High-internal-phase emulsions stabilized by soy protein isolate-β-cyclodextrin complexes: preparation, physicochemical properties, and use as fat substitutes

Herein, the effects of different concentrations of β-cyclodextrin (β-CD) (0.5, 1, 1.5, 2, 2.5%) on the conformation and interface properties of heat-induced soy protein isolate (HSPI), the physical stability and microstructure of the high internal phase emulsion (HIPE) stabilized by the complex (HSCD), and the sensory properties and flavor of surimi gel as a fat substitute were explored. The results indicate that β-CD forms a porous complex with HSPI, which imparts a more disordered conformation to HSPI through hydrogen bonding interactions and enhances its interfacial adsorption capacity. The emulsion stabilized by the HSCD composite has a more uniform particle size, a more compact interface network structure, and a higher viscoelastic modulus, which effectively extends the storage stability, oxidative stability, and freeze-thaw stability of the emulsion. Among them, the HSCD2.5 composite (the addition of β-CD is 2.5%) has the best functional characteristics. In addition, replacing fat with HIPE can reduce the cooking loss of surimi gel (13.05%) through hydrogen bonding and hydrophobic interaction, increase the water retention capacity (83.13%) and whiteness of gel (85.81%), improve the water distribution in surimi gel, and form a denser protein gel network, of which 60% is the most effective. Moreover, the texture characteristics and flavor evaluation showed that the addition of HIPE increased the tenderness and oxidative stability of surimi gel and effectively reduced the content of fishy substances in surimi gel. In conclusion, the gel properties of surimi gel can be optimized by regulating the structure of the complex, thus providing a new idea for developing new low-fat products.