Phenolic composition of authentic pineapple juice

The phenolic composition of authentic pineapple juice concentrate was analyzed by HPLC. Nine major peaks accounting for 70% of total peak area were characterized and their concentrations measured in 54 commercial samples. Means and standard deviations were as follows (mg/100 mL single-strength juice, normalized to 12.8 degreesBrix): tyrosine, 3.6(1.4); serotonin, 1.8(0.8); dimethylhydroxylfuranone, 1.4(0.7); dimethylhydroxylfuranone beta-glucoside, 6.2(3.0); tryptophan, 2.2(0.9); S-sinapyl-L-cysteine, 1.1(0.6); N-gamma-L-glutamyl-S-sinapyl-L-cysteine, 2.3(1.1); S-sinapyl glutathione, 5.4(1.4); and a p-coumaric acid-like phenolic compound (calculated as p-coumaric acid), 0.5(0.4). This information will be useful for evaluation of authenticity and quality.