Ferulic and coumaric acids, total phenolic compounds and their correlation in selected oat genotypes

Ferulic and coumaric acids were determined by high-performance liquid chromatography in 21 oat genotypes supplied from the gene bank of the Research Institute of Plant Production in Piestany (Slovak Republic) with the aim of selecting some genotypes suitable for the preparation of functional foods. The content of coumaric acid was higher than that of ferulic acid in 61.9% of samples. The latter acid exceeded proportionally the former one in genotypes with a low content of phenolic acids, namely in the amount of up to 50 mg/100 g of grain, especially in chaffless oats. Ferulic acid content varied in the range from 16.50 mg/100 g (cultivar Jakub) to 149.36 mg/100 g of grain (cultivar Izak). The content of coumaric acid ranged between 8.05 mg/100 g (cultivar Detvan) and 210.27 mg/100 g of grain (cultivar Izak). The fact that the samples were grown in the same year (2003) in one locality (Vigfas-Pstrusa, Slovak Republic) minimises the influence of soil and climatic conditions and proves that remarkable differences between the content of ferulic and coumaric acids and the total content of phenolic compounds were caused by the genetic outfit of oats. A high correlation was found between the contents of the total phenolic compounds, ferulic acid, coumaric acid and their sum. The corresponding correlation coefficients R had the values of 0.9229, 0.9141, and 0.9211, respectively. This correlation enables one to employ a simple and inexpensive method for the determination of the total phenolic compounds using Folin-Ciocalteu reagent for a rapid assessment of differences detectable in the content of the sum of ferulic and coumaric acids in oat samples in view of the selection of genotypes suitable for the preparation of functional foods.