DEPISTAGE DES ANOMALIES PHOSPHO-CALCIQUES LORS DE LA PRISE EN CHARGE EN HOSPITALISATION DE MEDECINE PHYSIQUE ET READAPTATION, CHEZ 94 PATIENTS AYANT EU UN TRAUMATISME OSTEOARTICULAIRE

NANTES-BU Médecine pharmacie (441092101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Determination of hydro-colloidal characteristics of milk protein aggregates using Asymmetrical Flow Field-Flow Fractionation coupled with Multiangle Laser Light Scattering and Differential Refractometer (AF4-MALLS-DRi)

During heat treatment, whey proteins (WP) are denatured and form different kinds of whey proteinaggregates (WPA) depending on the physico-chemical conditions. In the presence of casein micelles,mixed aggregates (MA), resulting from the interaction of k-casein and WP, are formed. The aim of thisstudy is to understand the effect of pH on the WPA structure and the impact of the casein/whey proteins(Cas/WP) ratio on MA morphology. In this work, WP solutions were heated at pH 5.8 or 7 to produceWPA. On the other hand, aqueous mixtures containing three Cas/WP ratios (82/18, 56/44 and 30/70)were heated at 80 C during 1 h at pH 6.3 to obtain MA. Milk protein aggregates were analyzed byTransmission Electron Microscopy (TEM) and Asymmetrical Flow Field-Flow Fractionation coupled withMultiangle Laser Light Scattering and Differential Refractometer (AF4-MALLS-DRi). Dense and sphericalWPA were formed at pH 5.8 whereas branched and fractal aggregates were obtained at pH 7. RegardingMA, results suggested that they were mainly produced with the 82/18 Cas/WP ratio whereas a majorityof WPA was obtained with the 30/70 ratio. At intermediate ratio, the mixture was composed of small MAand WPA that did not interact with k-casein. Moreover, WP seem to interact preferentially with largercasein micelles. Thereby, AF4-MALLS-DRi proved to be a powerfull technique to characterize the complexstructure of milk protein aggregates and an interesting alternative to size exclusion chromatographyespecially for MA and casein micelles which interact with the stationary phase and are retained in thecolum

Characterization of milk protein aggregates as a function of casein micelles/whey proteins ratio by Asymmetrical Flow Field Flow Fractionation (AF4) coupled with Multiangle Laser Light Scattering (MALLS)

Currently, most of dairy emulsions at neutral pH contain thickening or gelling agent for improving their texture. However, manufacturers are more and more seeking for the substitution of these food additives by natural ingredients like proteins. During heat treatment of milk, whey proteins are denatured and can interact with casein micelles (Cas) to form Mixed Aggregates (MA). In dairy emulsions, MA are able to adsorb at the oil-water interface and texturize emulsions by connecting oil droplets1. In this way, MA could be an alternative to additives used in dairy emulsions. The casein micelles/whey proteins (Cas/WP) ratio is a key parameter for the production of MA. Asymmetrical Flow Field Flow Fractionation coupled with MALLS could be an interesting method to define the best Cas/WP ratio (80/20 or 20/80) to use. Moreover, this technique can be used to determine the stability of MA to calcium concentration change and pH variation