The structure of casein micelles: a review of small-angle scattering data

摘要: Casein micelles are association colloids found in mammalian milk. Small-angle scattering data on casein have been collected and reviewed, including contrast variation. The spectra quite consistent at medium high wavevectors [Q = 4πnsin(θ/2)/λ, where n is the refractive index, λ wavelength θ angle]. Differences noted, especially low Q, which may be attributed to sample preparation, particularly presence of residual fat globules. Scattering calculated using a generalized function composite particle model, it possible give self-consistent calculation one set parameters for all contrasts both small-angle X-ray neutron scattering. calculations show that micelle homogeneous particle. polydispersity size about 35% therefore experimental depend very much method used. A `reference set' numbers proposed from pooled cows' milk, given as follows: β 0.35, R10 60 nm, Rg 110 nm, Rhydr 96 nm (at 90° scattering). Often, use made dynamic light (DLS), gives an 〈R6〉/〈R5〉 80–100 nm Values will considerably higher low(er) angles, lower backscattering currently used many DLS setups. Larger values probably due clusters or fat. structure can best described protein matrix calcium phosphate (2 nm radius) dispersed. has density variations similar length scale. micelle–submicelle model models with large voids channels highly improbable.