F. Thiemig et P. Oelker, METHOD OF DETERMINING THE GAPING EFFECT I N FROZEN MEAT-PRODUCTS BEFORE FINAL COOKING, Die Fleischwirtschaft, 78(3), 1998, pp. 221-224
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%.