Validation of a fast gas chromatographic method for the study of semiochemical slow release formulations

in Journal of Pharmaceutical & Biomedical Analysis (2010), 53

The validation of a fast GC-FID analytical method for the quantitative determination of semiochemical sesquiterpenes (E-β-farnesene and β-caryophyllene) to be used in an integrated pest management ... [more ▼]

The validation of a fast GC-FID analytical method for the quantitative determination of semiochemical sesquiterpenes (E-β-farnesene and β-caryophyllene) to be used in an integrated pest management approach is described. Accuracy profiles using total error as decision criteria for validation were used to verify the overall accuracy of the method results within a well defined range of concentrations and to determine the lowest limit of quantification for each analyte. Furthermore it allowed to select a very simple and reliable regression model for calibration curve for the quantification of both analytes as well as to provide measurement uncertainty without any additional experiments. Finally, this validated method was used for the quantification of semiochemicals in slow release formulations. The goal was to verify the protection efficiency of alginate gel beads formulations against oxidation and degradation of sesquiterpenes. The results showed that the alginate beads are adequate slow release devices which protect the bio-active molecules during at least twenty days. [less ▲]

NIRS for the Determination of Internal Quality of Entire Apples

in NIR-2009 Breaking the Dawn (2009, November)

Study of thermomyces ianuginosa lipase in the presence of tributyrylglycerol and water

in Biophysical Journal (2009), 96(12), 4814-4825

The Thermomyces lanuginosa lipase has been extensively studied in industrial and biotechnological research because of its potential for triacylglycerol transformation. This protein is known to catalyze ... [more ▼]

The Thermomyces lanuginosa lipase has been extensively studied in industrial and biotechnological research because of its potential for triacylglycerol transformation. This protein is known to catalyze both hydrolysis at high water contents and transesterification in quasi-anhydrous conditions. Here, we investigated the Thermomyces lanuginosa lipase structure in solution in the presence of a tributyrin aggregate using 30 ns molecular-dynamics simulations. The water content of the active-site groove was modified between the runs to focus on the protein-water molecule interactions and their implications for protein structure and protein-lipid interactions. The simulations confirmed the high plasticity of the lid fragment and showed that lipid molecules also bind to a secondary pocket beside the lid. Together, these results strongly suggest that the lid plays a role in the anchoring of the protein to the aggregate. The simulations also revealed the existence of a polar channel that connects the active-site groove to the outside solvent. At the inner extremity of this channel, a tyrosine makes hydrogen bonds with residues interacting with the catalytic triad. This system could function as a pipe (polar channel) controlled by a valve (the tyrosine) that could regulate the water content of the active site. [less ▲]

Contribution to the study of semiochemical slow release formulations. Development of flash chromatographic methods

Conference (2009, April 24)

Survival of Freeze-dried Leuconostoc mesenteroides and Lactobacillus plantarum Related to Their Cellular Fatty Acids Composition during Storage

in Applied Biochemistry and Biotechnology (2009), 157(1), 70-84

Lactic acid bacteria strains Lactobacillus plantarum CWBI-B534 and Leuconostoc ssp. mesenteroïdes (L. mesenteroïdes) Kenya MRog2 were produced in bioreactor, concentrated, with or without cryoprotectants ... [more ▼]

Lactic acid bacteria strains Lactobacillus plantarum CWBI-B534 and Leuconostoc ssp. mesenteroïdes (L. mesenteroïdes) Kenya MRog2 were produced in bioreactor, concentrated, with or without cryoprotectants. In general, viable population did not change significantly after freeze-drying (p>0.05). In most cases, viable population for cells added with cryoprotectants was significantly lower than those without (p<0.05). Cellular fatty acids (CFAs) from the two strains in this study were analyzed before and after freeze-drying. Six CFAs were identified, namely, palmitic (C16:0), palmitoleic (C16:1), stearic (C18:0), oleic (C18:1), linoleic (C18:2), and linolenic (C18:3) acids were identified. Four of them, C16:0, C16:1, C18:0, and C18:1, make up more than 94% or 93% of the fatty acids in L. mesenteroides and L. plantarum, respectively, with another one, namely, C18:3, making a smaller (on average 5–6%, respectively) contribution. The C18:2 contributed very small percentages (on average≤1%) to the total in each strain. C16:0 had the highest proportion at most points relative to other fatty acids. Moisture content and water activity (a w) increased significantly during the storage period. It was observed that C16:1/C16:0, C18:0/C16:0 and C18:1/C16:0 ratios for freeze-dried L. mesenteroides or L. plantarum, with or without cryoprotectants, did not change significantly during the storage period. According to the packaging mode and storage temperatures, C18:2/C16:0 and C18:3/C16:0 ratios for freeze-dried L. mesenteroides and L. plantarum with or without cryoprotectants decreased as the storage time increased. However, a higher C18:2/C16:0 or C18:3/C16:0 ratio for L. mesenteroides and L. plantarum was noted in the freeze-dried powder held at 4 °C or under vacuum and in dark than at 20 °C or in the presence of oxygen and light [less ▲]

