Effect of different dietary levels of natural-source vitamin E in grow-finish pigs on pork quality and shelf life

Improving pork quality and shelf life is important in today’s swine industry because higher levels of DDGS are incorporated into pig diets. Relatively high level of poly-unsaturated fatty acids (PUFA) in DDGS may increase pork susceptibility to lipid oxidation and thus reduce pork shelf life. Antioxidants such as vitamin E may delay the onset of pork lipid oxidation when used as an ingredient in the diet. This experiment examined carcass characteristics, meat quality, shelf life, and color stability in pork from pigs (n = 150) fed five levels of a natural vitamin E (Nova-E) and one level of synthetic vitamin E. Natural vitamin E and synthetic vitamin E had no effect on carcass characteristics or meat quality. Increasing dietary natural vitamin E from 10 to 200 mg/kg decreased lipid oxidation. Lipid oxidation of pork chops and ground pork was similar between pigs fed 40 mg/kg and higher levels of natural vitamin E, indicating no additional benefits from supplementing beyond 40 mg/kg natural vitamin E. Supplementing 200 mg/kg synthetic vitamin E decreased pork lipid oxidation when compared to supplementing 10 mg/kg natural vitamin E. High levels of natural vitamin E or synthetic vitamin E, however, did not prevent discoloration of loin chops. These data indicate that natural vitamin E was effective to help reduce lipid oxidation and the effective minimal level of dietary supplementation appeared to be 40 mg/kg.     

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.     

Use of dietary vitamin E and selenium (Se) to increase the shelf life of modified atmosphere packaged light lamb meat

The aim of this work was to determine the increase in the shelf life of modified atmosphere packaged fresh lamb meat due to the effect of dietary vitamin E and selenium supplementation on colour and lipid oxidation. 128 lambs were fed on a concentrate with standard levels of vitamin E (C), a concentrate enriched with vitamin E (V), a concentrate with sodium selenite (S) and a concentrate enriched with both vitamin E and sodium selenite (VS). The lambs were slaughtered at 27.3±1.45 kg LW, and chops stored on MAP for 7, 9, 11 and 13 days. CIELab colour and TBARs were studied on these days. Use of dietary vitamin E extended the shelf life a further 4 days from the commercial sell-by date in terms of lightness, hue angle, metmyoglobin formation and lipid oxidation. Selenium could be used to increase the lightness of meat without vitamin E supplementation in lambs' diets.     

Vacuum-Packaged Precooked Pork from Hogs Fed Supplemental Vitamin E: Chemical, Shelf-Life and Sensory Properties

Precooked longissimus chops and semimembranosus/adductor roasts from pigs (n = 30) given no supplemental vitamin E (CON) or supplemented with 100 mg vitamin E/kg diet (VITE) were evaluated for lipid oxidation, microbial growth, sensory characteristics, cooking/storage losses and reheating losses. Chops and roasts were vacuum packaged, precooked to 60°C and stored at 2°C for 0, 7, 14, 28, or 56 days. Lipid oxidation was lower in VITE chops and roasts than in CON chops and roasts. Off-flavor intensity scores were more acceptable and storage/ cooking losses were lower for VITE roasts than for CON roasts. Supplementation of vitamin E in a swine diet provided added protection against lipid oxidation and precooking pork under vacuum provided a palatable product with a shelf-life of 56 days.     

