51A-12

F. ERDOGDU, M. O. Balaban, W. S. Otwell, and L. Garrido. Agricultural and Biological Engineering, University of Florida, P.O. Box 110570, Gainesville, FL 32611

JUSTIFICATION: Cooking changes quality attributes, affects textural and thermophysical properties of shrimp, and causes yield loss by decreasing the water holding capacity of proteins due to denaturation and connective tissue shrinkage. In addition to the cooking time and temperature, pre-treatments, e.g. dipping in sodium tripolyphosphate (STP) solutions, cooking procedure, and cooling method also affect the yield loss of shrimp.

OBJECTIVES: The objective of this work was to experimentally determine the changes in yield loss of different sizes of cultured white and wild brown shrimp treated with different concentrations of STP solutions, cooked in boiling water and cooled in air.

METHODS: To accomplish the objectives, cooking-related yield loss of 8 different sizes of white and 3 sizes of brown shrimp treated with different concentrations of STP solutions (2 and 4%) were experimentally determined. Shrimp were cooked in boiling water for different times. Cooling was done in air for 15 min. The effects of shrimp size ans species, different internal temperatures and their related cooking times, and STP concentrations on yield loss were measured.

RESULTS: Increasing the internal temperature resulted in higher yield losses. The increase in STP concentration reduced yield loss for different sizes and species, and STP was found to be more effective in smaller sizes compared to the larger sizes. The effect of species on the yield loss was found to be significant in larger sizes. Wild brown shrimp tended to lose more yield than cultured white shrimp.

SIGNIFICANCE: The results indicated that dipping in STP solutions can be used to prevent the large cooking-related yield losses, and the effects of STP were greater in smaller shrimp. The mechanism of diffusion of STP solutions into the flesh should partly explain these results.