title: Elaboration and characterization of whey protein beads by an emulsification/cold gelation process: application for the protection of retinol.
abstract: Whey protein beads were successfully produced using a new emulsification/cold gelation method. The principle of this method is based on an emulsifying step followed by a Ca(2+)-induced gelation of pre-denatured (80 degreesC/30 min) whey protein. Beads are formed by the dropwise addition of the suspension into a calcium chloride (CaCl(2)) solution. IR results show that bead formation has a pronounced effect on the secondary structure of whey protein, which leads to the formation of intermolecular hydrogen-bonded beta-sheet structures. Their preparation conditions (CaCl(2) concentrations of 10, 15, and 20% (w/w)) influence their sphericity and homogeneity: an increase in CaCl(2) favors regular-shaped beads. The physicochemical and mechanical characterizations of beads were also carried out. Their properties, such as swelling, elasticity, deformability, and resistance at fracture, change according to pH levels (1.9, 4.5, and 7.5) and preparation conditions. Indeed, protein chain networks exhibit different behavior patterns with respect to their charge. Finally, bead degradation by enzymatic hydrolysis reveals that beads are gastroresistant and form good matrixes to protect fat-soluble bioactive molecules such as retinol, that have in vivo intestinal absorption sites. The experiment demonstrated the potential of whey protein beads to protect molecules sensitive (i.e., vitamins) to oxidation.
authors.affiliation: STELA (Dairy Research Centre) and Groupe de recherche en nutrition humaine, Faculté des sciences de l'agriculture et de l'alimentation, Université Laval, Québec, Québec, Canada G1K 7P4.
authors.forename: Lucie
authors.initials: L
authors.lastname: Beaulieu
authors.forename: Laurent
authors.initials: L
authors.lastname: Savoie
authors.forename: Paul
authors.initials: P
authors.lastname: Paquin
authors.forename: Muriel
authors.initials: M
authors.lastname: Subirade
mesh_terms: D002122:Calcium Chloride / Q000737:chemistry; D002214:Capsules / Q000737:chemistry; D004339:Drug Compounding / Q000379:methods*; D004655:Emulsions; D010450:Endopeptidases; D005782:Gels; D006863:Hydrogen-Ion Concentration; D008854:Microscopy, Electron; D008894:Milk Proteins / Q000737:chemistry* / Q000648:ultrastructure; D011489:Protein Denaturation; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared; D013314:Stress, Mechanical; D014801:Vitamin A / Q000737:chemistry*
chemical_list: D002214:Capsules; D004655:Emulsions; D005782:Gels; D008894:Milk Proteins; C024471:whey acidic proteins; D014801:Vitamin A; D010450:Endopeptidases; D002122:Calcium Chloride