Application de couplages de procédés baromembranaires et électromembranaires pour la séparation de peptides bioactifs d'hydrolysats de protéines de soya et étude du colmatage des membranes échangeuses d'ions par des peptides

Authors: Langevin, Marie-Eve
Advisor: Bazinet, Laurent; Moresoli, Christine
Abstract: Soy is an important legume produced in Canada and its culture and production rate increased significantly in the recent years. Developing new competences to create by-products instead of exporting soya to other countries is of interest for the economy. The functional food and nutraceutical industry have great interests on soya due to its high bioactivity potential in regard of the protein content. Technologies using membranes offer the possibility of fractionating solutions to concentrate and isolate molecules of interest. These technologies can be divided in two main categories: Pressure-driven processes in which ultrafiltration (UF) and nanofiltration (NF) take part and electrically-driven processes in which electrodialysis with ultrafiltration (EDUF) membrane takes place. Working with protein or hydrolyzate solutions (soya in this case) can be problematic since these proteins or peptides have the tendency to foul the membranes. The aim of this study was 1) to evaluate the ion-exchange membranes potential to fouling by soy peptides 2) to compare pressure- and electrically-driven process in terms of mass flux and mass balance 3) to characterize the fractions in terms of molecular weight and amino acid profile, protein and peptide contents and 4) to evaluate their antioxidant potential and neuroprotection capacity. The study on ion-exchange membranes fouling by peptides showed that electrostatic interactions are the main cause of this phenomenon and its intensity depends on the type of membrane (cationic or anionic) used and the medium characteristics (acid or basic). Simple cleaning steps with NaCl solution could enhance performances of this process and improve its efficiency. Both processes showed a similar mass balance, however UF/NF process showed a higher mass transfer than UF/EDUF process when considering the time and membrane surface used to complete the run. UF/NF system produced a permeate with small molecular weights while UF/EDUF system produced fractions with a large range of molecular weights with a very specific molecular weight range depending on the pH value. Both processes produced similar fractions in terms of protein content. Specific fractions of EDUF were composed of a high level of polar amino acids. KCl 1 pH 3 and 6 from EDUF showed antioxidant capacities by the ORAC test. The same fractions as well as KCl 1 pH 9 and NF permeate pH 6 showed an interesting effect in the redox potential. Therefore none of these fractions showed protection against oxidative stress induced in cells.
Document Type: Mémoire de maîtrise
Issue Date: 2011
Open Access Date: 17 April 2018
Grantor: Université Laval
Collection:Thèses et mémoires

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