Casein micelle size from elastic and quasi-elastic light scattering measurements.
The average molecular weight, particle radius and size distribution of particles in skim milk from eight cows in mid-lactation have been measured by means of elastic and quasi-elastic light scattering techniques. The properties of sub-micellar casein particles in the milk of each cow were also studied. Particular attention has been given to the effects of particle size heterogeneity in the interpretation of results. The weight average molecular weight of the particles from different cows varied from 2.6-10(8) to 15-10(8) and the corresponding average particle radius varied between 90 and 130 nm. An unusual feature of these particles is their high water content, which was found to vary from 2.4 to 6.4 ml/g with a positive correlation between average particle density and average particle mass. Variations in particle water content can be most readily understood in terms of a gel-like casein micelle.
D000818:Animals; D002364:Caseins / Q000032:analysis*; D002417:Cattle; D003102:Colloids; D004548:Elasticity; D005260:Female; D007774:Lactation; D008027:Light; D046911:Macromolecular Substances; D008433:Mathematics; D008667:Metalloproteins / Q000032:analysis; D008823:Micelles; D008892:Milk / Q000032:analysis; D008894:Milk Proteins / Q000032:analysis; D008970:Molecular Weight; D010316:Particle Size; D011247:Pregnancy; D012542:Scattering, Radiation
D002364:Caseins; D003102:Colloids; D046911:Macromolecular Substances; D008667:Metalloproteins; D008823:Micelles; D008894:Milk Proteins