Deterioration of Fresh‐Water Whitefish Muscle During Frozen Storage at −10°C

Abstract

SUMMARY— Organoleptic and chemical deterioration of freshwater whitefish muscle frozen at −10°C for periods up to 16 weeks was assessed. As frozen storage of muscle progressed, the toughness and rancidity of baked muscle increased. The solubility of the myofibrillar protein fraction, “actomyosin,” dropped from about 72 to 22% over the 16 week storage period of whitefish muscle. No change in the solubility of sarcoplasmic protein in frozen stored muscle was observed. However, with polyacrylamide disc electrophoresis, two new sarcoplasmic protein bands were detected after 16 weeks of storage. With storage of frozen muscle, water‐binding capacity diminished. Although the total lipid and cholesterol contents of muscle remained constant throughout frozen storage, the phospholipid content decreased as the free fatty acid content increased. Oxidative deterioration of lipid in frozen muscle was estimated.

Quality loss during the frozen storage of sea salmon (Pseudopercis semifasciata). Effect of rosemary (Rosmarinus officinalis L.) extract

“…Diverse studies have demonstrated that the myofibrillar proteinsand not the sarcoplasmic proteins -were insolubilized during the frozen storage of fish (Awad et al, 1969), this process being dependent on the storage temperature (Careche, Del Mazo, Torrejó n, & Tejada, 1998). Taking into account the information obtained from DSC and extractability analysis, it is possible to observe that the aggregation process -causing the reduction of the MEP at 2 months of storage -would occur previous to the denaturation process of the myosin which was detectable after 3 months.…”

“…Protein denaturationmyofibrillar proteins specially -is an important factor of quality loss of frozen fish that can be produced by diverse factors (Badii & Howell, 2002;Shenouda, 1980). This process has been associated with texture changes such as ''hardening'' and with functional alterations such as liquid loss and changes in gelation properties (Awad, Powrie, & Fennema, 1969). Lipid hydrolysis and oxidation occur during the frozen storage of fish, even in those with low lipid content due to their high proportion of polyunsaturated fatty acids (PUFAs), and have an important influence on product acceptability (Aubourg, Rey-Mansilla, & Sotelo, 1999).…”

Partial characterization and nutritive value of proteins from pacu (Colossoma mitrei, Berg 1895)

“…The 8 5% protein that remained in the insoluble residue was considered stroma and denatured or complexed proteins. Similar extraction (93%) was obtained by Awad et al (1969) from the freshwater fish Coregonus clupeiformis. Khalil et al (1980) found 66.7 % for the myofibrillar proteins and 24.8 % for the sarcoplasmic proteins in T. nilotica.…”

Effect of Cryoprotectants on Frozen Whitefish Fillets

“…Awad et al (1969) studied the deterioration of untreated whitefish muscle stored for 16 wk at -10°C. They found that protein extractability and water-holding capacity of the muscle decreased with time and that these changes were accompanied by increases in free fatty acid concentration, sensory toughness and oxidative rancidity.…”