Effects of Dietary Rape Seed Oil, Copper(II) Sulphate and Vitamin E on Drip Loss, Colour and Lipid Oxidation of Chilled Pork Chops Packed in Atmospheric Air or in a High Oxygen Atmosphere

The effect of addition of rapeseed oil (canola), CuSO(4) and vitamin E (all-rac-α-tocopheryl acetate) to pig diets on pork meat quality (lipid oxidation, colour and drip loss) was studied. Pigs were reared on ten different diets, either a control diet (no supplementation of rapeseed oil, CuSO(4) or vitamin E) or 6% rapeseed oil diets supplemented with CuSO(4) (0, 35 or 175mg/kg) and vitamin E (0, 100 or 200mg all-rac-α-tocopheryl acetate/kg). The natural content of vitamin E originating from feed ingredients amounted to 9-23mg vitamin E (α-tocopherol) per kg feed. Muscle vitamin E levels reflected the dietary intake and pigs fed the control diet had significantly lower levels than pigs fed rapeseed oil diets. The quality of fresh pork chops packed in air or in 80% O(2):20% CO(2) was followed during chill storage for 8 and 13 days, respectively. Colour, as measured by tristimulus colorimetry of pork chops packed in 80% oxygen atmosphere, was significantly improved with respect to redness when compared to chops packed in air, regardless of dietary treatment. The low vitamin E content in pigs fed the control feed significantly decreased a values and the oxidative stability of pork chops during chill storage compared to the other feeding groups. Packing of chops in a high-oxygen atmosphere increased lipid oxidation, especially in chops with low levels of vitamin E. Supplementation of rapeseed oil diets with 100 or 200mg vitamin E significantly decreased lipid oxidation of chill stored chops. Supplementation with CuSO(4) did not influence meat quality attributes (drip loss, colour stability and lipid oxidation) for any of the storage conditions.     

Effects of dietary vitamin e supplementation and packaging on the quality of minced beef

Friesian cattle, aged 26-27 months, were fed a diet supplemented with 2000IU α-tocopheryl acetate/kg feed/day and another group was fed a basal diet (20IU/kg feed/day) for approximately 50 days prior to slaughter. Following frozen storage (-20°C for 8 weeks) semimembranosus muscles from basal and α-tocopheryl acetate supplemented cattle were minced and vacuum packaged, aerobically packaged or packaged under modified atmospheres (MAP) (30% O(2): 70% CO(2); 70% O(2): 30% CO(2); 80% O(2): 20% CO(2)). Samples were held under refrigerated (4°C) display (fluorescent lighting, 616 lux) for eight days. Vacuum-packaged samples were held under similar conditions but in complete darkness and allowed to bloom for a minimum of 4hr prior to taking colour readings. TBARS values and Hunter a values in minced beef were measured every two days. α-Tocopherol concentrations were significantly (p<0·05) higher in minced meat samples from the supplemented group than in the basal group. Significant (p<0·05) reductions in α-tocopherol concentrations in supplemented meat samples were observed with increased concentrations of oxygen in different packaging systems after eight days of refrigerated storage. TBARS values were reduced over the whole retail display period for all packaging systems when α-tocopheryl acetate supplemented beef was used. TBARS values increased as oxygen levels increased in MAP. Hunter a values showed that vitamin E supplementation in combination with vacuum packaging and MAP improved the colour stability of meat during the first 4 days of storage, however, the failure of MAP to extend meat colour for longer periods of time was probably the result of prior storage at -20°C for 8 weeks.     

Effect of dietary α-tocopherol supplementation and gamma-irradiation on α-tocopherol retention and lipid oxidation in cooked minced chicken

The effects of dietary α-tocopherol supplementation and gamma-irradiation on α-tocopherol retention and lipid oxidation in cooked minced chicken during refrigerated storage were studied. Minced breast and thigh meat from broilers fed diets supplemented with 100, 200 or 400 mg α-tocopheryl acetate/kg feed was irradiated at 2.5 or 4.0kGy. Cooked irradiated and unirradiated meat was stored at 4 °C for 5 days. α-Tocopherol concentrations increased with increasing dietary supplementation. Concentrations decreased during storage, but retention was not affected by irradiation. Lipid stability was determined by measuring the formation of thiobarbituric acid-reacting substances (TBARS) and cholesterol oxidation products (COPs) during storage. TBARS and COPs increased during storage and were reduced by increasing levels of dietary α-tocopheryl acetate supplementation. Irradiation accelerated TBARS formation during storage, but this was prevented by supplementation with 200 mg α-tocopheryl acetate/kg feed. Irradiation tended to increase COPs during storage, although no consistent effects were observed. In general supplementation with over 400 mg α-tocopheryl acetate/kg feed may be required to control cholesterol oxidation in minced chicken. The results suggest that, overall, irradiation had little effect on lipid stability in α-tocopherol-supplemented meat following cooking and storage.     

