Assays of the Amino Acid Tryptophan in Cherries by HPLC-Fluorescence

Seven varieties of cherry from the “Valle del Jerte” in the Spanish Region of Extremadura were analyzed quantitatively and qualitatively for their content of the amino acid tryptophan. Tryptophan is an essential amino acid in humans, being the precursor of the indolamines serotonin and melatonin which are biogenic amines with great importance in human sleep function. It is also of great importance in the synthesis of indole alkaloids in fruit. The objective of the present work was to determine the levels of tryptophan in “Valle del Jerte” (Extremadura, Spain) cherry varieties by high-performance liquid chromatography with fluorescence detection. Tryptophan was found in all seven varieties tested, the mean concentration being 54.48 ± 17.14 g/ml. There were major differences between the varieties. The highest levels corresponded to the variety Navalinda and the lowest to Pico colorado. The tryptophan content of all the cherry varieties tested, in particular Navalinda, will have importance as the precursor for the biosynthesis of the biogenic amines.