Determination of Important Phenolic Compounds in Pakistani Brown Rice Varieties in Controlled, Germinated and Fermented Conditions by High Performance Liquid Chromatography

Abstract

A simple and novel high performance liquid chromatography (HPLC) method has been developed for the simultaneous determination and quantification of phenolic compounds in brown whole grain rice varieties of Pakistani origin. The accumulation of these compounds was studied during germination stages and fermentation process, thereby, providing a reliable and rapid method for their quantification in food samples. Calibration curves for the standard phenolic compounds showed good linear regression values (r2 =0.996-0.998) within the test ranges. The limit of detection and the limit of quantification were found in the range of 0.04-0.06 µg/mL and 0.166-0.205µg/mL, respectively. Precision (%RSD) of the method was found in the range of 0.05-5.25 and 0.05-0.58 for inter-day (n=3) and intra-day (n=5), respectively. The robustness (%RSD) was found in the range of 1.05-2.65. Excellent recoveries were attained within the range of 93%-106%. The average amount of phenolic compounds was found to be 0.185 g/100g in controlled condition whereas, further accumulation of these compounds was noticed during germination and fermentation phases. The maximum average amount of phenolic compounds after germination period of 120 hours and fermentation process was found to be 0.284 g/100g and 0.565 g/100g, respectively.