Organic acids in beer

SieberL K.J., Modeling the flavor thresholds of organic acids in beer as a function of their molecular properties. Food Qual. Pref, 10, 129-137, 1999. 

Figure 10.218 Separation of inorganic and organic acids in beer by anion-exchange chromatography. Separator column lonPac AS11-HC-4pm column dimensions 250 mm x 2 mm i.d. column temperature 30 °C eluent KOH (EG)/MeOH gradient 1 mmol/L KOH with 2% (v/v) MeOH isocratically for 8 min, step to 10% (v/v) MeOH in 0.1 min, 1-15 mmol/L KOH with 10% (v/v) MeOH in lOmin, 15-30mmol/L KOH with 10% (v/v) MeOH in 10 min, and...

For the analysis of organic acids in beer, the literature describes separation on ion exchangers utilizing UV detection [213, 214]. However, detection via measuring the light absorption at 210 nm is interfered with by other matrix components such as phenols, bitter components, and fructose, which also absorb at this wavelength. To avoid extensive sample preparation, the application of conductivity... 

Fig. 9-143. Separation of organic acids in beer by ion-exclusion chromatography. -Separator column lonPac 1CE-AS6 eluant ...

EmyGL, Rodrigues JEA, GUAM, BarrosAS, Esteves VI (2009) Analysis of non-aromatic organic acids in beer by CE and direct detection mode with diode array detection. Chromatographia 70 1737-1742... 

In one study a photochemical-CL detection system was combined with HPLC and successfully applied in analyzing organic acids in a variety of real samples, which included beer, wine, milk, fruit, and soft drinks. The HPLC method is based on selective photodecomposition of organic acids... 

Cortacero-Ramirez, S., Segura-Carretero, A., Hernainz-Bermudez de Castro, M., and Ferndndez-Gutifeez, A., Determination of low-molecular-mass organic acids in any type of beer samples by coelectroosmotic capillary electrophoresis, J. Chromatogr. A, 1064, 115, 2005. 

Organic acids In beverages such as wines, beers, and fruit juices, IC has also been widely applied in the determination of various organic acids, although in many cases ion exclusion chromatography is often used in preference to anion exchange. 

Montanari L, Perretti G, Natella F, Guidi A, Fantozzi P (1999) Organic and phenolic acids in beer. LWT - Food Sci Technol 32 535-539... 

The acidity of beer is due partly to various organic acids (especially lactic), partly to acid phosphates and, particularly in badly kept beers, partly to volatile acids (acetic). In some cases, the volatile acidity is determined separately from the fixed acidity. 

Most people are familiar with ethanol as being the active constituent of beers, wines and spirits, whereas ethanoic acid is usually associated with chips - it is in vinegar. When the two substances are mixed, they react slowly to form a compound, an ester called ethyl ethanoate it has a distinctive sweet and fruity smell, and is used to make varnishes and glues. This esterification reaction, which is typical of alchohols and organic acids (see Module 7), is relatively easy to monitor and so... 

Ion-exclusion chromatography finds numerous applications for identification and determination of acidic species in complex matrix materials, such as dairy products, coffee, wine, beer, fruit juice, and other commercial products which can be quickly analyzed with minimal sample preparation before injection (usually only filtration, dilution, or centrifugation). Organic acid determination is also of great importance in biomedical research (e.g., physiological samples, in which most of the Krebs cycle acids (tricarboxylic acid cycle) are present). 

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