Antioxidant properties of free, soluble ester and insoluble-bound phenolic compounds in different barley varieties and corresponding malts

• Type: Article in International Scientific Journal
• Date: 2008

Authors

Marketa Dvorakova (Author) Other; Luis F Guido (Author) FCUP; Pavel Dostalek (Author) Other; Zuzana Skulilova (Author) Other; Manuela M Moreira (Author) Other; Aquiles A Barros (Author) FCUP

Journal

Title: Journal of the Institute of Brewing

Vol. 114

Pages: 27-33

ISSN: 0046-9750

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 98 Citations

Scopus - 106 Citations

Scientific classification

FOS: Agrarian Sciences > Other Agrarian Sciences

Other information

Authenticus ID: P-004-3ZM

Abstract (EN): Ten different barley cultivars and their corresponding malts were used to obtain different fractions. Phenolics extracted belonged to free, soluble esters and insoluble-bound fractions. Total phenolic content (TPC) of the free fraction, as measured according to the Folin-Ciocalteu method, ranged from 37.7 to 167.2 mg gallic acid equiv/kg of dried material (GAE/kg(dw)) for barley and between 34.1 and 72.3 mg GAE/kg(dw) for malt. The bound phenolic content ranged from 210.3 to 320.5 and between 81.1 and 234.9 mg GAE/kg(dw), for barley and malt, respectively. The contribution of bound phenolics to the TPC was significantly higher than that of free and esterified fractions. Catechin and ferulic acid, quantified by high performance liquid chromatography with diode array detector (HPLC-DAD), were the most abundant phenolics in the free and bound fractions, respectively. The p-coumaric acid content was lower in hulless genotypes, as compared to hulled genotypes, showing that it is mainly concentrated in the hull. The antioxidant activities of the phenolic fractions were investigated using the radical scavenging assay (DPPH) and ferricyanide reducing power. The bound phenolics demonstrated a significantly higher antioxidant capacity compared to the free and esterified phenolics. During the malting process, a significant decrease of the bound phenolics was observed with a corresponding increase of the esterified fraction.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 7