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

Abstract

RESUMELe 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. Mots clés : Morphologie du fruit ; mangue ''Boko'' ; indice de maturation ; productivité en éthanol. ABSTRACTEffect 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 overripened 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.

Morphological and Physicochemical Parameters of Three Mango (Mangifera Indica L) Varieties Exported In North of Ivory Coast

“…These values were substantially similar to the results of Passannet et al [7] which were 9.72 ± 0.50 for Kent and 9.52 ± 0.60 for Keitt. Moreover our values were appreciably close to those of Diakabana et al [9] who in their studies on the Boko mango in Cameroon, found a size of 8.62 ± 1 (when the values of lengths (L); width (l) and thickness (e) were expressed in centimeter (cm)). In addition, Lechaudel & Joas [15] showed that the size of the fruit is a quality criterion that strongly depends on the accumulation of water and dry matter in the three (03) compartments of the fruit: the stone, the pulp and the skin.…”

“…The total weight of the fruit was determined using a balance of precision (OHAUS brand, CS200E type, USA). The measures of the mass of the components of the fruit were determined by weighing, according to the methods of Diakabana et al [9]. However, the mass of the skin was determined by deduction between that of the fruit and the stone.…”

Morphological, Physical and Biochemical Characteristics of the three Main Varieties of Mango (Mangifera indica L.) Cultivated in the Poro Region (North of Côte d'Ivoire)

“…Indices caliber of Kent and Keitt were close to those, respectively 9.72 and 9.52, reported for the same varieties grown in Chad [34]. In contrast, the three varieties demonstrated higher caliber indices than that of the mango cultivar Boko from Congo, which was 8.62 when length (L); width (w) and thickness (e) are expressed in cm [35]. Moreover, according to [40], fruit caliber depends on the accumulation of water and dry matter in the three compartments of the fruit: stone, pulp and peel.…”

“…On the other hand, fruit volume of Kent was higher than those, between 353.91 and 428.58 cm 3 , reported for Kent also from the North of Côte d'Ivoire, and harvested on four harvest periods: 90, 95, 100 and 105 days after inflorescence [21]. Furthermore, in their study on mango Boko in Congo, [35] found a fruit volume of 380 cm 3 which is lower than those of Kent and Amelie; but, superior to that of Keitt. Thus, the mangoes Kent and Amelie were obviously larger than those of Keitt.…”

Correlation between Initial Content of Starch of the Mash of Cassava (Manihot esculenta L) in Fermentation and Temperature of Distillation of Alcoholic Fermented Wort in the Course of the Production of Bioethanol in Congo

“…For the planting of the samples of cassava mash at low and high densities, the following contents of dry yeast Saccharomyces cerevisiae were employed ( Chlup et al, 2007) after activation (Diakabana et al, 2013a): for E1 1g/L, E2 1.5g/L, E3 2g/L, E4 2.5g/L, E5 3.5g/L and E6 4g/L. After mixing, the mixture of the ingredients obtained was introduced into micro tank (Diakabana, 2008a) and the volum standardized with cool water added in sufficient quantity to make 4 liters.…”