was constructed by removing samples corresponding to abandoned trials such as certain post-harvest treatments or fertilizer tests. This led to a specific database for BP comprising 670 spectra of green coffees. From that collection, 250 random samples were analysed at the CIRAD laboratories, using reference methods, for their caffeine, chlorogenic acids, trigonelline, fat, sucrose and moisture contents. Those values were added to CIRAD?s Arabica NIR database to develop specific calibration for BP coffees using Partial Least Squares Regression. This approach revealed that it was possible to authenticate BP coffee from Reunion using NIRS fingerprinting. The calibrations developed in this study made it possible to quantify the content of 6 major quality-related chemical compounds in BP green coffee. (Resume d'auteur)

Cafestol and kahweol are two coffee-specific diterpenes. Although various effects of these compounds have been shown or hypothesized on human health, little information is currently available on the genetic and molecular bases of their metabolism. This work presents data on diterpenes accumulation during fruit development and analysis of gene expression for three key enzymes of the diterpenes biosynthesis pathway. (Resume d'auteur)

Coffee fruits grown in shade are characterized by larger bean size than those grown under full-sun conditions. The present study assessed the effects of shade on bean characteristics and sugar metabolism by analyzing tissue development, sugar contents, activities of sucrose metabolizing enzymes and expression of sucrose synthase-encoding genes in fruits of coffee (Coffea arabica L.) plants submitted to full-sun (FS) and shade (SH) conditions. Evolution of tissue fresh weights measured in fruits collected regularly from flowering to maturation indicated that this increase is due to greater development of the perisperm tissue in the shade. The effects of light regime on sucrose and reducing sugar (glucose and fructose) contents were studied in fresh and dry coffee beans. Shade led to a significant reduction in sucrose content and to an increase in reducing sugars. In pericarp and perisperm tissues, higher activities of sucrose synthase (EC 2.4.1.13) and sucrose-phosphate synthase (SPS: EC 2.4.1.14) were detected at maturation in the shade compared with full sun. These two enzymes also had higher peaks of activities in developing endosperm under shade than in full sun. It was also noted that shade modified the expression of SUS-encoding genes in coffee beans; CaSUS2 gene transcripts levels were higher in SH than in FS. As no sucrose increase accompanied these changes, this suggests that sucrose metabolism was redirected to other metabolic pathways that need to be identified.

Les souches productrices d'Ochratoxine A (A. ochraceus et A. niger) representent 3 a 25% de la contamination fongique du cafe Arabica mexicain. Aucune souche d'Aspergillus carbonarius et de Penicillium verrucosum n'a ete isolee sur les differents cafes. L'etude de l'impact du type de traitement post-recolte sur la contamination et la toxinogenese pour l'OTA a montre qu'A. ochraceus est sensible a la competition avec la flore autochtone du cafe, alors que ce n'est pas le cas pour A. niger qui colonise le milieu facilement. Cependant A. niger ne produit pas la toxine aussi rapidement et en aussi grande quantite qu'A. ochraceus. Les procedes sec et avec depulpage et demucilagination mecaniques donnent des resultats sensiblement differents de ceux obtenus avec le procede humide traditionnel utilisant une demucilagination microbienne: ce dernier procede est moins favorable a la croissance fongique meme s'il y a peu de difference sur l'aptitude a la production d'Ochratoxine A. La presence du stade de fermentation microbienne est cependant un facteur de limitation de risque au meme titre que l'obtention d'une baisse rapide de l'Aw pendant le sechage. (Resume d'auteur)

Millions consumers are attracted by coffee aroma and flavor all over the world. Among the few countries producing, Brazil is the main producer responsible for the production of more than 110 million of bags consumed annually. This position of larger producer is due to because the ample adaptability of the coffee culture to environmental conditions encountered in the country. In the last years the quality of the this beverage became a point of reference for additional remuneration to the producers. The quality of coffee is influenced by the environmental conditions and of the cultural practices and of the post harvest processes. The beverage coffee is the result of the transformations among the chemical components of the grain during the roasting of the bean. The coffee growing area in Parana is localized in a region of climatic transition with great climate and soil diversity and the district of Jesuits is located on its limits at latitude south 24° 19’ 38. The objective of this study was to evaluate the effect of the environmental conditions in the chemical composition of the coffee of the region of Jesuitas-Pr. Samples of coffee ripe cherries were picked in 46 small properties. In those samples the contents of proteins, lipids, chlorogenic acids, total tannins, total sugars, reducing sugars, sucrose, caffeine, trigonelline and titrable acidity in the green grains were determined. It was verified a great influence of the environmental in the components responsible for the the formation of the aroma and flavor of the beverage coffee during roasting. The concentrations of lipids, proteins and total sugars were influenced by the environmental conditions of Jesuits-PR. Significant correlation were found between chlorogenic acids and tannins, between caffeine and proteins, between total sugars and tannins between lipids and the global score of the beverage. These modifications on the composition of the grains bring a character of special quality to the coffee of the area of Jesuitas-PR