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ARS Home » Midwest Area » Madison, Wisconsin » Cereal Crops Research » Research » Publications at this Location » Publication #93033
Title: ANTIOXIDANT ACTIVITY AND PHENOLIC ANTIOXIDANT CONTENTS OF OAT FRACTIONS

Author
item Emmons, Cheryld
item Peterson, David
item PAUL, GREG
item BLUMBERG, JEFFREY
item HANDELMAN, GARRY
item Prior, Ronald
item CAO, GUOHUA

Submitted to: Oat Newsletter
Publication Type: Abstract Only
Publication Acceptance Date: 7/26/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: The potential of oat fractions to contribute to dietary antioxidants was evaluated. Antioxidant activity was measured in methanol extracts of flour, pearlings, bran fines, and trichomes from groats by 1) inhibition of coupled autoxidation of linoleic acid and beta-carotene (AOA), 2) inhibition of copper and peroxyl radical-induced low-density-lipoprotein oxidative damage (LDL-C, LDL-P, respectively), 3) oxygen radical (peroxyl and hydroxyl) absorbance capacity (ORAC-P and ORAC-H, respectively). Pearlings had greater AOA (62-78% inhibition) than flour (53%), bran fines (57%), or trichomes (47%). Pearlings had greater ORAC-P (5.81) and ORAC-H (6.34) than flour (3.40, 3.70) bran fines (2.71, 1.80) and trichomes (2.74, 1.11). LDL-P and LDL-C were greatest for pearlings (3.82 and 3.42, respectively), followed by trichomes (1.54, 1.87), flour (1.26, 0.55), and bran fines (1.28, 0.46). AOA was correlated to LDL-C (r=0.75). Total phenolic content (TPC), determined using the Folin-Ciocalteau phenol reagent (gallic acid equivalents). Pearlings contained the greatest TPC (318 mg/kg), followed by flour (156 mg/kg), trichomes (139 mg/kg), and bran fines (107 mg/kg). TPC was correlated to AOA, ORAC-P and LDL-C. Phenolic compounds were separated by HPLC. Tannic acid, p-hydroxy-benzoic acid, vanillic acid (VA), caffeic acid (CA), syringic acid, vanillin, p-coumaric acid, and ferulic acid were identified and quantified in each sample. AOA was correlated to VA and CA contents. LDL-C was correlated to CA. Three peaks correlated to AOA and LDL-C were tentatively identified as avenanthramides. A fourth peak, with a spectrum similar to catechin (a flavan-3-0l), was correlated with AOA and LDL-C.