Uptake of α-tocopherol in porcine plasma and tissues

The effect of feeding α-tocopheryl acetate to pigs on the rate and extent of uptake of α-tocopherol in various tissues was investigated. The rate of iron ascorbate-induced lipid peroxidation was also studied. One hundred and eight Landrace × Large White pigs were assigned at random to one of the following barley-based diets: 20 mg α-tocopheryl acetate/kg feed for up to 126 days; 20 mg/kg feed to day 91, followed by 200 mg/kg feed to day 126, or 200 mg/kg feed for up to 126 days: Pigs from each group were slaughtered at specified intervals. For pigs fed the diet supplemented with 200 mg α-tocopheryl acetate/kg feed, α-tocopherol levels increased with increasing supplementation time up to day 126 in all tissues studied. The highest levels of α-tocopherol were observed in kidney fat and subcutaneous fat (inner layer) followed by subcutaneous fat (outer layer), liver, lung, heart, kidney, with muscle and brain containing approximately the same level. The α-tocopherol concentrations in all tissues examined, from pigs fed 200 mg α-tocopheryl acetate/kg feed from weaning to day 126 were greater than those fed the supplemented diet for 35 days. Iron-induced lipid peroxidation was reduced by dietary α-tocopheryl acetate supplementation, and muscle samples from pigs supplemented for 126 days were significantly (p < 0.05) less susceptible to peroxidation compared to muscle from pigs fed the same supplemented diet for 35 days.     

Antioxidative activity of α-tocopherol in cooked and uncooked ground pork

The effect of α-tocopherol (0, 100, 200 ppm) on lipid oxidation either in cooked or uncooked ground pork was studied during aerobic storage at 4°C and -20°C. Lipid oxidation was measured using the 2-thiobarbituric acid (TBA) method and rancidity development was scored by a trained sensory panel. Alpha-tocopherol slowed the rate of oxidation in cooked ground pork stored at either 4°C or -20°C and uncooked samples refrigerated for extended periods of time (12 days). In cooked product stored at 4°C where oxidation development was intense and off-flavors were strong, panelists did not detect flavor differences due to treatments. But in cooked product stored at -20°C sensory results were consistent with TBA analysis. Pre-rigor grinding, known to induce a high pH and inhibit lipid oxidation in uncooked fresh pork, had no protective effect on lipid oxidation as measured by TBA values in cooked ground pork, regardless of storage condition. TBA numbers increased during storage of cooked product at 4°C with an increase in internal cooking temperature between 50°C and 80°C. Internal cooking temperatures of 70°C or higher induced a rapid rate of oxidation when stored at 4°C.     

Degradation of γ- and α-tocopherol and formation of 5-nitro-γ-tocopherol induced by peroxynitrite in liposomes and skeletal muscle

Peroxynitrite, formed from the reaction between nitric oxide and superoxide, can participate in free radical-mediated reactions with cellular components in muscle to (1) initiate lipid oxidation via the production of lipid hydroperoxides, and (2) produce novel nitrated products. 5-Nitro-γ-tocopherol (NGT) is formed by the electrophilic substitution reaction between peroxynitrite and γ-tocopherol. The objective of this research was to examine the utility of NGT as a lipid-phase, peroxynitrite-specific biomarker in muscle foods. NGT was detected when exogenous peroxynitrite was added to liposomes containing γ-tocopherol and homogenates from chicken dark and turkey light muscle with added γ-tocopherol. Detectable levels of NGT were not observed in either minced turkey light muscle stored at -20?°C or chicken dark muscle stored at 4?°C. These results suggest that NGT is not a suitable biomarker to confirm the presence of endogenously produced peroxynitrite in muscle foods.     

Rapid determination of α-tocopherol in muscle and adipose tissues of pork

A fast, sensitive and reproducible method for the analysis of -tocopherol in pork tissues is presented. It combines saponification of the tissue and -tocopherol extraction in a single vessel, followed by HPLC separation and fluorescence detection. Added -tocopherol was recovered quantitatively. The reduction of lipid peroxides with potassium iodide before the saponification step did not alter the amounts of -tocopherol detected. Membranebound -tocopherol was not oxidized by lipid peroxides during the procedure. The coefficient of variation of -tocopherol analysed using this method was ±4.2% for muscle and ±2.5% for adipose tissues.

