Abstract
Katsuobushi is one of the most famous Japanese traditional foods and it has been empirically known that giving moisture was effective to realize good shaving with yielding less powder. In this article, in the aim of finding scientific elucidation for this presumption, shaving experiments were carried out with varying moisture content of the Katsuobushi under the almost constant temperature as 25°C. For the experimental consistency, the moisture content of the sample was controlled by using saturated salt solutions and the commercial shaving equipment was introduced. As a result, it was found that most of the shaved product was obtained as powder if the moisture content was less than 0.5% d.b. With gradual increasing of moisture content of Katsuobushi, the powder content gradually decreased, and at the condition moisture content reached about 14% d.b., the powder content drastically decreased. By referring existing data, the glass transition temperature of Katsuobushi of 14.4% d.b. in moisture content was appeared to be about 25°C, that coincided with the sample temperature at the shaving. From the result, it would be elucidated that moistured Katsuobushi could be shaved with less powder content because the glass transition temperature of the Katsuobushi went down below the actual temperature at the shaving and the Katsuobushi turned into rubbery state.