Adsorption of essential oil components of Xylopia aethiopica (Annonaceae) by kaolin from Wak, Adamawa province (Cameroon).

in Applied Clay Science (2009), 44(1-2), 1-6

Essential oils of aromatic plants are nowadays cited as suitable tools for better protection of stored grains from insect pest attacks. These chemical insecticides are less attractive to producers because ... [more ▼]

Essential oils of aromatic plants are nowadays cited as suitable tools for better protection of stored grains from insect pest attacks. These chemical insecticides are less attractive to producers because of their low persistence and difficulty to use as pure product. There is therefore a need to formulate themas an easy handling chemical with better persistence. The present work aimed to study the formulation through adsorption of active components of Xylopia aethiopica Dunal (Annonaceae) essential oil on kaolin. X. aethiopica essential oil was obtained by hydrodistillation in a Clevenger type apparatus unit. Essential oil obtained was analysed by a GC–FID and a GC–MS. The adsorption measurements were performed with collected two kaolin fractions (F1 <100 μm; F2 <50 μm) and two kaolin fractions after H2O2 treatment (F3 <50 μm; F4 <2 μm). The kaolin was characterized by XRD, XRF, FTIR; its specific surface area was determined by the B.E.T method. The amount of essential oil adsorbed was inversely proportional to the particles size. Treatment of kaolin with hydrogen peroxide increased the adsorption capacity of essential oil components. The components adsorbed in highest amounts were sabinene, β-pinene, α-pinene and β-phellandrene. [less ▲]

Contribution to the study of semiochemical slow release formulations. Development of flash chromatographic methods.

Poster (2009)

Les huiles essentielles de menthe d’Algérie:« Mentha pulegium & Mentha rotundifolia ».

Conference (2009)

Interesterification of rapeseed oil with anhydrous milk fat and its stearin fraction

Poster (2009)

The compositional changes occurring during the lipase-catalysed interesterification of AMF/rapeseed oil (RO) and AMF stearin fraction (AMFSF)/RO blends were described in the first part of this study. In ... [more ▼]

The compositional changes occurring during the lipase-catalysed interesterification of AMF/rapeseed oil (RO) and AMF stearin fraction (AMFSF)/RO blends were described in the first part of this study. In the present and second part are reported the resulting changes in physical properties, especially the melting behaviour through solid fat content (SFC), dropping point (DP) and fusion profiles by differential scanning calorimetry (DSC). [less ▲]

Study of Essential Oils of Some Plants from Algeria (Salvia officinalis, Thymus vulgaris and Ruta chalepensis)

Poster (2009)

The essential oil of three plants (Salvia officinalis, Thymus vulgaris and Ruta chalepensis) collected from Chlef, in the north west of Algeria, was isolated by steam distillation and investigated by GC ... [more ▼]

The essential oil of three plants (Salvia officinalis, Thymus vulgaris and Ruta chalepensis) collected from Chlef, in the north west of Algeria, was isolated by steam distillation and investigated by GC and GC/MS. The yield of essential oil (g/100g) was 1.6% for Salvia officinalis, 2.6% for Thymus vulgaris and 1.1% for Ruta chalepensis. The Salvia officinalis was mainly composed of b-thujone (25%), camphor (23.6%), 1,8-cineole (21.5%), viridiflorol (9.5%) and a-thujone (6%). The main constituents of Thymus vulgaris were carvacrol (48.4%), g -terpinene (14.9%), p-cymene (14.7%) and thymol (5.6%) while 2-undecanone (83.2%) constituted the major component of Ruta chalepensis essential oil. [less ▲]