Color Stability Of Beef Research Articles

Effect of packaging cycle on the colour stability of six beef muscles stored in a modified atmosphere mother pack system with oxygen scavengers

SummaryThe effect of two packaging cycles (double flush, 28 s; triple flush, 55 s) on the colour stability of beef in retail trays with oxygen scavengers within a mother pack (50% CO2/50% N2) was assessed. Steaks from six muscles, M. longissimus dorsi, M. psoas major, M. semimembranosus, M. gluteus medius, M. semitendinosus and M. biceps femoris, were examined. The residual oxygen in mother packs was unaffected by the packaging cycle and was below 0.1% in trays for both treatments for up to 6 weeks storage. After storage for 2, 4 or 6 weeks, the packaging cycle had no effect on colour stability (HunterLab a and hue) during 96 h of display. Panel scores for visual and odour acceptability of packaged steaks were generally as high as for fresh controls. Based on reflectance measurements (R630 –R580), M. longissimus dorsi and M. semitendinosus steaks had a display life of 4 days after storage for up to 6 weeks. M. psoas major and M. semimembranosus steaks had a display life as long as fresh controls after 4 weeks, whereas M. gluteus medius and M. biceps femoris steaks had a shorter display life than fresh steaks. It was concluded that the double‐flush cycle could be used without affecting the colour or acceptability of beefsteaks.

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.

Effect of Slaughter Age on Beef Color Stability during Display of Four Muscles from Japanese Black Steers

Effect of slaughter age (24, 28 and 38 months of age) on beef color stability during display of m. serratus ventralis, m. psoas major, m. semitendinosus and m. longissimus thoracis from Japanese Black steers was studied. Steak samples from muscles were over-wrapped with PVC film and displayed under fluorescent lights at 4°C for 12 days. Percentages of metmyoglobin of steak samples were determined at days 0, 3, 6, 9 and 12. The percentage of metmyoglobin of m. psoas major at day 3 of display in the 24 months group was lower (p<0.05) than that in the 38 months group. The percentage of metmyoglobin of m. semitendinosus at day 6 of display in the 38 months group was higher (p<0.05) than that in the other groups. The percentage of metmyoglobin of m. longissimus thoracis at day 3 of display in the 24 months group was lower (p<0.01) than that in the other groups. The percentage of metmyoglobin of m. longissimus thoracis at day 6 (p<0.01), 9 (p<0.01) and 12 (p<0.05) of display in the 38 months group were higher than those in the other groups. Crude fat concentration in m. longissimus thoracis increased (p<0.05) after 28 months of age. α-Tocopherol concentration in m. serratus ventralis in the 38 months group was higher (p<0.001) than that in the other groups. In m. psoas major the α-tocopherol concentration in the 38 months group was higher (p<0.05) than that in the 24 months group. The α-tocopherol concentration in m. longissimus thoracis increased (p<0.001) with age. These results suggested that in spite of increase in both the crude fat and the α- tocopherol concentrations in m. longissimus thoracis, the beef color stability during display became short with age. (Asian-Aust. J. Anim. Sci. 2003. Vol 16, No. 9 : 1364-1368)

Effects of Carbon Monoxide Packaging on Color and Lipid Stability of Irradiated Ground Beef

ABSTRACT: The effects of packaging atmosphere (aerobic, vacuum, or modified atmosphere with carbon monoxide) on ground beef treated with ionizing radiation were investigated. Measurements of color (CIE L*, a*, b*), lipid oxidation (TBA value), and sensory quality were conducted during 28 d of storage at refrigerated (0 to 2°C) temperatures. Irradiation significantly (p&gt; 0.001) decreased color scores and increased TBA and off‐odor scores. The MAP + CO treatments increased the L* and a* values (p &lt; 0.001), regardless of irradiation dose. The TBA values for MAP + CO‐packaged samples were well below the levels considered “rancid” (about 1.0). In addition, sensory scores indicated minimal production of irradiation off‐odors with MAP + CO packaging.

