T. KUNZ (1), K. Rudolph (1), H. Gierth (1), G. Dingel (1), F. J. Methner (1); (1) Technische Universität Berlin, Berlin, Germany
Enzymes, Finishing and Stability
Fining agents are used to improve the filtration performance of clear and bright beers, wines, and juices, as well as to lower their production time. Conventional agents that are being used within the beverage industry like isinglass or gelatin are derived from animals. In the literature pectin is mentioned as a possible vegetarian alternative to the conventional fining agents. The aim of this study was to investigate the use of pectin as a fining agent in the brewing process and its applicability as a substitute for traditional fining agents like isinglass. Therefore, elementary filtration and settling tests with pectins of variable degree of esterification (DE) and amidation (DA) were carried out to get a better insight into the flocculation mechanism and the ideal conditions in different beer matrices. Beside the suitable pectin types the focus of the investigations was on the right practical application and dosage conditions. For this it was necessary to figure out the best conditions for the use of various pectin types depending on different beer matrices. The affinity of pectin depends strongly on the degree of esterification and amidation and the beer matrix. So for each given beer it is necessary to find the best acting pectin and its optimum concentration to achieve an efficient fining effect. Settling tests have shown that pectin can be an alternative agent for isinglass, but the density of the yielded precipitation is rather fluffy and needs longer settling time. In the brewing process the application of pectin shortly before or after separation of the hose beer proved to be most effective. Additional large-scale trials indicated that the flow conditions in CCVs can disturb the sedimentation performance of the fluffy pectin floc. Against this background the use of a centrifuge after pectin application in the brewing process is suggested. By treating pectin this way, it was possible to shorten the filtration time up to 30–40%. Nevertheless a suboptimal pectin concentration can cause an insufficient fining effect or lead to filtration problems. After pectinase application, galacturonic acid residue was not detectable (IC) in the filtrated beer, which indicates that pectin is completely removed after filtration. With the right handling and dosage, pectin can be an effective and low-cost alternative to conventional fining agents for 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 studying 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 and scientific assistant in the Department of Biotechnology, Chair of Brewing Sciences, Berlin Institute of Technology (Technische Universität Berlin). As head of the laboratory since 2009 his main research focus lies in analyzing the influences of brewing process stages, filter aids, stabilizing or fining agents, and specific beer ingredients on radical reaction mechanisms and the oxidative stability of beer or other beverages using ESR spectroscopy and GC-MS. Another part of his research is the influence of oxygen during brewing and oxygen permeation through a wide range of different packaging materials during storage.