Whey proteins analysis in aqueous medium and in artificial gastric and intestinal fluids

Whey proteins isolates (WPI) were treated in aqueous medium at various pH values. Zeta potential, turbidity and particle size measurement were determined as a function of pH. FTIR analysis was performed in ATR mode (attenuated total reflectance). Digestibility was assessed by treating whey proteins with artificial gastric and intestinal fluids. Proteolytic enzymes such as pepsin from porcine stomach mucosa was added in the gastric fluid. Pancreatin and trypsin from porcine and bile salts were added in the intestinal fluid. SDS-PAGE revealed hydrolysis of á-lactalbumin and bovine serum albumin by pepsin while â-lactoglobulin was not hydrolyzed by gastric fluid. All the proteins of WPI were easily hydrolyzed in the intestinal fluid. The zeta potential of WPI went from positive values to negative values as the pH was increased. Turbidity values indicated the presence of particles in the solution which were confirmed by the measurement of particle size. FTIR analysis determined the fingerprint of WPI macromolecule

Deficiency of alpha-Tocopherol in Seminal Fluid as a Probable Factor in Low Fertility in Côte d’Ivoire

To evaluate the level of alpha-Tocopherol in seminal fluid of patients with low fertility, forty subjects with low fertility (17 with asthenospermia and 32 with oligoasthenospermia) and 21 subjects with normal sperm parameters were recruited into this study for assessing their alpha-Tocopherol seminalfluid level. The mean level of alpha-Tocopherol in subjects with normal sperm profile was 0.62 ìmol/l compared to those with pathological profile such as asthenospermia (0.29 ìmol/l) and oligoasthenospermia (0.28 ìmol/l). The determination of alpha-Tocopherol in human seminal fluidprovides useful information concerning the exploration of low fertility in Cote d’Ivoire (Afr J Reprod Health 2009; 13[3]:123-125)

Caractérisations physicochimiques de biofilms synthétisés à partir de la pectine et de la gélatine

Trois types de biofilms à base de polymères naturels ont été préparés à partir de la pectine, un polyélectrolyte anionique, et de la gélatine, une espèce cationique. Les propriétés physicochimiques (épaisseur,perméabilité à la vapeur d’eau et pouvoir gonflant) des biofilms ont été déterminées; de même, leur morphologie a été évaluée. Au niveau micrométrique, les épaisseurs des biofilms étaient respectivement de101,2±0,2 μm; 64,6±0,1 μm et 39,0±0,1 μm pour la gélatine, le mélange gélatine/pectine et la pectine. Le pouvoir gonflant était de 300% pour la gélatine, 215% pour le mélange gélatine/pectine et 90% pour la pectine.La perméabilité à la vapeur d’eau était de 9,20 g mm/m2 h KPa pour la gélatine; 6,59 g mm/m2 h KPa pour le mélange gélatine/pectine et 3,98 g mm/m2 h KPa pour la pectine. Au niveau morphologique, des différencessignificatives ont été observées. Toutefois, les différents films formulés ont mis en évidence des potentialités physicochimiques intéressantes.Mots clés : Biofilms, polymères naturels, analyse physicochimiqu

Role of calcium alginate and mannitol in protecting Bifidobacterium

Fourier transform infrared (FTIR) spectroscopy was carried out to ascertain the mechanism of Ca-alginate and mannitol protection of cell envelope components and secondary proteins of Bifidobacterium animalis subsp. lactis Bb12 after freeze-drying and after 10 weeks of storage at room temperature (25°C) at low water activities (aw) of 0.07, 0.1, and 0.2. Preparation of Ca-alginate and Ca-alginate-mannitol as microencapsulants was carried out by dropping an alginate or alginate-mannitol emulsion containing bacteria using a burette into CaCl2 solution to obtain Ca-alginate beads and Ca-alginate-mannitol beads, respectively. The wet beads were then freeze-dried. The aw of freeze-dried beads was then adjusted to 0.07, 0.1, and 0.2 using saturated salt solutions; controls were prepared by keeping Ca-alginate and Ca-alginate-mannitol in aluminum foil without aw adjustment. Mannitol in the Ca-alginate system interacted with cell envelopes during freeze-drying and during storage at low aws. In contrast, Ca-alginate protected cell envelopes after freeze-drying but not during 10-week storage. Unlike Ca-alginate, Ca-alginate-mannitol was effective in retarding the changes in secondary proteins during freeze-drying and during 10 weeks of storage at low aws. It appears that Ca-alginate-mannitol is more effective than Ca-alginate in preserving cell envelopes and proteins after freeze-drying and after 10 weeks of storage at room temperature (25°C)