For the FRAP assay, we measured the increase in absorbance at 593 nm resulting from the formation of TPTZ-FeⅡcomplexes in the presence of a reducing agent (Corral-Aguayo et al., 2008). The FRAP reagent was prepared fresh daily, and consisted of a 10:1:1 (v/v/v) mixture of 300 mM sodium acetate buffer (pH 3.6), 10 mM TPTZ solution in 40mMHCl, and 20mMFeCl3 solution. The FRAP reagent was warmed to 37 C in a water bath before use. Then, 0.1 mL appropriately-diluted sample solutionwas mixed with 2.0 mL FRAP reagent and incubated at 37 C for 30 min. The results were expressed as Trolox equivalent antioxidant capacity (mmol TEAC/g oat DW), derived from a Trolox (0e250 mM) standard curve. All tests were carried out in triplicate.