HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Guo, Q. Articles by Gerrard, D. E. Search for Related Content PubMed PubMed Citation Articles by Guo, Q. Articles by Gerrard, D. E.

Effect of dietary vitamin E supplementation and feeding period on pork quality¹

Q. Guo^*, B. T. Richert^*, J. R. Burgess, D. M. Webel, D. E. Orr, M. Blair, A. L. Grant^* and D. E. Gerrard^*,2

^* Department of Animal Sciences, and Department of Foods and Nutrition, Purdue University, West Lafayette, IN 47907; and JBS United, Sheridan, IN 46069; and and Adisseo USA Inc., Alpharetta, GA 30005

	Abstract

Top Abstract INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION IMPLICATIONS LITERATURE CITED

 
Feeding increased levels of dietary vitamin E can inhibit lipid oxidation. The aim of this study was to investigate the effect of levels of dietary -tocopherol acetate (VE) and feeding duration on meat quality and lipid oxidation. Eighty-one pigs were allocated to 1 of 3 diets containing 40, 200, or 400 IU of VE/kg of feed, and each diet group was divided into 3 feeding periods (3, 6, or 9 wk). Carcass characteristics and meat quality were evaluated. Oxidative stability of fresh and cooked pork patties and pork chops was determined after chilled or frozen storage. Increasing dietary concentrations of VE did not affect any growth performance parameter. Drip loss, however, decreased (P < 0.05) with increased dietary VE levels. Moreover, an increased duration of VE feeding improved (P < 0.05) pH and drip loss. Less lipid oxidation (P < 0.05) was detected in fresh ground pork from pigs fed greater concentrations of VE after 4 d of storage. A greater (P < 0.05) resistance to oxidation in cooked ground pork was observed in pigs fed 200 or 400 IU of VE/kg at 2 and 6 d of storage. Fresh and cooked pork patty oxidation decreased (P < 0.05) linearly as feeding duration increased from 3 to 9 wk. After 6 mo of freezer storage, lipid oxidation of pork chops from pigs fed 200 or 400 IU of VE/kg was lower (P < 0.05) than for pigs fed 40 IU of VE/kg. Likewise, lipid oxidation of pork chops of pigs fed VE for an extended period of time (6 wk) was lower (P < 0.05) after 9 mo of storage. Fatty acid profiles of neutral lipid fraction of the LM became more unsaturated (P < 0.05) with added VE to the feed. These results indicate an increased intake of dietary VE concentration, and prolonged feeding of VE can improve drip loss and reduce lipid oxidation in ground pork and pork chops. This study suggests that supplementation with 200 IU of VE/kg of feed for 6 wk before market is beneficial in improving lipid stability and pork quality.

Key Words: lipid oxidation • meat quality • pork • vitamin E

	INTRODUCTION

Top Abstract INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION IMPLICATIONS LITERATURE CITED

 
Oxidation of lipids leads to deterioration of pork quality by producing off-flavors (Spanier et al., 1988) and decreased appearance, texture, and nutritive values (Buckley et al., 1995). It is generally accepted that lipid oxidation in meat products is initiated in the highly unsaturated phospholipid fraction, which consists mainly of subcellular membranes (Gray and Pearson, 1987). Dietary vitamin E (-tocopherol acetate; VE) supplementation delays this process (Monahan et al., 1992; Jensen et al., 1997). Some studies have shown that increased levels of -tocopherol in finishing pig diets can increase lipid stability in pork (Cannon et al., 1995b).

Asghar et al. (1991a) and Monahan et al. (1994a) reported that feeding 200 IU/kg of VE feed results in reduced lipid oxidation as measured by thiobarbituric acid reactive substances (TBARS). In addition to reduced lipid oxidation, color stability and drip loss characteristics were enhanced in fresh pork chops. Others have shown that high levels of VE supplementation (300 mg/kg) in the last 60 d of finishing increased -tocopherol levels in tissues and reduced the production of TBARS (Corino et al., 1999). Furthermore, feeding VE at up to 700 mg/kg of feed improved oxidative stability of lipids in pork by decreasing TBARS by 52% in fresh and cooked meat during refrigerated storage, yet little positive effect was observed on color and drip loss characteristics (Jensen et al., 1997). However, simply adding -tocopherol (0 to 1,000 IU/kg) during processing had little effect on lipid oxidation during frozen storage (–18°C) for 37 wk (Channon and Trout, 2002), suggesting -tocopherol must be biologically integrated into the tissue before beneficial effects can be realized.

