Characteristic Physicochemical of Oil Extract from Moringa oleifera and the Kinetics of Degradation of the Oil during Heating

Abstract: The aim of the study was to investigate the physicochemical properties and the kinetics of degradation of Moringa oleifera seed oil during heating. The seed is a good source of oil (40%). The physical properties of the oil extracts showed the state to be liquid at room temperature and indicated that the oil had refractive index, 1.4680; the peroxide value, 1.67 (meq O 2 /kg oil); free fatty acid, 2.10%; iodine value, 66.2%; saponification value, 167; unsaponifiable matter content, 0.87% and viscosity, 47.24 (mPa.s at 25°C). Gas liquid chromatography technique has been developed for identification and quantitative determination of total unsaturated and saturated fatty acids shows that the crude oil had 79.57 and 20.42% respectively. Differential Scanning Calorimetry (DSC) indicates the presence of three components in oil extracted. The first peak at low melting point appears at -31.10°C (∆H f = -5.36 J/g), the second peak appears to -7.03°C (∆H f = +49.56 J/g) and the last peak appears to +6.30°C (∆H f = +0.55 J/g). The degradation kinetic of the oil was also investigated. The thermal oxidation of the double bonds of the oil showed a first-order thermal oxidation kinetic and the Arrhenius plot yielded a straight line with a slope equivalent to activation energy of 1.593 KJ/mol. There is the possibility of considering the seed as feed supplement and its oil for industrial application

MODELISATION DISCRETE DE L'AGGLOMERATION DES FINES MINERALES EN SUSPENSION

International audienceRESUME : La demande en eau des fines est une caractéristique importante pour la formulation des coulis, mortiers et bétons. Cette demande en eau dépend étroitement de l'agglomération des fines en suspension qui piège une partie de l'eau libre. Dans cette étude, une formulation aux éléments discrets (DEM) (Cundall, et Strack, 1979) est utilisée afin d'étudier la fragmentation des agglomérats lors d'un cisaillement et de caractériser, à l'équilibre, la compacité de ces agglomérats. Le modèle permet la prise en compte des forces de contact, des forces de Van der Waals et des forces électrostatiques. Les forces hydrodynamiques sont pour le moment décrites à partir de la force de Stokes. La restructuration des agglomérats en fonction du gradient de vitesse appliqué est étudiée. Les résultats montrent que la taille et la dimension fractale des agglomérats varient avec le gradient de vitesse

Characteristics and Composition of Jatropha curcas Oils, Variety Congo

Abstract: The oil from Jatropha curcas seeds variety "Congo-Brazzaville" was extracted using two oils extraction methods with petroleum ether (Soxlhet) and extraction with a mixture of chloroform:methanol (1:1) (Blye and Dyer). The oils were compared of Jatropha curcas other countries. The oil concentration ranged from 50% (Soxlhet) to 47% (Blye & Dyer). The minerals, viscosity, acidity, saponification value, iodine value, fatty acid methyl esters, unsaponifiable matter content, peroxide value, activation energy and differential scanning calorimetry were determined. Jatropha curcas seeds have ash content of 4.2% (with the presence of following minerals: Ca, Mg, K and Na). The oil was found to contain high levels of unsaturated fatty acids, especially oleic (up to 40.10%) and linoleic (up to 37.60%). Jatropha curcas oil can be classified in the oleiclinoleic acid group. The dominant saturated acids were palmitic (up to 15.63%) and stearic (up to 5.78%). Jatropha curcas seeds were also founded to contain high levels of crude protein (25%). The content of insaponifiables is 0.89 %. Taking into account these results, Jatropha curcas can be cultivated for the production of oil of technical interest (biocarburant, soap, painting, lubricants, insecticides, etc)