Malting procedure and its impact on the composition of volatiles and antioxidative potential of naked and covered oat varieties
Alan Gasiński, Joanna Kawa‐Rygielska, J. Błażewicz, Danuta Leszczyńska
Abstract
Grains from four naked oat varieties (Amant, Maczo, Polar and Siwek) and one covered oat variety (Kozak) grown with three different nitrogen fertilization regimes were malted in a laboratory setting using specifications typical for barley malt production (45% moisture content, temperature of germination equal to 15 °C, germination time equal to 120 h). The goal was to determine, whether malting process could be used to improve pro-health properties and aroma of the covered oat and naked oat grain. Malting increased concentration of phenolic compounds (from 44.92 to 64.39 mg GAE per 100 g of grain to 158.06–393.69 mg GAE per 100 g of malt) and increased the antioxidative potential of grains (analysed by ABTS, DPPH and FRAP assays) by 200–300%. Malting also had an effect on the changes in composition of volatile compounds: the HS-SPME-GC-MS detected 23 compounds in grain samples and 34 compounds were detected in malt samples. The total concentration of volatiles in malts was significantly higher (1659.70–39708.33 ng per 100 g) than in grain samples (882.45–2098.74 ng per 100 g). Malting mostly increased concentration of aldehydes, such as nonanal, decanal and undecanal and pyrazines, such as trimethyl- and tetramethylpyrazine in the acquired malts.