TEXTURAL AND MICROSTRUCTURAL PROPERTIES OF FROZEN FISH MINCE AS AFFECTED BY THE ADDITION OF NONFISH PROTEINS AND SORBITOL

Changes in textural and microstructural properties of washed and unwashed frozen fish mince were studied as affected by the addition of nonfish proteins (soy protein isolate, milk protein isolate, egg white, and wheat gluten at 2, 4 or 6%) and 6% crystalline sorbitol. Soy and milk proteins and sorbitol reduced the hardness of frozen fish mince, while egg white and wheat gluten made the texture firmer without rubberiness developing after frozen storage. All nonfish proteins and sorbitol stabilized the myofibrillar organization by reducing freeze-induced contraction of myofibrils. The mechanisms of reducing texture hardening appear to be different between sorbitol and nonfish proteins. Water binding properties and dispersibility made the difference among nonfish proteins in reducing freeze-contraction of myofibrils. Nonfish proteins not only reduced texture hardening during frozen storage, but also modified texture during cooking as they underwent thermal gelation specific to each protein used.