title: Structure and gelation properties of casein micelles doped with curcumin under acidic conditions.
abstract: In this study, the ability of micellar casein (MC) to interact with curcumin during acidification and to produce acid gel was investigated. Steady-state fluorescence spectroscopy of curcumin variation and fluorescence quenching of caseins upon binding with curcumin molecules were evidenced. Increasing the temperature from 20 to 35 °C enhanced MC-curcumin interactions as reflected by the increase in the binding constant from 0.6 ± 0.3 × 10(4) to 6.6 ± 0.6 × 10(4) M(-1). From changes in entropy, enthalpy and Gibbs free energy, hydrophobic interactions were proposed as major binding forces. Static fluorescence MC quenching was demonstrated for the MC-curcumin complex during acidification. From pH 7.4 to pH 5.0, the binding site numbers varied in the range from 1.25 ± 0.05 to 1.49 ± 0.05 and the binding constant kb varied from 3.9 ± 0.4 × 10(4) to 7.5 ± 0.7 × 10(4) M(-1). Small angle X-ray scattering profiles demonstrated that the MC internal structure was unchanged upon curcumin binding. The ζ-potential value of curcumin-doped MC indicated that curcumin did not modify the global charge of MC particles. Acid gelation studied by oscillation rheology and static multiple light scattering at 20 and 35 °C led to a similar behavior for native and curcumin-doped MC suspensions. For the first time, it was demonstrated that the colloidal and functional properties of MC were unchanged when doped with curcumin during acidification.
authors.affiliation: Université de Lorraine, Laboratoire d'Ingénierie des Biomolécules (LIBio), 2 avenue de la Forêt de Haye, TSA40602-F-54518, Vandœuvre-lès-Nancy, France. sylvie.desobry@univ-lorraine.fr and St Joseph University, Faculty of Sciences, UR TVA, Dept Chemistry, BP 11-514, Beirut 11072050, Lebanon.
authors.forename: Aya N
authors.initials: AN
authors.lastname: Khanji
authors.affiliation: Université de Lorraine, Laboratoire d'Ingénierie des Biomolécules (LIBio), 2 avenue de la Forêt de Haye, TSA40602-F-54518, Vandœuvre-lès-Nancy, France. sylvie.desobry@univ-lorraine.fr.
authors.forename: Florentin
authors.initials: F
authors.lastname: Michaux
authors.affiliation: Université de Lorraine, Laboratoire d'Ingénierie des Biomolécules (LIBio), 2 avenue de la Forêt de Haye, TSA40602-F-54518, Vandœuvre-lès-Nancy, France. sylvie.desobry@univ-lorraine.fr.
authors.forename: Jordane
authors.initials: J
authors.lastname: Jasniewski
authors.affiliation: Université de Lorraine, Laboratoire d'Ingénierie des Biomolécules (LIBio), 2 avenue de la Forêt de Haye, TSA40602-F-54518, Vandœuvre-lès-Nancy, France. sylvie.desobry@univ-lorraine.fr.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Petit
authors.affiliation: Université de Lorraine, Laboratoire d'Ingénierie des Biomolécules (LIBio), 2 avenue de la Forêt de Haye, TSA40602-F-54518, Vandœuvre-lès-Nancy, France. sylvie.desobry@univ-lorraine.fr.
authors.forename: Emna
authors.initials: E
authors.lastname: Lahimer
authors.affiliation: Université de Lorraine, Laboratoire d'Ingénierie des Biomolécules (LIBio), 2 avenue de la Forêt de Haye, TSA40602-F-54518, Vandœuvre-lès-Nancy, France. sylvie.desobry@univ-lorraine.fr.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Cherif
authors.affiliation: St Joseph University, Faculty of Sciences, UR TVA, Dept Chemistry, BP 11-514, Beirut 11072050, Lebanon.
authors.forename: Dominique
authors.initials: D
authors.lastname: Salameh
authors.affiliation: St Joseph University, Faculty of Sciences, UR TVA, Dept Chemistry, BP 11-514, Beirut 11072050, Lebanon.
authors.forename: Toufic
authors.initials: T
authors.lastname: Rizk
authors.affiliation: Université de Lorraine, Laboratoire d'Ingénierie des Biomolécules (LIBio), 2 avenue de la Forêt de Haye, TSA40602-F-54518, Vandœuvre-lès-Nancy, France. sylvie.desobry@univ-lorraine.fr.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Banon
mesh_terms: D000818:Animals; D001665:Binding Sites; D002364:Caseins / Q000737:chemistry*; D003474:Curcumin / Q000737:chemistry*; D005782:Gels / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D008823:Micelles; D008892:Milk; D012212:Rheology; D013696:Temperature
chemical_list: D002364:Caseins; D005782:Gels; D008823:Micelles; D003474:Curcumin