It is interesting to have insider information regarding the milk biochemistry from ascientific perspective. This website provide us a nice representation of how milk is made of. Our milk is opaque whitish, free flowing liquid. You can clearly imagine how our milk is made up about 87% of fluid.
Milk fat globules are surrounded by casein micelle. Milk fat is important for cheese processing as the value for cheeses are determined by the amount of fat present in the cheese.
Milk also contains destructive enzymes such as lipases that can cause rancidity of the milk fat. Milk processing deactivates these enzymes to preserve milk quality.
Milk contains milk salts such as calcium, magnesium, and phosphorus together with vitamin D, making milk a source of calcium that have enhanced absorption.