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Methode zur schnellen Bestimmung von -Tocopherol in Muskel- und Fettgeweben des Schweines

Zusammenfassung Es wird eine schnelle, empfindliche und reproduzierbare Methode zur Bestimmung von -Tocopherol im Schweinefleisch vorgestellt. Die Methode verbindet die Verseifung des Gewebes und die Extraktion in einem Gefäß. Nach HPLC-Abtrennung wird das -Tocopherol mit einem Fluoreszenzdetektor bestimmt. Zugesetztes -Tocopherol wurde quantitativ wiedergefunden. Die Reduktion der Lipidperoxide mit Kaliumjodid vor der Verseifung hatte keinen Einfluß auf die im Gewebe bestimmten -Tocopherolgehalte. Das membrangebundene -Tocopherol wird während der Bestimmung nicht durch Lipidperoxide oxidiert. Der Variationskoeffizient der Methode lag für Muskelgewebe bei ±4,2% und für Fettgewebe bei ±2,5%.

     

Oxidative stability enhancement of broiler bird meats with α-lipoic acid and α-tocopherol acetate supplemented feed

Depression of meat quality is known to be caused by lipid peroxidation occurring in meat. Supplementation of antioxidants in feed decreases lipid peroxidation and improves the oxidative stability of meat after slaughtering. The present study demonstrated that meat obtained from broiler birds fed feed supplemented with α-tocopherol acetate (200 mg/kg feed) along with α-lipoic acid (25, 75, or 150 mg/kg feed) exhibited increased oxidative stability and reduced fat content. The total phenolic content and α-lipoic acid content increased in the meat as the concentration of α-lipoic acid supplementation increased. The protein content in the meat was not changed by the supplementation of α-lipoic acid and α-tocopherol acetate. The results of DPPH and TBA assays demonstrated that feed supplemented with α-lipoic acid and α-tocopherol acetate also enhanced the antioxidant activity of broiler meat. On the other hand, the meat from broiler birds fed feed supplemented with oxidised oil (4% in feed) reduced its oxidative stability.     

Enrichment of dry-cured ham with α-linolenic acid and α-tocopherol by the use of linseed oil and α-tocopheryl acetate in pig diets

The use of α-linolenic acid and α-tocopherol enriched pork on the fatty acids and the sensory characteristics of Spanish dry-cured hams have been studied. Five batches of hams were manufactured using the posterior legs of pigs fed on diets with the same ingredients except for the oil source: sunflower (C), linseed (L) or linseed and olive (1/1, w/w, LO). Two different α-tocopheryl acetate concentrations [20 (C, L and LO) or 220 (LOE and LE)mg/kg diet] were used. Biceps femoris and Semitendinosus/Semimembranosus muscles from hams with low polyunsaturated fatty acid n-6/n-3 ratio (less than 3) were obtained from animals fed on linseed and linseed/olive oil enriched diets. However, hams from animals fed on diets added with linseed and α-tocopheryl acetate (20mg/kg diet) (batch L) were rejected by consumers because of less acceptable sensory characteristics and higher TBARs. The remaining hams had satisfactory sensory and nutritional characteristics.     

Effect of dietary α-tocopherol supplementation on color and lipid stability in pork

Myoglobin and lipid oxidation are major causes of quality deterioration in fresh pork. A process to enhance color and lipid stability would prove valuable to the pork industry given the current trend of centralized packaging and distribution to retail markets. Our objective was to determine the effects of dietary α-tocopherol (α-Toc) supplementation on color and lipid stability in ground pork, and loin chops stored in modified atmosphere packaging (MAP). Yorkshire crossbred pigs (n=20) were randomized into two groups and fed diets containing 48 (CON) or 170 mg α-Toc acetate/kg feed (VIT-E) for 6 weeks before slaughter. Plasma α-Toc concentration was measured weekly. Post-slaughter, Boston butt shoulders were ground, formed into patties with or without 1.5% salt, and stored fresh at 4°C for 0, 2, 4, or 6 days, and frozen at −20°C for 45 or 90 days. Pork loin chops were packaged aerobically and stored at 4°C for 0, 2, 4 or 6 days, or in MAP at 4°C for 7, 10 or 13 days prior to Hunter L*,a*,b* and TBARS analyses. α-Toc concentration of longissimus dorsi, psoas major, biceps femoris, semimembranosus and semitendinosus muscles was determined. Plasma α-Toc was greater (P<0.05) in VIT-E animals compared with CON and α-Toc concentrations were greater (P<0.05) in all VIT-E muscles compared with CON. TBARS values of both fresh and salted patties were less in VIT-E than in CON meat following 6 days at 4°C; VIT-E TBARS of salted patties were less (P<0.05) after 45 days at −20°C compared with CON. α-Toc supplementation did not influence (P>0.05) color of aerobically packaged or MAP chops, or of fresh or salted pork patties. α-Toc supplementation reduced TBARS formation in fresh and salted pork but had no significant impact on color.     

