Chitin microfibers reinforce soy protein gels cross-linked by transglutaminase.

To improve the gel strength, we attempt to introduce the microcomposite concept into the food gel system. A stable positively charged chitin microfibers (CMFs) suspension was fabricated by a facile microfluidizer approach without changing its chemical structure. The obtained CMFs bearing width of about 0.5-5 μm and length of more than 500 μm were then developed in a transglutaminase cross-linked β-conglycinin (7S) gel. The morphological and rheological characterizations of the 7S-CMF composited gels were done as a function of the protein and CMFs concentrations. Results showed that the presence of the CMFs network improved the gel strength significantly. This effect was CMFs content dependent and was related to the formation of a sponge-like porous microstructure. We inferred that the CMFs provided an initial framework for gel formation and added structural rigidity to the protein gel. The role of protein was to participate in network development as an electrostatic coating and gelation component.