Abstract
Effects of air-blast freezing and cryogenic freezing, thawing by microwave and refrigerator, and freeze–thaw cycle on changes in thiobarbituric
acid (TBA), salt-soluble protein (SSP), %freezing loss (%FL), %thawing loss (%TL) and cutting force (CF) of tiger shrimp
(Penaeus monodon) were investigated. Air-blast freezing was done at -28 ± 2 C and air velocity of 4–8 m/s while cryogenic freezing
was done at -70 to (-100) C. Shrimps frozen at the air velocity of 6 m/s had the least %FL and similar CF to the fresh samples. Thawing
method did not affect SSP and CF. Samples thawed by the microwave had higher TBA than those in refrigerator. Increasing the
freeze–thaw cycle increased the TBA and CF but decreased the SSP. Combined effect of thawing method and freeze–thaw cycles affected
%TL only. The histological examination of cryogenic-frozen shrimps showed an increase in spacing between the muscle fiber and torn
muscle fiber bundles as the number of freeze–thaw cycles increased.
Key