Optimization of Parameters for Extraction of Avenanthramides from Oat (Avena sativaL.) Grain Using Response Surface Methodology (RSM)

Avenanthramides play a role as phytoalexins in oat. Recently, various bioactivities have been found in avenanthramides as an antioxidant activity, anti-inflammatory, anti-atherogenic and anti‑proliferative effect. In this study, the optimal conditions for the extraction of avenanthramides 2c, 2p and 2f from oat grain, cultivar Avenuda, were determined using response surface methodology (RSM). The effects of three independent variables (methanol concentration, extraction temperature and time) on the yield of aventhramides were investigated. A second-order polynomial model adequately fitted the experimental data with the R2 values of 0.959, 0.970 and 0.984 for the response of avenanthramides 2c, 2p and 2f, respectively. The optimization method which combined RSM with desirability function was chosen to find the best extraction conditions. The optimal conditions for the highest yield of avenanthramides were a methanol concentration of 70%, extraction temperature 55 °C and time 165 min. Under these conditions, the yields of avenanthramides 2c, 2p and 2f were 9.70 ± 0.38 mg kg-1, 10.05 ± 0.44 mg kg-1 and 19.18 ± 0.80 mg kg-1 oat grain, respectively.