Therefore, a study was designed to determine whether feeding increasing levels of -tocopherol for various durations could affect carcass traits and oxidative status of raw and cooked pork during short- and long-term storage.

	MATERIALS AND METHODS

Top Abstract INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION IMPLICATIONS LITERATURE CITED

 
Animals and Diets
All animal handling protocols were approved by the Purdue Animal Care and Use Committee.

A total of 81 barrows were blocked by BW and randomly assigned to 3 treatment groups within blocks. One group (n = 27) was allocated to 1 of 3 finishing diets containing 40, 200, or 400 mg of VE/kg of feed. Each diet group was further divided into 3 subgroups for feeding durations of 3, 6, or 9 wk, providing a 3 x 3 factorial arrangement of treatments. Treatments began 3, 6, or 9 wk before the anticipated slaughter date. Mean initial BW for pigs fed for 3-wk (96.5, 96.6, and 97.0 kg), 6-wk (83.2, 83.2, and 82.9 kg), and 9-wk durations (69.6, 69.1, and 69.8 kg) were similar among the 40, 200, and 400 IU of VE/kg levels. Pigs were provided ad libitum access to feed and water and were individually housed (1.17 x 1.70-m pens) in environmentally controlled facilities. Because this was not considered a performance-based trial, detailed performance data were not maintained beyond initial and final BW.

The source of VE used in this study was DL-alpha tocopheryl acetate (Microvit E Promix 50, Adisseo, Alpharetta, GA). All diets were corn- and soybean meal-based and formulated to meet or exceed all nutrient requirements (NRC, 1998). Diets were fed in 2 phases (35 and 28 d, respectively) during the study and were formulated to 0.83 and 0.67% Lys for phase 1 and phase 2, respectively, with both phases formulated to 3.7% dietary fat (all percentages on an as-fed basis). Diets were analyzed for vitamin E concentrations by 2 laboratories (Iowa Testing Laboratories Inc., Eagle Grove, IA, and CN Laboratories, Courtland, MN), with average analyzed concentrations of 71, 214, and 581 IU/kg for phase 1 diets and 47, 252, and 503 IU/kg for phase 2 diets, for the 40, 200, and 400 IU of VE/kg levels, respectively. Before the beginning of the study, pigs were fed diets at the NRC (1998) recommended level of VE (11 IU/kg) from approximately 25 kg of BW until beginning their respective level and duration of VE.

After the completion of the feeding period, pigs were transported from United Feeds (Frankfort, IN) to the Purdue University abattoir, where they were slaughtered at a live weight of approximately 114 kg over 3 d, with 27 pigs slaughtered/d (3 pigs·treatment^–1·d^–1). Animals were processed at the Purdue University Meat Science Research and Education Center using normal commercial processing procedures, except that pigs were skinned during processing to expedite the slaughter time.

Sampling and Preparation of Patties
After slaughter, carcasses were held at 4°C for 24 h. After this 24-h period, carcasses were fabricated into primal cuts. Loins were fabricated into 2-cm-thick chops beginning from the eighth- to the ninth-rib region, and 4 chops were individually vacuum-packaged, frozen, and stored at –20°C for 0, 3, 6, or 9 mo. A fifth chop was separated into subcutaneous fat and lean. Lean and fat were vacuum-packed and frozen separately for analysis of fatty acid profiles. A sixth chop was subjected to objective color measurements with a Hunter Lab 45°/0° D25-PC2Colorimeter (Hunter Associates Laboratory Inc., Reston, VA), and L* (lightness), a* (redness), and b* (yellowness) were recorded. A seventh chop was used to determine the water-holding capacity (Rasmussen and Stouffer, 1996). Color, marbling, and firmness scores of the LM between the 10th and 11th ribs were subjectively collected according to National Pork Producers Council standards (NPPC, 1991).

Muscle pH at 45 min (pH₄₅) and 24 h (pH_u) was monitored as previously reported (Bowker et al., 1999). Briefly, LM pH values were recorded adjacent to the last rib at 45 min postexsanguination using a Beckman 110 ISFET pH meter with a spear-tipped KCl^– gel probe (Fullerton, CA) that compensated for temperature differences. The pH meters were calibrated before and after measurement of every 4 carcasses using pH 4.00 and 7.00 buffers at 37°C. Probes were cleaned after each measurement by sequentially soaking in 10% bleach and 10% pepsin (0.1 g/mL; Fisher Scientific, Pittsburgh, PA) solutions, each for 10 min. To ensure measurements were taken near the center of the muscle, the pH probes were inserted approximately 4.5 cm lateral to the midline of the carcass to a depth of approximately 5 cm at an angle perpendicular to the long axis of the LM.

