Physical defects in milk and cream

In addition to the flavour defects initiated or influenced by damage to the fat globule membrane, such damage also results in a variety of physical defects in milk and especially in cream. The more important of these are oiling-off , cream plug and age thickening . 

Two somewhat related instability problems are feathering and bitty cream. Feathering is characterized by the appearance of white flecks when milk or cream is poured on hot coffee and is a form of heat-induced coagulation the white flecks are mainly destabilized protein. The heat stability of cream and its resistance to feathering are reduced by  

Protein-lipid interaction is enhanced by homogenization, while high temperatures, low pH and high divalent cation concentration induce aggregation of the casein-coated fat globules into large visible particles. Stability 

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