Identification and function of antioxidants from oat groats and hulls

Abstract

Antioxidant components of methanolic extracts of groats and hulls from Ogle oats were identified and quantified by using gas chromatography-mass spectrometry (GC-MS) and gas chromatography after N,O-bis(trimethylsilyl)acetamide derivatization. Ferulic, p-coumaric, vanillic, p-hydroxybenzoic, 4-hydroxyphenylacetic acids and vanillin and catechol were quantified in groat and hull extracts. Additionally, caffeic acid in groat extracts, and o-coumaric, sinapic and salicylic acids in hull extracts were quantified. Extracts from groats and hulls at levels of 0.05, 0.1, 0.2, and 0.3% w/w, based on total phenolic content, were added to soybean oil, and their antioxidant effectiveness was compared with that of 0.02% w/w tertiary butylhydroquinone (TBHQ) and a control (no additives) at 60°C in the dark by measuring peroxide values. Antioxidant activities of both extract sources increased with increased concentration. During 20 d of storage, the groat extract (0.3%) was not significantly different from TBHQ after day 16, and hull extracts (0.2 and 0.3%) were not significantly different from TBHQ on day 20. Oils containing pure phenolics at the same concentrations measured in the groat and hull extracts oxidized more quickly than did oils containing the extracts. JAOCS 74, 303-307 (1997). FIG. 2.Peroxide values (PV) for SBO at 60°C. ▲, SBO; • •, SBO with 0.3% oat groat extract; ◆, SBO with 0.3% oat hull extract; SBO with the amount and proportion of the phenolics identified in 0.3% groat extracts (■); 0.15% groat extracts (▲ ▲); 0.3% hull extracts (•); 0.15% hull extracts (■ ■). For abbreviations, see Figure 1.

The cereal grains: focus on vitamin E

“…The highest content of hull was found in buckwheat and oat. PRZYBYLSKI et al (1998) andXING andWHITE (1997) reported a similar content of buckwheat and oat hulls. The hull content in barley grain was in the range reported by other authors (G¥SIOROWSKI 1997).…”

Antioxidant activity, β-glucan and lipid contents of oat varieties

“…Most of the previous studies in literature reported a good antioxidant capacity of oats (Xing & White 1997;Peterson et al 2001;Chen et al 2004;Mattila et al 2005). However, to the best of our knowledge, the correlations between the antioxidant and radical scavenging capacities, determined by EPR/spin trapping, and the contents of biologically active compounds in oats have not been studied.…”

Antioxidant and Pasting Properties of Oat <i>β</i>-Glucan Hydrocolloids

“…Also, the measurement of the true "total antioxidant activity" is still a challenge because of the diverse polarity of antioxidants and the fact that most of them are covalently bound to an insoluble matrix [34]. Total phenolic content has been reported to be higher in oat hulls than groats [35] but total antioxidant capacity was higher in oat groats [36]. Perhaps these prior references may partly explain the low antioxidant activities in oat hydrocolloids since they are produced from processed oat bran.…”