DETERMINATION OF FOOD PROTEIN QUALITY BY A NEW BIOLOGICAL APPROACH. II. IDENTIFICATION OF THE ORDER OF LIMITING AMINO ACIDS AND EXTENT OF THEIR DEFICIT IN PEA PROTEIN BY AN AMINO ACID REMOVAL TECHNIQUE.
 
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Pol. J. Food Nutr. Sci. 2004;54(2):203–208
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ABSTRACT
In Part I, N-retention responses of growing rats to supplementation of pea protein, with either the same protein at a level equivalent to 0.66 of dietary protein, derived as (1-BV)/BV, or the mixture of essential amino acids, formulated to reproduce the pea protein, were equal. Having proved this, the aim of this study (Part II), was to determine the order and extent of amino acid limitation in pea protein by an amino acid removal technique. The synthetic EAA mixtures, with the same composition as that of pea protein, from which amino acids were selectively removed, were fed to rats, at the level indicated above, and the respective N-retention responses was determined. A Polish cultivar of peas (Cyrkon), was a source of protein. Experiments were conducted on albino rats fed semi-purified diets, using the N-balance method of Thomas-Mitchell, as described by Eggum [1973]. Removal of Met from the EAA mixture supplementing basal diet (G1) led to significant (p0.05). On the other hand, removal of branched-chain amino acids (Leu, Ile, Val) did not affect N-retention. The obtained results allowed the identification of the order and extent of amino acid limitation (excluding tryptophane). Met, Lys and Thr were identified as the first, second and third limiting amino acid. The extent of their limitation was Met 15.4, Lys 32.2 and Thr 17.5 mg/g, in rats fed pea as the only protein source.
ISSN:1230-0322