Effects of fish oil on the gel properties and emulsifying stability of myofibrillar proteins: A comparative study of tilapia, hairtail and squid

The objective of this study was to determine the effects of the myofibrillar protein (MP) characteristics from tilapia, hairtails, and squid on gel properties, microstructure, and emulsification stability of surimi gels with increasing concentrations of fish oil (FO). The surface hydrophobicity (38 mu g) of the squid MP was significantly lower than that of the tilapia and hairtail (P < 0.05), and its content (21 g/100 g) and emulsification characteristics were significantly higher than those of the tilapia and hairtail (P < 0.05). Combined with the firmer structure of the squid surimi in the microstructure more intuitively indicated FO occupied the void spaces of the squid protein matrix, revealed the interaction between FO and MPs. Moreover, infrared spectroscopy (FT-IR) and texture analysis demonstrated that tilapia MPs had the highest B-sheet (18%) and B-turn (39%) contents and the lowest alpha-helix (23%) content compared with the hairtail and squid. Contributed to higher gel strength, reflecting the influence of secondary structure of MPs on the texture of surimi. These results further elaborated the effects of MPs' structure on surimi emulsified FO and the mechanism of FO on surimi gel, which is meaningful for functional surimi production.