Effect of partial replacement of water-soluble cod proteins by soy proteins on the heat-induced aggregation and gelation properties of mixed protein systems

The interest for partially replacing animal proteins by plant proteins is growing. However, this is challenged by the arising negative effects on textural properties of the animal protein systems induced by the partial replacement. In this study, we investigated the aggregation behavior and mechanical properties of gels prepared with mixtures of water-soluble cod proteins (CPs) and preheated soy proteins (SPs) with different 7S/11S ratio. Results revealed that higher 11S ratio in the mixture resulted aggregates with larger size, higher surface hydrophobicity, and more disulfide bonds, affording the formation of porous network with higher storage modulus. In addition, rheological and microstructural results evidenced that the gel cross-linking was markedly strengthened when SPs were preheated and also dependent on temperature and protein concentration. The present study demonstrated the successful preparation of mixed protein gels with desirable rheological and microstructural properties, which was achieved by simply altering the 7S/11S ratio or preheating of SPs fraction. Additionally, these findings may provide fundamental knowledge for structuring food products based on mixed protein system.