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 °Brix): tyrosine, 3.6(1.4); serotonin, 1.8(0.8); dimethylhydroxylfuranone, 1.4(0.7); dimethylhydroxylfuranone β‐glucoside, 6.2(3.0); tryptophan, 2.2(0.9); S‐sinapyl‐L‐cysteine, 1.1(0.6); N‐γ‐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.