Enzymatic hydrolysis of pea protein: Interactions and protein fractions involved in fermentation induced gels and their influence on rheological properties

In the light of changing nutritional trends and recommendations, yoghurt style gels from plant proteins are a promising way to incorporate relevant amounts of plant derived proteins into the diet. However, in order to attain a high level of consumer acceptance, a thorough understanding of rheological behaviour, involved protein fractions and relevant interactions is mandatory in order to later be able to customise properties of fermentation induced gels. Therefore, the aim of this study was to first characterise the type of dominating interactions within the gel network and the protein fractions involved followed by determination of the rheological properties of gels made from pea protein and pea protein hydrolysates. Results showed that the protein-protein interactions were mainly hydrophobic in nature and involved mostly the legumin fraction. A smaller contribution could be ascribed to electrostatic interactions between vicilin and the basic legumin-β chain, thus incorporating some vicilin into the gel. The interaction between vicilin and the basic legumin-β chain was influenced by modification of the molecular weight distribution via enzymatic hydrolysis. Especially hydrolysis with trypsin led to an enhanced involvement of vicilin in the gel structure due to the increased availability of legumin-β. The molecular weight distribution only had a minor impact on the rheological properties of the fermentation induced pea protein gels leading to the conclusion that in rheology the type of interactions is more important, than the protein fractions involved.