51A-13

B. L. BUSSELL¹, A. A. Bushway, R. Bayer, K. Davis-Dentici, D. I. Skonberg, and M. E. Camire. (1) Dept. of Food Science and Human Nutrition, University of Maine, 208 Holmes Hall, Orono, ME 04469

Justification: Polyphosphates are used by the seafood industry as a cryoprotectant in frozen products to prevent drip loss and toughening. Polyphosphate addition to lobster tissue extends shelf-life and textural qualities; features which may serve to increase the market for cryogenically processed lobsters.

Objective: The objective of this study was to determine the effect of sodium tripolyphosphate (STP) on the quality of fully cooked lobster during frozen storage.

Method: STP solutions of 0.1%, 0.3%, and 0.5% prepared in 0.9% saline solution were injected into the tails of 40 lobsters per treatment, and controls were injected with 0.9% saline solution. Lobsters were cooked for 9 minutes in a continuous steam cooker. Chemical and sensory analyses were performed of frozen storage at 0, 1, 4, and 6 months. Salt soluble proteins were determined by Lowry, phosphorus by inductively coupled plasma spectroscopy and sodium by atomic absorption spectroscopy. A 30-member consumer panel evaluated sensory properties.

Results: Salt soluble protein varied significantly (p<0.05) between control, 0.3% and 0.5% STP treatments, and between 0.5% treatment and remaining treatments at month 1. The salt soluble protein did not vary significantly (p>0.05) during months 0, 4, and 6. The phosphorus content significantly differed between control, 0.1% and 0.5% STP, and between 0.3% and all other STP treatments at month 0. At month 6, the phosphorus contents varied significantly between control and 0.3% STP treatments, and remaining STP treatments. The phosphorus content did not vary significantly at months 1 and 4. Sodium content differed significantly between control and STP treated lobsters due to the varying concentrations of STP that were incorporated into the lobsters. Sensory analyses detected significant differences for texture of 0.1% STP treated lobster at month 4.

Significance: The significance of the results indicates that polyphosphates added at low concentrations may extend the shelf-life of cryogenically frozen lobsters.