The extraction with n-hexane only (method 1, experiments 1–8 on sample 1) gave fat in very low yields (4–8%), probably because most of the fat remains associated into lipoproteic structures or encapsulated and only the superficial one can be extracted with this solvent (Kim et al., 2009). In fact when peanut oil was added to milk, it was quantitatively recovered thus confirming the hypothesis.