The Role of Small Wort Peptides in Brewing Fermentations

C. Lekkas¹, A.E. Hill^1,3, B. Taidi², J. Hodgson², and G.G. Stewart¹
¹ The International Centre for Brewing and Distilling, Heriot Watt University, Edinburgh, EH14 4AS, UK.
² Scottish & Newcastle PLC, 2–4 Broadway Park, South Gyle, Edinburgh, EH12 9JZ, UK
³ Corresponding author. E-mail: A.Hill@hw.ac.uk.

J. Inst. Brew. 115(2), 134–139, 2009 | VIEW ARTICLE

ABSTRACT
The utilisation of small peptides by brewing yeast is poorly understood despite a wealth of information on peptide transport by other microorganisms. A novel method for detection, isolation and measurement of small peptides during brewery wort fermentations was used to monitor utilisation by ale and lager yeast strains. Oligopeptide levels in wort were found to fluctuate throughout the fermentations. Measurement of extracellular protease activity provided evidence that yeast are able to continually regulate protease production in order to break down wort polypeptides into utilisable nitrogeneous materials.

Key words:
free amino nitrogen, wort oligopeptides, yeast proteases.