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.