Composition of Casein in the Smallest Casein-Containing Particles of Milk

Abstract

When skimmilk is subjected to centrifugal forces up to 39,500 times gravity for a time theoretically sufficient to remove all particles having sedimentation constants greater than 65 x 10-13, casein colloid particles representing 5 to 10% of the total casein are not removed. If these residual colloids are precipitated at pH 4.6 and the casein purified, analytical data show that the organic phosphorus to total nitrogen ratio is constant and equal to that of the centrifugable particles.