Fidèle P. Tchobo

Plant latex lipase as biocatalysts for biodiesel production

Industrial-scale processes currently developed make use of chemical catalysis processes that are highly efficient but require very complex product purification steps. Enzymatic catalysis through plant lipases as biocatalysts is an alternative which, in contrast to chemical catalysis processes, appeared simple to perform, and can be done at low investment cost. Although microbial lipases have been extensively studied, little research has been focused on the use of plant lipases namely plant latex lipases. The present article outlines the most advanced knowledge concerning plant latex characterization in order to show how plant latex can be a promising alternative to catalyze transesterification for biodiesel production. This paper provides an overview regarding the main aspects of latex, such as the reactions catalyzed, physiological functions, specificities, sources and their industrial applications. Key words: Plant latex, lipase, Transesterification, purification, biodiesel.

Profiling the quality characteristics of the butter of Pentadesma butyracea with reference to shea butter.

BACKGROUND Pentadesma butyracea is a tropical plant species. Its kernels are rich in edible butter similar to shea butter. This study evaluated the quality characteristics of the Pentadesma butter produced by cottage enterprises in Benin, using a quantitative survey approach and physicochemical and sensorial analysis methods. RESULTS The butter of Pentadesma is mostly used for food preparation, cosmetic and therapeutic applications. It is characterized by a yellow colour, a hard texture, a relatively sweet taste and a bright appearance. Consumers preferred Pentadesma butter to shea butter for colour, taste, texture and appearance. Instrumental analysis showed that the average water content (6.5 g kg(-1) ) and peroxide value (0.74 mEq O2 kg(-1) ) of Pentadesma butter were lower than those of shea butter, for which average water content and peroxide values were 20.7g kg(-1) and 2.09 mEq O2 kg(-1) respectively. The fatty acid profile of Pentadesma butter is similar to that of shea butter. CONCLUSION This study showed that the Pentadesma butyracea butter produced by cottage enterprises in Benin exhibited quality characteristics which are better than that of shea butter. The data generated can be used for a better exploitation of the butter in food and cosmetic industries.

Aeollanthus pubescens Benth. from Benin: A Potential Source of Essential Oil with High Antiradical Efficiency

The chemical composition of the essential oils obtained by hydrodistillation from leaves of three samples of Aeollanthus pubescens Benth. (Lamiaceae) growing wild in Benin were analyzed by GC and GC-MS. To date the biological functions of A. pubescens essential oils have not been demonstrated scientifically even if this plant is traditionally used by local population in alimentary and medicine. We investigated the chemical composition of A. pubescens essential oils and their antiradical and anti-inflammatory activities. Twenty four compounds were identified and quantified in the essential oils, the major compounds being thymol (63.6 %; 9.5 %; 63.4 %), carvacrol (3.1 %; 51.1 %; 2.1 %), thymyl acetate (9.8 %; 0.8 %; 10.2 %), carvacryl acetate (0.8 %; 6.1 %; 0.7 %), p-cymene (5.6 %; 9.0 %; 5.5 %) and γ-terpinene (6.4 %; 11.2 %; 6.6 %). The antiradical activity of these oils was found to be high and a low anti-inflammatory activity was observed. Fractionation of a thymol rich sample allowed the identification of the bioactive fractions and their contribution to the efficiency of the whole extract. This study suggests that A. pubescens essential oils may be useful in the food industry where the antioxidants are used to retard the degradation of fatty substances, but also in cosmetics or in the field of herbal medicine, where the radical species are associated with the concept of antiaging.

Catalysis by Candida antarctica B (CALB) immobilized on natural pure silica by adsorption: comparison with the free enzyme

Objective: In this work, a lipase B from Candida antarctica strain was immobilized onto natural silica carriers via adsorption to enhance its feasibility in practical applications. Methodology and results: The biocatalyst was prepared by simple adsorption on the support whose composition was beforehand characterized and the activities in ethyl ester hydrolysis and synthesis evaluated. The natural silica carriers were rich in silicon dioxide (SiO2) (97.36%). The optimum temperature of immobilized lipase was 40 °C, which was identical to that of the free enzyme. The immobilized lipase exhibited a higher relative activity than that of free lipase over 40 °C. The optimal pH for immobilized lipase was 7.5, which was similar to that of the free enzyme. After 10 recycled batches, a high residual esterification conversion (90%) was maintained. Conclusions and application of findings: The results in the present work indicate that pure silica is a potential material as an immobilization matrix for industrial process. There may have a promising future as support of the biocatalysts in various syntheses.

Physicochemical Characterization and Polyphenolic Content of Beninese Honeys

The physicochemical and phytochemical analyses of honeys (n = 50) from Sudanese, Sudano-Guinean, and Guinean areas of Benin were investigated. Results showed that dark amber is the dominant color. Moisture content ranged from 15.50% to 23.50%, and 72% of honeys respected the Codex Alimentarius recommendation. pH varied between 2.87 and 6.15, and free acidity ranged from 9.00 to 39.00 meq/kg. Electrical conductivity varied from 0.37 to 1.43 mS/cm. The content in fructose varied from 21.67% to 94.21%, and proline content ranged between 306.31 and 1187.93 mg/kg. All physicochemical characteristics varied with the areas. A negative correlation was found between pH and moisture content (r = −0.55; p < 0.01). A positive correlation was established between pH and conductivity (r = 0.79; p < 0.01) and between proline and color (r = 0.44; p < 0.01). Total phenolic content varied between 55.97 and 224.99 mg GAE/100 g, and flavonoid content ranged between 1.43 and 29.81 mg CAE/100 g. Flavonoid was positively correlated with color (r = 0.78; p < 0.01) and proline (r = 0.47; p < 0.01). Tukeys test revealed differences between total phenolic and flavonoid contents of honeys from five areas (p < 0.01). In general, Sudanese and Sudano-Guinean honeys showed potential toward therapeutic applications because of their high phenolic contents.

Performance and design optimisation of an apparatus for distilling palm wine (Elaeis guineensis) by controlling thermal operations

Mastery of thermal control in the craft distillation processing operations of fermented wine from Elaeis guineensis is needed to improve and enhance the resulting Beninese alcoholic drink, sodabi. In this study, craft distillation of palm-wines from three municipalities of southern Benin was investigated and the influences of wine vapour temperature on some physical-chemical parameters of the liquor produced were analysed. Palm wines, handcraft distilled, presented relative density values between 0.90 to 0.96, volumetric alcoholic strength from 35.16 to 46.29% (v/v), acetic acid content of 1.17 to 3.29 g/l and pH-values of 3.7– 4.2. A series of palm-wine distillations, from liquor-producing farms, controlled by maintaining the heating temperature at 94 ± 1 °C, was also performed. The values of characteristic parameters were then respectively 0.84 to 0.93, 38.05 to 52.72% (v/v), 0.35 to 0.39 g/l and 4 to 4.25. From analysis of these results, we conclude that the high values of wine heating temperature, well above 100 °C, induce a significant increase in relative density and acetic acid content of sodabi and a decrease of its volumetric alcoholic strength and pH-value. Controlled laboratory distillation yielded a distillate which has the best features of spirituous and thermal efficiency.