title: Interaction of a cationic acrylate polymer with caseins: biphasic effect of Eudragit E100 on the stability of casein micelles.
abstract: When whole or skim milk was incubated with the cationic acrylate polymer Eudragit E100, a biphasic effect on the stability of casein micelles was observed. A precipitation phase was observed at low polymer/casein ratios. Strikingly, a solubilization phase of the aggregates was observed when the ratios of polymer/casein were increased. Purified alpha(s)-, beta-, and kappa-caseins or dephosphorylated caseins were equally precipitated and resolubilized by the cationic polymer, indicating no special selectivity for a particular protein or phosphate residue for these events. An increase in the size of the aggregates as the optimum precipitating amount of Eudragit E100 was reached suggests a crossbridging of the micelles by the polymer. The inhibition of the precipitation phase by high ionic strength indicates that electrostatic interactions play a critical role in complex formation. Furthermore, a dramatic reduction in size of the protein colloidal particles upon solubilization of the aggregates was observed by dynamic light scattering, indicating a dissociation of the micellar structure. Taken together, the results indicate that at low concentration Eudragit E100 may act as a precipitant of casein micelles, mainly by ionic interaction and at high concentration as an amphipathic agent, solubilizing casein micelles with a disruption of their internal structure.
authors.affiliation: Centro de Excelencia en Productos y Procesos de Córdoba (CEPROCOR), Agencia Córdoba Ciencia, Pabellón CEPROCOR, CP 5164, Santa María de Punilla, Córdoba, Argentina.
authors.forename: Salvador F
authors.initials: SF
authors.lastname: Ausar
authors.forename: Ismael D
authors.initials: ID
authors.lastname: Bianco
authors.forename: Leonardo F
authors.initials: LF
authors.lastname: Castagna
authors.forename: Roxana V
authors.initials: RV
authors.lastname: Alasino
authors.forename: Dante M
authors.initials: DM
authors.lastname: Beltramo
mesh_terms: D000179:Acrylates / Q000008:administration & dosage* / Q000737:chemistry*; D000818:Animals; D002364:Caseins / Q000737:chemistry*; D002412:Cations; D011232:Chemical Precipitation; D004355:Drug Stability; D008823:Micelles; D008892:Milk / Q000737:chemistry; D009994:Osmolar Concentration; D010710:Phosphates / Q000032:analysis; D011108:Polymers / Q000008:administration & dosage* / Q000737:chemistry*; D012995:Solubility
chemical_list: D000179:Acrylates; D002364:Caseins; D002412:Cations; C477020:Eudragit E100; D008823:Micelles; D010710:Phosphates; D011108:Polymers