Presenter: Thomas Kunz, Technische Universität Berlin,
Institute of Food Technology and Food Chemistry, Chair of
Brewing Science, Berlin, Germany
Coauthors: Gunnar Dingel, Kerstin Rudolph, and Frank-Jürgen
Methner, Technische Universität Berlin, Institute of Food
Technology and Food Chemistry, Chair of Brewing Science,
Berlin, Germany
Fining agents are used to improve the filtration performance
and reduce the production time of clear and bright beers, wines,
and juices. Established fining agents like isinglass or gelatin are
animal derived, and due to their allergenic potential, labeling
is mandatory. In the literature pectin is described as a possible
non-allergenic, plant-derived alternative to conventional fining
agents. The aim of this study was to evaluate the application
of pectin as a fining agent in the brewing process and to get a
deeper insight into the mechanism of flocculation. Furthermore,
the stabilizing effect of an aqueous pectin solution that
contains sodium citrate, citric acid, and potassium metabisulfite
was investigated to verify the possible suitability
of pectin as a stabilizing agent as described in the literature.
Lastly, a potential concept for the use of pectin was created.
The results reveal that a pectin solution without additives does
not increase the colloidal stability of beer by the removal of
haze active polyphenol-protein compounds as described in the
literature. Rather, the additives used, such as citric acid and
particularly SO2, are responsible for a higher colloidal stability
by increasing oxidative stability. Nevertheless, the suitability of
pectin as a fining agent in the brewing process could be clearly
verified. The efficiency of clarification depends on the pectin
type used described by the degree of esterification, respectively
amidation and the ratio of the beverage matrices (pH, AE,
Ca2+). Due to these complexities it is difficult to choose the
right pectin for a new beer matrix without a testing method. For
the creation of a potential concept for the pectin application
in the brewing process and for the assessment of the fining
suitability of pectins in a given beer matrix it was necessary
to develop a laboratory quick test. Through the application of
pectin two key factors of filtration, flow rate and filtrate haze,
could be improved significantly. Lower filtrate haze did not
lead to significantly better colloidal stability, but the possible
reduction of filtration time by about 33% is emphasized.
Residual galacturonic acid was not detectable (IC) in the final
beer, which indicates that pectin is completely removed after
filtration. With the right application of pectin in the brewing
process and further optimization, pectin seems to be an efficient
option to the established fining agents used in the brewing
process.
After qualifying as a certified technician in preservation
engineering (1991–1993), Thomas Kunz completed his basic
studies in chemistry at the University of Applied Sciences,
Isny (1994–1995), and his basic studies in food chemistry at
Wuppertal University (1995–1998), before starting to study
food technology at the University of Applied Sciences, Trier
(1998–2002). After graduating, he worked as a chartered
engineer in the area of ESR spectroscopy at the Institute of Bio
Physics at Saarland University (2002–2004). Since 2005, he
has been employed as a Ph.D. student at the Research Institute
of Brewing Sciences, Berlin Institute of Technology (Technische
Universität Berlin). His main research focus lies in analyzing
radical reaction mechanisms in beer and other beverages using
ESR spectroscopy.
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