Qualitative and quantitative determination of dansylated derivatives of free amino acids in brewage by HPLC technique
1990
Mekis, E. | Seres, G. | Bendek, Gy. (Kobanyai Sorgyar (Hungary))
To obtain a sample, 2 liters of brewage were deproteinated for 10 minuts on a Sephadex G column, using 0.04 M borate buffer as eluant, then the solution was dansylated for 45 min at 20 C degrees. A sample of 20 umol was injected onto a high efficiency liquid chromatograph (HPLC). Separation was carried out for 32 min on the C18 inverted phase column. In the next step the sample was detected with a spectrophotometer and evaluated by the application of an integrator/plotter//using an external standard/. The amino acids left the column in the order of increasing hydrophobicity to enter into a cross-flow cuvette. The dansylated amino acids revealed a fluorescence of significantly higher intensity than the solvent. The chromatogram was recorded by the integrator. Then the quantity of the amino acids (mg per 1) was determined in the brewage of different composition and enzyme content. The results permit the conclusion that a brewage of 50-50 o/o composition is competitive with malt brewage in relation to both individual amino acids and the total amino acid content. The lysin content was found even higher. This new method of amino acid determination provides more information than the alfa-amino-nitrogen measurement in every phase of beer manufacture that the method used at present, and it is suitable to follow up the protease enzyme activity.
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