Determination of phenolic acids in Korean rice (Oryza sativa L.) cultivars using gas chromatography-time-of-flight mass spectrometry

Total soluble phenolic acids (free and esterified forms) from 15 Korean rice cultivars (Oryza sativa L.) were characterized to determine the total soluble phenolic acid contents and the diversity among the phenolic acids. The individual phenolic acids were identified by GC coupled to time-of-flight MS (TOFMS) including tertbutyldimethylsilyl (TBDMS) derivatization. This method requires only 13 min for the GC-TOFMS run. Total soluble phenolic acid contents were higher in pigmented rice (168-368 mu g/g) than nonpigmented rice (146-172 mu g/g). Freeform phenolic acids accounted for less than 10% of the total soluble phenolic acids. The dominant compounds were ferulic and sinapic acid, which were detected as cisand trans-isomers. The content of salicylic acid in rice grain varied, ranging from 7.95 to 29.61 mu g/g. The quantitative results of this study indicate that the black rice 'Josengheugchalbyeo' could facilitate development of phenolic-rich rice or food.