Effect of a simulated kilning regime on the profile and antioxidant activity of the free phenolic acids extracted from green malt

Ames, J.M., Inns, E.L., Buggey, L.A. and Nursten, H.E. (2005) Effect of a simulated kilning regime on the profile and antioxidant activity of the free phenolic acids extracted from green malt. Master Brewers Association of the Americas Technical Quarterly, 42 (3). pp. 204-208. ISSN 0743-9407

Abstract/Summary

Free phenolic acids were extracted from a laboratory-produced sample of green malt. Aliquots of the phenolic acid extract were heated from 25 to 110°C over 27 h, representative of a commercial kilning regime. Samples were taken at regular intervals throughout heating and were assessed for changes in antioxidant activity by both the 2,2(prime)-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical-cation scavenging (ABTS(^•+)) and the ferric-reducing antioxidant potential (FRAP) assays. Changes in the profile of the phenolic acids of the extracts were determined by HPLC. Overall, there was a decrease in both antioxidant activity level and the level of phenolic acids, but as the temperature increased from 80 to 100°C, there was an increase in both the antioxidant activity level and the level of detected phenolic acids.