香辛料提取物对低温油炸肉丝软罐头的抗氧化效应研究

目的通过添加具有抗氧化活性和较高安全性的香辛料提取物,解决中式肉类菜肴的软罐头食品中变色、风味变差以及脂肪氧化酸败等问题。方法向低温油炸肉丝软罐头中添加不同添加量的迷迭香、肉桂和VE提取物以及2种人工合成抗氧化剂丁基羟基茴香醚(butyl hydroxy anisd,BHA)和没食子酸丙酯(propylgallate,PG),测定其对软罐头菜肴产品在贮藏过程中硫代巴比妥酸值(thiobarbituric acid-reacitive substances,TBARS值)、过氧化物值(peroxide value,POV值)和色差值的影响。结果添加的3种共9组天然抗氧化剂中,迷迭香提取物抑制初级氧化产物氢过氧化物和次级氧化产物丙二醛的效果最好(P0.05)。添加300 mg/kg迷迭香、90 mg/kg PG和120 mg/kg BHA的3组处理组在21 d冷藏期内,其POV值和TBARS值显著小于其他各组(P0.05),说明添加300 mg/kg迷迭香可以替代人工抗氧化剂。结论低温油炸肉丝软罐头中添加300 mg/kg迷迭香提取物,可以减缓脂肪氧化速度,进而延长产品的货架期。     

Effect of oxidized dietary lipid and vitamin E on the colour stability of pork chops

The effect of oxidized corn oil and vitamin E (α-tocopheryl acetate) in pig diets on the oxidative stability of muscle lipids and on the surface colour characteristics of fresh and previously frozen pork chops in refrigerated storage was investigated. Lipid oxidation (TBARS values) and surface redness (Hunter 'a' values) were significantly influenced (P < 0·01) by dietary α-tocopheryl acetate levels but not by degree of oxidation of dietary corn oil. Lipid oxidation and colour deterioration during refrigerated storage were greater in previously frozen chops compared to fresh chops. TBARS values were lower and Hunter 'a' values higher in pork chops from pigs fed 100 and 200 mg α-tocopheryl acetate/kg diet compared to pigs fed 10 mg/kg diet after 2, 4, 6 and 8 days of refrigerated storage. Hunter 'a' values were significantly correlated (P < 0·01) with the logarithm of TBARS values. The results suggest that oxidation of myoglobin precedes oxidation of muscle lipids in pork chops stored at 4°C.     

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 supplementation of vitamin E on characteristics of lamb meat packed under modified atmosphere

The effect of dietary vitamin E supplementation on modified-atmosphere packed lamb meat during storage was studied. Thirty-six weaned male Manchego breed lambs were fed diets supplemented with three different vitamin E concentrations (0, 250, 500 and 1000 mg/kg feed) for an average of 37 days, in the 13–26 kg live weight growth range. Slices of m. longissimus dorsi were packaged under modified atmosphere (70% O₂ and 30% CO₂), stored at 2 ± 1 °C in darkness for 14 and 28 days. Meat quality parameters after both storage periods were assessed. Dietary vitamin E supplementation significantly increased -tocopherol concentration in muscle. Initially, lipid oxidation (TBARS), meat colour and bacterial load were similar in all groups. Lipid and colour oxidation of meat increased significantly (P < 0.001) throughout storage. The increase was greater in non-supplemented lambs than in supplemented ones. The bacterial counts after 28 days of storage reached the limit for microbiological shelf life (7 log₁₀cfu/cm²). Dietary vitamin E supplementation increased the shelf life of meat packaged under modified atmosphere to 14 days. TBARS, pigment oxidation and bacterial load were inside the acceptable limit. The meat maintained its quality for 28 days of storage only when lambs were fed with the 1000 mg/kg dietary supplement, though the bacterial load was at the limit of acceptability.     

Oxidative stability of frozen-stored raw pork chops, chill-stored pre-frozen raw pork chops, and frozen-stored pre-cooked sausages in relation to dietary CuSO4, rapeseed oil and vitamin E

