熱伝導度型湿度センサによる食品ゲルの水分活性測定

抄録

In order to investigate the state of water in food hydrogels from the standpoint of water activity (Aw), their desorption isotherm was recorded at 25°C using a hand-made Aw meter equipped with a thermal conduction type humidity sensor. In the free water region of the isoltherm, little difference was observed between the Aw of 5% gelatin or starch gels and that of their 10% gels, but the Aw of the 10% gels decreased before that of the 5% gels by lowering their water content. The isotherm of kon-nyaku jelly was not unduly changed by heating at 80°C for 10min, but the Aw of chicken mince (pectorals) was increased by heating in the multilayer water region. The Aw decreased in this region by grinding the mince with 3% NaCl, but was not increased unduly by heating the mince after grinding. The addition of 4% dried egg white, soy protein, potato starch, or wheat gluten only slightly decreased the Aw of kamaboko from Alaska pollack frozen surimi in the free water region, but decreased it considerably in the multilayer region except in the case of the starch.