Determination of nonprotein tryptophan in yoghurts by selective fluorescence and HPLC

摘要: Abstract The concentrations of total nonprotein (protein-bound and free) free tryptophan were determined in various kinds market yoghurts prepared from raw, skimmed or partially cow's milk, with without fruit, coffee cereals. mean values plain yoghurt made whole milk 3.45 ± 0.46 3.25 0.38 mg/kg, respectively, that is, five to six times higher than milk. Instead, the fraction was 2.76 0.50 2.44 0.36 respectively (seven eight milk). In quite similar those yoghurt, although they varied within each type yoghurt. highest contents both fractions found cereal, due contribution these food. increase improves its nutrition value, as more is available for brain synthesis neurotransmitter serotonin, which precursor.