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Behaviour of Antioxidants Derived from Hops During Wort Boiling
Author(s) -
Wietstock Philip,
Kunz Thomas,
Shellhammer Thomas,
Schön Thore,
Methner FrankJürgen
Publication year - 2010
Publication title -
journal of the institute of brewing
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.523
H-Index - 51
eISSN - 2050-0416
pISSN - 0046-9750
DOI - 10.1002/j.2050-0416.2010.tb00412.x
Subject(s) - chemistry , hop (telecommunications) , polyphenol , boiling , radical , dpph , food science , hydroxyl radical , quenching (fluorescence) , antioxidant , organic chemistry , chromatography , computer network , physics , quantum mechanics , computer science , fluorescence
The oxidative stability of wort at different stages during wort production and the radical scavenging characteristics of α‐, β‐, iso‐α‐acids and a hop polyphenol extract were evaluated using ESR spectroscopy and DPPH• radical quenching measurements. Radical generation in unhopped wort was significantly, positively correlated with heating rate prior to boiling but not with dissolved oxygen content. Hop α‐ and β‐acids showed similarly significant radical quenching abilities, while iso‐α‐acids and a hop polyphenol extract displayed a negligible effect. Isomerization of α‐acids to iso‐α‐acids reduced wort's antioxidative capacity. Commercially available hop products with varying polyphenol content showed similar radical inhibiting properties, which were a function of hop acid content. Relative to an unhopped treatment, hop additions to wort resulted in significantly lower amounts of Strecker aldehydes in stored beer.