Structuring emulsion gels with peanut protein isolate and fish oil and analyzing the mechanical and microstructural characteristics of surimi gel

Herein, peanut protein isolate (PPI) and fish oil (FO) emulsion gels are fabricated and added to surimi gel, and their effects on the mechanical and microstructural characteristics of surimi gel are investigated. Emulsion gels consisting of PPI, FO, and water were treated using microbial transglutaminase (MTGase) and termed PPI-based emulsion gels (PEG). Next, surimi gel samples were prepared with PEG contents ranging from 4 to 16 wt%. Texture profile and rheological analyses indicated that compared with the control group obtained by the direct addition of FO, surimi gels with 4–8 wt% PEG showed a significant improvement in hardness, adhesiveness, and chewiness, and had a higher degree of crosslinking. Nevertheless, the color attributes of the surimi gels containing PEG were evidently lower than those of the control group owing to the emulsification in the protein–oil–water system. Moreover, at a concentration of 4–8 wt%, PEG uniformly filled the void spaces of the protein matrix and formed a firmer network structure, as revealed using scanning electron microscopy and confocal laser scanning microscopy. This study provides new sustainable perspectives for the application of PEG fabricated from PPI and FO as a fat substitute in food products.