Lipid and protein oxidation of α-linolenic acid-enriched pork during refrigerated storage as influenced by diet supplementation with olive leaves (Olea europea L.) or α-tocopheryl acetate

The objective of this study was to evaluate the effect of diet supplementation with olive leaves or α-tocopheryl acetate on lipid and protein oxidation of raw and cooked n-3 enriched-pork during refrigerated storage. Enrichment of pork with α-linolenic acid through diet supplementation with linseed oil enhanced (p≤0.05) lipid oxidation in both raw and cooked chops but had no effect (p>0.05) on protein oxidation during refrigerated storage while decreasing (p≤0.05) the sensory attributes of cooked pork. Diet supplementation with olive leaves or α-tocopheryl acetate had no effect (p>0.05) on the fatty acid composition of pork but decreased (p≤0.05) lipid oxidation while exerting no effect (p>0.05) on protein oxidation in both raw and cooked α-linolenic acid-enriched chops stored and chilled for 9days. Moreover, olive leaves and α-tocopheryl acetate supplemented at 10g/kg and 200mg/kg diet, respectively, exerted (p≤0.05) a beneficial effect on the sensory attributes of cooked α-linolenic acid-enriched pork chops.     

Antioxidative effect of dietary tea catechins on lipid oxidation of long-term frozen stored chicken meat

The antioxidative effect of dietary tea catechins (TC) supplementation at levels of 50, 100, 200 and 300 mg kg(-1) feed on susceptibility of chicken breast and thigh meat to lipid oxidation during frozen (-20°C) storage for 9 months was investigated. Day-old chickens (Cobb 500, n=200) were randomly divided into six groups. Chickens were fed a basal diet containing 20 mg α-tocopheryl acetate kg(-1) feed as control, or a vitamin E supplemented diet (basal diet plus 200 mg α-tocopheryl acetate kg(-1) feed), or TC supplemented diets (basal diet plus 50, 100, 200 or 300 mg TC kg(-1) feed) for 6 weeks prior to slaughter. Lipid oxidation (TBARS) was assessed after 0 and 10 days of refrigerated display (4°C) following 1, 3, 6, and 9 months of frozen (-20°C) storage. TC supplementation at all concentrations showed antioxidative effects for both breast and thigh chicken meat during the 9 months of frozen storage compared to the control sample. TC supplementation at levels of 200 and 300 mg kg(-1) feed were more effective (P<0.05) in delaying lipid oxidation in all meat samples compared to the control. TC supplementation at a level of 200 mg kg(-1) feed showed antioxidant activity equivalent to α-tocopheryl acetate fed at the same level up to 3 months of frozen storage. For long-term frozen storage up to 9 months, however, TC supplementation at 300 mg kg(-1) feed was required as a replacement for α-tocopheryl acetate at a level of 200 mg kg(-1) feed. The results obtained showed a long-term antioxidative effect exhibited by dietary tea catechins on chicken meat during frozen storage and demonstrated that tea catechins are effective alternatives to vitamin E as natural dietary antioxidants.     

Effects of Dietary Antioxidants and Oxidized Oil on Membranal Lipid Stability and Pork Product Quality

The effects of dietary tocopherol and oxidized oil on the oxidative stability of membranal lipids in pig muscles and on the oxidative stability of pork products during refrigerated and frozen storage were evaluated. Membrane-bound α-tocopherol stabilized the membranal lipids and reduced the extent of lipid oxidation occurring in pork patties and pork chops during storage. Oxidized dietary oil had an adverse effect on the stability of both the membranal lipids and pork products. The addition of salt to the pork patties accelerated the oxidative process when the patties were stored under fluorescent light and in the dark.     