Pasture and Grain Finishing Affect the Color Stability of Beef

ABSTRACT: We determined the effect of pasture feeding (P0) or sorghum feeding with 2500 IU/head/d; (G2500) or without (G0) vitamin E supplementation on the color stability of gluteus medius (GM), longissimus lumborum (LL) and semimembranosus (SM). Diets did not affect the total pigment concentration of the muscle. Color stabilities were G2500 &gt; P0 &gt; G0 for fresh GM and SM and G2500 &gt; G0 &gt; P0 for fresh LL. Color stabilities of aged beef from the P0 and G2500 treatments were similar and higher than those from unsupplemented animals. Color stability of minced beef ranked as: P0 aged &gt; G0 and G2500 fresh &gt; P0 fresh &gt; G0 and G2500 aged.

Effect of dietary β-carotene supplementation on beef color stability during display of two muscles from Japanese Black steers

Effect of dietary β-carotene supplementation (7500 mg/head/day) for 28 days prior to slaughter on beef color stability during display of M. semimembranosus (SM) and M. longissimus lumborum (LL) from Japanese Black steers was studied. Steak samples from two muscles were over-wrapped with PVC film and displayed under fluorescent lights at 4°C for 12 days. Metmyoglobin percentages of steak samples were determined at days 0, 3, 6, 9 and 12. The β-carotene concentration in both muscles was increased ( P<0.001) by dietary β-carotene supplementation. Color display-life of muscles was calculated by the metmyoglobin threshold method based on a threshold value of 20% metmyoglobin. Color display-lives of SM and LL were extended 1.5 and 3 days by dietary β-carotene supplementation, respectively.

Maximizing desirable ground beef color with cold storage and display temperatures (2002)

This study evaluated the combined effects of storage temperature, storage time, display temperature, display time, and fat level on ground beef color. Storage at 32°F minimized discoloration during display compared to storage at 40° and 48°F. Storage up to 12 days at 32°F did not affect ground beef color stability, whereas prolonged storage at 40° and 48°F increased discoloration dramatically. When storage was at 32°F, sales loss was 0.4%, compared to 62% at 48°F. Fat level did not influence discoloration. The use of 32°F during storage and display is essential for maximizing ground beef color life.

The influence of storage temperature and storage time on color stability, retail properties and case-life of retail-ready beef

Steaks from three different muscles were either vacuum or carbon dioxide packed and stored for up to 24 weeks at three different storage temperatures (−1.5, 2, or 5 °C). Following storage, they were displayed for up to 30 h. CIE color coordinates, the oxidative states of myoglobin and pH were measured and muscle color, surface discoloration, retail appearance, and odor were evaluated prior to storage and during display (0, 1, 2, 4, 6, 24 and 30 h), and/or immediately prior to and following display. Prior to display, pH was negatively related to duration of storage, and samples stored at −1.5 °C had the highest and samples stored at 5 °C, had the lowest pH. Perception of muscle color was influenced by duration of storage and display, but lower storage temperatures appeared to produce a stabilizing effect. Both lightness of muscle color and deoxymyoglobin content were apparently not influenced by storage temperature or duration of storage or display. Both oxymyoglobin (OMB) and redness, as defined by CIE a* values, were lost progressively during storage and display, but this loss was progressively lower as storage temperature decreased. Yellowness of muscle color, as defined by CIE b* values, generally decreased as storage was prolonged, and this decrease was observed more quickly at higher storage temperatures. Surprisingly, b* values were not related to duration of display. Both surface discoloration and metmyoglobin (MMB) content increased progressively during storage and display. Samples stored at 5 °C displayed the most surface discoloration, while samples stored at −1.5 °C contained the least MMB and displayed the least surface discoloration. Retail appearance deteriorated progressively during storage in all samples stored at 2 and 5 °C and in samples stored at −1.5 °C, which were displayed for at least 24 h. Retail appearance also deteriorated progressively during display in samples stored at −1.5 and 2 °C for three weeks or longer and in samples stored at 5 °C for 0 to 15 and 24 weeks. In unstored samples, samples to be stored at −1.5 °C generally received the lowest retail appearance scores, but after prolonged storage and display, samples stored at −1.5 °C received higher retail appearance scores than samples stored at 5 °C, particularly when samples were stored for 12 weeks or longer and displayed for 1 h or more. Odor deteriorated progressively during storage when measured both prior to display and after 30 h of display. In samples stored for three weeks or longer, samples stored at −1.5 °C generally received the lowest odor scores and were perceived to have the least prevalent off-odors. Samples stored at −1.5 °C maintained a retail case-life of 30 h, when stored for up to 17 weeks, while samples stored at 2 and 5 °C maintained a retail case-life of 30 h, when stored for only eight and seven weeks, respectively. Consequently, storage life can be more than doubled by storage at subzero temperatures (−1.5 °C).