Both hams from each pig were removed from the carcass and separated into fat and lean. Lean (>90% lean) was coarse-ground (6.4-mm plate), salt was added (2% wt/wt), and the preparation was mixed, reground (3.2-mm plate), and subjected to patty formation. Fresh patties (n = 2/pig) were placed on polystyrene trays and overwrapped with an oxygen-permeable PVC meat stretch-wrap (O₂ transmission rate: 6,000 to 8,000 mL of O₂·[m²]^–1·24 h^–1 at 1 atmosphere, 23°C, and 75% relative humidity). Patties were stored at 4°C under fluorescent lighting for 0, 2, 4, or 6 d. Additional patties (n = 2/pig) were sealed in 30 x 18-cm retortable vacuum bags, placed in a hot water bath, and cooked to an internal temperature of 70°C for 30 min (Monahan et al., 1990). After cooking, the samples were cooled and stored at 4°C under fluorescent light and assessed for lipid oxidation at 0, 2, 4, or 6 d.

Measurement of Lipid Oxidation
Lipid oxidation in the meat samples were assessed by the thiobarbituric acid distillation method (Tarladgis et al., 1960), modified according to Guo et al. (2006). Briefly, minced samples were placed in a 50-mL test blender cup and homogenized. Butylated hydroxytoluene (0.2 mL of solution containing 1.5 g of butylated hydroxytoluene in 10 mL of 100% ethanol) was added before the blending step to prevent autoxidation. Slurries were transferred to round-bottom boiling flasks, and boiling beads and Antifoam Emulsion A (Sigma, St. Louis, MO) were added. Slurries were boiled, and distillate was collected. After cooling, distillate was transferred to a test tube, and thiobarbituric acid solution was added. The mixture was vortexed and boiled to develop color. After cooling, absorbance was recorded (Beckman Instruments Inc., Fullerton, CA) at 538 nm. Absorbance values were multiplied by 7.8 to obtain thiobarbituric acid values. Malonaldehyde standard curves were prepared by making appropriate dilutions of 1,1,3,3-tetraethoxy-propane (Sigma) standard solutions. The TBARS value was calculated from standard curve and expressed as milligrams of malonaldehyde equivalents/kilogram of tissue.

Fatty Acid Profiles
Fatty acid determination was conducted as previously reported (Guo et al., 2006). Briefly, loin, lean, or subcutaneous fat samples were mixed with methanol, and chloroform was added. After a 30-min incubation, 2 M KCI was added, and the solutions were centrifuged. Organic layers were transferred and reextracted. Chloroform was then eliminated by N₂ gas evaporation. Dried samples were reconstituted and loaded onto SPE cartridges (SPE cartridge, PrepSep columns, Fisher Scientific, Pittsburgh, PA). Neutral lipids were collected with 12 mL of MTBE:acetic acid (100:0.2, vol/vol) solution, and polar lipids were collected with 12 mL of MTBE:methanol:ammonium acetate (10:4:1, vol/vol). All of the eluate was transferred to acid-washed tubes. Samples were dried and tetramethylguanidine (Fisher Scientific) in methanol (1:4, vol/vol) was added. Tubes were capped tightly and boiled. After cooling, saturated NaCl solution was added. Esters were extracted with petroleum ether. The organic layer was collected and reextracted. Ether was then eliminated by N₂ gas evaporation. Dried samples were reconstituted, vortexed, and centrifuged. The clear portion of the sample was transferred to Target DP, glass gas chromatography (GC) vials with polypropylene caps (Fisher Scientific). Samples were stored at –80°C for GC analysis. An anti-oxidant (butylated hydroxytoluene) was added (0.01%, vol/vol) to all solvents used for homogenization. After fatty acid extraction, total fatty acids were analyzed using a GC. A Hewlett Packard 5890 series II gas capillary, gas-liquid chromatograph equipped with a flame ionization detector, HP Chemstation, and autosampler (Hewlett-Packard Co., Palo Alto, CA) was used. An Omegawax 320 capillary column (Supelco Inc., Bellefonte, PA; 30 m x 0.32 mm x 0.25 µm) was used, with helium as the carrier gas. An initial oven temperature (175°C) was maintained for 4 min and then increased at 3°C per min to a final temperature of 220°C. The final temperature was held for 15 min. The total gas chromatographic run was 34 min for lean and fat samples. All samples were introduced by split injection (1:33). Fatty acid identification was achieved by comparing retention times with an animal source standard (lard, Supelco). Fatty acid proportions are presented as area percentages.

