Floral Aromas and Funky Flavors : An Analysis of the X-zyme Brewing Adjunct and its Associated Enzyme Activity

Abstract

Adjuncts have been used for centuries to improve various qualities of beer. Enzyme adjuncts work by facilitating specific chemical reactions to attain results that would normally take much longer or not be possible at all without the adjunct. The X-zyme enzyme adjunct is intended to act as a beta-glucosidase and release glycosidically bound volatile terpene alcohols (VOC’s) to improve aroma and flavor. When performing GCMS analysis to look for increased VOC profiles we also saw an increase in the level of 4-vinylguaiacol (4-VG). 4-VG is a “funky”, clove-like, off flavor in beer that is usually undesirable. It has been characterized in the brewing community as a Phenolic Off Flavor (POF) which has been shown to rely on enzymatic decarboxylation to be derived from ferulic acid. With the knowledge that 4-VG is a derivative of ferulic acid, spectroscopic and HPLC ferulic acid esterase assays for in vitro and in situ X-zyme activity were developed. Both showed consistently higher ferulic acid content with X-zyme treatment. Results from our test brews suggest that there is little increase in terpene alcohols but when coupled with specific strains of yeast strains there is a large increase in the “funky” 4-VG aroma.