The use of sodium dodecyl sulphate in the study of protein interactions during the storage of cod flesh at –14°

Abstract

An aqueous 1% solution of sodium dodecyl sulphate (SDS) will completely dissolve the myofibrillar proteins of fresh cod flesh, and of cod flesh stored at –14° until it is very tough. With the aim of detecting the formation of detergent stable intermolecular protein crosslinks during cold storage of cod flesh, a comparison has been made of the weight and z‐average molecular weights of the mixture of components in detergent solutions prepared from fresh cod flesh and cod flesh stored at –14° for various periods of time. This comparison has shown that very few, if any, such crosslinks are formed during cold storage of the flesh. By separately determining the average molecular weights of the individual constituent myofibrillar proteins in detergent solutions, probable limits to the extent of intermolecular crosslinking in the cold stored flesh by detergent‐stable bonds could be established.

Cryoprotective additives and cryostabilisation effects on muscle fillets of the freshwater teleost fish Rohu carp (Labeo rohita) during prolonged frozen storage

“…The denaturation of fish myofibrillar proteins during frozen storage is known to occur owing to the formation of protein aggregates by crosslinking of myosin chains either via covalent bonding or via secondary forces such as hydrogen bonding or hydrophobic interactions 4–10. In addition, during frozen storage of fish muscle the formation of ice crystals, the dehydration of proteins and an increase in salt concentration promote protein aggregates.…”

“…This may result in interactions among the various contractile proteins of the muscle. It may also promote changes in the conformation of protein molecules due to the formation of ionic crosslinkages between polypeptide chains or crosslinking reactions of myosin heavy chains 10–12. With extended frozen storage, all these factors can significantly influence the quality attributes of fish muscle foods 13–15…”

Cryoprotective Effects of Some Materials on Cod‐Surimi Proteins during Frozen Storage

“…Although the exact mechanism is still not understood, evidence favors crosslinking of myosin chains via covalent bonding (Buttkus, 1970;OwusuAnsah and Hultin, 1986) as well as via secondary forces such as hydrogen bonding or hydrophobic interactions (Connell, 1965(Connell, , 1975Iwata and Okada, 1971;Owusu-Ansah and Hultin, 1986). As reviewed by Shenouda (1980), during frozen storage of fish muscle, the formation of ice crystals, the dehydration of proteins and the increase in salt concentration promote protein aggregation and loss of solubility.…”

Functional properties of Rohu (Labeo rohita) proteins during iced storage

“…Degradation of muscle protein is a major problem associated with fish during storage (Reddy & Sirkar, 1991;Shenouda, 1980). Protein denaturation involves the formation of intermolecular aggregates through hydrogen, hydrophobic (Connell, 1960(Connell, , 1965 and disulfide bonds (Buttkus, 1971), making denaturation an irreversible process. Changes in turbidity and light scattering (Deng, Toledo, & Lillard, 1976;Zeigler & Acton, 1984), solubility (Zayas, 1997) and ATPase activity (Arai & Fukuda, 1973;Taguchi, Tanaka, Nagashima, & Amako, 1986;Yamashita, Arai, & Nishita, 1978) has been reported during protein denaturation.…”