853
Views
1
CrossRef citations to date
0
Altmetric
Original Articles

Thermal Deterioration of the Trans-/Cis-Ratio of Bittering Agents of Commercial Beers

, &
Pages 1277-1285 | Received 13 Oct 2009, Accepted 24 Jan 2010, Published online: 13 Oct 2011
 

Abstract

The use of reduced isomerised hop extracts to achieve both bitterness and light stability became very popular during the last decade. Changes during storage in four hop extracts and seven commercial lager beers are studied using HPLC and spectrophotometric techniques. The degradation of the iso-α-acids and tetrahydro iso-α-acids as a function of time is represented by the ratio, in percentage, of the sum of trans-isomer concentration to the sum of the cis-isomer concentration (T/C). The results provided conclusive evidence that the gradual decreased of bitterness intensity in beer was due to the degradation of iso-α-acids, notably to the instability of the trans-iso-α-acids. When the beers were stored for 14 days at 45°C the decrease of the T/C average varied from 8.6 to 14.0%, except in lemon beer, in which case, T/C decreased 36.9%. The results allowed us to infer that in open storage and/or warm conditions the deterioration of beer was critical above 35°C. On the other hand, the results showed that tetrahydro iso-α-acids remained unaltered.

ACKNOWLEDGMENT

The authors would like to acknowledge the financial support from the Consejería de Educación de la Junta de Castilla y Leon.

Reprints and Corporate Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

To request a reprint or corporate permissions for this article, please click on the relevant link below:

Academic Permissions

Please note: Selecting permissions does not provide access to the full text of the article, please see our help page How do I view content?

Obtain permissions instantly via Rightslink by clicking on the button below:

If you are unable to obtain permissions via Rightslink, please complete and submit this Permissions form. For more information, please visit our Permissions help page.