Volume 8, No. 3 (2007)
Articles
APPLICATIONS OF FUNCTIONALIZED CHITOSAN
CAMELIA E. OLTEANU
Recent studies of the chemical modification of chitosan are discussed from the viewpoint of biomedical applications. In this review are presented the current applications of the various types of chitosan derivatives synthesized in the field of drug delivery vehicle, tissue engineering, wound dressing material, antimicrobial, biotechnology, pharmaceuticals, and cosmetics.
SYNTHÈSE DE LA 1-DÉAZA-EUPOLAURAMINE
VÉRONIQUE RYS, AXEL COUTURE, ÉRIC DENIAU, PIERRE GRANDCLAUDON*
A concise and efficient synthesis of 1-deaza-eupolauramine 2 is disclosed. The key steps are the connection of a metalated isoindolinone equipped with the synthetic auxiliary benzotriazolyl group with an ortho-halogenobenzaldehyde, followed by interception of the transient oxanion with bulky pivaloyl chloride. Removal of the temporary auxiliary under acidic conditions followed by free radical cyclization of the resulting enelactam derivative and ultimate replacement of the pivaloyloxy group by the methoxy functionality completes the synthesis of the targeted compound.
PURIFICATION OF TRI-n-OCTYL PHOSPHINE OXIDE BY EXTRACTION AND PRECIPITATION. EXTRACTION OF Zn, Mo AND Fe IN ACID MEDIUM
LALDJA MEDDOUR, MOHAMED A. DIDI*
The aim of this work was a process of purification of tri-n-octyl phosphine oxide (TOPO) based on extractability properties. In this context, the extraction parameters (acid concentration, volume ratio of the phases, mixing time) were optimized. The extraction operation was followed by the precipitation of the formed complex. This purification technique made it possible to increase the TOPO purity from 27.8% to 92%. The liquid–liquid extraction of Zn, Mo and Fe was carried out using the purified TOPO, starting from the aqueous solutions of hydrochloric acid. It was carried out under various operating conditions including the variation of the HCl concentration, the molar ratio [TOPO]/[Zn], the volume ratio of the phases (organic/aqueous) and the contact time between phases. The best extraction yields were obtained for the concentrations of HCl varying between 3 – 7 mol/L, for the contact times varying from 5 – 20 minutes and the volume ratios of phases between 1 and 4, according to studied metal. For a molar ratio [TOPO]/[Zn] > 10, the value of extraction yield of Zn by TOPO is doubled.
CHEMICAL CHARACTERIZATION AND TOXICOLOGICAL EVALUATION OF THE ESSENTIAL OIL OF MENTHA PIPERITA L. GROWING IN MOROCCO
A. DEBBAB(1)*, B. MOSADDAK(1), A.H. ALY(2), A. HAKIKI(1), M. MOSADDAK(1)
In this study the chemical composition and oral acute toxicity of the essential oil of Mentha piperita L. growing in Morocco were investigated. The volatile extract was isolated using hydro-distillation technique followed by continuous liquid-liquid fractionation (Water / Ethyl acetate). The essential oil was then analyzed by gas chromatography (GC) and chromatography-mass spectroscopy (GC-MS). The major compounds which characterized the essential oil of this plant were linalool (1) (60.72 %) and its acetate (2) (20.79 %), as well as geraniol (3) (3.26 %), 1,8-cineol (4) (2.33 %) and limonene (5) (1.54%). The acute toxicity of Mentha piperita L. oil was investigated in mice. The total essential oil in form of suspension in water with Tween 80 was tested by gavage. Acute toxicity evaluation of this essential oil showed a mortality percentage of 0, 10, 30, 50, 70, 100 for the doses 250, 500, 1000, 2000, 3000, 4000 mg/kg body weight of mice, respectively. Moreover, the lethal amount 50 (LD50) of the essential oil of Mentha piperita L. was found to be 1612.45 mg/kg with confidence limits 1461.41 mg/kg and 1779.11 mg/kg.
A POSSIBLE INTERACTION BETWEEN CATECHOLAMINE AND GLUCAGON TO INDUCED THERMOGENESIS IN DUCKLING (CARINA MOSCHATA): A HPLC STUDY
M. SLIMANI(1), S. EL ANTRI(1), M. EL HADDAD(2), H. BARRÉ(3), T. FECHTALI(1)*
The aim of the present study was to investigate whether the thermoregulation in avian results from a direct action of glucagon or requires the participation of other agents such as catecholamines. We focused our study on the effects of central glucagon on plasma catecholamine and heart rate on thermoneutral (TN) and glucagon treated (GT) ducklings in cold environment. Our results showed that cold exposure (4 °C) induced an increase of circulating Norepinephrine (NE) in TN (42%) but not significantly in GT, while Epinephrine (E) decreased only in TN (-45%). After glucagon injection, we found that circulating E increase in TN 280%, whereas NE concentrations decreased only in thermoneutral ducklings (-23%). Central glucagon injection causes a decrease in heart rate in thermoneutral duckling whereas it has no effect on glucagon treated ducklings. The increase in E levels in thermoneutral ducklings may be due to a massive release of adrenal catecholamine in response to cold. Treatment with glucagon twice daily rendered probably ducks insensitive to the effect of intracerebroventricular (ICV) glucagon injection.
