Mohamed M. Soumanou

Highly selective synthesis of 1,3‐oleoyl‐2‐palmitoylglycerol by lipase catalysis

1,3-Oleoyl-2-palmitoylglycerol (OPO), an important structured triglyceride in infant nutrition, was synthesized by a two-step process in high yields and purity using sn1,3-regiospecific lipases. In the first step, tripalmitin (TP) was subjected to an alcoholysis reaction in an organic solvent catalyzed by sn1,3-regiospecific lipases yielding the corresponding 2-monopalmitin (2-MP). The 2-MP was isolated in up to 85% yield and >95% purity by crystallization and esterified in the second step with oleic acid using the same lipases to form the structured triglyceride OPO in up to 78% yield containing 96% palmitic acid in the sn2-position. Water activity, solvent, as well as carrier for lipase immobilization strongly influenced the yield and purity of products in both steps. The best results were achieved with lipases from Rhizomucor miehei and Rhizopus delemar immobilized on EP 100 and equilibrated to a water activity of 0.43. Special emphasis was given to develop this process in solvents that are allowed to be used in foodstuffs and to perform the second step in a solvent-free system.

Synthesis of structured triglycerides by lipase catalysis

The synthesis of structured triglycerides containing medium chain fatty acids (M) in sn1 and sn3-position and an unsaturated long-chain fatty acid (L) in sn2-position of the glycerol backbone (MLM) with 1,3-regiospecific lipases has been investigated. In an one-step synthesis (acidolysis or transesterification) various commercial lipases were tested. In all reaction systems, the recovered product contained considerable amounts of undesired byproduct (e.g. MLL). A significantly higher concentration of MLM was obtained in a two-step process under the control of the water activity: in the first step, the 2-monoglycerides (2-MG) were prepared by alcoholysis (e.g. with ethanol) of pure triglycerides (triolein and trilinolein) or a natural oil (cottonseed oil) with lipase from Rhizopus delemar immobilized on Celite in organic solvents (e.g. methyl tert-butyl ether).The 2-MGs were purified by crystallization and isolated in yields up to 71.8% (e.g. from triolein). The 2-MGs obtained from cottonseed oil was esterified in the second step with caprylic acid in n-hexane using lipase from Rhizomucor miehei (Lipozyme). The final product contained more than 94% caprylic acid in sn1- and sn3-position. whereas the sn2-position was composed of 78% of unsaturated long-chain fatty acids.

Nutritional Composition of Shea Products and Chemical Properties of Shea Butter: A Review

Increasing demand of shea products (kernels and butter) has led to the assessment of the state-of-the-art of these products. In this review, attention has been focused on macronutrients and micronutrients of pulp, kernels, and butter of shea tree and also the physicochemical properties of shea butter. Surveying the literature revealed that the pulp is rich in vitamin C (196.1 mg/100 g); consumption of 50 g covers 332% and 98% of the recommended daily intake (RDI) of children (4–8 years old) and pregnant women, respectively. The kernels contain a high level of fat (17.4–59.1 g/100 g dry weight). Fat extraction is mainly done by traditional methods that involve roasting and pressing of the kernels, churning the obtained liquid with water, boiling, sieving, and cooling. The fat (butter) is used in food preparation and medicinal and cosmetics industries. Its biochemical properties indicate some antioxidant and anti-inflammatory activities. Large variations are observed in the reported values for the composition of shea products. Recommendations for future research are presented to improve the quality and the shelf-life of the butter. In addition, more attention should be given to the accuracy and precision in experimental analyses to obtain more reliable information about biological variation.

