Print Email Facebook Twitter Orthokinetic flocculation of caseinate-stabilized emulsions: Influence of calcium concentration, shear rate and protein content Title Orthokinetic flocculation of caseinate-stabilized emulsions: Influence of calcium concentration, shear rate and protein content Author Schokker, E.P. Dalgleish, D.G. Centraal Instituut voor Voedingsonderzoek TNO Publication year 2000 Abstract Calcium-induced flocculation of caseinate-stabilized soybean oil-in- water emulsions in conditions of Couette flow was studied. A concentrated emulsion (20% oil, 0.5-2.0% sodium caseinate in 20 mM imidazole, pH 7) was diluted 20 times in buffer containing concentrations of CaCl2 between 9 and 17 mM and sheared at rates between 335 and 1340 s-1. The average particle size (d43), measured by integrated light scattering, increased in a sigmoidal manner with shearing time. An increased shear rate resulted in an increased flocculation rate, because of the increased number of collisions between particles, but a decreased value of the maximum d43, because higher shear rates increasingly disrupted the flocs. The flocculation rate was increased by increasing the calcium concentration, indicating an increased collision efficiency. The orthokinetic stability of the emulsions was increased with increased protein content, and it is postulated that the increased surface coverage and hydrodynamic thickness of the adsorbed protein layer increased steric repulsion between droplets, so that higher calcium concentrations were necessary to induce sufficient conformational change of the proteins to allow flocculation. At high caseinate concentrations, calcium may also induce precipitation of unadsorbed caseins from the serum to the oil-water interface, thereby in increasing steric repulsion and hence increasing orthokinetic stability. Chemicals/CAS: Calcium, 7440-70-2; Caseins; Chelating Agents; Emulsions; Proteins Subject Calcium-induced flocculationCaseinate-stabilized emulsionsOrthokinetic flocculationShearCalciumCaseinChelating agentProteinEmulsionFlocculationKineticsMolecular dynamicsMolecular stabilityProtein contentShear rateSoybeanCalciumCaseinsChelating AgentsEmulsionsFlocculationKineticsProteinsSoybeansGlycine max To reference this document use: http://resolver.tudelft.nl/uuid:a84a51ce-d921-49e1-9e77-f0c7d8c8e553 DOI https://doi.org/10.1021/jf9904113 TNO identifier 56537 ISSN 0021-8561 Source Journal of Agriculture and Food Chemistry, 48 (2), 198-203 Document type article Files To receive the publication files, please send an e-mail request to TNO Library.