banner 12. Non-volatile metabolites associated with flavor stability in beer

A. L. HEUBERGER (1), D. Sedin (2), P. Bouckaert (2), L. Guerdrum (2), K. Kirkpatrick (2), C. D. Broeckling (1), J. E. Prenni (1); (1) Colorado State University, Fort Collins, CO, U.S.A.; (2) New Belgium Brewing, Fort Collins, CO, U.S.A.

Technical Session 4 - Flavor and Product Stability I
Monday, June 15
10:45 a.m.–12:00 p.m.
Fiesta 3,4,6,8

Flavor stability is vital to the brewing industry as products are often stored for long durations. The use of an accelerated model that evaluates new brewing techniques to improve flavor stability is invaluable. We tested a model that stores bottled beer at high temperatures to estimate flavor stability after long-term cold storage. Additionally, three brewing methods were compared that are predicted to improve flavor stability: use of antioxidant crowns, removal of pro-oxidants, and varying hops. Two beers, an amber ale (AA) and India pale ale (IPA) were brewed using modified methods with the goal of improving flavor stability during storage. Control and test beers were stored for 2 months at cold temperatures and also at 37°C for 1–7 days. Non-targeted metabolomics was conducted by injecting 1 µL of beer into a Waters Acquity UPLC (1.0 × 100 mm C8 column, water-acetonitrile gradient) coupled to a Waters Xevo G2 ESI-TOF-MS (positive ionization) operating in MSE mode. Data analysis was performed using XCMS, RamClust (a custom feature clustering algorithm), and the NIST-MS search program for compound annotation. Sensory analysis revealed no significant difference in flavor, aroma, or appearance for the AA beer after 2 months of cold storage; however the test IPAs resulted in superior aging (i.e. more stable) profiles within the first 2 months. The UPLC-MS metabolite profiling revealed metabolites that varied among the IPA methods, but not the modified AA beer, and included purines, amino acids, iso-α-acids, and alkaloids. The high temperature incubation revealed metabolites that differed between the control and test beers over the 7-day time course, including several purines previously shown to change during beer storage. Taken together, these data support that variation in purine compounds can be interpreted as a marker of beer aging. Thus, the association between purines and aging could be used to screen experimental methods for improved beer stability in conjunction with accelerated aging at high temperature.

Adam Heuberger is an assistant professor in the Department of Horticulture and Landscape Architecture at Colorado State University. He received his B.S. degree in molecular biology from the University of Wisconsin-Madison in 2004. In 2008, Adam received an M.S. degree in plant genetics at UW-Madison, where he studied molecular components of plant defense responses to pathogens. Adam received a Ph.D. degree in plant genetics from Colorado State University in 2011, where he characterized the influence of genetic diversity and growing environment on the rice metabolome. Adam joined the Colorado State University Proteomics and Metabolomics Facility in 2011 as a GC-MS specialist and as faculty in the Department of Horticulture in 2014. His laboratory studies biochemical and phytonutrient diversity in food crops and plant metabolites associated with sensory quality in foods. This research integrates techniques in the fields of metabolomics, analytical chemistry, food science, and plant genomics.