 Danish Landrace× Danish Yorkshire female pigs were fed either a standard diet or a standard diet enriched with 6% rapeseed oil and supplemented with increasing amounts of vitamin E (0, 100 or 200 mg all-rac-α-tocopheryl acetate/kg feed) and copper (0, 35 or 175 mg CuSO₄/kg feed), and the effect of dietary regimen on the oxidative stability of (1) frozen-stored raw pork chops packed in atmospheric air, (2) chill-stored pre-frozen pork chops packed in atmospheric air, and (3) freezer-stored, vacuum-packed pre-cooked sausages was investigated. The addition of 6% rapeseed oil did not influence the oxidative stability of the pork chops negatively, whereas the oxidative stability of a product such as the pre-cooked sausages (Danish dinner sausages) with a higher fat content (15%) decreased as a result of rapeseed oil feeding. Inclusion of rapeseed oil in the diets increased the amount of monounsaturated fatty acids and polyunsaturated fatty acids (PUFAs) in the meat and fat for the production of sausages at the expense of the content of the saturated fatty acids, and the higher content of PUFAs readily explains the decreased oxidative stability of the pre-cooked sausages. Feeding pigs 100 mg or 200 mg all-rac-α-tocopheryl acetate/kg feed significantly increased the oxidative stability of the pork chops and the detrimental effect of rapeseed oil observed in the pre-cooked sausages was effectively neutralised by both levels of vitamin E supplementation. Supplementation with copper did not affect the oxidative stability of any of the products. The presented results show that it is possible to produce pork products with a nutritionally improved fatty acid profile by inclusion of 6% rapeseed oil, without affecting the oxidative stability of the products negatively, through the protection provided by dietary vitamin E. Received: 23 March 1998 / Revised version: 28 May 1998     

Oxidative stability and dietary treatment with vitamin E, oleic acid and copper of fresh and cooked pork chops

Research has been conducted on the effects of feed supplementation with vitamin E, oleic acid (sunflower oil) and copper on some quality characteristics of pork chops. The study was based on the measurement of pH 45' and 24 hr post mortem, proximate composition, colour both objective and sensory, colour stability after packing in oxygen permeable film and protective atmosphere, copper and iron contents, vitamin E content in fresh and cooked chops, peroxide and TBARS value in raw and cooked meat, total cholesterol, cholesterol oxides and aldehydes in cooked meat, sensory evaluation of the eating quality of cooked chops and iodine number of subcutaneous fat. Vitamin E content was significantly higher with oil and vitamin supplementation. No variation has been observed in copper and iron contents. A higher stability of the colour of meat packed under modified atmosphere has been observed with increasing vitamin E content, but the same did not apply with meat packed in oxygen permeable film. No differences have been observed on fatty acid oxidative stability of fresh m. longissimus dorsi and cooked chops (peroxide and TBARS values), on cholesterol oxidation and aldehydes production of cooked chops with increasing vitamin E content. Iodine number in supplemented animals reached levels normally considered at risk for fat firmness.     

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.     

Effects of finishing period length with vitamin E supplementation and alfalfa grazing on carcass color and the evolution of meat color and the lipid oxidation of light lambs

Indoor-kept concentrate-fed light lambs (n = 54) were supplemented with 500 mg of dl-α-tocopheryl acetate/kg concentrate for 0, 10, 20 and 30 d before slaughtering at 22–24 kg BW. Simultaneously, 8 lambs with their dams were alfalfa-grazed and the lambs were slaughtered at the same weight. The age at slaughter and carcass characteristics were more affected by grazing than by supplementation with α-tocopherol. The grazing lambs had similar α-tocopherol levels to the lambs fed concentrate with dl-α-tocopheryl acetate for 10 days before slaughter. The length of the feeding period affected the evolution of the color, delaying the blooming and discoloration of the meat. Feeding lambs α-tocopherol enriched concentrate during the last 10 days of life or grazing them on alfalfa drastically diminished the lipid oxidation of the meat. Alfalfa grazing is a feasible alternative to increase light lamb meat shelf life without using additives.     

