A comparative study between the electro-activation technique and conventional extraction method on the extractability, composition and physicochemical properties of canola protein concentrates and isolates

A novel technology of electro-activation was used for protein extraction from canola meal. An alkaline solution was generated in the cathodic compartment under the influence of electric field. It has been reported to have improved extractive properties when compared to chemically alkalized solutions. The study aims to verify the efficiency of electro-activated solutions for protein extraction from canola oil cake by analyzing the effect of extraction method on the extractability rates, composition, and secondary structure of extracted proteins. The tested parameters included NaCl concentration (0.01-1 M), duration of electro-activation (10-60 mm), and current intensity (0.2, 0.3 A). The electro-activation was performed in a three-compartment cell separated by ion exchange membranes, after which the obtained solutions were used for 1-h extraction. Maximal protein extractability was 34.32 +/- 1.21% obtained with the electro-activated solution generated under 0.3A irrespective of the activation time The conventional extraction under the same conditions (pH 7-10) yielded 31.18 +/- 1.89% of proteins. Electrophoretic profiles of electro-activated protein concentrates and isolates analyzed by SDS-PAGE were clearly more distinguishable compared to those obtained by conventional method. FTIR study revealed considerable difference in proteins' secondary structures between different treatment conditions (pH and salt concentration) as well as between conventional and electro-activated samples, showing less denatured spectra for the latter. (C) 2015 Elsevier Ltd. All rights reserved.