Statistical Analysis
The GLM procedure of SAS (SAS Inst. Inc., Cary, NC) was used to analyze carcass data, pH, NPPC scores, Hunter color, drip loss, and fatty acid composition using animal as the experimental unit. These data were analyzed as a 3 x 3 factorial ANOVA, including the main effects of VE levels and feeding duration, as well as interactions between factors. The model included slaughter day as a blocking factor. Least squares means were generated, and multiple comparisons were done according to the Tukey-Kramer method with an overall significance level of P < 0.05. Lipid oxidation of patties and chops were analyzed using PROC MIXED of SAS for repeated measures of time of exposure or storage. Least squares means were generated and separated using the adjusted Tukey-Kramer test option of SAS for main and interactive effects.

	RESULTS

Top Abstract INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION IMPLICATIONS LITERATURE CITED

 
Carcass Traits and Meat Quality
Supplementation of pig diets with different concentrations of VE did not influence carcass traits or meat quality parameters except for drip loss (Table 1). Pigs fed 400 IU/kg of feed of VE had less (P < 0.05) drip loss than pigs fed 40 and 200 IU/kg of feed, suggesting 400 IU/kg of feed was more advantageous in controlling drip loss. The addition of VE to diet did not appear to influence pork pH_u values and color. No interactions of VE level and feeding period were observed for various carcass and meat quality traits.

Lipid Oxidation
Lipid oxidation was lower (P < 0.001) after 4 d of storage in fresh ground pork from pigs fed 200 and 400 IU of VE/kg of feed compared with pork from pigs fed 40 IU of VE/kg of feed (Table 2). Fresh ground pork had lower TBARS values in the long-term feeding periods (6 and 9 wk) than pork patties from pigs fed 3 wk of VE diets after 4 and 6 d of chilled storage (P < 0.001). No interaction was observed between VE level and feeding duration for fresh ground pork patties.

The concentration and duration of VE supplementation had no effect on lipid oxidation of pork chops after 3 mo of storage (–20°C). After 6 mo of storage, pork chops from pigs fed 200 IU of VE/kg had lower (P < 0.05) TBARS values than chops from pigs fed the 40 IU/kg of diet, but no further benefit was observed at 400 IU/kg of diet (Table 3). Initial (time 0) pork chop oxidation was lower (P < 0.01) after 9 wk of VE feeding than 3 wk of VE feeding. The TBARS values of chops after 9 mo of frozen storage were lower (P < 0.01) for pigs fed VE for 6 wk than for those fed VE for only 3 wk. Extended frozen storage did not significantly influence lipid oxidation of pork chops.

	DISCUSSION

Top Abstract INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION IMPLICATIONS LITERATURE CITED

No influence was observed among supranutritional dietary VE concentrations for loin chop color. Similar results were observed by Cannon et al. (1996) and Jensen et al. (1997). They indicated no effect of VE supplementation on color of aerobically packed pork chops. In addition, Hoving-Bolink et al. (1998) reported significant effects of enhanced VE feeding on color stability of fresh LM and Psoas major muscles. Even though routine positive effects of increased VE supplementation have been reported for color stability in beef (Faustman et al., 1989; Liu et al., 1995; O’Grady et al., 1998), varied results occur in pork (Asghar et al., 1991a; Monahan et al., 1994a). We did not determine tissue concentrations of VE, but it is possible that levels used in this study were not sufficient to realize levels necessary to change lean color. Alternatively, species-related variation may be responsible for differences in the stability of pork and bovine myoglobin (Suman et al., 2006).