Influence of dietary fat and α-tocopherol supplementation on lipid oxidation in pork

Sixty-four pigs, approximately 3 weeks old, were fed diets containing 3% beef tallow or 3% soya oil with either a basal (10-50 mg/kg diet) or supplemented (200 mg/kg diet) level of α-tocopheral acetate. In pigs fed the soya oil diet the neutral and polar lipid fractions of muscle tissue and the total lipid fraction of adipose tissue had significantly (P < 0·05) higher C18:2/C18:1 ratios when compared to pigs fed the tallow diet. Muscle from pigs fed the soya oil diet was significantly more susceptible (P < 0·05) to lipid oxidation than muscle from pigs fed the tallow diet. In pigs receiving the α-tocopherol supplemented diet, α-tocopherol levels were approximately 3·3, 2·8 and 2-times higher in plasma, muscle and adipose tissue, respectively, when compared to pigs fed the basal level of α-tocopherol acetate. α-Tocopherol supplementation significantly increased (P < 0·05) the oxidative stability of muscle from pigs fed both the tallow and soya oil diets.     

Antioxidant activity of tomato lipophilic extracts and interactions between carotenoids and α-tocopherol in synthetic mixtures

In the present study we assayed the antioxidant activity of lipophilic extracts obtained from different tomato varieties. The results showed that cherry tomatoes, characterized by a high carotenoid content, had the highest antioxidant activity. A quantitative analysis of lycopene, β-carotene, lutein and α-tocopherol was also performed and the correlation between the antioxidant content and the antioxidant activity was estimated. The highest correlation coefficient was found for lycopene (R² = 0.9236, P ≤ 0.001). The analysis of two-component mixtures containing α-tocopherol and carotenoids showed that significant synergism occurred for all the combinations which contained α-tocopherol and β-carotene mixed together. The highest synergistic effects were detected for α-tocopherol-lycopene mixtures, which were the most efficient combinations tested in the present study. The analysis of the carotenoid combinations indicated that synergism occurred for lycopene-β-carotene, lycopene-lutein and lutein-β-carotene mixtures. The analysis of four-component mixtures did not show statistically significant synergistic effects.     

Formulation and characterization of α-tocopherol loaded poly ?-caprolactone (PCL) nanoparticles

α-tocopherol-loaded poly ?-caprolactone (PCL) nanoparticles were prepared by emulsion solvent evaporation with ultrasonification technique. The influences of PCL concentration (3 and 5 g/100 mL), solvent in the oil phase (methylene chloride (DCM) and methylene chloride: acetonitrile = 50:50 (DCM:ACN)), and ultrasonification time (1, 2, and 3 min) were investigated. Encapsulation efficiency (%) was calculated by Duncan’s multiple rage tests and it decreased from 87.73 to 57.45 when ultrasonification time was increased from 1 to 3 min. DCM as a solvent in the oil phase and 5 g/100 mL PCL showed better encapsulation efficiency than DCM:ACN and 3 g/100 mL PCL. Particle mean size was decreased when ultrasonification time was increased from 1 to 3 min. Nanoparticles with DCM as a solvent in the oil phase had larger particle mean size than the particle with DCM:ACN. There were no significant differences in particle mean size between two PCL concentrations. PCL with 3 g/100 mL concentration had higher α-tocopherol loading (%) than 5 g/100 mL PCL. Overall, 5 g/100 mL PCL in DCM as solvent in the oil phase with 3 min ultrasonification time showed the best encapsulation formulation.     

