Effet du degré de maturation sur la cinétique de fermentation éthylique de la pulpe de mangue cultivar BOKO

Le fruit de la mangue « Boko » présente des caractéristiques physiques et organoleptiques très particulières comparées aux autres mangues produites au Congo. La masse de ce fruit est de 390g en moyenne et très proche de celle des variétés lippens et broagt, mais son rendement en pulpe (67% de la masse du fruit) est nettement  plus élevé. Sa largeur (107,94±20,09mm) et son épaisseur (72,27±5,35mm) sont assez régulières mais son indice de sphéricité (0,88±0,52) est très dispersé. Les  diverses caractéristiques physicochimiques du fruit de la mangue ’’Boko’’ sont fonction du degré de maturation physiologique évalué à partir de l’indice de maturation β (de β1 =18,22 à β3 = 83,5). La  surmaturation de ce fruit intervient lorsque la valeur de l’indice de maturation est supérieur (β3=83,5). Elle correspond  à une forte diminution du degré d’acidité de 72,6%, une diminution significative de la teneur en eau (de 83,98% à 81,18% d’eau), mais à une augmentation considérable de la teneur en sucre (de 10 à 19° Brix). La faible acidité (2g de H2SO4/l) de la pulpe de mangue surmaturée est responsable de la fermentation incomplète du jus testé. Afin d’améliorer la productivité horaire en éthanol du jus de pulpe de mangue surmaturée, il serait nécessaire de procéder à une acidification indirecte par l’apport d’une portion de pulpe de mangue moins mûre. ------------------------------------------------------------------------------------------------------------------------------------ Effect of the maturation index on the kinetic of ethyl fermentation of juice from the mango cultivar''Boko’’ pulp. The fruit of the mango''boko’’ presents physical and organoleptic characteristics very special compared to other mangoes produced in Congo. The mass of this fruit is 390g on average and very close to those of lippens and broagt varieties, but its pulp yield (67% of the mass of fruit) is much higher. Its width (107, 94±20,09mm) and thickness (72, 27±5,35mm) are fairly regular, but the sphericity index (0, 88±0, 52) is very varied. The various physicochemical characteristics of mango ‘’boko'' fruit depend on the degree of physiological maturity assessed from the maturation index β (from β1=18.22 to β3= 83.5). The over-ripening of this fruit occurs when the value of the maturation index was higher (β3= 83.5) and corresponds to a decrease pronounced of degree of acidity of 72.6%, a significant decrease in water content (from 83.98% to 81.18% of water), but a considerable increase in sugar content (from10° Brix to 19° Brix). The low acidity (2g of H2SO4/l) of over-ripened mango pulp is responsible for the incomplete fermentation of juice tested. To improve the hourly productivity in ethanol from juice of ripened mango pulp, it would be necessary to acidify indirectly by providing a portion of mango pulp less mature

Study of characteristic parameters of traditional process in the production of “Boganda”, a brandy of Congo

“Boganda” is an appreciated traditional distilled alcoholic beverage in Congo. It brings an interesting income to producers though its quality is extremely variable from a workshop to another. The production is based on three stages: malting of corn, fermentation and distillation. The corn used initially undergoes, during 5 days, an uncontrolled germination in medium quickly becoming anaerobic, with an increase in temperature up to about 49 ± 3 °C; that causes death of majority of corn germs and formation of various flavours. The obtained fermented malt is distilled without column. The distillate is collected empirically in fractions of volume according to the alcoholic amount corresponding to little distinct stages of temperature up to 98 °C. The final distilled alcoholic beverage has an alcoholic degree of approximately 24.2 ± 3 °GL, the volume of collected distillate being extremely variable. The study of physicochemical characteristics reveals a very great dispersion of parameters of manufacturing process and quality of product. Keywords: Brandy, ethanol, optimization, “Boganda”. Int. J. Biol. Chem. Sci. Vol. 2 (3) 2008: pp. 258-27

Evaluation of the traditional technology of production of lungwila, a wine of sugarcane of Congo

The aim of study was to evaluate the used technology in the production process of lungwila, a traditional drink of soils of sugarcane in the Basin of Congo. This beverage provided an interesting income for the producers although the quality varied from a workshop to another. The leaven used for the fermentation of lungwila wine was active and inoculated when the maximum of yeast cell concentration was reached (between 3.5x108 and 6x108 CFU of yeast/ml) from a propagation process carried out by adding up gradually of the increasing volume with fresh juice of sugarcane. During the fermentation, the consumption of sugars was limited to an average of 5.3°Brix marking the end of the process in 72-92 hours. At the end of the fermentation, the supernatant wine was crudely stripped of its amorphous particles by a natural decanting process and was subsequently drawed. The starter which results was regularly kept up every three to four cycles of fermentation by eliminating the superficial muddy phase and feeding, with fresh ingredients additives: it could serve on several other cycles of  fermentation for about a year. Analysis of physico-chemical parameters of finished product revealed that lungwila is an alcoholic beverage  (10.5±1.397% ethanol) having a sweet taste (6.29±2.40 °Brix) and sour (pH=3.22±0.173).Keywords: Lungwila, wine of soils, sugarcane, corn, fermentation on leaven