Color Stability and Microbial Growth Relationships in Beef as Affected by Endogenous α-Tocopherol

Longissimus muscle from Holstein steers supplemented with vitamin E at 500 or 2000 mg/head/day showed less surface metmyoglobin accumulation than controls during 12 days storage at 4°C. Temperature abuse at 25°C for 24 hr increased metmyoglobin formation; vitamin E supplementation diminished the adverse effect of temperature abuse. No differences (P > 0.05) in bacterial load were observed among the 3 vitamin E treatments during storage. Sensory panelists preferred vitamin E-supplemented beef steaks in visual acceptance. Panelist assessment of discoloration correlated highly with a value and hue angle. In general, elevated α-tocopherol concentrations in beef steaks did not affect panelist assessment of meat spoilage.     

Effect of pasture vs. concentrate feeding with or without antioxidants on carcass characteristics, fatty acid composition, and quality of Uruguayan beef

Thirty Hereford steers were finished either on pasture (n=10) or concentrate (n=20) to determine dietary and antioxidant treatment effects on carcass characteristics, fatty acid composition, and quality of Uruguayan beef. Half of the steers finished on concentrate were supplemented with 1000 I.U. vitamin E head(-1) day(-1) for 100 days. Postmortem vitamin C was added to ground beef (0.05% v/w) displayed for 8 days at 2?°C. Carcasses from steers finished on concentrate had greater (P<0.05) carcass weight, conformation, degree of finishing, fat depth, and ribeye area than pasture finished animals. Carcasses from pasture-fed steers showed darker (P<0.05) longissimus color and yellower (P<0.05) fat at 24 h postmortem than concentrate-fed. Initial longissimus Warner-Bratzler shear force (WBSF) values were similar (P>0.05) between pasture- and concentrate-fed animals. However, beef from pasture-fed cattle had lower (P<0.05) WBSF values at 7 and 14 days postmortem. Longissimus α-tocopherol concentrations were greater (P<0.01) for pasture- and concentrate-fed animals that were supplemented with vitamin E compared to concentrate-fed. Steaks from pasture-fed and vitamin E supplemented cattle had similar (P>0.05) TBARS values, which were lower (P<0.05) than steaks from concentrate-fed steers during 21 days of display. Ground beef from vitamin E supplemented steers had the lowest TBARS values; whereas samples from pasture-fed animals had the lowest lipid stability with higher TBARS levels than other treatments. Vitamin C addition to ground beef did not (P>0.05) reduce lipid oxidation. Vitamin E supplementation of concentrate-fed cattle had no effect (P>0.05) on color stability of ground beef or steaks. The a(?) (redness) and b(?) (yellowness) values were higher (P<0.05) when vitamin C was added to ground beef. Longissimus fatty acid content of concentrate-fed animals was twofold greater (P<0.01) than pasture-fed. The percentages of C14:0, C16:0, and C18:1 fatty acids were higher (P<0.01) in the intramuscular fat of concentrate-fed steers, whereas pasture-fed cattle showed greater (P<0.01) proportions of C18:0, C18:2, C18:3, C20:4, C20:5, and C22:5. Total conjugated linoleic acid (CLA) and CLA isomer c9t11 were higher (P<0.01) for pasture- than concentrate-fed cattle. Vitamin E supplementation of concentrate-fed steers increased lipid stability of ground beef and steaks, but was unable to improve color stability; whereas vitamin C addition to ground beef increased color stability without altering lipid oxidation. Finishing cattle on pasture enhanced the unsaturated fatty acid profile of intramuscular fat in beef including CLA and omega-3 fatty acids.     

Dietary vitamin E supplementation effects on the color and sensory characteristics of enhanced beef steaks

The objective of this study was to evaluate the effects of dietary vitamin E supplementation on characteristics of enhanced beef cuts during retail display. Twelve steers were fed either a control (E-) diet or a diet supplemented with dl-alpha tocopheryl acetate (E+) for 117 days prior to slaughter. Paired strip loins, clods, and inside rounds served as the control (C) or were pumped (P) to 110% of raw weight to contain 0.4% sodium chloride and 0.4% phosphate on a finished weight basis. Steaks were cut (2.5 cm) for sensory evaluation and retail display. No flavor or texture differences existed in strip steaks due to vitamin E. Enhanced steaks were more tender, juicy and salty than controls, however they discolored more rapidly than did controls. Steaks from supplemented cattle were slightly, but significantly, less discolored, indicating that vitamin E may provide some improvements in color stability of enhanced meat products. Vitamin E supplementation may improve short term color stability (up to 2 days in display) of retail beef enhanced by injection of a salt-phosphate solution.     