Effects of calf diet, antioxidants, packaging type and storage time on beef steak storage

The effect of basal dietary supplemented with vegetable oils plus vitamin E (sunflower, soybean, linseed and a basal diet control), type of packaging (MAP or vacuum), addition of natural antioxidant (grape seed, rosemary) and storage time (0, 7, 14 and 21 days) on lipid oxidation, color stability, vitamin E content, and total aerobic bacterial counts in steaks of Longissimus thoracis was studied. The triple interaction diet × time × packaging affected oxidative stability, redness and yellowness of the meat. TBARS values did not increase with time in vacuum-packaged samples for all dietary treatments. However, samples from MAP and control showed the highest TBARS values after 21 days of storage (0.72 mg MDA/kg of meat, P < 0.05). Both exogenous antioxidant extracts and MAP maintained low total aerobic counts in steaks until the 21st day. Calves should be fed a diet supplemented with L-VE, stored in MAP and treated with grape seed extract to extend the shelf life of their meat.     

Effect of the dietary supplementation with vitamin E on colour stability and lipid oxidation in packaged, minced pork

The effect of supplementation of vitamin E (200 W kg⁻¹ feed) in the diet of pigs on colour stability and lipid oxidation in minced pork was studied. Control and enriched diets were provided for the last 12 weeks before slaughter. Half of the samples of minced shoulder meat from control and supplemented pigs were packaged on trays with oxygen-permeable overwraps and half in modified atmosphere packs (initial gas mixture: O₂/CO₂/N₂ = 66/ 27/7). Meats were stored for 10 days at 7 °C in an illuminated retail display cabinet. The meat from vitamin E-supplemented pigs was more resistant to lipid oxidation than was the control meat. Gas packaging appeared to increase lipid oxidation in control meat, whereas lipid oxidation was stable in meat from vitamin E-supplemented pigs. Colour stability for gaspacked meat was comparable for both dietary groups. However, oxygen-permeable overwraps had a negative effect on colour stability in vitamin E-enriched meat. The reason for this is not known. The shelf-life of enriched and control meat was similar. Thus supplementation of pig feeds with vitamin E is recommended if an improved stability against lipid oxidation of (minced) pork is required.     

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 9 days. Moreover, olive leaves and α-tocopheryl acetate supplemented at 10 g/kg and 200 mg/kg diet, respectively, exerted (p ≤ 0.05) a beneficial effect on the sensory attributes of cooked α-linolenic acid-enriched pork chops.     

Influence of dietary vitamin C and selenium,alone and in combination,on the composition and oxidative stability of meat of broilers

Information on the combined effect of dietary vitamin C and Se on the composition and oxidative stability of meat of broilers is not available in the literature. In the present experiment, male broiler chickens were fed a maize–wheat–soya diet supplemented with vitamin C at 280 and 560 mg/kg of diet, and Se (sodium selenite or selenised yeast; Se) at 0.3 mg/kg for 5 weeks. After slaughter, samples of thigh meat were analysed. The supplementation of diets with vitamin C or Se increased the protein concentration of the meat at the expense of fat. Vitamin C supplementation increased the vitamin C content of the meat in a dose-dependent manner and decreased the vitamin A concentration in the meat of broilers fed diets with sodium selenite or without a Se supplement. In the meat of the broilers that were fed these diets, the vitamin C decreased the lipid oxidation in meat that was stored for 5 days. No sparing effect of vitamin C was apparent on the amount of vitamin E in the meat. Selenised yeast was more effective in the enrichment of meat with Se than was selenite. Both Se sources increased the activity of glutathione peroxidase and the oxidative stability of the meat.     

Effects of Potassium Sorbate, Sodium Acetate, Phosphates and Sodium Chloride Alone or in Combination on Shelf Life of Vacuum-Packaged Pork Chops

Microbiological and some physical and chemical effects of treating pork chop surfaces with sodium acid pyrophosphate, a commercial phosphate blend, potassium sorbate and phosphate/sorbate/sodium acetate solutions, with or without sodium chloride, before packaging were studied in pork chops vacuum-packaged and stored at 2–4°C for 10 weeks. All treatments containing potassium sorbate reduced (P<0.05) counts of mesophiles, psychrotrophs, EnterobacteriaCeae, facultative anaerobes, and lactobacilli. Treatment of chops with 10% phosphates/ 10% potassium sorbate solutions improved pork color and decreased purge. Potassium sorbate alone reduced microbial counts more than it did when combined with phosphates, but chops were darker and had more exudate (P<0.05). Combined use of 10% phosphates/10% potassium sorbate extended shelf life in vacuum-packaged fresh pork chops to 10 weeks at 2–4°C compared with 4 weeks for untreated pork and protected meat color.     

