Chemistry of non-enzymic Browing. IV. Determination of Amino acids and amino acid-deoxyfructoses in Browned Freeze-dried Apricots

Abstract

1-(N-Amino acid)-1-deoxyfructoses have been determined by elution chromatography on columns of a buffered cation exchange resin following the method described by Moore and Stein (1954a) for the determination of amino acids. This method has been used to determine the free amino acids and ammonia in freeze-dried apricots before and after storage for 12 months at 25 °C and 70 per cent. R.H., as well as to determine the 1-(N-amino acid)-1-deoxyfructoses and related compounds formed (Anet and Reynolds 1957) during storage. The total free amino acid decreased by 61 per cent. and the ammonia by 9 per cent., the changes in individual amino acids ranging from 22 to 81 per cent. The amino acid-deoxyfructoses and related compounds accounted for 90 per cent. of the free amino acid lost, the actual discrepancy being 1.2 mM/100 g dry weight of fruit.