Czynniki wpływające na fermentację brzeczki i ocena przebiegu fermentacji

Magda Costa
Universiteit Gent

Słowa kluczowe: brewer’s yeast, fermentation follow-up, MALDI-TOF-MS

Fermentation is an important step in beer production and so are thus the wort composition and fermentation conditions. As yeast behaviour can be very unpredictable, wort fermentation must be controlled through careful management of yeast quantity and health.

Yeast’s well-being needs to be correctly assessed, since poor quality negatively affects attenuation, the final beer quality, and the beer flavour profile due to off-flavour production. Measuring the specific gravity, extract, alcohol content, pH and colour of the fermenting wort are the traditional methods to follow-up the fermentation progress, due to their easy performance compared to reliable yeast viability and vitality tests, carbohydrate profiling or protein fingerprinting.

The aim of this research work is to explore new, fast and low-cost methods for follow-up of brewer’s yeast fermentation. MALDI-TOF MS (Matrix Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry) already proved its potential for profiling beers from different brands [1], and spoilage organisms from a large spectrum of bacteria to wild yeasts [2]–[4].

Moreover, this technique can be used for yeast protein fingerprinting during fermentation. It is known that brewer’s yeast behaves differently in terms of proteome depending on the stage of fermentation. Therefore, identifying target proteins by MALDI-TOF MS from each stage of the fermentation will thus help to draw a more complete map of yeast metabolism during this important step in the brewing process. In order to investigate this, yeast samples at different stages of the fermentation from different brews will be analysed by MALDI-TOF MS, in addition to carbohydrate profiling of the fermenting wort by HPAEC-PAD (high-performance anion-exchange chromatography coupled with pulsed amperometric detection), and amino acids profiling by UPLC MS/MS (ultra-high-performance liquid chromatography tandem mass spectrometry). It is excepted that this study will contribute to the development of a new analysis method for yeast performance in brewing science.

[1] O. Šedo, I. Márová, and Z. Zdráhal, Food Chem., vol. 135, no. 2, pp. 473–478, 2012.
[2] M. E. Turvey, F. Weiland, J. Meneses, N. Sterenberg, and P. Hoffmann, Appl. Microbiol. Biotechnol., vol. 100, no. 6, pp. 2761–2773, 2016.
[3] A. D. Wieme, F. Spitaels, P. Vandamme, and A. Van Landschoot, J. Inst. Brew., vol. 120, no. 4, p. n/a-n/a, 2014.
[4] A. D. Wieme, F. Spitaels, M. Aerts, K. De Bruyne, A. Van Landschoot, and P. Vandamme, Int. J. Food Microbiol., vol. 185, pp. 41–50, 2014.”