アイスクリームの保存温度の変動による 氷結晶形態の変化

抄録

The quality of ice cream surface degrades significantly from alteration of the surface properties due to the repetition of thaw-recrystallizing accompanied with temperature vibration at subzero temperature, a little above the melting temperature. For understanding the phenomena in detail, ice crystals in ice cream after once thawed and recrystallized was observed morphologically, and evaluated quantitatively by fractal analysis. It was shown that the shape of ice crystal recrystallized from once thawed ice cream was modified from round shape to complex shape, of which the degree depended on thawing temperature at subzero temperature. However, the ice crystal retuned gradually into round shape with increasing the holding time at the thawing temperature. These phenomena would be caused by spatial micro distribution of high concentration part which was organized in thawed ice cream by freezing concentration. That is, the complex ice crystal formed in thawed ice cream at subzero temperature would be induced by losing the micro uniformity of concentration.