Crude oil yield and properties of rice bran oil from different varieties as affected by extraction conditions using soxhterm method

The current study was employed to investigate the effect of solvent type, extraction time and bran ratio on the rice bran oil (RBO) properties from three varieties of rice bran namely Bario, lowland and upland rice. RBO was extracted by using soxtherm extraction method using methanol solvent at different extraction time (3, 4 and 5 h) and bran ratio (10, 20 and 30 g). Free fatty acid (FFA), total phenolic content (TPC) and antioxidant properties were assessed. Solvent that has low polarity exhibited the attraction of polar component of oil with the highest yield by ethanol (16.16%), followed by methanol (15.38%). FFA contents occurred higher in lowland types of rice bran in all types of solvents at P<0.05 with ethanol (12.73%), methanol (11.96%) and hexane (11.13%), while the total phenolic content and antioxidant properties were influenced by the types of rice bran and solvents used for extracting components out of the bran. The highest phenolic content in the crude oil was extracted using ethanol in lowland (0.509 mg/ml), and the lowest was extracted by hexane in Bario (0.061 mg/ml). The highest antioxidant activity was observed in RBO extracted using methanol of lowland (73.74%) and RBO extracted using ethanol of upland (73.65%), while the lowest were observed in RBO extracted using hexane. The different types of solvent have the significant impact on the crude oil yield and properties of crude oil extracted

The effect of metal ions on lipid oxidation, colour and physiochemical 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

Development of yellow pigmentation in squid (Loligo peali) as a result of lipid oxidation

The impact of lipid oxidation on yellow pigment formation in squid lipids and proteins was studied. When the squid microsomes were oxidized with iron and ascorbate, thiobarbituric acid reactive substance were observed to increase simultaneously with b values (yellowness) and pyrrole compounds concomitantly with a decrease in free amines. Oxidized microsomes were not able to change the solubility, sulfhydryl content, or color of salt-soluble squid myofibrillar proteins. Aldehydic lipid oxidation products were able to decrease solubility and sulfhydryl content of salt-soluble squid myofibrillar proteins but had no impact on color. Aldehydic lipid oxidation products increased b values (yellowness) and pyrrole compounds and decreased free amines in both squid phospholipid and egg yolk lecithin liposomes. The ability of aldehydic lipid oxidation products to change the physical and chemical properties of egg yolk lecithin liposomes increased with increasing level of unsaturation and when the carbon number was increased from 6 to 7. These data suggest that off-color formation in squid muscle could be due to nonenzymatic browning reactions occurring between aldehydic lipid oxidation products and the amines on phospholipids headgroups

Yellow discoloration of cuttlefish liposome system 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 \u3c 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