Evaluation of carbon monoxide treatment in modified atmosphere packaging or vacuum packaging to increase color stability of fresh beef

Our goal was to obtain > 21 days red color stability for carbon monoxide (CO)-treated beef steaks in vacuum packaging (VP). In preliminary tests, pretreatment for 24 h in a 5% CO modified atmosphere package (MAP) was needed to maintain redness after re-packaging in VP. Pressure pretreatment with 5% CO for 2 h developed redness, but was impractical for large-scale application. Color stability and microbial load were then compared after treatment of steaks in 5% CO-MAP for 24 h, then VP; 100% CO-MAP for 1 h, then VP; steaks and ground beef in 0.5% CO-MAP; and steaks and ground beef in polyvinyl chloride (PVC) wrap. Steaks remained red for 5, 6, 8 and <1-week storage at 2°C, respectively. Steaks microbial load exceeded spoilage levels (>10 6cfu/cm 2) at 5, 6, 7 and <2-weeks, respectively. Thus, extended color stability in VP was achieved by pretreatment with 5% CO for 24 h or 100% CO for 1 h.

Antioxidant status affects color stability and tenderness of calcium chloride-injected beef.

The objectives of this study were to determine whether vitamin E supplementation influences color and tenderness of beef injected with calcium chloride. Market heifers (n = 12) were fed a standard finishing diet with minimal levels of vitamin E (NE group). Another 12 market heifers were fed the NE diet with the inclusion of 1,000 IU/d of DL-alpha-tocopherol per animal for the last 125 d on feed (E group). Animals were slaughtered after 125 d on the diets and upon reaching an ultrasound backfat thickness > 10 mm. Half of the longissimus muscles from each treatment group (NE and E) were pumped to 10% over the original weight with 250 mM CaCl2 (Ca) at 24 h postmortem. Remaining muscles (NE and E) were pumped to 10% over the original weight with water (NC) at 24 h postmortem. After equilibrating overnight, steaks (2.54 cm) were overwrapped with O2-permeable film and stored for 7 d after injection. Hunter "L," "a," and "b" values were obtained each day of storage. Trained panelists evaluated color on d 1, 4, and 7 after injection. 2-Thiobarbituric acid-reactive substances (TBARS) values were measured on d 1 and 7 after injection. Warner-Bratzler (W-B) shear force values and trained sensory panel evaluations at 1, 3, and 7 d after injection were obtained. Immunoblotting techniques were used to monitor the 30-kDa degradation product of troponin-T at 1, 3, and 7 d after injection. At 4 d after injection, E/Ca steaks were the least discolored (P < 0.05). The E/Ca steak TBARS values were not significantly different from values for NE/NC steaks at 7 d after injection, whereas NE/Ca steaks had greater (P < 0.05) TBARS values after 7 d following injection compared with all other groups. Treatment with Ca resulted in higher off-flavor scores (P < 0.05). The E/Ca samples had the most rapid tenderization and proteolysis of all treatment groups. Warner-Bratzler shear values were lower in the E/Ca samples than in the E/NC samples at 1, 3, and 7 d after injection (P < 0.05). No difference in shear force was noted between NE/Ca and NE/NC samples at any time point. No difference in sensory tenderness was noted between NE/Ca and NE/NC samples at 1 d after injection. However, Ca-injected samples (NE/Ca and E/Ca) were rated as being significantly more tender than their uninjected counterparts (NE/NC and E/NC) at 3 and 7 d after injection. Injection of CaCl2 may result in more rapid and immediate tenderization if beef from animals supplemented with vitamin E is used. Vitamin E incorporation into muscle tissue may potentiate the action of exogenously added calcium by protecting the calpains from oxidation.