Effect of gamma radiation on levels of α-tocopherol in red meats and turkey

The effect of low dose ionizing radiation on free α-tocopherol levels in beef, pork and lamb longissimus dorsi muscle and on turkey leg and breast muscle were determined. The samples were irradiated in air with a ¹³⁷Cs source at eight dose levels between 0 and 9.4 kGy at 5 °C. Irradiation resulted in a significant decrease in α-tocopherol levels in all of the meats studied. There were no statistically significant differences in the rate of loss of tocopherol due to species, with the exception of turkey breast. The rate of loss of tocopherol in turkey breast tissue was greater than the other meats. The information obtained in this study may be of use for ‘chemiclearance’ purposes since the relative effects due to species variation were examined.     

Effects of rendering and α-tocopherol addition on the oxidative stability of horse fat

Food Science and Biotechnology - Oxidative stability of horse fat rendered at 70&nbsp;°C, − 0.1&nbsp;MPa under vacuum and 110&nbsp;°C, 0.1&nbsp;MPa from horse...     

Distribution of α-tocopherol in beef muscles following dietary α-tocopheryl acetate supplementation

The objective of this study was to determine the effect of dietary vitamin E supplementation on the distribution and concentration of α-tocopherol in beef muscles. Crossbred cattle (n=8) were selected and divided into two groups and fed diets containing 20 (basal) and 3000 mg (supplemented) α-tocopheryl acetate/head/day for 135 days prior to slaughter. Carcasses were split centrally and chilled at 4°C for 10 days. Muscles (n=16) were identified and removed from the left side of each animal and stored at -20°C until required. Mean α-tocopherol levels in muscles were significantly (P<0.05) higher in all supplemented muscles with the exception of m. infraspinatis and m. deltoidous compared to controls. Mean α-tocopherol levels in muscles from the supplemented group decreased in the order m. supraspinatis > m. psoas major > m. trapezius > m. gluteus medius > m. triceps caput brachii lumborum > m. rhomboidous > m. seratus ventralis > m. gluteobiceps > m. semitendinosus > m. semimembranosus > m. infraspinatis > m. subscapularis > m. tricepscaputbrachiilaterale > m. deltoidous > m. longissimus thorasis > m. longissimus lumborum. Significant (P<0.05) differences in α-tocopherol distribution within muscles were observed for supplemented m. psoas major and control m. seratus ventralis (highest levels in posterior ends and lowest in anterior ends) only. However, trends showed definite distribution patterns for other muscles. Levels of α-tocopherol were found to be highest in oxidative muscles (m. psoas major and m. gluteus medius) and lowest in glycolytic muscles (m. longissimus thoracis and m. longissimus lumborum) while moderate levels of α-tocopherol occurred in intermediate muscles (m. semimembranosus).     

Effects of chitosan and collagen containing α-tocopherol on the oxidative stability in bulk oil and oil-in-water emulsion

To provide efficient antioxidant capacities, proper carriers are needed to protect antioxidants against oxidative stress. Collagen mesh structure or chitosan gel was loaded with α-tocopherol and their effects were evaluated in bulk corn oil or oil-in-water (O/W) emulsion at 60 °C. Added collagen and chitosan enhanced oxidative stability in corn oil and O/W emulsions at 60 °C compared to corn oils without carriers or with addition of α-tocopherol (p < 0.05). Stability of α-tocopherol in corn oil loaded in collagen or chitosan was significantly enhanced compared to that in oils without carriers (p < 0.05). In O/W emulsions, α-tocopherol loaded collagen showed higher antioxidant properties than α-tocopherol loaded chitosan (p < 0.05). Collagen mesh structure and chitosan gel retarded the rates of lipid oxidation efficiently in both food matrices when α-tocopherol was not loaded. Collagen mesh structure and chitosan gel can be useful carriers for α-tocopherol in bulk oil or O/W emulsion.     

