Behaviour of Antioxidants Derived from Hops During Wort Boiling

作者：Wietstock Philip; Kunz Thomas; Shellhammer Thomas; Schoen Thore; Methner Frank Juergen^*

来源：Journal of the Institute of Brewing, 2010, 116(2): 157-166.

DOI：10.1002/j.2050-0416.2010.tb00412.x

• Antioxidant potential
• Electron Spin Resonance Spectroscopy (ESR)
• flavour stability
• hops
• wort

The oxidative stability of wort at different stages during wort production and the radical scavenging characteristics of alpha-, beta-, iso-alpha-acids and a hop polyphenol extract were evaluated using ESR spectroscopy and DPPH center dot 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 alpha- and beta-acids showed similarly significant radical quenching abilities, while iso-alpha-acids and a hop polyphenol extract displayed a negligible effect. Isomerization of alpha-acids to iso-alpha-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.

• 出版日期2010