Abstract
The structure of casein micelles has been studied by small-angle neutron scattering and static light scattering. Alterations in structure upon variation of pH and scattering contrast, as well as after addition of chymosin, were investigated. The experimental data were analyzed by a model in which the casein micelle consists of spherical submicelles. This model gave good agreement with the data and gave an average micellar radius of about 100–120 nm and a submicellar radius of about 7 nm both with a polydispersity of about 40–50%. The contrast variation indicated that the scattering length density of the submicelles was largest at the center of the submicelles. The submicelles were found to be closely packed, the volume fraction varying slightly with pH. Upon addition of chymosin the submicellar structure remained unchanged within the experimental accuracy.
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Hooydonk van ACM, Hagedom HG, Boerrigter IJ (1986) Neth Milk Dairy J 40:281–286
Israelachvili JN (1991) Intermolecular and surface forces (2nd edn) Academic Press, London
Kruif de CG, May RP (1991) κ-Casein micelles: structure, interaction and gelling studied by small-angle neutron scattering. Eur J Biochem 200:431–436
Martin JE, Hurd AJ (1987) Scattering from fractals. J Appl Crystallogr 20:61–78
McMahon DJ, Brown RJ (1984) Enzymatic coagulation of casein micelles: A review. J Dairy Sci 67:919–929
Pedersen JS (1994) Determination of Size Distributions from SmallAngle Scattering Data for Systems with Effective Hard-Sphere Interactions. J Appl Crystallogr 27:595–608
Pedersen JS, Posselt D, Mortensen K (1990) Analytical treatment of the resolution function in small-angle scattering. J Appl Crystallogr 23:321–333
Roefs SPFM, Walstra P, Dalgleish DG, Home DS (1985) Preliminary note on the change in casein micelles caused by acidification. Neth Milk Dairy J 39:119–122
Roefs SPFM, van Vliet T, van den Bijgaart HJCM, de Groot-Mostert AEA, Walstra P (1990) Structure of casein gels made by combined acidification and rennet action. Neth Milk Dairy 44:159–188
Schmidt DG (1982) Association of caseins and casein micelle structure. In: Development in dairy chemistry. Fox PF, (ed.) Applied Science Publication, London, pp 61–86
Schmidt DG, Both P, van Markwijk BW, Buchheim W (1974). The determination of size and molecular weight of casein micelles by means of light scattering and electron microscopy. Biochim Biophys Acta 365:72–79
Stothart PH (1989) Subunit structure of casein micelles from smallangle neutron-scattering. J Mol Biol 208:635–638
Stothart PH, Cebula DJ (1982) Small-angle neutron scattering study of bovine casein micelles and sub-micelles. J Mol Biol 160:391–395
Visser J, Minihan A, Smits P, Tjan SB, Heertje I (1986) Effects of pH and temperature on the milk salt system. Neth Milk Dairy J 40:351–368
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Correspondence to: S. Hansen
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Hansen, S., Bauer, R., Bredsted Lomholt, S. et al. Structure of casein micelles studied by small-angle neutron scattering. Eur Biophys J 24, 143–147 (1996). https://doi.org/10.1007/BF00180271
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DOI: https://doi.org/10.1007/BF00180271