Effect of the pre-freezing rate on the quality of lyophilized Alaska pollack was examined.
The cut meats of Alaska pollack were freeze-dried at a platen temperature of 35°C and under a chamber pressure of 300 ?? 40μHg, after being frozen by vacuum freezing and still air fre-ezing at -30°C.
After storing the sample at room temperature for a definite period, the qualities of the sample were estimated.
When the cut meat of fish was frozen at a higher rate by vacuum, the tissue of lyophilized product was fine, whereas the one frozen at a slower rate formed a spongy meat.
The amount of soluble nitrogen decreased on freeze-drying, especially after still air fre-ezing. After storing for one month, however, the protein practically denatured and there was no difference between the two samples.
Immediately after drying, both samples re-absorbed water completely, but the water could easily be squeezed out again only by just applying a slight pressure.
Organoleptically dried products when cooked, were not equal in texture to fresh fish. But they were quite palatable during the 3 months storage preriod, especially those forzen by vacuum freezing.