3 research outputs found
Structural Elucidation of Humulone Autoxidation Products and Analysis of Their Occurrence in Stored Hops
The transformation of α-acids
[in hops (<i>Humulus lupulus</i> L.)] to iso-α-acids
(in beer) during the brewing process is
well known, but the occurrence and structure of the oxidized α-acids
during hop storage are not well documented. Because an understanding of these
oxidized compounds is essential to optimize the effects of oxidized
hops on the quality of beer, we investigated the autoxidation products
of humulone (a representative congener of α-acids) using a simplified
autoxidation model. Among the oxidation products, tricyclooxyisohumulones
A (<b>1</b>) and B (<b>2</b>), tricycloperoxyisohumulone
A (<b>3</b>), deisopropyltricycloisohumulone (<b>4</b>), and the hemiacetal <b>5</b> of tricycloperoxyhumulone A
(<b>5</b>′) were isolated, and their structures were
elucidated for the first time. The occurrence of compounds <b>1</b>–<b>4</b> in stored hops was verified using LC/MS/MS
analysis. We also monitored the levels of compounds <b>1</b>–<b>4</b> during hop storage using LC/MS/MS analysis