APPORT DU PROCEDE DE LYOPHILISATION SUR LA QUALITE DES FRAISES MAROCAINES. CONTRIBUTION OF FREEZE-DRYING PROCESS ON MOROCCAN STRAWBERRIES QUALITY
MAHACINE AMRANI(1)*, AMIN LAGLAOUI(2)
This work exposes the analysis and the modeling of the kinetics of desiccation of strawberries during the freeze-drying process. A lyophilisator Virtis 35L Gardiner was used. Freeze-drying was carried out at various temperatures. The impact study of the various parameters of freeze-drying process of Moroccan strawberries showed that the temperature has an important incidence on the reduction process duration, thus minimizing the cost of the process while preserving the quality of the dry fruit and opening the field with the application of this technology to the treatment of new food products.
EVALUATION OF THE HYDRODYNAMIC REGIME OF AEROBIC STIRRED BIOREACTORS USING THE MIXING DISTRIBUTION CRITERIA. SUSPENSIONS OF PENICILLIUM CHRYSOGENUM PELLETS
STEFANICA CAMARUT(1), ANCA-IRINA GALACTION(2), DAN CASCAVAL(1)*
The study on mixing distribution for an aerobic stirred bioreactor and P. chrysogenum pellets broths indicated the significant variation of mixing time on the bioreactor height. The uniform mixing in whole bulk of fermentation broth can be reached only for 500 rpm and biomass concentration below 24 g/L d.w. The influence of aeration rate has to be correlated with the fungus concentration. At lower biomass concentration, below 16 g/L d.w., due to the appearance of flooding, the mixing time initially increased with the increase of aeration rate, reached a maximum value, decreasing then (the critical air flow rate varied with the position of pH electrode into the broth and fungus concentration, being of 150 - 300 L/h). For higher P. chrysogenum concentration, the increase of air flow rate lead to the continuous mixing intensification for all the considered positions into the fungus broth.
ESTABLISHING OF CHROMATIC AND ANTIOXIDANT CHARACTERISTICS OF SOME RED WINES FROM MINIS VINEYARD
MARIANA-ATENA POIANA(1)*, IOSIF GERGEN(2), ERSILIA ALEXA(1)
Were characterized in relation to the antioxidant and chromatic properties the red wines processing in Minis vineyard from tree grapes varieties: Cabernet Sauvignon, Merlot and Pinot Noir harvested in 2004. It was determined the total antioxidant capacity, total polyphenols content and monomeric anthocyanins amount, as well as the main chromatic characteristics for young and aged in bottle for 12 months red wines. Total antioxidant capacity it was determined by FRAP method (expressed as mM Fe2+/L). The polyphenols content it was determined by Folin-Ciocalteu method (expressed such as mM gallic acid/L). The monomeric anthocyanins it was evaluated by differential pH method and the chromatic properties by standardized method and by Glories method. It was obtained that the chromatic and antioxidant characteristics of red wines present the distinctive values in rapport with wine’s evolution stage and grapes variety. By ageing, the antioxidant capacity decreases due to diminishing of total polyphenols content, especially monomeric forms of anthocyanins. The highest values for antioxidant capacity were founding in young red wine (particularly from Cabernet Sauvignon grape’s variety). The antioxidant capacity was highly correlated with the polyphenols amount (R= 0.9731).
THE EFFECT OF STARTER CULTURES ON THE PHYSICAL AND BIOCHEMICAL CHARACTERISTICS OF DRIED SAUSAGES
AURELIA IONESCU, MARGARETA ZARA*, IULIANA APRODU, AIDA VASILE, RADU ISTRATE
We have monitored the physical and biochemical modifications which have taken place during the ripening of the home-made sausages with and without starter cultures. Baktoferment 61 (Staphylococcus carnosus) and Biobak Sal Plus (Lactobacillus plantarum and Pediococcus acidilactici) starter cultures have intensified the conversion of glucides to lactic acid, have reduced the value of the pH and increased the acidity and have sped up drying and forming of colours and textures processes. Also, the utilized starter cultures have led to a more intense proteolytic activity, the increase of the free amino acid and non-protein nitrogen content being higher than those of the sample with normal ripening. The rate of producing free amino acids was lower than that of the non-protein nitrogen but higher than that of forming the ammonia by oxidative deamination of some free amino acids. The presence of meat bacterial starter cultures selected, guarantees lower values of pH and the water’s activity (aw), and furthermore safety products.