Effects of Several Defrosting Conditions on the Quality of Frozen Whale Meat

Abstract

In order to obtajn a suitable method for defrosting, effects of defrostjng temperature and defrosting velocity on the quality of defrosted whale meat were investigated by various methods, such as air defrosting at 0°, 10°, 20°, 30° and 50°C and high frequency defrosting.
Some changes occured in the defrosted meat by raising defrosting temperature. Ratios of weight reduction and free drip increased and Young's modulus and maximum strain energy measured with a Tensilon decreased and slope of stress-strain curve lowered. Under the microscopic observation of the defrosted meat, some damages in muscular tissue and in meat fiver which was defrosted at high temperature such as 30° and 50°C were shown. The close reverse correlation was observed between Young's modulus and ratio of free drips. Total nitrogen contents in free drip from the meats defrosted at 0°, 30° and 50°C were higher than those defrosted at 10° and 20°C.
It was recognized that these facts were caused from the difference of the time taken for the zone of maximum ice crystal in each defrosting temperatures. Defrosting at 10° and 20°C, followed by the high frequency defrosting gave best results in quality, but some defects such as uneven defrosting were shown.