2022 Volume 101 Issue 4 Pages 56-65
In this study, Japanese cedar powder (JCP) were produced in a vibration mill with ring media by applying two types of pulverization forces: shear-dominant and compression-dominant. The JCP samples was investigated to understand the effects of the two pulverization treatments on particle size and shape, enzymatic digestibility, domain size, and cellulose crystallinity index (CrI). Furthermore, particle shape of the holocelulose and holocellulose specific surface area (H-SSA) were examined by removing lignin from pulverized JCP. As a result, the relationships among the structural changes, types of pulverization treatment, and observed enhancements in the H-SSA and enzymatic digestibility were revealed. Upon shear-dominant pulverization, the holocellulose sample exhibited a fibrous structure; the domain size of JCP was reduced from 18 to 8 nm after pulverization, and the CrI decreased slightly (from 37% to 27%). Upon compression-dominant pulverization, the holocellulose structure was spherical; the CrI of the pulverized JCP decreased from 37% to 9% with no corresponding reduction in the domain size. Both the domain size reduction upon shear-dominant pulverization and the CrI decrease upon compression-dominant pulverization contributed to the increase in the H-SSA, indirectly improving the enzymatic digestibility of the JCP samples.