Effect of dietary α-tocopheryl acetate supplementation on α-tocopherol distribution in raw turkey muscles and its effect on the storage stability of cooked turkey meat

Day-old turkey chicks (n = 99) were divided at random into three groups (n = 33) and fed diets containing 20 (E20), 300 (E300) and 600 (E600) mg all-rac-α-tocopheryl acetate per kg feed per day for 21 weeks prior to slaughter. After slaughter, breasts and legs were removed and examined for α-tocopherol content. Breast muscle from birds fed the three diets was oven cooked, cooled, sliced and overwrapped. The oxidative and colour stability of the slices was examined. Mean α-tocopherol levels in turkey muscle were significantly (p < 0.05) higher in the E300 and E600 groups compared to the control group fed the E20 diet. α-Tocopherol levels in the E300 and E600 groups showed that concentrations in leg muscle were significantly (p <0.05) higher than in breast muscle. α-Tocopherol levels in leg and breast muscles from birds fed E20 and E600 diets decreased significantly (p < 0.05) during 12 months of frozen (-20 °C) storage. TBARS numbers for breast slices from all three dietary groups, cooked both 24 hr after slaughter and following frozen (-20 °C × 11 months) storage, increased during refrigerated (4 °C) display for 10 days. TBARS numbers for slices produced from meat previously held in frozen storage increased more rapidly than those for meat cooked following slaughter. In both cases, E300 and E600 diets significantly (p < 0.05) suppressed lipid oxidation compared to E20 samples. In general, Hunter a values for meat slices from turkeys fed the E300 and E600 diets were higher than those for meat slices from turkeys fed the E20 diet.     

Proteolysis and tenderisation in reindeer (Rangifer tarandus tarandus L.) bull longissimus thoracis muscle of varying ultimate pH

The effect of dietary α-tocopheryl acetate supplementation on the uptake of α-tocopherol in ewe plasma, lamb plasma, milk, organs and muscles was investigated. The oxidative stability and colour in fresh M. longissimus dorsi and frozen M. longissimus dorsi, M. psoas major and M. gluteus medius were also investigated. Ewes (n = 12) were selected and scanned to assess pregnancy. They were divided into two groups (n = 6). The control group was fed a diet containing 20 mg α-tocopheryl acetate/kg feed/day and the supplemented group fed a diet containing 1000 mg α-tocopheryl acetate/kg feed/day, for 9 weeks ante-parturition and 3 weeks post-parturition. The lambs were weaned at 3 weeks and fed supplemented or basal feed for 10 weeks before slaughter. Plasma α-tocopherol increased significantly (p < 0.01) in ewes in the 9 weeks ante-parturition, and lamb plasma taken just before slaughter was significantly (p < 0.01) higher for the supplemented group than the basal group, following 13 weeks of supplementation. Milk α-tocopherol levels were significantly (p < 0.01) higher from ewes fed the supplemented diet at parturition and for the three weeks of supplementation post-parturition (p < 0.05). Supplementation increased the α-tocopherol levels in all tissues sampled. The α-tocopherol concentrations in M. longissimus dorsi and M. psoas major were also determined after frozen storage at -20 °C for 34 weeks. Frozen storage resulted in a significant (p < 0.01) reduction in mean α-tocopherol levels for M. longissimus dorsi but not M. psoas major. Dietary supplementation with α-tocopheryl acetate significantly (p < 0.05) increased the oxidative stability of lamb muscle. Surface colour (Hunter L, a, b) was found to be negatively correlated with metmyoglobin content. Supplementation reduced surface discolouration in refrigerated display under fluorescent light over a 6-7 day storage period. The effect was more pronounced in frozen displayed muscles than in freshly displayed samples.     

Effects of supranutritional dietary vitamin E levels on subcellular deposition of α-tocopherol in the muscle and on pork quality

The influence of three levels of vitamin E in the diet of pigs on the subcellular deposition of α-tocopherol in the muscle and on selected quality characteristics of pork meat (oxidative stability of lipids, colour, drip loss, microbial growth) was studied. The content of α-tocopherol in adipose tissue and L. dorsi muscle as well as in mitochondrial and microsomal fractions of the muscle significantly increased (P < 0.05) with increasing levels of dietary vitamin E. The differences in the concentrations of α-tocopherol in the subcellular fractions were evident in the enhanced stability of the membranes when exposed to metmyoglobin/hydrogen peroxide. The beneficial effect of dietary vitamin E on the oxidative stability of pork lipids during the storage of pork chops and ground pork was also demonstrated. Even though lipid oxidation increased in all cases during storage, the pork products from the pigs receiving the highest level of vitamin E (200 IU kg^?1 feed) exhibited the smallest increase in thiobarbituric acid reactive substances. In addition, increased colour stability and decreased drip loss were observed on keeping pork chops, which had been previously frozen for three months, at 4°C under fluoresent light for 10 days. The possible effect of α-tocopherol on membrane fluidity in this context is discussed.     

