characterization of beer using af4 - 36th congress … · characterization of beer haze using af4...
TRANSCRIPT
CONFIDENTIAL
Experimental
Characterization of beer haze using AF4
Pieter Stam, Jozé Mutsaers, Angela de Bruine – Paulus, Wilbert Heijne* and Erwin Kaal
DSM Biotechnology Center, part of DSM Food Specialties B.V., Delft, The Netherlands
*DSM Food Specialties, Delft, The [email protected]
Introduction
Crystal clear beer and colloidal beer haze stability are
important quality parameters of many beer types.
Beer haze is in most cases unwanted and consists of a
very complex mixture of macromolecules, including
polysaccharides, polyphenols and proteins.
Better understanding of the nature of the beer haze is
essential to prevent or resolve it. For this, advanced
analytical methods enable to assess the complex
structure of haze. Recently, the applicability of
Asymmetrical Flow Field-Flow Fractionation (AF4) was
investigated for beer haze characterization.
In this study, the development of a novel analytical
method for (native) beer haze profiling based on AF4-UV-
FLR-MALLS-dRI (ultraviolet, fluorescence, differential
refraction-index and multi angle laser light scattering
detector) is described. Preliminary results are shown of
several randomly chosen (lager type) beers from the
market. AF4 reduces sample preparation to a minimum
and the obtained beer haze profiles contain valuable
information on haze composition.
Detector settings Specificity
UV 280 nm Proteins + polyphenols
UV 320 nm Polyphenols
DAD UV/VIS spectrum
240-800 nm
Any compound with UV
absorption in the 240-800
nm range
FLR Ex278, Em338 nm Proteins +
probably some polyphenols
FLR Ex280, Em305 nm Polyphenol like
FLR Ex280, Em440 nm Polyphenols
FLR Ex320, Em450 nm Polyphenols
dRI Refractive index Polysaccharides after
corrections
MALLS 19 angles Molecular size properties
104 5×104 105 106 108MW (Da)
Results
104 5×104 105 106 108MW (Da)
Conclusions
• This AF4 method developed for beer shows to be
very promising for characterization of
macromolecules in beer.
• Allows quick and easy sample preparation: the
sample is directly injected, after degassing the beer.
• Interesting information can be obtained from the
results; 6 different regions can be recognized in the
AF4 profiles.
• The AF4 method allows for easy fractionation of the
samples, for further characterization with different
techniques: NMR, proteins-, polyphenols-, and sugar
analyses.
• Next steps focus on correlating observed particular
beer hazes to specific signals in the spectrum
Figure 1. Principle of AF4 separations [Picture: Wyatt Technologies,
http://www.wyatt.com/images/graphics/theory/fff/fff-crossflow.png]
Figure 2. Analytical setup for beer analysis using AF4-DAD/FLR/dRI
Table 1. Detector settings
Figure 3. Results of the AF4-UV/FLR/dRI/MALLS analyses of 4 different
commercial beers and 2 ’other’ beers with a haze.
References
1. Işılay Tügel, J. Ray Runyon, Federico Gómez Galindo and Lars
Nilsson, Analysis of polysaccharide and proteinaceous
macromolecules in beer using asymmetrical flow field-flow
fractionation, Institute of Brewing & Distilling,
(wileyonlinelibrary.com) DOI 10.1002/jib.195
2. Karl J. Siebert. Haze formation in beverages, LWT 39, 2006, p.
987-994
3. Paola Quifer-Rada, et al. A comprehensive characterisation of
beer polyphenols by high resolution mass spectrometry (LC-
ESI-LTQ-Orbitrap-MS), Food Chemistry, 2015, Volume 169, p.
336-343
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Region Information
1 Rich in polysaccharides, ~5×104 Da
(cut-off of the AF4 membrane)
2 Rich in proteins, 104 -105 Da
3 Rich in proteins, ~105 Da
4 Flat part in the fractograms of the
lager beers. A protein rich peak was
detected in the 2 ‘other’ beers,~105 Da
5 Rich in polyphenols, ~106 Da
6 Ultrahigh MW part, 106 - 108 Da, only
detected in ‘other’ beers, with haze.
Figure 4. Analyzed (international) lager beer samples
Table 2. Characterization of the AF4 profiles.
Pink Other beer #1, with haze
Black Other beer #2, with haze
Orange Other beer #1, with haze
Green Other beer #2, with haze