Influence of the malting parameters on the haze formation of beer after filtration
Malting changes the chemical and enzymatical composition of barley. During malting, enzymes are synthesized, cell walls (pentosans,
proteins, etc.) degraded and starch becomes available for enzymatic attack. The progress of germination defines the final
beer quality and processability in several aspects: mouthfeel, foam and haze formation (different proteins), processability
(viscosity caused by certain substances, like β-glucan), fermentation progress (FAN, sugar content), etc. The objective of
this research was to study the influence of different modified malt on turbidity in beer after filtration. This was achieved
by analyzing selected malts at different germination stages and afterward studying their influence on the final beer composition,
focusing on protein content and composition. Protein fractions were analyzed using a Lab-on-a-Chip technique, which separates
the proteins—based on their molecular weight—by capillary electrophoresis. This analysis was supported by the use of two-dimensional
gel electrophoresis (2D-PAGE). Additionally, common malt and beer analyses and turbidity and filterability measurements were
performed. The protein composition could be followed from malt to beer with both the Lab-on-a-Chip technique and 2D-PAGE.
No differences in protein composition could be seen in the final protein composition of the beer. However, it could be observed,
with Lab-on-a-Chip technique, that high amounts of a protein fraction with a size of 25–28kDa caused increased turbidity
in the beer.
Available from: Martin Zarnkow
- "They are required for yeast nutrition; they contribute to foam and are involved in the flavor development that malt contributes to beer and whiskey. The protein content of teff (11 %) is in the range (9.5 to 11.5 %) that a good quality malting material should possess to yield the above-mentioned quality-attributes (Asano and Hashimoto 1980; Bamforth 1985; Bishop 1930; Chen et al. 2006; Kunze 2004; Steiner et al. 2011). Thus, its protein content is an indicator for production of good quality gluten-free malt from teff grains. "
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ABSTRACT: The demand for gluten-free foods is certainly increasing. Interest in teff has increased noticeably due to its very attractive nutritional profile and gluten-free nature of the grain, making it a suitable substitute for wheat and other cereals in their food applications as well as foods for people with celiac disease. The main objective of this article is to review researches on teff, evaluate its suitability for different food applications, and give direction for further research on its applications for health food market. Teff is a tropical low risk cereal that grows in a wider ecology and can tolerate harsh environmental conditions where most other cereals are less viable. It has an excellent balance of amino acid composition (including all 8 essential amino acids for humans) making it an excellent material for malting and brewing. Because of its small size, teff is made into whole-grain flour (bran and germ included), resulting in a very high fiber content and high nutrient content in general. Teff is useful to improve the haemoglobin level in human body and helps to prevent malaria, incidence of anaemia and diabetes. The nutrient composition of teff grain indicates that it has a good potential to be used in foods and beverages worldwide. The high levels of simple sugars and α-amino acids as a result of breakdown of starch and protein, respectively, are essential for fermentation and beer making.
Available from: Rosanne M Guijt
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ABSTRACT: Chemical characterization and monitoring of fermentation broths and cell culture media provide significant information on the changes occurring within these complex and dynamic systems. Analytical methods based on CE in capillaries and microchips are attractive for integration in instrumental tools to obtain this critical data, improving the understanding and control of bioprocesses. In this review, the use of CE for chemical characterization and monitoring fermentations is discussed, organized by analyte class, including organic acids, pharmaceuticals, proteins, sugars, amino acids, and metabolites published between 1992 and October 2012. A section is dedicated to the roles CE plays throughout the wine making process, where applications range from characterization and increase in fundamental understanding of the fermentation to forensic applications, verifying the authenticity of the wine.
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Filterability is an essential quality parameter of barley malt and significantly impacts productive efficiency and quality of beer. In the study, differences of metabolic capability, rather than of initial contents of macromolecules in barleys, were found to be the main reason for malt filterability gap between the widely used cultivars Dan'er and Metcalfe in China. Comparative proteomics based on fluorescent difference gel electrophoresis (DIGE) was employed to quantitatively analyze proteins of four commercial malts belonging to the two cultivars, and 51 cultivar-differential spots were identified to 40 metabolic proteins by MALDI-TOF/TOF mass spectrometry, mainly including hydrolases and pathogen-related proteins. According to their function analysis and abundance comparison between cultivars, filterability-beneficial and -adverse proteins were putatively proposed. Two most remarkable differential proteins, β-amylase and serpin Z7, were further investigated to verify their effects on Dan'er malt filterability. These results provide biological markers for barley breeders and maltsters to improve malt filterability.
To the best of our knowledge, this is the first report of comprehensive investigation of metabolic proteins related to wort filterability of barley malts, and sheds light on clues for filterability improvement. Visible differences in the expression level of metabolic proteins between Dan'er and Metcalfe malts using 2D-DIGE signify a valuable tool for cultivar comparison, illustration of key proteins responsible for filterability and even other qualities of barley malts. And with these explorations on biomarkers of malt filterability and other aspects, there will be higher efficiency and quality of beer brewing, less application of exogenous hydrolases and more expending market for Chinese malting barleys. This article is part of a Special Issue entitled: Translational Plant Proteomics.
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