Date of Award
Master of Science
Dr. Andre R. Venter
Dr. Sherine Obare
Dr. Steve Bertman
Dr. Todd Barkman
Hops analysis, mass spectrometry, hop variety characterization, paper spray, leaf spray
Masters Thesis-Open Access
The objective of this research is to develop a new and innovative method of hops analysis, which is much faster than standard testing methods, as well as reduce the amount of consumables and solvent used. A detailed discussion on the development of an ambient ionization mass spectrometry method called paper spray (PS-MS) and leaf spray (LS-MS) mass spectrometry will be presented. This research investigates the use of PS-MS and LS-MS techniques to determine the α- and β- acids present in hops. PS-MS and LS-MS provide a fast way to analyze hops samples by delivering data as rapidly as a UV-Vis measurement while providing information similar to lengthy liquid chromatographic separations.
The preliminary results shown here indicate that PS-MS could be used to determine cohumulone and α/β ratios. A low cohumulone ratio is desirable for brewers to prevent a harsh bitterness in beer flavor. The α/β ratio is also important for brewers because during the aging process of hops, the bittering potential of α- acids decreases while it increases for β- acids. Leaf spray suffers from low reproducibility and poor quantitative performance but should prove useful for rapid qualitative analysis.
A separate aspect of this research involves investigating if hops varieties could be typified using PCA analysis of PS-MS or LS-MS data. Good grouping of hops varieties were observed for samples of the same variety from different sources and in different stages of processing. An attempt was made to develop a fingerprint database of PS-MS and LS-MS data to provide an alternative approach for differentiating and identifying hops varieties
Blain, "Direct Analysis of Hops by Leaf Spray and Paper Spray Mass Spectrometry" (2012). Master's Theses. 100.