Determination of selected phenolic acid and majoritarian avenanthramides in different varieties of naked oats (Avena sativa L.) grown in Slovakia

Abstract

Oats are important cereals. Oats are a good source of protein and lipids, polyphenolics, phenolic acids, flavonoids and avenanthramides. Avenanthramides is phenolic group, which is unique in oats and have antioxidant activity, anti-inflammatory, anti-atherogenic and anti-proliferative effect. The aim of study is determination of the majoritarian avenanthramides (2c, 2p and 2f) and phenolic acids (p-coumaric and ferulic) in selected varieties of oat (Avena sativa L.) grown in two consecutive years using the HPLC method. The oats were exposed to ultrasound supported extraction (two 15 min cycles).The simultaneous separation was performed using C18 type of stationary phase. The method showed a good linearity in the concentration range 0.04 - 5.24 μg/mL for p-coumaric acid, 0.04 - 5.13 μg/mL for ferulic acid, 0.19 - 24.5 μg/mL for avenanthramide 2c, 0.53 - 17.1 μg/mL for avenanthramide 2p, 0.8 - 25.6 μg/mL for avenanthramide 2f. Correlation coefficients were higher than 0.9997. Detector operated at a wavelength 320 nm. The repeatability of the method was evaluated in three concentration levels with satisfactory results for each analyte. The content of both phenolic acids is significantly lower (50- - 100-times) compared to the total content of avenanthramides in both years’ harvests for all analyzed varieties. Content of total avenanthramides was the highest in varieties Racoon (723.28 mg/kg) followed by Oliver (578.59 mg/kg) and Kamil (384.17 mg/kg).