Effect of dietary vitamin E supplementation on cholesterol oxidation in vacuum packaged cooked beef steaks

The effect of dietary vitamin E supplementation on cholesterol oxidation in vacuum packaged, cooked, refrigerated and frozen beef steaks, was investigated. Steers (Friesian×Charolais×Black Hereford) were fed diets providing 20 or 3000 mg α-tocopheryl acetate/head/day for 135 days prior to slaughter. α-Tocopherol concentrations in M. psoas major (PM) and M. longissimus dorsi (LD) were significantly (p<0.05) increased by supplementation and were significantly (p<0.05) higher in PM than LD. Cholesterol oxidation (monitored by measuring 7-ketocholesterol formation) increased during refrigerated and frozen storage in some, but not all, groups, and tended to be higher in PM than LD. Dietary vitamin E did not affect 7-ketocholesterol formation in LD, but significantly (p<0.05) reduced concentrations in PM during refrigerated and frozen storage. Supplementation significantly (p<0.05) reduced TBARS in PM and LD, indicating that vitamin E improved oxidative stability in both muscles. The results show that dietary vitamin E supplementation inhibits cholesterol oxidation in vacuum packaged, cooked beef during refrigerated and frozen storage, but may be influenced by muscle type.     

Effect of dietary rosemary and α-tocopheryl acetate on the oxidative stability of raw and cooked pork following oxidized linseed oil administration

The effect of a 2% dietary administration to pigs of oxidized linseed oil (targeted level of 150mEq.O(2)/kg oil after heating at 50°C and exposure to air for 3-4 days following addition of 10ppm CuSO(4)), either or not in combination with antioxidants, on the oxidative stability of raw and cooked pork during illuminated chill storage was assessed. The antioxidant treatments were: 40ppm α-tocopheryl acetate, 40ppm rosemary extract, 40ppm rosemary extract+2ppm gallic acid, and 40ppm α-tocopheryl acetate+40ppm rosemary extract. A total of 20ppm of α-tocopheryl acetate (ATA) was added to all diets in order to meet the physiological requirement of the animals. The antioxidant treatments did not exert any effect on colour and protein oxidation. Lipid oxidation was only decreased by dietary ATA when comparing the ATA supplemented groups combined versus a control treatment group for raw but not for cooked meat. This was due to a higher content of α-tocopherol in the meat and subcutaneous fat. The lipid oxidation results suggested a lack of antioxidant effect for the rosemary extract. No evidence for a synergistic effect of the antioxidant combinations was observed.     

The effects of dietary oregano essential oil and α-tocopheryl acetate on lipid oxidation in raw and cooked turkey during refrigerated storage

The effects of dietary oregano essential oil and α-tocopheryl acetate supplementation on the susceptibility of raw and cooked turkey breast and thigh meat to lipid oxidation during refrigerated storage for 9 days were examined. Thirty 12-week-old turkeys were divided into five groups and fed a basal diet containing 30 mg α-tocopheryl acetate kg(-1) feed as control, or basal diet plus 200 mg α-tocopheryl acetate kg(-1), or basal diet plus 100 mg oregano oil kg(-1), or basal diet plus 200 mg oregano oil kg(-1), or basal diet plus 100 mg oregano oil and 100 mg α-tocopheryl acetate kg(-1), for 4 weeks prior to slaughter. Lipid oxidation was assessed by monitoring malondialdehyde formation in raw and cooked meat at 0, 3, 6 and 9 days of refrigerated storage, through use of a third-order derivative spectrophotometric method. Results showed that all dietary treatments significantly (P<0.05) increased the stability of both raw and cooked turkey meat to lipid oxidation compared with the control. Oregano oil at 200 mg kg(-1) was significantly (P<0.05) more effective in delaying lipid oxidation compared to the level of 100 mg kg(-1), equivalent to α-tocopheryl acetate at 200 mg kg(-1), but inferior (P<0.05) to oregano oil plus α-tocopheryl acetate at 100 mg kg(-1) each, which in turn was superior (P<0.05) to all dietary treatments, indicating a synergistic effect. Thigh muscle was more susceptible to oxidation compared with breast muscle in all treatments, although it contained α-tocopherol at significantly (P<0.05) higher levels.     

