Influence of sugarcane dietary fiber on water states and microstructure of myofibrillar protein gels

The effects of different size particles and contents of sugarcane dietary fiber(SDF) on water state, water holding capacity(WHC), gel strength and microstructure of myofibrillar protein gels was studied. It was found that gel strengths were improved with the increase in SDF particle size and content, and the value of water holding capacity (WHC) reached a maximum with the addition of 80-mesh SDF at 2%. Discrete exponential fitting analysis and multi-exponential function analysis of the T2 relaxation time revealed that three categories of water, each having different mobility states in the gels, had different effects on the blended gel systems. Also, the intrinsic T21 relaxation time of immobile water in gels containing SDF was shorter than that in pure gels. Pronounced differences in myofibrillar gel network structures were observed during heating at 80 °C for 20 min. The fractal dimension which was determined by the box count method and the pore density (diameter < 0.1 μm or < 1 μm) further demonstrated that the homogeneity and compactness of gels increased with higher SDF content. However, the formation of numerous SDF cavities, whose particle size and number was enormously affected by the particle size and ratio of SDF added, is likely to have been responsible for the decrease in WHC and the extension of the intrinsic T21 relaxation times of immobilized water.