Takamasa Kasai

Water Absorption Characteristics and Volume Changes of Milled and Brown Rice During Soaking

ABSTRACT The water absorption characteristics and volume changes of rice with various degrees of milling during soaking were measured at five temperatures (5–40°C). The measured data were fitted to the exact solution for the infinite plane sheet diffusion model, which is an exact solution for the diffusion equation. The measured results agreed well with the model. The effects of temperature and the degree of milling on the water absorption rate constant were investigated. Volume changes of samples were determined by measuring particle density and bulk density. An empirical equation relating the moisture content of the sample during soaking and at temperatures of 10–50°C to specific volume was derived. In addition, bulk density was related to the quadratic function of the moisture content of the sample during soaking.

Sex and age differences in meat composition of Yeso sika deer (Cervus nippon yesoensis) reared for a short period after capture in the wild

Yeso sika deer captured in winter around Lake Akan in Hokkaido were reared for 8-10 months at Tokyo University of Agriculture in Abashiri. Six 1-year-old females and males and six 2-year-old or older (adult) females and males were slaughtered and their carcasses were processed. The chemical composition, mineral contents and fatty acid composition of the loin were measured. No marked influence of gender or age was noted in the chemical composition of loin. In the mineral contents, significant differences were noted. The potassium and sulfur contents were lower and the sodium content was higher in adult deer meat (P < 0.05, respectively) and the potassium content was higher in male deer meat (P < 0.05). Arsenic, cadmium or lead were not detected. In the unsaturated fatty acid, a significant interaction was detected (P < 0.05), and it was high in 1-year-old female deer meat and low in 1-year-old male deer meat. Significant gender or age differences were noted only in the mineral contents in the loin of deer reared for a short period after capture.

Drying Characteristics of Japanese Yam (Dioscorea opposita Thunb.)

The drying characteristics (changes of mass (moisture content), volume, drying surface area, and surface and internal temperature of sample during drying) of Japanese yam (Dioscorea opposita Thunb.) were measured under various operating conditions (temperature, relative humidity, and absolute pressure (vacuum level)). Japanese yam was dried by two methods, hot air drying and continuous vacuum drying. The effects of temperature, relative humidity, and absolute pressure on the drying rate of the sample were investigated. The moisture content change of the sample was analyzed under two conditions, considering or not considering the drying surface area change. When surface area change is considered, two periods, the constant rate period and the falling rate period, existed in both hot air drying and vacuum drying of the sample. In each case, mathematical models to describe the changes of the moisture content were derived, and the measured data agreed well with the values calculated from the models. The effects of temperature, relative humidity, and vacuum level on the drying rate constant were investigated. The drying rate constants were related to the temperature and relative humidity for hot air drying, or the temperature and vacuum level for vacuum drying using empirical equations which are modified form an Arrhenius-type equation.