The impact of different ale brewer’s yeast strains on the proteome of immature beer

Torben Berner,Nils Arneborg,Susanne Jacobsen

doi:10.1186/1471-2180-13-215

Torben Berner, Nils Arneborg + Show 1 more

Open Access

https://doi.org/10.1186/1471-2180-13-215

Copy DOI

Abstract

BackgroundIt is well known that brewer’s yeast affects the taste and aroma of beer. However, the influence of brewer’s yeast on the protein composition of beer is currently unknown. In this study, changes of the proteome of immature beer, i.e. beer that has not been matured after fermentation, by ale brewer’s yeast strains with different abilities to degrade fermentable sugars were investigated.ResultsBeers were fermented from standard hopped wort (13° Plato) using two ale brewer’s yeast (Saccharomyces cerevisiae) strains with different attenuation degrees. Both immature beers had the same alcohol and protein concentrations. Immature beer and unfermented wort proteins were analysed by 2-DE and compared in order to determine protein changes arising from fermentation. Distinct protein spots in the beer and wort proteomes were identified using Matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and MS/MS and revealed common beer proteins, such as lipid transfer proteins (LTP1 and LTP2), protein Z and amylase-protease inhibitors. During fermentation, two protein spots, corresponding to LTP2, disappeared, while three protein spots were exclusively found in beer. These three proteins, all derived from yeast, were identified as cell wall associated proteins, that is Exg1 (an exo-β-1,3-glucanase), Bgl2 (an endo-β-1,2-glucanase), and Uth1 (a cell wall biogenesis protein).ConclusionYeast strain dependent changes in the immature beer proteome were identified, i.e. Bgl2 was present in beer brewed with KVL011, while lacking in WLP001 beer.

Highlights

It is well known that brewer’s yeast affects the taste and aroma of beer
Beer fermentation To investigate the influences of fermentation and brewer’s yeast on the beer proteome, we used two different ale brewing yeast strains (WLP001 and KVL011) to produce beer
Some fermentable sugars were still present in the beer brewed with WLP001, while all fermentable sugars were depleted by the KVL011 yeast strain (Figure 1, Table 1)

Summary

Introduction

It is well known that brewer’s yeast affects the taste and aroma of beer. the influence of brewer’s yeast on the protein composition of beer is currently unknown. The most comprehensive proteome studies report that beer proteomes consist of only 20–30 different proteins from barley [4,5,6], all heat stable and protease resistant [7]. It is proteins from barley that are identified in the beer proteome; proteins origin of the identified proteins vary from proteins localized in the cytosol, such as enolase and triosephosphate isomerase, to proteins like Swc and Uth that are associated to the cell wall [4,5,8]. One common feature for all beer proteome studies, so far, is that commercial beers have been used where no information on raw materials, choice of brewer’s yeast strain, or fermentation conditions have been given

Methods

Results

Discussion

Conclusion