This work concerned the valorization of shea butter, palm, coconut and kolo oils and, essential oils from Eucalyptus citriodora, Ocimum gratissimum, Cymbopogan citratus and Plectranthus glandulosus by applying a few stages of quality management procedures for soap making. For this purpose, the consumers' needs regarding the soap quality characteristics have been identified. It emerged that the soap smell was of more concern to them. The product was then designed by mixture design of experiment and, 50 g soap samples produced were subject to consumer assessment. Results showed that samples made with coconut (25 g) and kolo (25 g) oils gave the most popular soap according to the rates they received. Among the data of the four quality characteristics, only those from physical measurements of foam height suited the quadratic model. This lead to optimize this characteristic and the values of variables found were coco (17.171 g) and kolo (32.829 g) for a 9 cm maximum and 8 cm minimum foam height. There was no significant discrimination between both the odors of lemongrass and waya essential oils tested. The soaps perfumed with essential oils from Eucalyptus citriodora, Ocimum basilicum and Plectranthus glandulosus exerted an antimicrobial activity against Bacillus subtilis, Pseudomonas aeruginosa and Staphylococcus aureus.

L’ecorce de Fagara heitzii est utilisee au Congo-Brazzaville dans la prevention des chiques et la peche, comme la rotenone. Nous avons observe que la poudre et l’extrait a l’hexane des ecorces de cet arbre contiennent des composes insecticides. La DL50 de la poudre seche appliquee sur le fond de la boite de Petri est de 14,5 mg/ml pour 20 adultes de charancon de mais, Sitophilus zeamays, apres 48 heures. La DL50 du meme compose teste sur la bruche du niebe, Callosobruchus maculatus, est de 16,144 mg/ml apres 48 heures. Ces insectes causent d’importants dommages economiques dans les stocks de mais et de niebe au Congo-Brazzaville. Les extraits a l’hexane de l’ecorce de Fagara heitzii sont egalement toxiques aux deux insectes. Les symptomes observes laissent supposer que ces extraits sont neurotoxiques et/ou inhibiteurs respiratoires. Ces extraits sont egalement toxiques a la blatte americaine, Periplaneta americana. Les blattes testees ont exprime, en plus des symptomes observes chez les precedents insectes, un reflexe de fuite. Elles semblent detecter le compose. Des signes d’irritation ou de mobilite exageree observes chez les trois insectes peuvent s’expliquer par un effet sur les nerfs .

Zanthoxylum heitzii bark extracts have insecticidal properties and have been reported to be used against malaria in Western Africa. Previously, it has been shown that a hexane extract of the bark is toxic to adult females of the mosquito Anopheles gambiae, a malaria vector. As part of our project on the control of malaria vectors using plant extracts, the phytochemistry of Z. heitzii bark hexane extract has been investigated with the aim to identify the major components with adulticidal and larvicidal effects on An. gambiae.

La composition en tri-acylglycerols des lipides d’atherure africain et du cephalophe bleu a ete determinee. Une biodisponibilite des acides gras constitues par les Sn-2- monoacylglycerols, obtenus a partir des isomeres issus des triacylglycerols totaux provenant de l’analyse chromatographique par HPLC des lipides de ces deux especes animales, a ete envisagee afin d’en degager la valeur nutritionnelle. Il ressort de ce travail que les lipides de la viande de l’atherure africain fournissent a l’organisme plus d’acide linoleique suivi de l’acide oleique ; tandis que ceux du cephalophe bleu fournissent plus l’acide oleique suivi de l’acide linoleique. Les acides palmitique et stearique dans les deux cas ne sont fournis qu’en tres faible quantite. De ce fait, sur le plan lipidique, la viande de l’atherure africain et celle du cephalophe seraient tres energetiques et fournisseuses des acides gras polyinsatures de la serie n-6. Par consequent, elles n’auraient aucun effet deletere chez les consommateurs.

The olon tree, Zanthoxylum heitzii (syn. Fagara heitzii) is commonly found in the central-west African forests. In the Republic of Congo (Congo-Brazzaville) its bark is anecdotally reported to provide human protection against fleas. Here we assess the insecticidal activities of Z. heitzii stem bark, seed and leaf extracts against Anopheles gambiae s.s, the main malaria vector in Africa. Extracts were obtained by Accelerated Solvent Extraction (ASE) using solvents of different polarity and by classical Soxhlet extraction using hexane as solvent. The insecticidal effects of the crude extracts were evaluated using topical applications of insecticides on mosquitoes of a susceptible reference strain (Kisumu [Kis]), a strain homozygous for the L1014F kdr mutation (kdrKis), and a strain homozygous for the G119S Ace1R allele (AcerKis). The insecticidal activities were measured using LD50 and LD95 and active extracts were characterized by NMR spectroscopy and HPLC chromatography. Results show that the ASE hexane stem bark extract was the most effective compound against An. gambiae (LD50 = 102 ng/mg female), but was not as effective as common synthetic insecticides. Overall, there was no significant difference between the responses of the three mosquito strains to Z. heitzii extracts, indicating no cross resistance with conventional pesticides.

