Étude des interactions peptide-peptide dans un mélange de peptides issu d'un hydrolysat trypsique de ¿-lactoglobuline et de leur influence sur le fractionnement par nanofiltration

Authors: Groleau, Paule Émilie
Advisor: Pouliot, YvesGauthier, Sylvie
Abstract: Whey protein enzymatic hydrolysates contain several functional and bioactive peptides which justify their fractionatation to isolate such interesting molecules. Membrane separation technologies have an excellent potential for peptide separation but peptide-peptide interactions seem to reduce their efficiency. The objectives of this study were to demonstrate the occurrence of peptide-peptide interactions in a tryptic hydrolysate of β-LG, to identify the optimal physico-chemical conditions and peptides responsible of such interactions, as well as to evaluate the influence of such interactions on the fractionation of this hydrolysate by nanofiltration. Isoelectric focusing was used to fractionate the hydrolysate and to demonstrate a peptidic aggregation phenomena at acidic pH. Turbidimetry was then used to highlight the solubility of the hydrolysate according to the pH and some physico-chemical conditions. Peptide aggregates formed at pH 4 were centrifuged and separated, and peptides responsible for this aggregation were identified. From these peptides, the presence of chymotryptic peptides has justified a study of the impact of residual chymotryptic activity in the tryptic preparation on the aggregation phenomena. The second part of this work allowed the evaluation of the effect of these aggregates on the fractionation of the tryptic hydrolysate of β-LG by nanofiltration. It was shown that peptide-peptide interactions do not impair the fractionation. On the contrary, these interactions taking place in the polarized layer may have a positive impact on the fractionation.
Document Type: Thèse de doctorat
Issue Date: 2003
Open Access Date: 11 April 2018
Permalink: http://hdl.handle.net/20.500.11794/17853
Grantor: Université Laval
Collection:Thèses et mémoires

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