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Distinct proteolytic activity was observed in the incubated muscle tissue of arrowtooth flounder. Absorbance measurements of the TCA filtrates indicated maximum proteolytic activity between 55°C and 6O"C, and minimum activity below 40°C. In&on puncture tests of raw, baked, steamed, deep-fat fried and microwaved samples of arrowtooth demonstrated that rapid inactivation of the protease by microwave cooking significantly improved textural properties. Myxosporean parasites tentatively classified as Kudos thyrsitis were identified in all but one of the arrowtooth samples. However, no clear relationship between parasite density and textural deterioration of the cooked fillets was observed.

Postmortem formation of 5'-inosine monophosphate, inosine and hynoxanthine in Pacific cod and nottock fillets during chilled storage was monitored over a two week period. Accumula~on of hypoxanthine in Pacific cod (Gadus macrocephalus) fillets proceeded more slowly than has been reported for Atlantic cod (Gadus morhua) but similar to North Sea cod (Gadus callatias L.). For both both cod and pollock, hypoxanthine was negatively correlated with flavor and desirability (p < O.Ol), while both inosine and 5'4nosine monophosphate were positively correlated with overall desirability (p < 0.01).

Hypoxanthine was the major catabolite of adenosine triphosphate (ATP) in rock, yellowfin, flathead and Dover soles examined from the Gulf of Alaska. Inosine monophosphate (IMP)/hypoxanthine (Hx) ratios were as effective as Kr values for assessing freshness. In contrast, inosine (HxR) was the end catabolite in rex sole and hypoxanthine was barely detectable. The gradual accumulation of hypoxanthine in rock and yellowfin soles made this catabolite a useful freshness indicator for these species.