Biodiversity conservation with the improvement of living conditions requires the efficiency in use of all resources. For instance, A better exploitation of the endemic oleaginous plants of the tropical forests should mitigate the extension of the palm plantations which is one of the greatest threats of the biodiversity in this area. The raffia palm fruit contains edible oil richer in nutrients than oil palm. However, oil raffia production remains weak because entirely based on empirical methods. This study compares the effect of convective and microwave dryings on the drying kinetics, color and hardness of the raffia pulp. Moreover, four drying kinetics models and the concept of characteristic drying curve have been tested for this pulp. To this end, six drying temperatures and four power levels have been used. The results show that the drying time passes from 10 h at 40°C to 3 h at 90°C and from 30 min at 140 W to 5 min at 560 W. The results could be represented by one characteristic drying curve. Among the four models used, the Modified Khazaei model is the best. The coefficient of effective diffusivity varies from $0.63×10^{-10}$ to $3.8×10^{-10} m^2/s$ for convective drying and from $10.05×10^{-10}$ to $88.5×10^{-10} m^2/s$ for microwave. The activation energy is 34±2 KJ/mol. It is found that convective drying degrades the color and increases the hardness of the pulp more than microwave drying.

Microwave drying characteristics of safou pulp (Dacryodesedulis) were evaluated in a laboratory scale microwave dryer. The drying experiments were carried out at 0.42, 0.56 and 0.70 kW. Three commonly used mathematical models were evaluated with the experimental data. The results indicated that the Page model was most adequate in predicting moisture transfer for safou pulp, just a falling rate period was observed in the microwave drying processes; the values of effective diffusivity were increased with the increment of the experimental power levels. The regression equations of drying rate against drying duration or moisture were found to describe very well the drying characteristics for safou pulp; it took nearly 70% of total drying time to remove the latter half of moisture in the microwave drying safou pulp. The above findings can facilitate the design and operation of microwave drying of safou pulp. Key words: Dacryodesedulis, microwave drying characteristics, modelling, diffusivity, drying rate.

The bark of the Fagara heitzii tree in the west-central African Republic of Congo (Congo–Brazzaville) is known anecdotally to provide protection for human residents against fleas and to be of use as a narcotic in fishing (similar to rotenone). We found that powder and hexane extracts from the bark of the Fagara heitzii tree contain insecticidal compounds. Dried powder (14.5 mg) on the bottom of a Petri dish is the residue at 14.494 mg per dish (LD 50 ) for 20 adult maize weevils Sitophilus zeamays after four days. The LD 50 of the same material to 20 adult cowpea weevils Callosobruchus maculatus was slightly higher at 16.144 mg/dish (after 48 h). These weevils cause significant economic damage to cowpea and maize in Congo–Brazzaville. Hexane extracts of the bark of Fagara heitzii were also toxic to these weevils. Symptoms of toxicity suggested the extracts were slow-acting nerve poisons or respiratory inhibitors or both. The time needed to develop full toxicity suggested a respiratory poison. The hexane extract was also toxic to the American cockroach Periplaneta americana . The symptoms in the cockroach were similar, but cockroaches also exhibited apparent escape attempts suggesting they could detect the compounds. Signs of apparent irritation or exaggerated locomotion in all three insects also suggested irritation or nerve effects.

An assessment of the softening of safou (African plum) pulp was used to specify the nature and importance of its various physical causes and to evaluate the impact of this process on the chemical composition of the pulp. Individual tree characteristics or fruit size, or stalk ablation, had no significant influence on pulp softening, which appeared 3-4 days after harvest when the fruits were stored in an open air room (25-30 degrees C). Lowering room temperature by storage in an air-conditioned room (16-22 degrees C) extended the preservation time of the fruit by 4 days.Softened fruits preserved their nutritional qualities. Although such fruits are unsuitable for consumption as mouth fruits, they can still be readily used to obtain oil. (c) 2006 Elsevier Ltd. All rights reserved.