Analysis of ε-fructosyl-lysine (Furosine) in milk and dairy products

The effects of milk thermal treatments or the addition of powder milk or UHT to crude or pasteurized milk can be determined by using indicators like furosine and lactulose.
The determination of furosine enables to assess the intensity of the initial phase of Maillard’s reaction (that causes heated milk to develop a brownish color), which is in turn linked to milk thermal processes.
ε-fructosyl-lysine is the first stable product of Maillard’s reaction and can be converted into furosine by subjecting milk to an acid hydrolysis. Furosine is then analyzed with the HPLC method, which is rather long, complex and expensive. Thus, ε-fructosyl-lysine, which is the first stable product of Maillard’s reaction and a precursor of furosine, can provide the same information resulting from the furosine test.