Rapid and accurate determination of d- and l-lactate, lactose and galactose by enzymatic reactions coupled to formation of a fluorochromophore: Applications in food quality control

A fluorometric-coupled reaction for the accurate and rapid determination d- and l-lactate and lactose, galactose in foods is presented. The method was found useful for an accurate determination of these metabolites in heterogeneous, opaque and colourful foods without pretreatments. Example for the determination of lactose, galactose, d- and l-lactate in milk, and yogurts and d- and l-lactate in milk, wine and beer is provided. Unexpectedly, we found that the composition of some commercial bio-yogurts produced in Israel is not consistent with the classical definition of yogurts. Thus, this method offers rapid and accurate methodology, which should be particularly valuable in food quality control.