4. Conclusions
Freezing the shrimps under the air-blast freezer at the
air velocity of 6 m/s gave the least %freezing loss and same
cutting force as the fresh shrimps. For cryogenic freezing, it
was found that all temperatures used did not affect the
%freezing loss with the shrimps frozen at 70 C had the
same cutting force as the fresh samples. Samples thawed
under the microwave had slightly higher TBA value than
those thawed at the refrigerator temperature. An increase
in the freeze–thaw cycles resulted in an increase in TBA
value and cutting force and a decrease in SSP value. The
combined effect of thawing method and freeze–thaw cycle
of the shrimps frozen under both methods had the influence
on %thawing loss. The microwave thawing gave the
samples with the higher %thawing loss than those thawed
at refrigerator temperature in every cycle and the increase
in the freeze–thaw cycles gave the samples having the
higher %thawing loss. The samples could be freeze–thawed
up to 2 cycles. Therefore, it is important to prevent temperature
fluctuations during transportation and storage to
avoid the freezing and thawing effect and to maintain the
quality of the frozen shrimps.