Kerth et al. (2001) found that supplementing halothane-free pigs with VE via the finishing diet at 600 IU/ kg during the last 36 to 70 d before slaughter resulted in a slower decline in muscle pH postmortem. Differences in rate and extent of muscle pH decline are related to adverse pork quality development (Wismer-Pedersen, 1978). In particular, a rapid pH decline in muscle early postmortem results in a lower pH when carcass temperatures are greater, which is thought to promote greater protein denaturation and water loss (Sayre and Briskey, 1963; Honikel and Kim, 1986). In the current study, VE supplementation had little influence on muscle pH, which is consistent with other studies (Cannon et al., 1996; Eikelenboom et al., 2000; Phillips et al., 2001). However, our results indicated greater pH₄₅ and pH_u in 6 wk of feeding VE, which could be linked to a change in drip loss as a result of the extended feeding period.

Drip loss is one of the major quality factors affecting the pork industry (Cannon et al., 1995a); the inability of meat to bind water leads to tenderness problems and increases in cooking loss (Topel et al., 1976). Asghar et al. (1991a) reported frozen pork chops from pigs fed 200 IU of VE/kg of diet exhibited less drip loss on thawing. Others have reported drip loss decreases when dietary VE levels are fed at 100 to 200 mg/kg (Monahan et al., 1994b; Cheah et al., 1995). In the current study, supplementation of the diet with 200 IU/kg of VE did not alter drip loss values. However, feeding levels at 400 IU/kg reduced drip loss. The integrity of the cell membranes influences drip loss in fresh meat (Offer and Knight, 1988). High concentrations of VE in meat likely protect the integrity of cell membranes by reducing the oxidative changes in the membrane lipids. As a result, membranes remain intact longer, reducing the leakage of sarcoplasmic fluid into the extracellular spaces (Asghar et al., 1991a). In addition, Cheah et al. (1995) and Den Hertog-Meischke et al. (1997) reported that VE inhibits phospholipase A₂ and results in pro-longed stability of mitochondria membranes and hindering leakage of Ca²⁺ from the sarcoplasmic reticulum, which may improve sarcomere length and thereby reduce exudate loss from the cell. When considering the duration of VE supplementation, our data revealed only a reduction in drip loss at 6 wk of feeding. Although it is difficult to know exactly why this discrepancy occurred in our study, these values mirrored changes in pH₄₅ and pH_u values. As alluded to earlier, the relationship between the rate and extent of postmortem pH declines and ultimate pork quality are well documented. Even so, the drip loss values in this study across all treatments were quite low and may simply be an artifact in the data.

Pork patties, both raw and cooked, from pigs fed VE-supplemented diets were more resistant to lipid oxidation than those from control pigs (40 IU/kg of VE). This is consistent with previous reports (Monahan et al., 1990; Asghar et al., 1991b). Corino et al. (1999) showed dietary supplementation at levels of 100 and 300 mg/ kg of VE in the last 60 d before slaughter significantly improves oxidative stability of raw pork. Moreover, Jensen et al. (1997) reported 200 or 700 mg/kg of VE enhanced lipid oxidation stability in cooked patties. In our study, the influence of dietary VE on lipid oxidation of pork chops remained evident for up to 6 mo of freezer storage. In addition, we detected a greater resistance to oxidation after 4 d of refrigeration in fresh ground pork patties. Alpha-tocopherol acts to accept free radicals during the initial steps of oxidation (Gray et al., 1996). This is particularly evident by the fact that lipid oxidation product formation is delayed in fresh and frozen product, especially that subjected to salt, a powerful prooxidant.

Lipid oxidation is directly proportional to the level of USFA present in membranes (Gray and Pearson, 1987). Again, VE inhibits this process by quenching free radicals that form in the membranes and other lipid-rich environments, thereby preventing PUFA oxidation (Bramley et al., 2000). However, we observed a reduction in the percentage of palmitic acid, stearic acid, and SFA in response to dietary VE supplementation. In contrast, USFA content increased with VE supplementation, but PUFA were not influenced. This observation may be partially explained by the fact that VE protects fatty acids against oxidation (Buckley et al., 1995; Fuhrmann and Sallmann, 1996; Rey et al., 2001). Lauridsen et al. (2000) demonstrated fatty acid composition in the mitochondria of the Psoas major muscle of VE-supplemented pigs had a greater proportion of C18:3 and C20:1 at the expense of C16:0 and C18:0. Curiously, however, other studies report little effect of VE supplementation on the fatty acid composition in muscle (Lin et al., 1989; Nam et al., 1997; Onibi et al., 1998). Postulating that VE feeding changes de novo synthesis of fatty acids in pig tissues is an intriguing hypothesis but requires further studies to validate such a claim.

