The effect of insoluble dietary fiber on myofibrillar protein emulsion gels: Oil particle size and protein network microstructure

The effects of insoluble dietary fiber (IDF) on myofibrillar protein (MP) emulsion gelations were investigated through a model system. Steady shear tests indicated an increase of molecular interaction/friction in composite solutions with IDF inclusion. It was noted that IDF addition prevented oil dispersion and resulted in the average enlargement oil globules volume diameter (d4,3) from 145.25 (control) to 200 μm (2% IDF), in emulsified systems. In dynamic rheology, the final G′ of the emulsion gelations significantly increased from 203 (control) to 462 Pa (2% IDF), while the T21 relaxation time of immobilized water, in emulsion gels containing 2% IDF (202.44 ms), was significantly shorter than in control gels (244.25 ms). In addition, the water- and fat-binding capabilities, and the gel strength of emulsion gelations, significantly increased with IDF addition. The aforementioned results indicate that IDF addition could promote the formation of a stronger gel network. As a result, the MP gel microstructure was further studied. The MP gel microstructure of gels containing IDF had reduced formation of interconnected water with a gel network possessing more integrity and overall compactness, especially 2% IDF addition. In conclusion, IDF addition was shown to play an important role in the physicochemical properties of low-fat emulsion gels through the enlargement of oil particle size and through the modification of the overall MP gel network.