Development of thermally processed bioactive pea protein gels: Evaluation of mechanical and antioxidant properties

Abstract

Thermal processing of plant proteins (e.g. from pea) is highly interesting due to its potential in the generation of new textures in food products. This processing route is particularly attractive when it is combined with the revalorization entailed by the bioactive properties of the processed gels. In fact, the antioxidant activity of food products, which has been found in numerous proteins and peptides from protein hydrolysates, is widely demanded by the society since it prevents the development of serious diseases.This work is focused on the evaluation of mechanical and antioxidant properties from a Pea Protein Concentrate (PPC) and two hydrolysates obtained from PPC (PPH25 and PPH120) at three different pH values (2.0, 6.5 and 8.0). The gelation process was monitored and, subsequently, mechanical spectra were obtained. In addition, protein interactions (ionic interactions, hydrophobic interactions, hydrogen bonds and disulphide bonds) were also determined in order to elucidate their contribution to the formation of the gel network. Finally, the characterisation of the antioxidant activity of the gels was carried out using three different reagents: DPPH, ABTS and Folin–Ciocalteu. Results put forward that each variable studied, the degree of hydrolysis and pH, are key factors over the thermal processing of gels, showing a remarkable influence on both mechanical properties and antioxidant activity.