Functional Properties of Fish Proteins

Abstract

Unilever’s fish business is largely based on frozen fish products. For the consumer the principal attributes determining the quality of these products are the flavour and the texture. Fish proteins impact primarily on the sensory attributes relating to the texture of products. Fish fillet is composed of parallel muscle fibres arranged in blocks known as myotomes. The myotomes are separated by collagenous sheaths and form the flakes of the cooked fillet. The texture of fish is determined to a large extent by the myofibrillar proteins within the muscle fibres. The handling of fish, throughout the supply chain, impacts on the state of fish proteins and thereby influences the final textural quality. For frozen fish products, the freezing process, and storage in the frozen state are important determinants of product quality. For gadoid species in particular, significant deterioration in texture can occur during frozen storage. These changes, although not fully understood, involve aggregation of the myofibrillar proteins. A patented process for the use of ultra high-pressure to control some of the textural sensory attributes of cod during frozen storage is described.