Gel properties and in vitro digestion of sea bass (Lateolabrax japonicus) myofibrillar protein – Lipid composite gels: Focus on lipid type and content

The effects of lipid type and content on gel and digestion properties of myofibrillar proteins (MPs) were studied. The MPs sol was combined with three types of lipid (peanut oil, sunflower oil, and lard) with different contents (0.5–2%) to obtain composite gels. As for whiteness, no differ was observed in composite gels without or with lipid addition. The water holding capacity and hardness of composite gels with lipid addition increased. Moreover, fourier transform infrared spectra (FTIR) demonstrated composite gels with 1% emulsion addition exhibited the highest β-sheet content. The confocal laser scanning microscope (CLSM) revealed that networks of composite gels with 1% emulsion addition possessed more densely compared to control group. During the in vitro digestion, high performance liquid chromatography (HPLC) results showed the peptide (>10 kDa) contents of composite gels with lipid addition were lower than that of control group under the simulated gastric phase. Moreover, the 2–5 kDa polypeptide content of composite gels with lipid addition was higher than that in observed in control group under intestinal phase. The results illustrated the gel and in vitro digestion mechanism of composite gels with lipid addition, which can be valuable for the fabrication of functional surimi products.