Effet de Garcinia kola (Clusiaceae) dans les processus de fermentation du vin de canne à sucre ( Saccharum officinarum ; Poaceae) au Gabon

Le nectar de canne a sucre (Saccharum officinarum L.) est utilise au Gabon non seulement pour la fabrication du sucre industriel, mais egalement pour la synthese traditionnelle de vins locaux appeles ‘‘Musungu’’ ou ‘‘Malamba’’. Ces syntheses alcooliques necessitent l’emploi de nombreux adjuvants dont le role exact reste mal defini. Le present travail a ete initie pour etudier l’un d’eux, le bois amer (Garcinia kola) utilise dans diverses syntheses alcooliques. La methodologie a consiste a analyser l’evolution de certaines qualites physicochimiques et biochimiques de 1 l des nectars de canne a sucre seuls (temoin), associes a la lie d’anciens vins de canne (Li), au bois amer (Gk) ou a ces 2 amendements (LG), avant et apres 4 semaines de fermentation. Les resultats obtenus ont revele la baisse de l’acidite, de la densite et des sucres totaux dans tous les traitements essais, contrairement aux temoins, apres les 28 jours d’incubation. Tous les traitements (essais et temoins) ont en revanche produit des alcools de fortes teneurs comprises entre 7,4 °GL et 9,9 °GL. Mais les vins des traitements temoins quoique tres alcoolises ont tous ete juges aigres et de tres mauvaise qualite gustative. Le bois amer ne parait donc pas intervenir dans les processus de fermentation alcoolique, mais dans la constitution des qualites organoleptiques, en empechant la proliferation des germes lactiques. Ainsi, dans la perspective d’optimiser la qualite du vin, identifier les germes participants a la fermentation du nectar de canne, sous l’influence de Garcia kola semble etre necessaire.Mots cles : Nectar, Levures, Adjuvants, Alcool, Qualite organoleptique. English Title: Effect of Garcinia kola (Clusiaceae) in the fermentation processes of sugar cane wine (Saccharum officinarum ; Poaceae) in Gabon Sugarcane nectar (Saccharum officinarum L.) is used in Gabon not only for the production of industrial sugar, but also for the traditional synthesis of local wines called ''Musungu'' or ''Malamba''. These alcoholic syntheses require the use of many adjuvants whose exact role remains poorly defined. The present work was undertaken to study one of them, the bitter wood (Garcinia kola) used in various alcoholic syntheses. The methodology consisted of analyzing the evolution of certain of physicochemical and biochemical qualities of 1 l of sugar cane nectars alone (control), associated with the lees of old cane wines (Li), bitter wood (Gk) or 2 amendments (LG), before and after 4 weeks of fermentation. The results obtained revealed the decrease of the acidity, the density and the total sugars in all the treatments tests, contrary to the controls, after the 28 days of incubation. On the other hand, all the treatments (tests and controls) produced alcohols with high contents of between 7.4 °GL and 9.9 °GL. But the wines of the control treatments, although very alcoholic, have all been judged as sour and of very poor taste quality. Bitter wood therefore does not appear to be involved in the processes of alcoholic fermentation, but in the constitution of organoleptic qualities, by preventing the proliferation of lactic acid bacteria. Thus, in order to optimize the quality of the wine, identifying the germs involved in the fermentation of cane nectar, under the influence of Garcia kola seems to be necessary.Keywords: Nectar, Yeasts, Additive, Alcohol, Organoleptic quality.