Partitioning of ρ‐tocopherol in aqueous mixtures of TAG and isolated muscle membranes

Abstract

To study the uptake of δ-tocopherol by aqueous suspensions of membranes isolated from chicken muscle and the partitioning of the antioxidant in mixtures of chicken TAG and membranes, δ-tocopherol was added to suspensions of these components and they were centrifuged. In an aqueous suspension of membranes only, the tocopherol uptake increased linearly with tocopherol concentration, at about 50% of the added δ-tocopherol at all concentrations. The incorporation of tocopherol into the membranes was independent of incubation temperature in the range of 0-37°C. Studies with aqueous mixtures of membranes and TAG suggested a very low exchange of tocopherol between the different lipid fractions upon mixing when the tocopherol resided initially in one lipid fraction. Adding δ-tocopherol in ethanol favored incorporation of the antioxidant into the membranes; little antioxidant was incorporated into the membranes when it was added to the suspensions in oil. The results suggest that partitioning of exogenous δ-tocopherol between TAG and membrane lipids in muscle foods may be controlled in part by proper selection of the solvent in which it is added.

Effect of Pretreatments and Defatting of Seabass Skins on Properties and Fishy Odor of Gelatin

“…Disodium hydrogen phosphate solutions with concentrations of 0–15 μg/mL were used to prepare a standard curve for estimation of phospholipid content. A factor of 25 was used for converting phosphorus content to phospholipid based on an average molecular weight of phosphatidyl choline divided by the atomic weight of phosphorus (Sigfusson and Hultin ). The removal of phospholipid was expressed as a percentage of phospholipid reduction compared to that found in fresh skin.…”

Effect of Carrier Solvent Polarity on Selective Incorporation of Exogenous Δ‐tocopherol Into Muscle Membranes

“…The membranes from the cod muscle‐canola oil system were isolated by a method similar to that of Sigfusson and Hultin (2002a). The cod muscle‐canola oil system was mixed with four volumes of 4‐(2‐hydroxyethyl) piperazine‐1‐ethanesulfonic acid (HEPES) buffer (pH 7.5) containing 0.2% w/v ascorbate and homogenized at speed 4 for 40 s using a Kinematica Polytron Homogenizer (Brinkmann Instruments, Westburg, NY).…”

“…The total lipid content of the minced muscle and the membrane suspensions were determined by extracting a 10‐g sample with 50 mL of a 1 : 1 (v/v) chloroform: methanol mixture for 3 h using 0.5% NaCl solution for phase separation (Sigfusson and Hultin 2002a). The chloroform layer was separated and used for total lipid and phospholipid determination.…”

Effect of pretreatment on lipid oxidation and fishy odour development in protein hydrolysates from the muscle of Indian mackerel

“…Disodium hydrogen phosphate solutions with concentrations of 0 to 15 lg/ml were used as a standard. A factor of 25 was used for converting phosphorus content to phospholipid based on an average molecular weight of phosphatidyl choline divided by atomic weight of phosphorus (Sigfusson & Hultin, 2002). The phospholipid content was expressed as mg/100 dry sample.…”