Effect of a dietary vitamin E supplementation on colour stability and lipid oxidation of air- and modified atmosphere-packaged beef

The effects of dietary vitamin E supplementation on tissue α-tocopherol level and on the susceptibility of fresh and modified atmosphere-packaged beef on myoglobin and lipid oxidation were investigated. Charolais cattle, aged 32-44 months, were fed diets containing 75 (control, n=8) or 1000 mg (supplemented, n=8) α-tocopheryl acetate/kg feed/day for 111 days prior to slaughter. Following vacuum packaging, M. Longissimus lumborum and M. triceps brachii were aerobically packaged and held under refrigerated display (3°C) for 9 days or packaged under modified atmosphere (MAP; 20% CO(2): 80%O(2)) and held under refrigerated display (8°C) for 13 days under fluorescent light. α-tocopherol concentrations were significantly higher (P<0.05) in meat from the supplemented group than from the basal one. Whatever the measured colour characteristics (a*, R(630)-R(580),% MetMb), the vitamin E supplementation had a positive but non-significant effect on the rate of discoloration. But by visual assessment, essentially with MAP, a significant and positive effect of vitamin E supplementation was noted to lower discoloration (P<0.05). TBARS values were significantly lowered (essentially at the end of storage time for the two packaged modes) after an α-tocopheryl acetate-supplementation.     

Effects of dietary α-tocopheryl acetate supplementation on α-tocopherol deposition in porcine m. psoas major and m. longissimus dorsi and on drip loss, colour stability and oxidative stability of pork meat

The effect of feeding supra-nutritional levels of α-tocopheryl acetate on its deposition in two porcine muscles of different metabolic rates (m. longissimus dorsi and m. psoas major) and the effect on meat quality (lipid oxidation, colour stability and drip loss) was studied. Pigs were fed a standard diet supplemented with three levels: 100, 200 and 700 mg/kg of α-tocopheryl acetate from the time of weaning to slaughter at 90kg live weight. Muscle α-tocopherol levels were linearly related to the logarithm of dietary α-tocopheryl acetate supplementation and the linear relationship was estimated for the two muscles. The levels of α-tocopherol in the two muscles differed by a parallel displacement with consistently higher α-tocopherol levels in m. psoas major compared to m. longissimus dorsi. Dietary α-tocopheryl acetate supplementation significantly reduced lipid oxidation as measured by thiobarbituric acid reactive substances (TBARS) in both raw and cooked meat during storage at 4 °C for 6 days. Drip loss and colour stability of raw muscles were not affected by dietary α-tocopheryl acetate levels, 100mg α-tocopheryl acetate/ kg feed resulted in sufficient α-tocopherol levels in muscles to ensure minimum drip loss and optimum colour stability.     

The effect of dietary oregano essential oil on lipid oxidation in raw and cooked chicken during refrigerated storage

The antioxidative effect of dietary supplementation with oregano essential oil on susceptibility of raw and cooked breast and thigh muscle meat of chickens to lipid oxidation during refrigerated storage for 9 days was investigated. Day-old chickens (n=80) were randomly divided into four groups and fed a basal diet containing 30 mg α-tocopheryl acetate kg(-1) feed as control, or basal diet plus 200 mg α-tocopheryl acetate kg(-1) feed, or basal diet plus 50 or 100 mg oregano essential oil kg(-1) for 38 days prior to slaughter. Lipid oxidation was assessed by monitoring malondialdehyde (MDA) formation in raw and cooked meat during 0, 3, 6 and 9 days of refrigerated storage, using the thiobarbituric acid (TBA) assay and third-order derivative spectrophotometry. Results showed that dietary oregano essential oil supplementation exerted antioxidative effects, the supplementation being most effective in retarding lipid oxidation in stored raw and cooked meat at the 100 mg oregano essential oil kg(-1) feed. However, dietary α-tocopheryl acetate supplementation at 200 mg kg(-1) feed displayed greater antioxidant activity than oregano treatments. Thigh muscle was more susceptible to oxidation compared to breast muscle in all treatments, although the former tissues contained α-tocopherol at markedly higher levels.     

Effect of dietary antioxidant and fatty acid supply on the oxidative stability of fresh and cooked pork

The effect of dietary oil (linseed or soybean oil) and antioxidant treatment (α-tocopheryl acetate (AT; 40ppm) versus a cocktail (AOC; 200ppm): α-tocopheryl acetate+rosemary+citric acid+gallic acid) on colour, lipid and protein oxidation of fresh and processed pork was investigated. No effect of oil source on different parameters of oxidation was seen. No effect of antioxidant treatment on colour stability of fresh longissimus thoracis (LT) or cooked cured ham (CCH) was observed. For both antioxidant treatments, lipid oxidation in fresh LT and CCH was well controlled during display. However, lipid oxidation increased significantly in pre-frozen uncured cooked meat under aerobic conditions. No unambiguous effect of antioxidant treatment on protein oxidation was observed. There seemed to be no clear link between colour, protein and lipid oxidation. At the dose used in this study, no additional or synergistic effects of the extra components of the AOC on the different oxidation parameters was found.     