	IMPLICATIONS

Top Abstract INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION IMPLICATIONS LITERATURE CITED

 
Inclusion of vitamin E in pig finishing diets offers the pork industry benefits in pork quality development and lipid stability. Results of this study show vitamin E supplementation is effective in reducing lipid oxidation, thereby prolonging the length of time fresh and frozen pork can be stored. This would allow for greater shelf life and a more valuable product. Defining the contribution of dietary vitamin E to lean meat fatty acid profiles, postmortem pH decline, and water-holding capacity needs further study.

	Footnotes

 
¹ Purdue University Agricultural Research Programs Journal Paper.

² Corresponding author: dgerrard{at}purdue.edu

Received for publication October 6, 2005. Accepted for publication May 4, 2006.

	LITERATURE CITED

Top Abstract INTRODUCTION MATERIALS AND METHODS RESULTS DISCUSSION IMPLICATIONS LITERATURE CITED

 


Asghar, A., J. I. Gray, A. M. Booren, E. A. Gomaa, M. M. Abouzied, E. R. Miller, and D. J. Buckley. 1991a. Effects of supranutritional dietary vitamin E levels on subcellular deposition of alpha-tocopherol in the muscle and on pork quality. J. Sci. Food Agric. 57:31–41.

Asghar, A., J. I. Gray, E. R. Miller, P. K. Ku, and A. M. Booren. 1991b. Influence of supranutritional vitamin E supplementation in the feed on swine growth performance and deposition in different tissues. J. Sci. Food Agric. 57:19–29.[CrossRef]

Bowker, B. C., E. J. Wynveen, A. L. Grant, and D. E. Gerrard. 1999. Effects of electrical stimulation on early postmortem muscle pH and temperature declines in pigs from different genetic lines and halothane genotypes. Meat Sci. 53:125–133.[CrossRef]

Bramley, P. M., I. Elmadfa, A. Kafatos, F. J. Kelly, Y. Manios, H. E. Roxborough, W. Schuch, P. J. A. Sheehy, and K. H. Wagner. 2000. Vitamin E. J. Sci. Food Agric. 80:913–938.[CrossRef]

Buckley, D. J., P. A. Morrissey, and J. I. Gray. 1995. Influence of dietary vitamin E on the oxidative stability and quality of pig meat. J. Anim. Sci. 73:3122–3130.[Abstract]

Cannon, J. E., J. B. Morgan, J. Heavner, F. K. Mckeith, G. C. Smith, and D. L. Meeker. 1995a. Pork quality audit: A review of the factors influencing pork quality. J. Muscle Foods. 6:369–402.

Cannon, J. E., J. B. Morgan, G. R. Schmidt, R. J. Delmore, J. N. Sofos, G. C. Smith, and S. N. Williams. 1995b. Vacuum-packaged precooked pork from hogs fed supplemental vitamin E: Chemical, shelf-life and sensory properties. J. Food Sci. 60:1179–1182.[CrossRef]

Cannon, J. E., J. B. Morgan, G. R. Schmidt, J. D. Tatum, J. N. Sofos, G. C. Smith, R. J. Delmore, and S. N. Williams. 1996. Growth and fresh meat quality characterisitics of pigs supplemented with vitamin E. J. Anim. Sci. 74:98–105.[Abstract]

Channon, H. A., and G. R. Trout. 2002. Effect of tocopherol concentration on rancidity development during frozen storage of a cured and uncured processed pork product. Meat Sci. 62:9–17.[CrossRef]

Cheah, K. S., A. M. Cheah, and D. I. Krausgrill. 1995. Effect of dietary supplementation of vitamin E on pig meat quality. Meat Sci. 39:255–264.[CrossRef]

Corino, C., G. Oriani, L. Pantaleo, G. Pastorelli, and G. Salvatori. 1999. Influence of dietary vitamin E supplementation on "heavy" pig carcass characteristics, meat quality, and vitamin E status. J. Anim. Sci. 77:1755–1761.[Abstract/Free Full Text]

Den Hertog-Meischke, M. J. A., F. J. M. Smulders, J. H. Houben, and G. Eikelenboom. 1997. The effect of dietary vitamin E supplementation on drip loss of bovine Longissimus lumborum, Psoas major and semitendinosus muscles. Meat Sci. 45:153–160.[CrossRef]

Eikelenboom, G., A. H. Hoving-Bolink, I. Kluitman, J. H. Houben, and R. E. Klont. 2000. Effect of dietary vitamin E supplementation on beef colour stability. Meat Sci. 54:17–22.[CrossRef]

Faustman, C., R. G. Cassens, D. M. Schaefer, D. R. Buege, S. N. Williams, and K. K. Scheller. 1989. Improvement of pigment and lipid stability in Holstein steer beef by dietary supplementation with vitamin E. J. Food Sci. 54:858–862.

