Free and bound minor polar compounds in oats: Different extraction methods and analytical determinations

Abstract The extraction capacity of several solvent mixtures and comparison between alkaline and acid hydrolysis to extract free and bound minor polar compounds in oat samples were carried out. The extraction yield of each method was evaluated by correlating several spectrophotometric indices (absorption at 320 nm and total phenolic compounds by the Folin–Ciocalteu method) with HPLC-MS and the antioxidant activities of the oat extracts (DPPH radical method). The results showed that methanol and alkaline hydrolysis reported the highest recovery of polar compounds, and spectrophotometric indices overestimated the content of these compounds. Antioxidant compounds of five Romanian oat samples, named Comun, Jeremy, Mures, Lovrin 1, Lovrin 27-T were determined. Large intervarietal differences in phenolic compounds and their antioxidant activities among oat varieties were detected. Total minor polar contents content was in the range of 1179.47 and 1897.18 mg/kg of seed. According to the literature, we found that the majority of the minor polar compounds existed in bound form.