Vitamins in brewing: presence and influence of thiamine and riboflavin on wort fermentation

Abstract

Thiamine and riboflavin vitamers are present in a wide range of foods including beer. These vitamers play critical roles in a variety of enzymatic complexes and can promote and maintain metabolism. Currently, the presence and role of these vitamers in the malting and brewing industry have not been widely explored. This research investigated the effects of various fermentation conditions that may lead to the variations in the vitamin content in beer observed by previous researchers. The present research found that during fermentation, the thiamine content of wort is quickly utilized within the first 6 h of a standard fermentation and the uptake of this vitamin is not affected by increases in wort gravity. While no significant changes were observed in extracellular phosphorylated vitamers of thiamine, both free thiamine and thiamine diphosphate accumulated intracellularly during the wort fermentation. Meanwhile extracellular riboflavin vitamers were only poorly utilized during beer fermentations, however flavin mononucleotide rapidly accumulated intracellularly and more so under aerobic conditions. When yeast was exposed to an all-malt high-gravity wort, the thiamine or riboflavin utilization was not affected. However, thiamine utilization was reduced in adjunct-driven high-gravity worts. Notwithstanding the lowered thiamine uptake under high-gravity conditions; there were some minor improvements in fermentation performance and yeast viability. The addition of thiamine to an all-malt wort did appear to enhance yeast viability, both under normal and high-gravity conditions. Copyright © 2016 The Institute of Brewing & Distilling