We also determined antioxidant activity using the FRAP assay,and found that there was a rapid increase in FRAP value up to 15 min (41% higher relative to 0 min), then a stable increase up to 45 min, followed by a steady decrease of FRAP values until 75 min when treated with a-amylase. However, the FRAP value kept an overall decrease in the heating-only treatment (control) during the heating period (Fig. 4).The difference between amylase treatment and heating-only treatment was significant (p < 0.01). Moreover, both treating time and the interaction between treating time and treatment methods had significant influence on FRAP values at the level of p < 0.01 according to the two-way ANOVA analysis. In addition, the antioxidant activity in the FRAP assay was significantly correlated with the polyphenols content (r ¼ 0.78, p < 0.05).Therefore, the increase of phenolic content caused by amylase hydrolysis might be one of the major reasons that caused the increase of FRAP value of treated oat samples. Besides of this, the possible presence of reducing sugar in extracts from amylase treated sample might be another factor that contributed partly to the increase of FRAP values here, since it is known to reduce cations such as Fe3þ and Cu2þ, and thus increase the value of FRAP by promoting the formation of TPTZ FeⅡcomplexes.