Yellow discoloration of the liposome system of cuttlefish (Sepia pharaonis) as influenced by lipid oxidation

Lipid oxidation, discoloration, loss of amine groups and pyrrolization of the liposome systems of cuttlefish (Sepia pharaonis) in the presence of FeCl₃ and ascorbic acid were studied. Thiobarbituric acid-reactive substances (TBARS) and the b^∗-value of cuttlefish liposomes increased with a coincidental decrease in amine groups when the incubation temperatures (0, 4, 25, and 37 °C) and incubation times (0–24 h) were increased (p < 0.05). As lipid oxidation and yellow pigment formation in the cuttlefish liposome proceeded, a loss of amine groups and pyrrolization were also detected. The effects of FeCl₃ and ascorbic acid, at different concentrations, on TBARS production, b^∗-value, loss of amine groups and pyrrolization of cuttlefish liposome were also investigated. Both FeCl₃ and ascorbic acid showed prooxidative effects in cuttlefish liposome in a concentration-dependent manner. Sodium chloride (0–2%) reduced TBARS, b^∗-values and pyrrole compounds. These results suggest a positive correlation between lipid oxidation and the development of yellow pigments in cuttlefish phospholipids.     

Lipid Oxidation in Microsomal Fraction of Squid Muscle (Loligo peali)

Frozen squid is susceptible to both lipid oxidation and yellow/brown discoloration during frozen storage. The involvement of lipid oxidation in the microsomal fraction of squid muscle on oxidative rancidity and discoloration was investigated using iron and either enzymatic or non‐enzymatic redox cycling pathways. Lipid oxidation was measured by thiobarbituric acid‐reactive substances (TBARS), and color changes were measured spectrophotometrically using an integrating sphere. The lipid oxidation was not observed in the squid microsomes in the presence of Fe³⁺ and β‐nicotinamide adenine dinucleotide disodium salt (NADH) or β‐nicotinamide adenine dinucleotide phosphate, reduced (NADPH), suggesting that the enzymatic redox cycling pathway was not active. Iron‐promoted TBARS formation was observed in the non‐enzymatic pathway when ascorbic acid was used as a reducing compound. Non‐enzymatic lipid oxidation increased with increasing temperature (4 °C to 37 °C), iron (0 to 100 μM), and ascorbic acid (0 to 200 μM) concentrations. As lipid oxidation in the microsomes or isolated microsomal lipids increased, color changes were observed as could be seen by an increase in b* values (yellowness) and a decrease in a* (redness) values. The ability of iron and ascorbate to promote both lipid oxidation and pigment formation in the microsomal fraction suggests that this pathway could be responsible for quality deterioration of squid muscle during storage.     

The effect of metal ions on lipid oxidation,colour and physicochemical properties of cuttlefish (Sepia pharaonis) subjected to multiple freeze–thaw cycles

The effects of different metal ions at various concentrations (0, 5, 25 ppm) on lipid oxidation, discolouration and physicochemical properties of muscle protein in cuttlefish (Sepia pharaonis) subjected to multiple freeze–thaw cycles, were investigated. Lipid oxidation of all treatments increased as the freeze–thaw cycle increased. However, the rate of the TBARS increases varied, depending on concentration, type and valency of the metal ion. Fe(II) induced lipid oxidation most effectively and its prooxidative effect was in a concentration-dependent manner. Cu(I), Cu(II) and Cd(II) showed negligible effects on lipid oxidation. The increased lipid oxidation of cuttlefish with added iron was coincidental with the increase in b* values (yellowness), especially with increasing freeze–thaw cycles. Cu(I) and Cu(II) altered cuttlefish protein sulfhydryl content and the protein solubility decreased with a concomitant increase in the disulfide bond content. The oxidative changes of proteins were observed only when a concentration of metal ions of 25 ppm was used. Those changes were more intense with increasing freeze–thaw cycles. The Ca²⁺, Mg²⁺, and Mg²⁺–Ca²⁺–ATPase activities of cuttlefish natural actomyosin decreased markedly in the presence of copper, whereas the Mg²⁺–EGTA–ATPase was increased. SDS-PAGE revealed that Cu(I) and Cu(II) induced the polymerization of muscle proteins stabilised by disulfide bond formation. However, Fe(II), Fe(III) and Cd(II) exhibited no pronounced effect on the oxidation of cuttlefish muscle proteins. Therefore, copper mainly caused the oxidation of protein, while iron induced lipid oxidation and the formation of a yellow colour in cuttlefish muscle, particularly with multiple freeze–thaw cycles.     

The effect of antioxidants on the quality changes of cuttlefish (Sepia pharaonis) muscle during frozen storage

The changes in quality of cuttlefish (Sepia pharaonis) treated with 5% NaCl and 0.3% H₂O₂ and soaked with and without different antioxidants during frozen storage at -18 °C for 16 weeks were investigated. Thiobarbituric acid reactive substances (TBARS) in all cuttlefish samples increased when the storage time increased (P<0.05). Ascorbate (ASC) and erythorbate (ERT) showed a prooxidative effect while EDTA and tripolyphosphate (TPP) had no antioxidative effect in frozen cuttlefish. Soaking the cuttlefish in 5% NaCl and 0.3% H₂O₂ for 15 min could improve the color of cuttlefish by increasing the L^*-value and decreasing the a^*-value. ASC, ERT, EDTA and TPP solutions had no impact on the a^*-value and L^*-value of cuttlefish during frozen storage. However, the treated samples, which were soaked in ASC and ERT solutions had an increased b^*-value during frozen storage. Surface hydrophobicity (S₀ANS) of cuttlefish natural actomyosin increased when the frozen storage period increased up to 12 weeks. The increase in disulfide bond content was generally coincidental with the decrease in sulfhydryl content. ASC, ERT, EDTA and TPP had no significant effect on those changes. Protein solubility decreased slightly during prolonged storage. Soaking cuttlefish with 5% NaCl and 0.3% H₂O₂ together with 0.5% TPP could retard the decreases in solubility and increase in thaw drip of frozen cuttlefish. However, ASC, ERT and EDTA showed no impact on the solubility and thaw drip of frozen cuttlefish.