Sarcoplasmic Reticulum Ca²⁺‐ATPase and Cytochrome Oxidase as Indicators of Frozen Storage in Cod (Gadus morhua)

Abstract

Activities of 2 membrane-bound enzymes, Ca 2+ -ATPase from the sarcoplasmic reticulum and cytochrome oxidase from the inner mitochondria membrane, were measured during frozen storage of cod. Enzyme activities were higher in cod muscle samples frozen at -30 °C than at -20 °C. Freezing-induced activation of both enzymes was observed and the activation was amplified by ice storage prior to freezing. Sensory evaluation conducted at 9 mo of frozen storage showed differences between the sensory properties of cod frozen immediately after catch and frozen after 3 d of storage on ice. These results indicated that the enzymes might be useful as indicators of quality changes by frozen storage.

Effect of Frozen Storage Temperature on Quality-Related Changes in Rainbow Trout (Oncorhynchus mykiss)

“…This is in agreement with the results of Godiksen et al (2003), who were able to distinguish between cod stored for 5 months at −30 (highest SR Ca 2+ -ATPase activity) and −20 • C. Hsu et al (1993) reported a more rapid decrease in actomyosin Ca 2+ -ATPase activity in Pacific Whiting stored at −8 • C compared to samples stored at −20, −34, and −50 • C. However, del did not observe any significant differences between actomyosin Ca 2+ -ATPase activity in hake fillets stored at −20 and −30 • C for 49 weeks. The activity decreased significantly at both temperatures, and no activity was detected from 36 weeks onward, which was ascribed to denaturation of actomyosin.…”

“…Inoue et al (1992) reported an increased Ca 2+ -ATPase activity of frozen carp myosin during the first 12 h of frozen storage for samples stored at −15 and −20 • C, while the activity of samples stored at −5 to −13 • C decreased. Activation of SR Ca 2+ -ATPase activity as a result of freezing was also reported by Godiksen et al (2003), who suggested that the freeze-induced activation of the enzyme was due to changed interactions between Ca 2+ -ATPase and the surrounding membrane lipids.…”

COMPARISON OF SUPERCHILLING AND FREEZING ON THE MICROSTRUCTURE, MUSCLE QUALITY AND PROTEIN DENATURATION OF GRASS CARP (CTENOPHARYNGODON IDELLUS )

“…Myosin accounts for 50% of myofibrillar protein, which is the main protein of muscle from aquatic animals, while the globular heads of myosin are responsible for the activity of Ca 2+ ‐ATPase, a membrane‐bound enzyme (Godiksen et al . 2003).…”

“…This result indicated that superchilling could mitigate the decrease of Ca 2+ -ATPase activity in grass carp. Myosin accounts for 50% of myofibrillar protein, which is the main protein of muscle from aquatic animals, while the globular heads of myosin are responsible for the activity of Ca 2+ -ATPase, a membrane-bound enzyme (Godiksen et al 2003). Ca 2+ -ATPase is greatly inactivated by protein denaturation, especially in the head region (Benjakul et al 2003;Zhou et al 2006).…”

Cryoprotective Effects of Protein Hydrolysates Prepared from By-Products of Silver Carp (Hypophthalmichthys Molitrix) on Freeze-Thawed Surimi

“…The active site of Ca 2+ -ATPase is in the globular head of myosin [29]. Thus, the Ca 2+ -ATPase activity is a good indicator of the integrity of actomyosin molecule and protein freeze denaturation.…”