Effects of α-tocopherol level in raw venison on lipid oxidation and volatiles during storage

Relationships between α-tocopherol concentration in the muscle and development of lipid oxidation or volatiles in raw venison were studied. Fourteen Japanese Shika Deer (Cervus nippon) were fed various amounts (0–3.0 g of α-tocopheryl acetate per animal) during the different periods (0–37 days) and then M. longissimus thoracium et lumborum (LD muscles) with a range of α-tocopherol concentrations (4.1–15.1 mg/kg tissue) were obtained. For stabilizing the lipid during storage for 11 days under air, over ca. 9 mg of α-tocopherol per kg tissue were required based on levels of 2-thiobarbituric acid reacting substances (TBARS) numbers. Nine compounds were identified in headspace volatiles, and one of the volatiles was hexanal which has been recognized as off-flavour component. For depressing the hexanal evolution, at least ca. 9 mg of α-tocopherol per kg tissue were also required for 11 days’ storage. This value was much higher than other species. The reasons for higher requirement of α-tocopherol were possibly due to the higher concentration of unsaturated fatty acid and myoglobin in venison.     

Effect of ferulic acid and α-tocopherol antioxidants on properties of sodium caseinate edible films

Edible films, based on sodium caseinate containing three different concentrations of ferulic acid or α-tocopherol (20, 40 and 60 mg/g sodium caseinate), were obtained in order to evaluate the effect of these compounds on properties of the caseinate matrices. Special emphasis was placed on their effect on the films’ oxygen barrier properties, which are decisive in the prevention of the oxidation of foods containing lipids. Films were characterized as to their tensile, optical and surface properties as well as their barrier properties to water vapor, oxygen and aroma compounds (n-hexanal and n-hexanol). Ferulic acid was more efficient at reducing oxygen and n-hexanal permeability than α-tocopherol. Although ferulic acid slightly increased the stiffness of films at low concentration, in general, both antioxidants slightly reduce mechanical resistance, water vapor permeability, gloss and transparency of the films.     

Influence of α-tocopherol on physicochemical properties of chitosan-based films

Chitosan has been exploited as a material for the development of edible films, and additionally can be used as a carrier of functional compounds such as α-tocopherol. The aim of this work was to evaluate the effects of the incorporation of α-tocopherol in chitosan-based films. FTIR and thermal analyses were performed and showed that the incorporation of α-tocopherol affects the chemical structure of chitosan-based films with the establishment of new chemical bonds and the decrease of crystallinity. Results also showed that the increase of α-tocopherol concentration promotes a decrease of water content (from 12.6 to 11.4%) of the films. The addition of α-tocopherol to chitosan films leads to a significant reduction (p < 0.05) of tensile strength from 34.06 to 16.24 MPa, and elongation-at-break from 53.84 to 23.12%. Film opacity values (ranging from 4.74 to 7.83%) increased when α-tocopherol was incorporated into the film. Antioxidant capacity of chitosan-based films was evaluated and was enhanced when α-tocopherol was present in the film matrix. Results showed that α-tocopherol can be successfully added to the chitosan films enhancing the final quality and shelf-life extension of food products.     

Effect of vitamin E supplementation on α-tocopherol and β-carotene concentrations in tissues from pasture- and grain-fed cattle

The effects of dietary vitamin E supplementation of grain-fed cattle on lipid oxidation and meat colour have been extensively investigated, but little attention has been given to pasture-fed cattle where meat is likely to contain naturally high amounts of α-tocopherol and carotenoids. In the work described, we evaluated the effects of pasture-feeding alone and with vitamin E supplementation on tissue levels of anti-oxidants and compared the findings with those obtained for grain-fed cattle with and without supplementation. Sorghum was the major component of the grained-based ration. α-Tocopherol concentrations in plasma, muscle and fat tissues of pasture-fed cattle were not affected by vitamin E supplementation (2500 IU/head/day for 132 days prior to slaughter) while those of grain-fed cattle increased significantly. The α-tocopherol concentrations in the supplemented grain-fed cattle were similar in muscle and liver to pasture-fed animals but were lower in their fat (P<0.05). The major carotenoid present in all tissues studied from pasture-fed was β-carotene and its contents in plasma, liver, fat and muscles were decreased (P<0.05) by supplementation with vitamin E. Carotenoids were essentially absent in grain-fed cattle except for small amounts in liver. The implication of this study for the meat industry is that cattle grazed on good pasture can achieve concentrations of α-tocopherol in muscles and other tissues at least as high as those obtained by supra-nutritional supplementation of grain-fed cattle with vitamin E. However, α-tocopherol supplementation of pasture-fed cattle reduced tissue concentrations of β-carotene, which would reduce carcase fat yellowness and make pasture-fed cattle more acceptable to some Asian markets.