Fluorescence characteristics of several whey samples subjected to different treatments and conditions Original Research Article

The total fluorescence spectra of several wheis, obtained from the corresponding mammals’ milk, subjected to different treatments and conditions, were recorded. Whey was obtained after two treatments of the milk: precipitation of insoluble protein fraction at pH 4.6, and separation of the soluble fraction, whey, using a filter paper. Wheis corresponding to: cowʹs milk (whole, skimmed or partially skimmed) at different heat treatments (raw milk, Pasteurization and UHT treatment), goatʹs milk, sheepʹs milk and human milk, were studied. In all cases, two fluorescent bands, in the UV region, were obtained. It was also studied if some chemical conditions (whey dilution, pH and ethanol concentration) modify or not the intensity and the position of the two fluorescent bands. A liquid chromatographic study with fluorescence detection showed that the two fluorescent amino acids tyrosine and tryptophan, which are present at soluble fraction of milk, are responsible for the intrinsic fluorescence of whey.