Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 32131
Revea Ling Casein Micelle Dispersion under Various Ranges of Nacl: Evolution of Particles Size and Structure

Authors: Raza Hussain, Claire Gaiani, Joël Scher


Dispersions of casein micelles (CM) were studied at a constant protein concentration of 5 wt % in high NaCl environment ranging from 0% to 12% by Dynamic light scattering (DLS) and Fourier Transform Infrared (FTIR). The rehydration profiles obtained were interpreted in term of wetting, swelling and dispersion stages by using a turbidity method. Two behaviours were observed depending on the salt concentration. The first behaviour (low salt concentration) presents a typical rehydration profile with a significant change between 3 and 6% NaCl indicating quick wetting, swelling and long dispersion stage. On the opposite, the dispersion stage of the second behaviour (high salt concentration) was significantly shortened indicating a strong modification of the protein backbone. A salt increase result to a destabilization of the micelle and the formation of mini-micelles more or less aggregated indicating an average micelles size ranging from 100 to 200 nm. For the first time, the estimations of secondary structural elements (irregular, ß-sheet, α-helix and turn) by the Amide III assignments were correlated with results from Amide I.

Keywords: Casein, DLS, FTIR, Ionic environment.

Digital Object Identifier (DOI):

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1715


[1] L. Sawyer, P. N. Barlow, M. J. Boland, L. K. Creamer, H. Denton, P. J. B . Edwards, C. Holt, G. B. Jameson, G. Kontopidis, G. E. Norris, S. Uhrinova, and S. Y. Wu, Milk protein structure - What can it tell the dairy industry╦Ø╦Ø? Int. Dairy J. 12: 299-310, 2002.
[2] P. Walstra, Casein sub-micelles: Do they exist╦Ø╦Ø? Int. Dairy J. 9: 189- 192, 1999.
[3] H. E. Swaisgood, Characteristics of milk In Food Chemistry, 3rd ed.; Fenneman, O. R., Ed.Marcel Dekker, Inc.: New York: pp 841-878, 1996.
[4] M. H. Famelart, Y. Le Graet, and K. Raulot, Casein micelle dispersions into water, NaCl and CaCl 2: Physicochemical characteristics of micelles and rennet coagulation Int. Dairy J. 9: 293- 297.
[5] F. Gaucheron, Y. Le Graet, M. Piot, and E. Boyaval, Determination of anions of milk by ion chromatography Lait, 76: 433-443, 1996.
[6] T. F. Kumosinski, and J. J. Unruh, Quantitation of the global secondary structure of globular proteins by FTIR spectroscopy: Comparison with X-ray crystallographic structure Talanta, 43: 199- 219, 1996.
[7] D. M. Curley, T. F. Kumosinski, J. J. Unruh, and H. M. Farrell Jr, Changes in the Secondary Structure of Bovine Casein by Fourier Transform Infrared Spectroscopy: Effects of Calcium and Temperature J. Dairy Sci. 81: 3154-3162, 1998.
[8] D. M. Byler and H. Susi, Examination of the secondary structure of proteins by deconvolved FTIR spectra Biopolymers, 25: 469-487, 1986.
[9] S. Cai, and B. R. Singh, Identification of β-turn and random coil amide III infrared bands for secondary structure estimation of proteins Biophys.Chem. 80: 7-20, 1999.
[10] A. O. Karlsson, R. Ipsen, and Y. Ardö, Observations of casein micelles in skim milk concentrate by transmission electron microscopy LWT - Food Sci. Tech. 40: 1102-1107, 2007.
[11] M. Philippe, Y. Le Graët, and F. Gaucheron, The effects of different cations on the physicochemical characteristics of casein micelles Food Chem. 90: 673-683, 2005.
[12] T. Huppertz and P. F. Fox, Effect of NaCl on some physico-chemical properties of concentrated bovine milk Int. Dairy J. 16: 1142-1148, 2006.
[13] A. HadjSadok, A. Pitkowski, T. Nicolai, L. Benyahia, and N. M. Mostefa, Characterisation of sodium caseinate as a function of ionic strength, pH and temperature using static and dynamic light scattering Food Hydrocolloid. 22: 1460-1466, 2008.
[14] C. Gaiani, S. Banon, and J. Scher, P. Schuck, and J. Hardy Use of a turbidity sensor to characterize micellar casein powder rehydration: Influence of some technological effects J. Dairy Sci. 88: 2700-2706, 2005.
[15] H.M. Farrell Jr, E. D. Wickham, J. J. Unruh, P. X. Qi, and P. D. Hoagland, Secondary structural studies of bovine caseins: Temperature dependence of β-casein structure as analyzed by circular dichroism and FTIR spectroscopy and correlation with micellization Food Hydrocolloid. 15: 341-354, 2001.
[16] C. Gaiani, J. Scher, J. J. Ehrhardt, M. Linder, P. Schuck, S. Desobry, and S. Banon, Relationships between dairy powder surface composition and wetting properties during storage: importance of residual lipids J. Agr. Food Chem. 55: 6561-6567, 2007.
[17] R. Jost, Functional characteristics of dairy proteins Trends, Food Sci. 4: 283-288, 1993.
[18] P. Schuck, A. Davenel, F. Mariette, V. Briard, S. Méjean and M. Piot, Rehydration of casein powders: Effects of added mineral salts and salt addition methods on water transfer Int. Dairy J. 12: 51-57, 2002.
[19] C. Le Ray, J. L. Maubois, F. Gaucheron, G. Brulé, P. Pronnier, and F. Garnier, Heat stability of reconstituted casein micelle dispersions: Changes induced by salt addition Lait, 78: 375-390. 1998.
[20] M. B. Grufferty, and P. F. Fox, Effect of Added NaCl on Some Physicochemical Properties of Milk Irish. J. Food Sci. Tec. 9: 1-9. 1985.
[21] D. S. Horne, and C. M. Davidson, The effect of environmental conditions on the steric stabilization of casein micelles Colloid Polym. Sci. 264: 727-734. 1986.
[22] S. Cai, and B. R. Singh, A Distinct Utility of the Amide III Infrared Band for Secondary Structure Estimation of Aqueous Protein Solutions Using Partial Least Squares Methods Biochemistry, 43: 2541-2549. 2004.
[23] R. Hussain, C. Gaiani, L. Aberkane, and J. Scher, Characterization of high-milk-protein powders upon rehydration under various salt concentrations J. Dairy Sci. 2010, in press.
[24] P. Walstra, On the stability of casein micelles J. Dairy Sci. 73: 1965- 1979. 1990.
[25] M. J. Jonkman, P. Walstra, M. A. J. S. Van Boekel and D. J. Cebula, Behaviour of casein micelles at conditions comparable to those in ice cream Int. Dairy J. 9: 201-205. 1999.