I am trying to develop a procedure to test the percent mass of lipids in (update: homogenized) milk. It doesn't need to be very accurate, just an interesting application of chemical principles. As I was looking on traditional ways this is tested, I came across the Babcock method, which involves pouring concentrated sulfuric acid into the milk, heating, and centrifuging the sample. According to Wikipedia, "key to this process is that everything in milk except the fat dissolves in sulfuric acid."
The lipids of are surrounded by what is similar to a cell membrane. The fat is an emulsion with these surfacants holding it in the water. The other components of milk are water, colloidal micelles, which hold other proteins (of no interest to me). My question is, how does sulfuric acid dissolve "everything else"? In a biological procedure I know of to break cell membranes, isopropyl alcohol is used. The cell membrane in that case is broken when the alcohol behaves as a surfactant toward individual triglycerides. However, sulfuric acid does not have a nonpolar region, so how does it work to dissolve the phospholipid membrane?
Many Internet resources on this topic are not written from a chemical perspective. In addition, they seem to confuse the lipid bundles with the other colloidal particles.
Also, why not just heat the milk strongly (such as with a Bunsen burner) to break the protein, or add electrolytes to it, as is a common way to separate colloids?