This chapter reviews methods to analyse the free amino acids particularly during cheese ripening. More in detail are described two methods that are commonly used. The most accurate results are obtained with the ion exchange chromatography method with postcolumn ninhydrin derivatisation and photometry detection at 570 and 440 nm for primary and secondary amino acids, respectively. Because, most dairy laboratories are not equipped with such an amino acid analyser, another method has been developed using high performance liquid chromatography with reverse phase separation of OPA and FMOC derivates for primary and secondary amino acids. These derivates can be detected by photometry or by fluorescence detector at very low concentration. The use of several other derivates are discussed
