Kvasny Prum. 1959; 5(8): 189-192 | DOI: 10.18832/kp1959025

Determination of free amino acids in industrial and refined lactic acids.Peer-reviewed article

J. DYR, V. KRUMPHANZL

1. Anew method has been developed for isolation of amino acids present in various grades of lactic acid. 2. Chromatographic analyses disclosed the following amino acids: In industrial lactic acid manufactured by works A: aspartic acid, glycine, glutamicacid, alanin, tyrosine, γ-aminobutyric acid, valine, fenylalanin, leucine. Three stains on chromatogramms were not identified. Most likely they can be attributed to lysine, threonine and a substance giving after detection yellow stain. In edible lactic acid manufactured by work B: glycine, glutamic acid, alanin, γ-aminobutyric acid, leucine. Two stains were not identified. One stain was yellow. In edible lactic acid supplied by work C: aspartic acid, glutamic acid, alanin, γ-aminobutyric acid. In edible lactic acid manufactured by extracting from industrial lactic acid supplied by work A: aspartic acid, glycine, glutamic acid, alanin, γ-aminobutyric acid, alanin, γ-aminobutyric  acid, leucine. Two stains of which one was yellow were not identified. 3. Proportion of individual aminoacids present in edible lactic acid (sample from works B) extracted by ethylother and ethylacetate is on oll chromatograms - except aspartic acid - practically identical. Judging from the intensity of colours, it can be expected that the amounts of individual amino acids is approximately the samoe. The greatest part of substances in all samples is represented by glutamic acid and alanin. The est of amino acids is present in traces only. 4. Neither glycine, nor leucine were found in edible lactic acid manufactured by recrystallization (sample from works C). The intensity of stains permits to expect higher percentage of alanin than in lactic acid refined by extraction process in which organic solvents are used.
(In Czech, English summary only)

Keywords: lactic acid, aminoacids, determination

Published: August 1, 1959