Improvement of Color and Lipid Stability in Beef Longissimus with Dietary Vitamin E and Vitamin C Dip Treatment

The effects of dietary vitamin E supplementation and vitamin C dip treatment on color and lipid stability in longissimus muscle from Holstein and crossbred beef steers were studied during 16 days of display at 4°C. Dietary vitamin E supplementation retarded metmyoglobin formation of the meat and highly suppressed lipid oxidation compared to the control. Holstein longissimus showed higher metmyoglobin formation than crossbred beef longissimus. Dip treatment with a vitamin C solution was effective in maintaining stability of beef color and lipid.     

Effects of muscle α-tocopherol level and surface microbiological contamination on retail caselife of fresh beef from the US, Japan and Australia

This study evaluated effects of dietary supplementation of vitamin E (1000 IU vitamin E/daily for 100 days prior to harvest) to fed cattle on retail caselife performance of fresh US beef in an export market (Japan). Economic performance (monetary losses associated with color deterioration) for US beef from vitamin E supplemented cattle vs beef from non-vitamin E supplemented cattle was contrasted. An additional, controlled study was performed to compare muscle α-tocopherol concentrations, color changes and microbiological growth for fresh beef derived from vitamin E supplemented US cattle and fresh beef from cattle with an unknown history, but from other countries. Australian strip loin steaks had the highest muscle α-tocopherol concentrations (4.6 μg/g tissue), followed by US strip loin steaks derived from vitamin E supplemented cattle (3.4 μg/g tissue) and Japanese strip loin steaks (2.8 or 2.5 μg/g tissue). US strip loin steaks from non-vitamin E supplemented cattle had the lowest (p<0.05) α-tocopherol levels (1.7 μg/g tissue). Aerobic plate counts and total coliform counts were generally low at 0 days of retail display, and they changed similarly among treatments over 6 days of display, regardless of the country of origin of the beef. Vitamin E supplementation of US cattle reduced total Japanese retail store losses due to discoloration of US beef, in yen, by 5.2 percentage points (p<0.05), saving Japanese retailers US $0.24/kg. Data suggest that US beef-normally perceived, in Japan, to discolor more quickly in the retail display case than beef from Australia-would compete more favorably, in shelf-life, with beef from other countries if it was derived from cattle that had been fed supplemental vitamin E.     

Effect of dietary vitamin E supplementation for one week before slaughter on drip, colour and lipid stability during display in Japanese Black steer beef

Effects of dietary vitamin E supplementation for one week on drip, colour and lipid stability in raw beef steaks were studied. Four Japanese Black steers were fed no supplemental vitamin E and four were supplemented with 5000 mg of dl-α-tocopherol per animal daily for one week before slaughter. Steak samples from psoas major and longissimus thoracis muscles were over-wrapped with PVC film and displayed under fluorescent lights at 4 °C for 10 days. Drip loss percentages, L(?), a(?) and b(?) values, metmyoglobin percentages, and 2-thiobarbituric acid reactive substances values were determined at day 1, 4, 7 and 10. Dietary vitamin E supplementation increased (p < 0.01) α-tocopherol concentration in the plasma, liver and muscles. Vitamin E supplementation reduced (p < 0.001) drip loss compared to the control. Vitamin E supplementation maintained (p < 0.001) redness and retarded (p < 0.01) metmyoglobin formation in beef steak from day 4 to day 10 of display compared to the control. Vitamin E supplementation delayed (p < 0.001) lipid oxidation during 10 days of display compared to the control. The data indicated that dietary vitamin E supplementation for one week prior to slaughter improved lipid stability better than drip and colour stability in beef steak during 10 days of display.     

Flavor Constituents of Beef as Influenced by Forage- and Grain-Feeding

Hereford yearling steers (N= 144) were alloted to one of three pasture systems: tall fescue, smooth bromegrass-red clover or orchardgrass-red clover. After the grazing period, steers were finished in drylot and then serially slaughtered at 0, 56, 84 and 112 days. Carcass quality grades and yield grade numbers increased when steers were fed grain up to 112 days. Tenderness of loin steaks increased up to 84 days, after which no improvements were observed. Sensory panel scores for grassy flavor of steaks and ground beef decreased up to 112 days. Fifty-three compounds were identified in the volatiles of melted subcutaneous fat by direct sampling-gas chromatography/mass spectro-metry. The major differences between volatiles from fat of forage-fed compared to grain-fed steers were the higher concentrations of 2,3-octanedione and various diterpenoids present in the samples of the forage-fed animals.     

