2.2.7.4. HMF content
HMF content of milk samples was determined following the spectrophotometric method described by Keeney and Bassette (1958). Optical density was measured at 443 nm and the calibration curve in the range of 0.5–50 μmol/L (r = 0.999) was drawn. HMF content in milk samples was interpolated from the standard curve and results were expressed as micromoles HMF.