Rapid Screening Method for Phenolic Off-Flavor (POF) Production in Yeast

Abstract

Because of an increased interest in complex niche products and the ongoing quest for improved brewing efficiency and quality, the interest in novel yeasts is increasing. However, many of these nonconventional yeasts and newly developed hybrids often produce undesirable off-flavors and, in particular, are characterized by strong production of phenolic aromas such as 4-vinyl guaiacol (4VG). Here, we describe a novel high-throughput, low-cost absorbance-based screening method that allows quick determination of the phenolic off-flavor (POF) production capacity of yeasts. We show that this method correlates well with the standard, more laborious GC-based methods and that it can be used to assess POF production of many different strains in parallel with minimal hands-on labor. This new method therefore opens exciting new routes to select rare variants or mutations that combine desirable phenotypes without showing unwanted production of POFs such as 4VG.