Property Changes during Frozen Storage in Frozen Soy Bean Curds Prepared by Freezing Accompanied with Supercooling

Abstract

Ice crystals play an important role in the degradation of frozen food quality. Quality degradation occurs even in the frozen storage process owing to recrystallization. On the other hand, it is assumed that ice crystals formed with higher nucleation have the potential to be resistant to ice recrystallization since they have homogeneous size distribution of ice crystals when considering the mechanism of ice recrystallization. In this study, recrystallization behavior and quality degradation in oy bean curds prepared by freezing accompanied with supercooling (SCF) were investigated. As a result, ice crystal in SCF maintained the initial character of small particle size and homogenous ice structure after 28 day storage at -5°C, even though the characteristics of ice crystals in Conventional rapid freezing(CRF) and Conventional slow freezing (CSF) were changed dramatically during storage. Additionally it was observed soy bean curds prepared by SCF maintained their softness rather than those prepared by CRF and CSF; furthermore, SCF samples prepared with relative lower resolving temperatures of supercooling maintained the softness rather than the SCF samples prepared with relatively higher resolving temperature of supercooling maintained the softness rather than the SCF samples prepared with relatively higher resolving temperature of supercooling. The results indicated that the homogenous ice structure determined by SCF is an effective factor in preventing quality degradation as well as recrystallization, even though the storage temperature is higher.