Sensory quality of brown shrimp (crangon crangon L.) stored under various freezing conditions prior to cooking

Abstract

Freshly caught brown shrimp (Crangon crangon) are prone to rapid degradation after death. Freezing the unprocessed shrimp shortly after catch provides a possible solution to maintain product quality until further processing. In this study, Shrimp were frozen under three conditions (individually frozen, vacuum packed or glazed), either directly at −20°C or deep frozen at −50°C for three hours and subsequently stored at −20°C. A trained sensory panel assessed the organoleptic quality of brown shrimp that were cooked after 2 and 4 months of raw-frozen storage. Shrimp cooked under the same conditions immediately after the catch, then stored at −20 for maximum 1 month were used as reference. The quality of the frozen shrimp was also visually evaluated after one year. The individually frozen shrimp remained closest to the reference samples in terms of colour and odour when stored at −20°C, and closest to the reference for taste when initially frozen at −50°C. Vacuum-packed shrimp scored less well and glazed samples were omitted from the experiments beyond 2 months of storage due to visual deterioration. In conclusion frozen storage of raw shrimp is possible for short periods up to 4 months, albeit with perceivable changes in organoleptic properties of the final cooked product.