Effect of Dietary Supplementation with α-Tocopheryl Acetate on the Stability of Reformed and Restructured Low Nitrite Cured Turkey Products

The objective of this study was to investigate the effects of sodium (Na) nitrite reduction on the oxidative and colour stability of reformed and restructured cured cooked turkey products manufactured from meat containing high and low levels of dietary α-tocopheryl acetate. Turkeys were randomly assigned to either a control group, fed a basal α-tocopheryl acetate diet (20mg/kg feed), or a treatment group fed a supplemented α-tocopheryl acetate diet (600mg/kg feed). Diets were fed ad libitum from day 1 until slaughter on day 147. Breast meat from control and treatment groups was used to manufacture cured reformed cooked turkey ham and cured restructured cooked turkey patties. Residual levels of 60 and 120mg Na nitrite/kg of meat were used. Turkey products were packaged in either overwrap or vacuum packaging and stored under refrigerated (4°C) illuminated display for 10 days. Results showed that dietary supplementation with α-tocopheryl significantly (p<0·05) improved the oxidative and colour stability of all low nitrite products produced when compared to non-supplemented controls.     

Effect of dietary α-tocopheryl acetate supplementation on the shelf-life stability of reduced nitrite cooked ham products

Colour stability (Hunter 'a' values) and lipid oxidation (TBARS (thiobarbituric acid reactive substances) values) of overwrapped cooked ham slices and cooked ham patties were measured at 2-day intervals for 10 days. Ham products were manufactured from α-tocopheryl acetate supplemented and control M. gluteobiceps which were halved and cured with either 25 or 100 mg nitrite (kg meat)^–1. Vitamin E supplementation had a beneficial effect on reduced nitrite hams in terms of colour and oxidative stability.     

Effects of dietary magnesium and duration of refrigerated storage on the quality of vacuum-packaged, boneless pork loins

Quality data were initially collected on 78 pork loins from crossbred pigs fed diets containing 0, 1.25 or 2.5% magnesium mica (MM). Loins were then vacuum-packaged, and randomly assigned to either 4 or 8 weeks of storage at 2°C. Dietary MM had no (P > 0.05) effect on moisture loss/retention or subjective and objective color measurements. Purge volume increased (P<0.05) and drip loss decreased (P<0.05) as storage time increased. Moreover, longissimus thoracis et lumborum (LM) chops became lighter (P<0.05), redder (P<0.05), and more yellow (P<0.05) during 8 weeks of storage. Although TBARS values increased linearly (P<0.001) during extended storage, LM chops from pigs fed 2.5% MM tended to have lower (P<0.07) TBARS values after 4 weeks of storage than chops from pigs fed 0 and 1.25% MM. After 8 weeks of storage, however, there was a tendency for TBARS values of chops from pigs fed 1.25% MM to be lower (P<0.07) than chops from pigs fed 2.5% MM. Even though feeding swine diets containing MM did not affect color and water-holding capacity of pork loins during storage, the data indicated inclusion of MM in swine diets may retard onset of oxidative rancidity in vacuum-packaged pork loins.     

Effect of dietary Vitamin E on the stability of raw and cooked pork

Experiments were designed to investigate the effects of dietary α-tocopherol supplementation for 2 weeks prior to slaughter on plasma and muscle α-tocopherol levels and on the oxidative stability of raw and cooked pig muscle during refrigerated storage at 4°C. Plasma and muscle α-tocopherol levels of the pigs on the α-tocopherol supplemented diet (200 mg α-tocopherol acetate/kg feed) were ～2·5-fold higher than those of the pigs on the control diet (30 mg α-tocopherol acetate/kg feed). Dietary supplementation with α-tocopherol significantly (p < 0·01) improved the oxidative stability of both raw and cooked muscle after storage at 4°C for up to 8 days. α-Tocopherol stabilized the membrane-bound lipids against metmyoglobin/H(2)O(2)-initiated oxidation and also significantly (p < 0·05) improved the oxidative stability of rendered fat.