The data from this study were presented in part at the Sixth Annual Spring Workshop of AOAC, Ottawa, Canada, May 12–14, 1981. The authors acknowledge the statistical advice of G. Jarvis and the technical assistance of H.G. Botting, C Christ, M.J. Farmer, B. Krasin, V.J. Mellish, A.T. Noma and G.F. Parson.
Inter- and Intra-Laboratory Variation in Amino Acid Analysis of Food Proteins
Article first published online: 25 AUG 2006
Journal of Food Science
Volume 48, Issue 2, pages 526–531, March 1983
How to Cite
SARWAR, G., CHRISTENSEN, D. A., FINLAYSON, A.J., FRIEDMAN, M., HACKLER, L. R., MACKENZIE, S. L., PELLETT, P. L. and TKACHUK, R. (1983), Inter- and Intra-Laboratory Variation in Amino Acid Analysis of Food Proteins. Journal of Food Science, 48: 526–531. doi: 10.1111/j.1365-2621.1983.tb10781.x
- Issue published online: 25 AUG 2006
- Article first published online: 25 AUG 2006
- Ms received 7/23/82; revised 12/10/82; accepted 12/20/82.
Amino acid compositions of casein, egg white, beef, soy isolate, rapeseed concentrate, pea flour and wheat flour were studied by seven collaborating laboratories. Samples were hydrolyzed with 6N HCl, performic acid + 6N HCl, and (with one exception) 4.2N NaOH. Amino acids were then determined by ion-exchange chromatography using automatic analyzers. One laboratory, however, determined tryptophan by treatment with p-dimethylaminobenz-aldehyde. The colorimetric determination of tryptophan was comparable to the tryptophan values determined by ion-exchange chromatography. Interlaboratory variation of tryptophan (coefficients of variation, CV, up to 24%), cystine and methionine (CV up to 17%), was greater than that of most other amino acids (CV up to 10%). Intralaboratory variation for all amino acids was less than 5%.