Crucial role of support and water activity on the lipase-catalyzed synthesis of structured triglycerides

The synthesis of structured triglycerides (MLM) containing medium-chain fatty acids (e.g. caprylic acid) in the 1- and 3-positions and a long-chain fatty acid (e.g. oleic acid, linoleic acid) in the 2-position of glycerol has been investigated. Special emphasis was given on the influence of support, organic solvent, and water activity on the lipase activity. Water adsorption isotherms for different lipase preparations were determined. In the interesterification between triolein and caprylic acid, best results (up to 45% CyOCy and 46% CyOO) were found with Celite-immobilized lipases from Rhizopus sp. and Rhizomucor miehei at low water activity (0.11 < aw < 0.33) in n-hexane. Vmax/Km-values were similar using caprylic acid or the corresponding methyl or ethyl esters. Alternatively, a two-step reaction was investigated, where 2-mono-glycerides (2-MG) were produced with a 1,3-regiospecific lipase from Rhizopus delemar from pure triglycerides (triolein, trilinolein) or cottonseed oil. The 2-MG were isolated an...

Indigenous Knowledge of Shea Processing and Quality Perception of Shea Products in Benin

A survey among 246 people belonging to 14 ethnic groups and living in 5 different parklands in Benin revealed different practices to process shea kernels (namely boiling followed sun drying and smoking) and extract shea butter. A relation between parklands, gathering period, and sun-drying conditions was established. Moisture content and appearance of kernels were the selection criteria for users of shea kernels; color was the main characteristic to buy butter. Constraints to be solved are long processing times, lack of milling equipment and high water requirements. Best practices for smoking, sun drying, and roasting operations need to be established for further improvement.

Effect of Processing on the Quality of Pineapple Juice

Pineapple processing plays an important role in juice preservation. Because the quality of the pineapple juice is affected by the processing technology applied, the effects of pasteurization and other preservation methods on the overall juice quality were discussed. During juice processing, microorganisms are destroyed and chemical changes occur. To optimize processing conditions, knowledge of the kinetics of these reactions is needed, but as of yet, data on the degradation of the amino acids and vitamin C and the change in sugar contents during pineapple juice pasteurization are scanty. Furthermore, the kinetics of hydroxymethylfurfural production should be investigated by a precise technique such as high-performance liquid chromatography.

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.

Effect of fuel and kiln type on the polycyclic aromatic hydrocarbon (PAH) levels in smoked shrimp, a Beninese food condiment

Smoked shrimp is a food condiment widely used in Beninese local cooking practices. A previous study revealed that this product is highly contaminated with polycyclic aromatic hydrocarbons (PAH). The present study explored possibilities to reduce PAH levels in shrimp smoked using cottage industry smoking techniques with barrel and chorkor kilns, by replacing wood by charcoal from Acacia auriculiformis and Mangifera indica, as fuels. Results showed that only shrimp smoked using acacia charcoal in a chorkor kiln had PAH levels (benzo[a]pyrene = 5 µg kg−1 and sum of benzo[a]pyrene, chrysene, benzo[a]anthracene and benzo[b]fluoranthene = 28 µg kg−1) in accordance with a European standard of 5 and 30 µg kg−1, respectively, and suitable physicochemical characteristics for good storage (moisture content = 11.9% ± 1.5%; water activity = 0.46 ± 0.03). However, further investigations still needs to be done to reduce the duration of product contact with combustion gasses in order to reduce the PAH content of smoked shrimp to safer levels, largely below standards.

Indigenous Knowledge on Landraces and Fonio-Based Food in Benin

Fonio is a traditional cereal cultivated in many West African countries, where farmers are often the guardians of a rich diversity of landraces or traditional varieties. An investigation conducted in northwest of Benin on indigenous knowledge about fonio landraces and fonio-based traditional foods allowed us to inventory 35 landraces identified by the farmers. Ipormoa, Namba, Icantoni or Kopognakè or Icantoga and Iporhouwan landraces were good to cook paste and couscous and easy to dehusk. Besides, Ipormoa and Iporhouwan landraces had interesting agronomic characteristics. Paste, porridge, and couscous were the main fonio-based foods consumed by farmers in northwest of Benin.