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P 017
The use of confocal laser scanning
microscope (CLSM) for determination
of filtration inhibiting substances
in kieselguhr and membrane
filtration
P 018
Beta-glucan hazes - what‘s the
problem?
P 019
Changes of metal concentration in
beer production and their Influence
on the mechanism for haze formation
Michael Kupetz 1 , Martin Zarnkow 1 ,
Thomas Becker 1
1TUM Weihenstephan, Lehrstuhl für Brau- und Getränketechnologie,
Freising, Germany
Cecilia Damiani 1 , Karin Pawlowsky 1 ,
Giuseppe Perretti 2
1Campden BRI, Nutfield, United Kingdom, 2 Università di
Perugia, Perugia, Italy
Annika Burmeister 1 , Adelina Calean 2 ,
Thomas Kunz 3 , Frank-Jürgen Methner 3 ,
Peter Winterhalter 1 , Peter Fleischmann 1
1TU Braunschweig, Institute of Food Chemistry, Braunschweig,
Germany, 2 TU Braunschweig, Institute Geoecology,
Braunschweig, Germany, 3 TU Berlin, Institute of
Biotechnology, Berlin, Germany
DESCRIPTION OF TOPIC:
The filtration process of beer is enormously
influenced by reversible and irreversible blockages.
The aim of this research is to stain
and identify these components by CLSM. Staining
components were used which only react
with specific beer ingredients. The filtration
was performed on an automated laboratory
membrane, as well as kieselguhr precoat filter.
A combination of the dyes propidiumiodide,
fuchsine-acid and schiff´s reagent made
it possible to distinguish polysaccharides
(α-/β-glucans), proteins and yeast cells. The
staining was performed by filtration of the
dyes through the sample. Conclusions of the
particles could take on the basis of the available
wavelengths of the lasers. These allowed
identifying the blockages of the surface layer
and the interior of the filter medium.
DESCRIPTION OF TOPIC:
In some instances beer haze is caused by
beta-glucan molecules. Although this carbohydrate
haze has commonly been associated
with poor malt quality or mashing problems,
it can also originate from the yeast cell wall.
Indeed, with the increased use of centrifuges
for yeast separation and high gravity brewing,
yeast cells can be exposed to stresses
resulting in damage to cell walls and release
of beta-glucans. Until recently, there was no
simple test to distinguish between a yeast
and malt beta-glucan haze, which has made
trouble shooting the haze problem difficult.
However, we have now solved this technical
challenge and describe here a novel protocol
for the isolation/examination of beta-glucan
hazes and determination of whether they originate
from yeast or barley.
DESCRIPTION OF TOPIC:
Chill haze in beer causes an economical loss
for the brewing industry. Due to the precipitation
of protein-polyphenol-metal complexes
under inadequate storage conditions, consumers
confound these hazes with mold and its
associated health risk.
This work deals with the development of
concentrations of Mn, Cu, Zn and Fe in beer
raw materials, beers and their final concentrations
in isolated beer hazes (analyzed via
ICP-MS and ICP-OES). Independent from the
raw materials used the concentrations of Fe,
Mn, Cu and Zn in beers strongly depend on
the steps of brewing process. Metal concentrations
in the resulting hazes are 17 fold higher
for Fe, 4 fold higher for Cu, 6 fold higher
for Zn and 30 fold higher for Mn than in the
original beers.
Michael Kupetz
Cecilia Damiani
Annika Burmeister
Michael Kupetz graduated from Technische
Univeristät Müchnen in 2011 as a degreed
engineer for brewing sciences and beverage
technology. In 2012 he started his doctoral
thesis with Prof. Thomas Becker at the institute
of brewing science and beverage technology.
His research project is the ‚Comparative
identification of inhibitory substances in the
membrane and diatomaceous earth filtration
of beer‘
Cecilia Damiani graduated at the University
of Perugia (Italy) in 2012, having obtained a
B.Sc. in Food Science and Technology and a
M.Sc. in Food Technology and Biotechnology.
During her studies, she completed her Master
thesis at Campden BRI (UK) working on beta-glucan
haze in beer. After defending her
thesis at the University of Perugia, she has
been working as a scientist at Campden BRI
in the Analytical department since August
2012, carrying out chemical analyses on beer.
*10/2002 - 11/2007 Studies of Food Chemistry
at Goethe Universtiy Frankfurt/main,
Germany and Wilhelms University, Muenster,
Germany *12/2007 - 6/2009 Scientific
Researcher, Institute of Food Chemistry, Research
Group of Prof. Dr. Humpf, Wilhelms
University, Muenster,Germany *since 7/2009
PhD Student, Institute of Food Chemistry, Research
Group of Prof. Dr. Winterhalter and Dr.
Fleischmann, TU Braunschweig, Germany
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