Abstract
The purposes of this study are to measure the internal pressure which causes gape and heave of frozen body during the CaCl2 or ethanol brine immersion/spray freezing and to forestalI these undue defects of frozen foodstuffs by the internal pressure. The experiments were carried out on freezing of round type skipjack. Both of the temperature and the internal pressure of skipjack were measured and recorded continuously by a temperature sensor and a pressure sensor during the freezing. The result was that frozen body could supported to resist against considerable pressure during the freezing of round type skipjack, and that gape/heave of frozen body was created by the internal pressure during the freezing when the body had been some injuary or could not be expanded during the freezing. The internal pressure or stress of frozen bodies was released by a thermal equalizing process during freezing. Thus the methods which are able to prevent gape or heave of frozen bodies during the ethanol brine immersion freezing were found out.