Fuhrmann, H., and H. P. Sallmann. 1996. Phospholipid fatty acids of brain and liver are modified by alpha-tocopherol and dietary fat in growing chicks. Br. J. Nutr. 76:109–122.[CrossRef][Medline]

Gray, J. I., E. A. Gomoa, and D. J. Buckley. 1996. Oxidative quality and shelf life of meats. Meat Sci. 43:S111–S123.

Gray, J. I., and A. M. Pearson. 1987. Rancidity and warmed-over flavor. Adv. Meat Res. 3:221–269.

Guo, G., B. T. Richert, J. R. Burgess, D. M. Webel, D. E. Orr, M. Blair, G. E. Fitzner, D. D. Hall, A. L. Grant, and D. E. Gerrard. 2006. Effects of dietary vitamin E and fat supplementation on pork quality. J. Anim. Sci. 84:3089–3099.[Abstract/Free Full Text]

Hasty, J. L., E. van Heughten, M. T. See, and D. K. Larick. 2002. Effect of vitamin E on improving fresh pork quality in Berkshire-and Hampshire-sired pigs. J. Anim. Sci. 80:3230–3237.[Abstract/Free Full Text]

Honikel, K. O., and C.-J. Kim. 1986. Causes of the development of PSE pork. Fleischwirtsch. 66:349–353.

Hoving-Bolink, A. H., G. Eikelenboom, J. T. M. Diepen, A. W. Jongbloed, and J. H. Houben. 1998. Effect of dietary vitamin E supplementation on pork quality. Meat Sci. 49:205–212.[CrossRef]

Jensen, C., J. Guidera, I. M. Skovgaard, H. Staun, L. H. Skibsted, S. K. Jensen, A. J. Moller, J. Buckley, and G. Bertelsen. 1997. Effects of dietary alpha-tocopheryl acetate supplementation on alpha-tocopherol deposition in porcine m. psoas major and m. longissimus dorsi and on drip loss, colour stability and oxidative stability of pork meat. Meat Sci. 45:491–500.[CrossRef]

Kerth, C. R., M. A. Carr, C. B. Ramsey, J. C. Brooks, R. C. Johnson, J. E. Cannon, and M. F. Miller. 2001. Vitamin-mineral supplementation and accelerated chilling effects on quality of pork from pigs that are monomutant or noncarriers of the halothane gene. J. Anim. Sci. 79:2346–2355.[Abstract/Free Full Text]

Lauridsen, C., S. K. Jensen, L. H. Skibsted, and G. Bertelsen. 2000. Influence of supranutritional vitamin E and copper on alpha-tocopherol deposition and susceptibility to lipid oxidation of porcine membranal fractions of M. Psoas major and M. Longissimus dorsi. Meat Sci. 54:377–384.[CrossRef]

Lin, C. F., J. I. Gray, A. Asghar, D. J. Buckley, A. M. Booren, and C. J. Flegal. 1989. Effects of dietary oils and alpha-tocopherol supplementation on lipid composition and stability of broiler meat. J. Food Sci. 54:1457–1460, 1484.[CrossRef]

Liu, Q., M. C. Lanari, and D. M. Schaefer. 1995. A review of dietary vitamin E supplementation for improvement of beef quality. J. Anim. Sci. 73:3131–3140.[Abstract]

Monahan, F. J., A. Asghar, J. I. Gray, D. J. Buckley, and P. A. Morrissey. 1994a. Effect of oxidized dietary lipid and vitamin E on the colour stability of pork chops. Meat Sci. 37:205–215.[CrossRef]

Monahan, F. J., D. J. Buckley, J. I. Gray, P. A. Morrissey, A. Asghar, T. J. Hanrahan, and P. B. Lynch. 1990. The effect of dietary vitamin E on the stability of raw and cooked pork. Meat Sci. 27:99–108.

