Objective  Enzymatic hydrolysis was studied and optimized to modify the otherwise long and tough fibers of the bottom portion of a bamboo shoot (BDF) for a low-cost source of dietary fiber.

  Method  Various enzymes in varying dosages at different temperatures, pHs and digestion durations were applied on hot-water cooked BDF for the experiment. Size of the fibers was measured in a single factor test followed by a Box-Behnken response surface experiment at 3 levels of each factor to optimize the process. Physical properties of the raw material and the resulting dietary fibers were compared.

  Result  The optimized hydrolysis was found to include 0.20% addition of cellulase:xylanase at 1:1 ratio, temperature at 47℃, pH at 5.4 and digestion for 2.0 h. The BDF size (D₉₀) decreased from(146.2±0.21) μm to (97.2±0.14) μm after the enzymatic hydrolysis. The water and oil holding capacities and expansion of the hydrolyzed BDF increased by 1.30-, 2.16-and 1.64-folds, respectively, over the pre-treatment samples.

  Conclusion  The optimized composite enzymatic hydrolysis significantly reduced the fiber size and improved the physical properties of BDF making it as a dietary fiber ingredient feasible.