Dietary vitamin E supplementation and discoloration of pork bone and muscle following modified atmosphere packaging

The effects of modified atmosphere (80% O₂: 20% CO₂) and illumination on the discoloration rate of pork bone (lumbar vertebrae) and muscle (longissimus lumborum), and on muscle lipid stability were studied in vitamin E-supplemented and unsupplemented pigs. Bone-in pork chops were placed in 80% O₂: 20% CO₂ at 0 °C and stored for 5 days in the dark. The chops were then displayed under (a) fluorescent light in air or modified atmosphere or (b) in air with or without illumination. Lipid oxidation was increased by the modified atmosphere packaging but this detrimental effect was offset by vitamin E supplementation. Higher supplementation levels (198 and 207mg/kg) improved bone color stability regardless of the packaging atmosphere or the lighting conditions. Although vitamin E supplementation improved muscle color stability during display in air or modified atmosphere, the benefit of supplementation on muscle color was detectable only for illuminated storage.     

Effects of breed and a concentrate or grass silage diet on beef quality in cattle of 3 ages. II: Meat stability and flavour

This study examined the effect of breed and diet on meat quality, defined as lipid stability, colour shelf life and sensory quality. Ninety-six steers were used, half Aberdeen Angus (AA) cross and half Holstein-Friesian (HF). They were reared from 6 months of age on a standard concentrate diet or grass silage and slaughtered at 14, 19 or 24 months of age. Breed had small effects on quality with lower lipid stability in muscle of 24 month-old HF (P<0.05). Sensory scores were similar between the breeds, the few differences being in favour of AA. Diet had the biggest effects on meat quality, in all 3 age groups. The grass silage diet produced higher plasma and muscle levels of vitamin E, lower lipid oxidation in loin steaks measured at 4 and 7 days of retail display and better colour stability (saturation) during shelf life in MAP (O(2):CO(2); 75:25) (all P<0.001). The high values for lipid oxidation in the concentrate-fed steers were linked to high muscle PUFA concentrations and low levels of vitamin E.     

Measurement of lipid oxidation and porphyrins in high oxygen modified atmosphere and vacuum-packed minced turkey and pork meat by fluorescence spectra and images

This paper illustrates that fluorescence spectroscopy and imaging can be used to measure the extent and distribution of lipid oxidation in meat. Minced turkey thighs and pork semimembranosus muscles were stored for 7 and 12 days at 4°C in high oxygen (O(2)) modified atmosphere packages and vacuum. Turkey meat packed in high O(2) atmosphere was oxidised already after 7 days of storage. The sensory rancid odour score was 4.7 (on a scale from 1 to 9) and the TBARS value was 1.86mg MDA/kg. There was also an increase in fluorescence emission intensity in the 410-550nm region, which arises from lipid oxidation products. The combination of unsaturated fatty acids and access to O(2) resulted in lipid oxidation gradients in the turkey meat samples, and these gradients were clearly visualised by fluorescence images. In comparison, pork meat was more stable against lipid oxidation, with TBARS values <0.2mg MDA/kg and no development of fluorescent lipid oxidation products was detected. The fluorescence spectra measured in the present experiment suggest that turkey thighs and pork semimembranosus muscle in addition to protoporphyrin also have a natural content of Zn protoporphyrin. The porphyrin content was higher in pork meat than in turkey meat. It increased during storage time when the meat was packed in vacuum, and it decreased with O(2) availability. The distribution of porphyrins in the meat was visualised by fluorescence imaging.