Simultaneous Quantification of Anthocyanins and Phenolic Acids in Pigmented Rice (Oryza sativa) using UPLC-PDA/ESI-Q-TOF

Anthocyanins and phenolic acids are the major antioxidants in purple rice. The method conditions were specified and not coved for both anthocyanins and phenolic acids. The objective of this study was to adopt the UPLC coupled with ESI-MS method for determination of the major anthocyanins and phenolic acids under the same condition in purple, red and white rice varieties. A UPLC-PDA/ESI-Q-TOF method was optimized with a high linearity for all analyzed compounds with regression coefficients greater than 0.99. Repeatability was good with the relative standard deviation values generally less than 5.5%. The limit of detection and quantification ranged from 1.9-36.6 and 5.0-123.1 mu g kg(-1), respectively. Spike recoveries were between 81-116%. Mass spectroscopy was used to confirm identity in the positive ion mode for all analyzed compounds Cyanidin-3-glucoside and ferulic acid were the most abundant anthocyanins and phenolic acids, respectively. Bound ferulic acid was higher in purple rice than in red and white rice flours. This developed procedure can be used to facilitate the rapid screening of rice seed banks for anthocyanins and phenolic acids of interest for rice pre-breeding