Monahan, F. J., J. I. Gray, A. Asghar, A. Haug, G. M. Strasburg, D. J. Buckley, and P. A. Morrissey. 1994b. Influence of diet on lipid oxidation and membrane structure in porcine muscle microsomes. J. Agric. Food Chem. 42:59–63.[CrossRef]

Monahan, F. J., J. I. Gray, A. M. Booren, E. R. Miller, D. J. Buckley, P. A. Morrissey, and E. A. Gomaa. 1992. Influence of dietary treatment on lipid and cholesterol oxidation in pork. J. Agric. Food Chem. 40:1310–1315.[CrossRef]

Nam, K., H. Lee, B. Min, and C. Kang. 1997. Influence of dietary supplementation with linseed and vitamin E on fatty acids, -tocopherol and lipid peroxidation in muscles of broiler chicks. Anim. Feed Sci. Tech. 66:149–158.[CrossRef]

NPPC. 1991. Procedures to Evaluate Market Hogs. 3rd ed. Natl. Pork Prod. Counc., Des Moines, IA.

NRC. 1998. Nutrient Requirements of Swine. 10th ed. Natl. Acad. Press, Washington, DC.

Offer, G., and P. Knight. 1988. The structural basis of water-holding in meat. 2. Drip losses. Dev. Meat Sci. 4:173–243.

O’Grady, M. N., F. J. Monahan, J. Bailey, P. Allen, D. J. Buckley, and M. G. Keane. 1998. Colour-stabilising effect of muscle vitamin E in minced beef stored in high oxygen packs. Meat Sci. 50:73–80.

Onibi, G. E., J. R. Scaife, I. Murray, and V. R. Fowler. 1998. Use of alpha-tocopherol acetate to improve fresh pig meat quality of full-fat rapeseed-fed pigs. J. Am. Oil Chem. Soc. 75:189–198.

Phillips, A. L., C. Faustman, M. P. Lynch, K. E. Govoni, T. A. Hoagland, and S. A. Zinn. 2001. Effect of dietary alpha-tocopherol supplementation on color and lipid stability in pork. Meat Sci. 58:389–393.

Rasmussen, A., and J. R. Stouffer. 1996. New method for determination of drip loss in pork muscles. Pages 286–287 in 42nd Int. Congr. Meat Sci. Technol., Lillehammer, Norway.

Rey, A. I., J. P. Kerry, P. B. Lynch, C. J. Lopez-Bote, D. J. Buckley, and P. A. Morrissey. 2001. Effect of dietary oils and alpha-tocopheryl acetate supplementation on lipids (TBARS) and cholesterol oxidation in cooked pork. J. Anim. Sci. 79:1201–1208.[Abstract/Free Full Text]

Sayre, R. N., and E. J. Briskey. 1963. Protein solubility as influenced by physiological conditions in the muscle. J. Food Sci. 28:675–679.[CrossRef]

Spanier, A. M., J. F. Edwards, and H. P. Dupuy. 1988. The warmed-over flavor process in beef. A study of meat proteins and peptides. Food Technol. 42:110–118.

Suman, S. P., C. Faustman, S.L. Stamer and D. C. Liebler. 2006. Hydroxynonenal-induced redox instability of porcine and bovine myoglobins at pH 5.6, 4 C. J. Agric. Food Chem. (in press).

Tarladgis, B. G., B. M. Watts, M. T. Younathan, and L. R. Dugan Jr. 1960. A distillation method for the quantitative determination of malonaldehyde in rancid foods. J. Am. Oil Chem. Soc. 37:44–48.[Medline]

Topel, D. G., J. A. Miller, P. J. Berger, R. E. Rust, F. C. J. R. Parrish, and K. Ono. 1976. Palatability and visual acceptance of dark, normal, and pale colored porcine m. Longissimus. J. Food Sci. 41:628–631.[CrossRef]

Waylan, A. T., P. R. O’Quinn, J. A. Unruh, J. L. Nelssen, R. D. Goodband, J. C. Woodworth, M. D. Tokach, and S. I. Koo. 2002. Effects of modified tall oil and vitamin E on growth performance, carcass characteristics, and meat quality of growing-finishing pigs. J. Anim. Sci. 80:1575–1585.[Abstract/Free Full Text]

Wismer-Pedersen, J. 1978. Quality of pork in relation to rate of pH change post-mortem. Food Res. 24:711–714.

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Guo, Q. Articles by Gerrard, D. E. Search for Related Content PubMed PubMed Citation Articles by Guo, Q. Articles by Gerrard, D. E.