PhD Fellow Aarhus University Aarhus N, Midtjylland, Denmark
Utilization of plant proteins is gaining more and more attention. The protein structure and functionality are affected by the processing history, and commonly used practices for isolation comes with challenges, i.e. loss of protein solubility and functionality. Membrane filtration is gaining interest, both as a more gentle and sustainable method for concentration or separation of unwanted small molecular weight components, and to fractionate proteins. However, a better understanding of the physical and chemical properties of the plant protein concentrates during membrane filtration, as a function of the type of membranes used and other operating conditions is needed.
Rapeseed has been identified as a potential protein source due to its high protein content and significant amount of essential amino acids. The rapeseed proteins differ in size, supramolecular structure, isoelectric point and has been recognized with different functional characteristics.
In our previous study, presented at the AOCS Annual Meeting 2021, it was outlined how extraction pH and the use of pectinase had a significant effect on the chemical composition and colloidal structure of rapeseed protein extracts. The aim of our current research is to study how membrane filtration using various pore sizes can be used to create concentrates with different functional characteristics. Gel electrophoresis showed that proteins could be separated based on colloidal size into two fractions, one with emulsifying and one with gelling properties. The colloidal structures were investigated by transmission electron microscopy. A novel approach for evaluating membrane performance using confocal laser microscopy and thermogravimetric analysis is also presented. These results are relevant to the Forum audience, since understanding the colloidal properties of plant proteins is crucial when designing extraction processes.