Colour stability, under simulated retail display conditions, of M. longissimus dorsi and M. semimembranosus from steers given long-term daily exercise and supplemented with vitamin E

The objective was to determine if exercise has a negative impact on the colour stability of beef and if dietary vitamin E (VE) supplementation could counteract any negative effect. Steers were not exercised or were walked 4.41km/day for 18 weeks. Within exercise treatment animals consumed, on average, either 450 or 1050IU/day of VE. Muscle α-tocopherol increased (P=0.004) from 2.35 to 3.15μg/g with VE supplementation. Following ageing M. longissimus dorsi (LD) and M. semimembranosus (SM) steaks were packaged under 80%O(2):20%CO(2) and stored at 4°C. The LD of exercised steers was more red and more saturated (both P<0.05) after 0 and 2 days of storage than LD of unexercised steers. While redness of both muscles decreased over the display period, LD retained a higher redness than SM from day 2 to 7 (P<0.05). Colour shelf-life of LD was extended by 0.75 days, to 3.25 days, due to VE supplementation.     

Beef quality attributes as affected by increasing the intramuscular levels of vitamin E and omega-3 fatty acids

In order to investigate the effects of increasing beef n-3 fatty acid content and the protective effects of vitamin E antioxidant activity on meat quality characteristics, 80 feedlot steers were fed 4 different diets (control, high vitamin E, 10% ground flaxseed or high vitamin E-10% ground flaxseed). While dietary treatments had no effect (P > 0.05) on meat composition or tenderness values, the increase in oxidation products was lower (P = 0.046) in meat from vitamin E supplemented steers and higher (P = 0.006) in meat from flaxseed fed animals. The increase in α-tocopherol tissue levels (P < 0.001) in meat from animals fed flaxseed and increased dietary vitamin E resulted in the lowest drip loss values (P = 0.013). As expected, display time had a large effect on retail traits in both steaks and patties (P < 0.001). While retail traits of steaks were not affected by the dietary treatments (P > 0.05), feeding flaxseed decreased (P < 0.05) ground beef retail scores, which were not corrected by higher levels of dietary vitamin E. Finally, although no effect (P > 0.05) was observed among treatments for sensory attributes in steaks, the correlations of a combined n-3:α-tocopherol ratio against retail and sensory attributes (P < 0.05) suggest that increased n-3 fatty acids levels require increased dietary antioxidants, such as vitamin E to avoid negative effects on meat quality from a loss in oxidative stability.     

Effect of Prerigor Pressurization on the Retail Characteristics of Beef

Loin steaks were obtained from eight utility cows and ground beef from the bottom round of four choice steers. One side was randomly assigned to be prerigor pressurized (PRP) and the other side served as control (CON). Steaks and ground beef were displayed under simulated retail conditions for 5 and 3 days, respectively. PRP significantly improved lean color of the steaks for the first 4 days of display period. PRP steaks were significantly less discolored at the 5th day. No significant difference for any of the measured traits was observed for samples of ground beef. PRP had no detrimental effect on the case-life of steaks or ground beef.     

Effect of Cooking Method,Distiller's Grains,and Vitamin E Supplementation on the Vitamin Content of Value Cuts from Beef Steers Fed Wet Distiller's Grains and Solubles and Supplemental Vitamin E

ABSTRACT: Vitamin E, thiamin, riboflavin, niacin, vitamin B₆, and vitamin B₁₂ concentrations of flat iron steaks and petite tenders from steers fed finishing rations containing 0% and 40% corn wet distiller's grains and solubles (WDGS) with and without supplemental vitamin E were determined. Feeding treatment groups were: 0% WDGS with basal vitamin E, 0% WDGS with supplemental vitamin E (500 IU daily), 40% WDGS with basal vitamin E, and 40% WDGS and supplemental vitamin E. Cattle can be fed 40% WDGS diets more economically than corn diets. The incorporation of 40% WDGS, with and without vitamin E, was hypothesized to have little effect on the vitamin concentrations of these value meat cuts. Flat iron steaks and petite tenders were broiled and/or grilled to 70 °C internal temperature. Mean cooking yields ranged from 68.7% to 78.2%. The majority of the vitamin concentrations of broiled and of grilled meat were significantly different (P < 0.05) from that of raw meat. Vitamin E concentrations of raw and cooked meat from steers that received supplemental vitamin E were significantly higher (P < 0.05) than those fed basal vitamin E. Significant differences in thiamin, riboflavin, vitamin B₆, and vitamin B₁₂ concentrations in raw flat iron steaks and in vitamin B₆ in raw petite tenders were observed by WDGS. Thiamin, vitamin B₆, and vitamin B₁₂ concentrations of broiled flat iron steaks were significantly different (P < 0.05) than grilled. A few differences in vitamin concentrations of the flat iron steaks and petite tenders were observed by WDGS, vitamin E supplementation, and cooking treatments, but most of the vitamin concentrations were statistically similar.     

