Thermal and physical properties of Pacific white shrimp (Litopenaeus vannamei) meat as affected by additives and freeze-thaw process

Thermal and physical properties were used to describe the stability of Pacific white shrimp quality during the freeze-thaw process by adding sucrose and sodium citrate. Thermal properties of shrimp myofibrillar protein, namely transition temperature (T-max) and enthalpy (Delta H) of protein were measured by differential scanning calorimetry (DSC). The results indicated that Delta H of both myosin and actin decreased when shrimp meat was subjected to three freeze-thaw cycles due to denaturation. Adding sucrose resulted in slightly higher T-max than the control after freeze-thawing and in retention of high Delta H of both myosin and actin, while adding citrate exhibited similar effects, but without a difference in T-max of actin. The increase in fine and uniform continuous structure as well as higher thawing yield (similar to 90%), cooking yield (almost 90%) and less shear force were observed in additive treated samples after three freeze-thaw cycles. The colour of cooked shrimp with additives had lower L*, a* and b* which was coincident with the amount of water uptake. This suggested that sucrose and citrate can be employed as protective additives to prevent the reduction of protein stability, especially for myosin during the freeze-thaw process. (C) All Rights Reserved