Sensory properties of mince
The appearance and texture of mince are different from those of fillets because the flesh is fragmented, but limited tests have shown that the consumer is not unduly deterred by the unfamiliar form of mince when presented in fish fingers provided it is made from fresh raw material; indeed in tasting tests children showed an apparent preference for fish fingers made from mince rather than fillet.
There is some loss of the sweet flavour of fresh fish during mincing and, more seriously, a slight 'cardboardy' flavour can sometimes be detected, which is more usually associated with the cold storage of whole fish. There may also be a slight increase in firmness and dryness.
When blood-rich tissue from beneath the backbone is included among the raw material, the resulting mince will be red; the mince turns brown when cooked, and has an unacceptable and sometimes extremely objectionable metallic flavour.
Bone separators do not remove all pieces of bone; the table shows typical average bone contents of minces made from different parts of fish, using a 5 mm drum.
Some of the residual bones in mince from fillets or gutted whole fish are needle shaped and sometimes more than 6 mm long, which exceeds some specifications for limits of bone. Bone particles in mince made from frames, that is the skeletons of whole fish from which fillets have been removed, but which still carry some flesh, are blunt and irregular in shape; these would meet a specification that bones should not be capable of piercing the soft palate, but might not meet a specification limiting the permitted weight of bone present. Use of a drum with smaller perforations reduces bone content, but also yields a mince of poorer texture; perforations from 1 to 7 mm are available commercially, but a 5 mm drum generally offers the most reasonable compromise.