Consumer attitudes towards beef and acceptability of enhanced beef

The objective of this study was to evaluate consumer quality characteristics of enhanced steaks and roasts derived from cattle supplemented with vitamin E during finishing, and to assess the attitudes of these consumers towards beef. Twelve steers were fed either a control (E-) diet or a diet supplemented with dl-alpha tocopheryl acetate (E+). Paired strip loins and rounds were either used as controls (C) or were pumped (P) to 110% of raw weight to contain 0.4% sodium chloride and 0.4% sodium tripolyphosphate in the final product. Consumers (n=103) evaluated roasts and steaks for juiciness, tenderness, saltiness, and overall acceptability on a 9-point hedonic scale. Enhanced steaks and roasts were more acceptable than non-enhanced controls; E+ steaks were less acceptable than E- steaks. A beef quality questionnaire revealed that color, price, visible fat and cut were the most important factors underlying beef steak purchase, while tenderness, flavor and juiciness were weighted most heavily with regard to eating satisfaction.     

DISPLAY LIFE OF FRESH BEEF CONTAINING DIFFERENT LEVELS OF VITAMIN E AND INITIAL MICROBIAL CONTAMINATION

Strip loins from beef cattle fed diets supplemented or not supplemented with α-tocopheryl acetate (vitamin E; 500 IU·animal⁻¹·d^-1) were fabricated into steaks inoculated at three initial levels (1.7 to 1.9; 2.3 to 2.5; 6.4 to 7.1 log CFU/cm²) of bacterial contamination (from over aged retail steaks) and evaluated for psychrotrophic plate counts (PPC), overall appearance and color during 6 days of simulated retail display (0 to 4C). Initial contamination affected changes in PPC (P < 0.05) during display, while the highest level of initial contamination eliminated benefits of high vitamin E concentrations on product color within 4 days of retail display. However, increased vitamin E concentrations in steaks were associated with higher (P < 0.05) CIE a* values appearance scores when the level of initial contamination was less than 2.5 CFU/cm². Results indicated that vitamin E supplementation does not mask high levels of bacterial contamination.     

Reducing Postmortem Aging Time of Beef with Electrical Stimulation

Two studies (Study 1 = 23 forage-fed steers; Study 2 = 20 grain-fed steers and heifers) were conducted to determine relationships of electrical stimulation (ES) and/or postmortem aging (PA) to tenderness of beef. For Study 1, steaks from ES sides had lower (P < 0.05) Warner-Bratzler shear (WBS) values than steaks from not-ES sides for each PA period. In addition, the percentage reduction in WBS values was greater for the steaks from the ES-Day 2 group (–29.5%) than for steaks from even the longest PA period (14 days) from the not-ES group (–25.8%). For Study 2, during the fist three PA periods (1, 2 and 5 days), ES resulted in more desirable (P < 0.05) flavor ratings (Day l), higher (P < 0.05) tenderness ratings and lower (P < 0.05) WBS values (Day 1, 2, 5) and more desirable (P < 0.05) overall palatability ratings (Day 1, 2). During the last three PA periods (8, 11 and 14 days), ES resulted in higher (P < 0.05) tenderness ratings (Day 8), lower (P < 0.05) juiciness ratings (Day 11, 14) and lower (P < 0.05) WBS values (Day 8). Based on these results, ES had the greatest impact on beef palatability if the period of aging was 8 days or less; with additional aging time, ES effects on palatability were negated. When each treatment (ES, not-ES) was divided into two groups based on median tenderness ratings for the not-ES group, ES had the greatest impact on those carcasses in the “tough” group while ES had little impact on those carcasses in the “tender” group. ES will accelerate the postmortem aging of beef but the aging time reduction and extent of ultimate tenderization appears to be affected by the inherent tenderness of the beef.     

