Soluting the Pectin [5]: 1,25 g pectin soluted in 100 ml dist. water (75°C).

Standard beer analyses according to MEBAK [4]: Turbidity (2.14.2.1) colour (2.13.6.1), pH-value (2.17), apparent and real extract (2.9.6.3), bitter units (2.22.1)

Pectin's used: Two pectin's, that have proved in pre-tests as applicable in the used beer matrix, henceforth referred to as „pectin A“ and „pectin B.“

Filtration-Tests: The pectin-quick-test [1,2] was made with 10, 20, 30, 40 and 50 ppm pectin dosage and a final measurement of the turbidity. For the filtration test 100 mL assay were filtered using a fluted filter (Grade 597 1/2). The filtrate volume was monitored after 5 and 7 minutes.

Settling-tests: 1 L graduated cylinders or bottles were filled with 1 L unfiltered beer and treated with different pectin dosages. The settling test were carried out with different temperatures (e.g. 5°C, 20°C). The supernatant‘s were analysed after 24 h.

The usage of Pectin as an alternative plant derived

fining agent for the brewing process

Thomas Kunz, Hannes Gierth, Kerstin Rudolph and Frank-Jürgen Methner Technische Universität Berlin, Institute of Food Technology and Food Chemistry, Brewing and Beverage Technology, Germany

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 gelatine are derived from animals. In the literature [3] 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 the applicability as a substitute for traditional fining agents like Isinglass. Therefore elementary filtration- and settling tests with pectin 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 suited pectin types laid the focus of the investigations on the right practical application and dosage cconditions.

INTRODUCTION First studies [6] have shown that a useful pectin application is the dosage shortly after fermentation prior centrifugation

during pumping the beer to the separator (Fig.2). A well dispersion and the fast pectin reaction (≤ 10 sec) give enough

contact time for the clarification and guarantee a sufficient separation of the pectin floc in the separator upstream

resulting in an improved filtration performance of up to 31%.

After pre-selection of the most suitable pectin types for a yeast-tarnished stout additional quick-tests were carried out to figure out the right pectin dosage (Fig.3).

Fig.3: Correlation between pectin efficiency and its dosage. Green: optimal area; Dashed: ideal concentrations.

The results in figure 3 demonstrate that turbidity sags significantly with an increasing pectin dosage up to a certain reversal point wherefrom a higher pectin dosage leads to a slightly increasing turbidity. The range near to the reversal point describes the optimal pectin dosage with the best fining effect. Since the quick-test only contains centrifuged assays, the method gives just a few information about the sedimentation behaviour of the generated precipitation. The sedimentation was additionally to investigate for a possible pectin application as a substitute for Isinglass (Is). Therefore multiple settling tests were made, where beer was treated with pectin in comparison to Isinglass (Fig. 4).

Fig. 4: Monitored sedimentation. Top: After 30 minutes. Bottom: After 24 hours. All labelled concentration in ppm.

Figure 4 illustrates that the sediments in the Isinglass assays are build up faster. After an augmented settling time the pectin assays also start sedimenting.

BIBLIOGRAPHY [1] Rudolph, K. (2013), „Effektivität von Pektin bei der kolloidalen Stabilisierug und Klärung von Bier.“, Diplomarbeit, Institut für Lebensmitteltechnologie und Lebensmittelchemie, Fachgebiet Lebensmittelverfahrenstechnik,Technische Universität Berlin. [2] Kunz, T.; Dingel, G.; Rudolph, K. F.-J. Methner (2013): “Applicability of pectins as a stabilizing and fining agent for the brewing process “ EBC congress, Luxemburg 2013, [2] Kunz, T.; Dingel, G.; Rudolph, K. F.-J. Methner (2013): “Evaluation of pectin application as a stabilizing and fining agent for the brewing process “ MBAA Annual conference 2013, Austin, US, [3] Hosking, M.; Lentini, P.;, Oliver, A.; Rogers, T.; Smith, P.; Bacic, P.; A. & Liao, M. (2006): „Methods and compositions for fining beverages“(WO/2006/032088 A2). [4] Methodensammlung der Mitteleuropäischen Brautechnischen Analysenkommission (MEBAK), „Würze, Bier, Biermischgetränke.“, Self-Publishing of MEBAK,Freising-Weihenstephan, 2012 [5] Kunz, T. (2009) „Pektinschnelltest-Getränkematrix“- SOP- TU-Berlin

When comparing the turbidity values after 24 h (Fig. 5) it can be recognized, that the best sedimentation could be achieved with pectin concentration of 15 ppm, highlighting that the fining effects of both pectin types are close to that of Isinglass. Whereby the application of pectin A resulted in better sedimentation.

Fig.5: Turbidity values of the sedimentation test.

The increased pectin dosage leads to more turbidity caused by surplus pectin which in logical order can have a disadvantageous effect on filtration. To get a deeper insight into the possible negative effect of overdosed pectin a filtration test was carried out. The results in fig. 6 show the volumes of the filtrates after 5 and 7 minutes.

Fig. 6: Filtration speed in dependence of pectin dosage Green: Ideal area

It is obvious, that the filtration speed can be improved by

the pectin application up to an optimum and reversal point

with 15-25 ppm. In correlation to the slight increase of the

turbidity using the centrifuge quick-test a higher pectin

dosage causes a decrease in filtration performance.

TEST METHODS

The application of pectin shortly before separation of the

hose beer proved to be most effective. Residual galacturonic acid was not detectable (IC) in the final filtrated beer, which indicates that pectin is completely

removed after filtration. The 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. Large-scale tests have

additionally indicated, that the flow conditions in the 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. With a right handling and pectin dosage, pectin can be an effective and low-cost alternative to

conventional fining agents for the brewing process.

CONCLUSION RESULTS

Contact: Thomas Kunz thomas-kunz@tu-berlin.de +49 (30) 31427400

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Low esterified (NV) pectins form networks when

exposed to bivalent ions like Ca2+. These networks

surround tarnishing particles and precipitate in the

beer matrix (Fig. 1).

Fig. 1: Model of the process of turbidity enclosure [3]

It has been proven, that the affinity of a pectin

depends on the ratio in the beer matrix and is

strongly linked to its degree of esterification and

amidation. Against this background it is necessary to

find a ideal pectin and a optimal dosage for every

beer matrix anew. Therefore a developed quick-

method was applied using a centrifuge under

practical conditions [1,5].

Fig. 2: Possible filtration concept of the application of pectin as a fining agent in the brewing process.

1: fermentation tank, 2: dosage apparatus with pectin, 3: separator, 4: storage tank.