Effect of supplementation by bamboo shoot insoluble dietary fiber on physicochemical and structural properties of rice starch

The properties of rice starch supplemented with different contents (30, 60, 90, 120, and 150 g/kg) and sizes (<75, 75 to 106, 106 to 150, and 150–250 μm) of bamboo shoot insoluble dietary fiber (BIDF) were investigated. The setback viscosity and pasting time decreased, whereas the other pasting parameters, storage modulus, and loss modulus increased with increasing BIDF contents. The apparent viscosity and texture properties were significantly affected by 120 g/kg and 150 g/kg BIDF. Furthermore, small sizes of BIDF generated high water absorption ability, thereby decreasing the peak viscosity, final viscosity, hardness, storage modulus, and loss modulus. The honeycomb-like structure was clearly visible with high BIDF contents. The size of BIDF showed a negligible effect on the apparent viscosity, breakdown, springiness, resilience and structure. The Fourier-transform infrared spectra indicated that the electrostatic interaction and hydrogen bonds were strengthened, and the crystalline regions and short range-ordered structure increased with the addition of BIDF. Rice starch with BIDF had substantially uniform absorption peaks, indicating that the fundamental chemical structure was not destroyed due to BIDF contents and sizes. These results may help enhance the quality of rice starch and the development of IDF-enriched starchy products.