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ARS Home » Midwest Area » Madison, Wisconsin » Cereal Crops Research » Research » Publications at this Location » Publication #101353
Title: ANTIOXIDANT ACTIVITY OF OAT (AVENA SATIVA L.) EXTRACTS. II.

Author
item Emmons, Cheryld
item Peterson, David
item PAUL, GREGORY - QUAKER OATS COMPANY

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/6/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: It is becoming increasingly apparent that health benefits would accrue from an increase in antioxidants in the diet. These chemicals scavenge cell-damaging free radicals that naturally occur from several causes. One way to increase dietary antioxidants is to increase their concentrations in foods that we already eat. We initiated research to investigate the antioxidant activity and the concentrations of one group of antioxidants called phenolics in extracts from different physical fractions of oats. We found that a simple antioxidant test that measured the ability of the extracts to inhibit the oxidation of beta-carotene in a test tube correlated well with more sophisticated tests that measure the oxidation of low-density lipoprotein from human blood and an oxygen radical absorbance capacity test. This means that the beta-carotene test could be used for quick, initial screening of food extracts, saving time and money. The second finding was that the outer layers (pearlings) of the oat kernel contained the greatest concentrations of the antioxidant chemicals and had the greatest antioxidant activity. This is good news for consumers of whole-grain oats, and suggests that manufacturers could devise new products taking advantage of this natural concentration of antioxidants in the pearlings fractions.

Technical Abstract: Soluble extracts of oat milling fractions were examined for total phenolic content, tocol content, concentrations of phenolic acids, and in vitro antioxidant activity. The objective was to determine the potential of oat fractions to contribute to dietary antioxidants. Antioxidant activities of methanolic extracts of pearling fractions were greatest, flour and bran fines fractions intermediate, and trichomes least, as measured by inhibition of a coupled autoxidation of linoleic acid and beta-carotene. Pearlings fractions were also highest in total phenolic content and total tocol content. P-Hydroxybenzaldehyde, vanillic acid, caffeic acid, syringic acid, vanillin, p-coumaric acid, and ferulic acid were identified and quantified by HPLC. Three peaks tentatively identified as avenanthramides and a peak with a spectrum similar to (+)-catechin were also detected. Total phenolic content was significantly correlated to antioxidant activity, as were the concentrations of several phenolic acids. These data indicate a potential for oat products, especially those enriched in outer layers of the kernel, to contribute to dietary intakes of antioxidant phytonutrients.