Article

Antioxidant Activity of Free and Bound Compounds in Quinoa (Chenopodium quinoa Willd.) Seeds in Comparison with Durum Wheat and Emmer

Authors Laus, Gagliardi, Soccio, Flagella, and Pastore are with Dip. di Scienze Agrarie, degli Alimenti e dell'Ambiente, Univ. degli Studi di Foggia, Via Napoli 25-71122 Foggia, Italy. Authors Laus, Soccio, Flagella, and Pastore are with Centro di Ricerca Interdipartimentale BIOAGROMED, Univ. degli Studi di Foggia, Via Napoli 52-71122 Foggia, Italy. Direct inquiries to author Pastore (E-mail: ).
Journal of Food Science (Impact Factor: 1.79). 10/2012; 77(11). DOI: 10.1111/j.1750-3841.2012.02923.x
Source: PubMed

ABSTRACT Antioxidant activity (AA) of quinoa (Chenopodium quinoa Willd.) seeds, as well as of durum wheat (Triticum turgidum L. ssp. durum Desf.) and of emmer (T. turgidum L. ssp. dicoccum Schubler) grains, was evaluated by studying hydrophilic (H), lipophilic (L), free-soluble (FSP) and insoluble-bound (IBP) phenolic extracts using the new lipoxygenase/4-nitroso-N,N-dimethylaniline (LOX/RNO) method, able to simultaneously detect different antioxidant mechanisms, as well as using the Oxygen Radical Absorbance Capacity (ORAC) and the Trolox Equivalent Antioxidant Capacity (TEAC) assays, which measure the scavenging activity against peroxyl and ABTS [2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonate)] radicals, respectively. The species under study were compared with respect to the sum of AA values of H, L and FSP extracts (AA(H+L+FSP)), containing freely solvent-soluble antioxidants, and AA values of IBP extracts (AA(IBP)), representing the phenolic fraction ester-linked to insoluble cell wall polymers. The LOX/RNO and ORAC methods measured in quinoa flour a remarkable AA(H+L+FSP) higher than durum wheat, although lower than emmer; according to the same assays, the IBP component of quinoa resulted less active than the durum wheat and emmer ones. The TEAC protocol also revealed a high AA(H+L+FSP) for quinoa. Interestingly, the ratio AA(H+L+FSP)/AA(H+L+FSP+IBP), as evaluated by the LOX/RNO and ORAC assays, resulted in quinoa higher than that of both durum wheat and emmer, and much higher than durum wheat, according to the TEAC protocol. This may suggest that antioxidants from quinoa seeds may be more readily accessible with respect to that of both the examined wheat species.

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    • "Regarding polyphenols, Alvarez-Jubete et al. (2010) evaluated polyphenol composition and in vitro antioxidant activity of quinoa seeds and found that Favonols quercetin and kaempferol glycosides were the most abundant polyphenols, but also contain protocatechuic acid and a vanillic acid glucoside, and these components are related to the antioxidant activity of quinoa. Laus et al. (2012) compared antioxidant activity of quinoa and durum wheat seed and noticed that the antioxidants of quinoa seeds may be more readily accessible and may represent a better source of natural antioxidant compounds than wheat. It is important to highlight that the effects of polyphenols greatly depend on their transformation by specific components of the gut microbiota via esterase, glucosidase, demethylation, dehydroxylation and decarboxylation activities. "
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