Abstract
The fish muscles stored as a fillet and a round were compared. At 3h, the I-band disappeared in stressed fish fillet, while it disappeared or remained slightly narrow in the muscle as a round. Both types of unstressed fish muscles began to contract slowly and showed large breaking strength. At 10h, both types of stressed fish muscles were tenderized, weakening pericellular connective tissue since the contraction continued. In the muscle as a round, the I-band became narrow. In unstressed fish muscle stored as a round, the restraint of bony structure induced myofibrillar bendings during contraction and weakened pericellular connective tissue. As a result, the round was more tenderized than the fillet. At 48h, in stressed fish muscle as a fillet the contracted state continued, but in this muscle as a round the original length of the I-band was restored. However, these muscles showed similar small breaking strength since the weakening of pericellular connective tissue was in the similar extent. Unstressed fish muscle as a round was more tenderized than this muscle as a fillet due to the bony-structural resistance against contraction. The maintenance of full rigor index occurred in the process where the internal structure was adapted to contractile tension after the disappearance of ATP, as in the case of the restoration of the I-band in the round.