The Effect of Ethoxyquin and Vitamin E Supplementation on the Display Life of Beef Steaks

Steaks from cattle supplemented with 150 ppm ethoxyquin, an antioxidant, plus 150 or 250 IU of vitamin E per day, or 500 IU of vitamin E per day were evaluated for display life versus control steaks. Readings of a* indicated supplementation with vitamin E with or without ethoxyquin increased the display life of steaks compared with the controls. Thiobarbituric acid reactive substances (TBARS) were measured following 0, 3, and 7 d of retail display. All treatments had similar TBARS values on Day 0. On Days 3 and 7 control steaks had more lipid oxidation than the other treatments, with 500 IU of vitamin E having the least amount of oxidation. These data indicate supplementation with vitamin E improved the display life of steaks with no apparent interaction between vitamin E and ethoxyquin.     

SENSORY ATTRIBUTES AND RETAIL DISPLAY CHARACTERISTICS OF PASTURE- AND/OR GRAIN-FED BEEF AGED 7,14 OR 21 DAYS

Strip loin steaks were removed from steer carcasses fed on; (1) wheat-rye-grass pasture only, (2) wheat-ryegrass pasture followed by grain feeding, or (3) grain feeding. The steaks were analyzed for sensory panel attributes, Warner-Bratzler shear force and storage and display life. Steaks from pasture-fed steers were similar (P>.05) to steaks from grain-fed steers in sensory tenderness and connective tissue amount. Steaks from pasture-fed steers had similar (P>.05) shear force values to steaks from grain-fed steers. Off flavor incidence was greater (P<.05) in steaks from steers on pasture only than from steers on grain and pasture/grain. No differences (P>.05) due to treatment were found in visual color and discolor scores. The C.I.E. a* values showed steaks from steers fed pasture only and pasture/grain retained higher (P<.05) redness values than steaks from steers grain-fed during the 10 day display period. The results indicate pasture finishing systems could be as effective in maintaining beef tenderness and color shelf-life characteristics as grain finishing systems.     

Display Life and Internal Cooked Color of Ground Beef from Vitamin E-Supplemented Steers

The retail display life of fresh ground meat and the internal color of patties cooked to four endpoint temperatures (55, 65, 71, and 77°C) were determined for ground beef (10% fat) from vitamin E-supplemented (500 and 2000 IU) or nonsupplemented steers. Vitamin E supplementation increased (P < 0.05) the retail dissolve life of the meat by 12 and 42 lir for 500 and 2000 IU, respectively Vitamin E did not akect (P > 0.05) internal cooked color or expressible juice color of the patties, and it did not cause premature browning or persistent redness. Increased levels of vitamin E supplementation decreased (P < 0.05) TBA values but had no effect on total reducing activity or oxidation-reduction potential.     

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.     

Determining Acceptance of Domestic Forage- or Grain-Finished Beef by Consumers from Three Southeastern U.S. States

ABSTRACT:  Twenty-six crossbred steers were finished either on ryegrass ( Lolium multiflorum Lam.) forage (FOR, n = 13) or a primarily grain diet containing 85% corn, 7.5% cotton-seed hulls, and 7.5% vitamin/mineral/urea supplement (GRAIN, n = 13) to determine the consumer acceptance of forage- and grain-finished beef in 3 southeastern states. Shear force values were not affected by finishing treatment ( P = 0.62), and both total and heat-labile collagen content means of the FOR and GRAIN steaks were similar ( P = 0.88 and 0.14, respectively). Ribeye steaks were cut from wholesale roasts after 14 d of aging and were evaluated by 1250 consumers in a retail study and 87 consumers in a take-home study across Alabama, Tennessee, and Kentucky. Retail consumers rated GRAIN steaks higher for flavor ( P = 0.001), overall palatability ( P = 0.001), and price per kg ( P = 0.001) compared to FOR steaks, but consumers in the take-home study found no differences in any of the 3 traits. Consumers that preferred FOR steaks were willing to pay an average of $2.38/kg and $5.61/kg more for FOR steaks than for GRAIN steaks in the retail and take-home studies, respectively ( P = 0.001). Among consumers surveyed across all 3 states, 34.1% of retail consumers and 54.0% of take-home consumers preferred FOR steaks. At least one-third of the consumers surveyed preferred the taste of forage-finished beef and were willing to pay a premium.