METHOD OF DETERMINING THE GAPING EFFECT I N FROZEN MEAT-PRODUCTS BEFORE FINAL COOKING

The gaping effect is an undesirable development of gaps between the my omers of fish musculature due to a partial or complete tearing away of the muscle fibre ends of the sarcolema basal lamina complex. This can be due to a number of technological faults. Objective test methods of determining the gaping effect are available for fresh fish fillets bu t not for deep-frozen fish fillet blocks or for pre-fried frozen fish products before final cooking. The determination of rheological magnit udes, the maximum penetration force of test probes and the rise in the linear portion of the force-pathway curves in fish fingers was select ed from a number of relevant methods of examining structure and textur e. The method that provided the most information however was making th e gaping effect visible by means of defined stresses expanding the str ucture of thawed samples during vacuum freeze-drying. If collagen conn ective tissue fibres are torn away from the muscle fibres because of t echnological faults in the fish fillets and muscle tissue in the alrea dy damaged fillets opens up during this slight expansion of the struct ure to such an extent that the volume of the sample is increased where as the volume of the samples of good raw material is decreased. Fish s amples are regarded as ''gaping'' if the visible quality faults in tex ture take the form of clearly recognisable splits between myomers and/ or fibres pushed apart in a filigree effect and if the volume after tr eatment has increased by more than 3%.