Effect of dietary vitamin E supplementation, fat level and packaging on colour stability and lipid oxidation in minced beef

The effect of addition of vitamin E (2025 IU animal −1 day −1) to the diet of beef bulls on the colour stability and lipid oxidation of minced beef was studied. Control and enriched diets were provided for the last 136 days before slaughter. Batches of freshly minced meat were prepared containing approximately 1.3 and 22.2 wt% fat, respectively. Half of the samples of minced meat from control (CON) and supplemented (SUP) beef were packaged on trays with oxygen-permeable over wraps and half in modified atmosphere (MA) packs (initial gas mixture: O 2/CO 2/N 2=65/25/10). The minced beef was stored for 10 days at 7°C in an illuminated environment. The SUP meat at both fat levels was consistently more resistant to lipid oxidation than was the CON meat. The additional vitamin E had a greater anti-oxidant effect for the lean meat product. MA packaging in comparison to the oxygen-permeable foil over-wrap did increase lipid oxidation, the effect being most pronounced for the CON meat. A sensory panel considered the colour of the lean SUP meat during display as more attractive than that of lean CON meat, irrespective of packaging. A similar effect was observed occasionally for the relatively fat minced meat. These subjective findings were confirmed by objective assessment of colour. The stability of the colour of the MA packed meat was better than that of the oxygen-permeable foil-wrapped meat. Microbial growth patterns of enriched and control meat were similar. MA packaging retards the multiplication of mesophilic aerobic spoilage micro-organisms and Enterobacteriaceae.

Effect of dietary vitamin E supplementation on beef colour stability

The effect of dietary vitamin E upon colour, waterholding capacity, bacterial growth and lipid oxidation of beef longissimus thoracis (LT) and psoas major (PM) muscle were examined during aerobic display of fresh muscle and after aging in vacuum for 26 days. Forty crossbred beef bulls received a whole crop corn silage, supplemented with concentrate. Twenty bulls were each supplemented with 2025 mg vit E per day (added to the concentrate) for 136 day prior to slaughter and compared with non-supplemented control animals ( n=20). In fresh LT muscle drip loss did not differ between treatment groups, while in PM muscle drip loss was significantly higher for the supplemented group. The treatment did not affect bacterial growth in fresh and aged muscles. Lipid oxidation during 12 day storage of fresh muscle was significantly lower for the supplemented group, as indicated by the lower TBA-values. No effect of the vitamin E treatment was observed on a ∗ -values of both fresh and aged LT muscle during display for 8 and 5 days, respectively. In PM muscle, supplemented beef had lower a ∗ -values in fresh (at day 1) and aged (at days 1 and 2) muscle, due to a lower oxygenation. The reason for this lower oxygenation is unclear. After aging, colour stability was decreased and more variable than in fresh muscle. Similar results were obtained when the difference in reflection values at 630 and 580 nm (R630-580), instead of the a ∗ value, was used as a parameter for colour stability. The absence of an effect of vit. E on the rate of discoloration, might possibly be explained from the observation that α-tocopherol levels in control muscle were relatively high (LT: 2.1 and PM: 3.2 μg/g muscle), compared with data from literature. Analysis of the feed for vit. E suggests that this was due to a relatively high natural vit. E uptake from the feed, which was calculated to be approx. 330 mg vit. E per animal per day for the control group.

Colour stability and lipid oxidation of fresh beef. Development of a response surface model for predicting the effects of temperature, storage time, and modified atmosphere composition

Samples of fresh beef muscles ( Longissimus dorsi) were packed under varying modified atmosphere conditions (20–80% oxygen) and stored at 2–8°C for 10 days. At 2 day intervals meat samples were analysed for surface colour and extent of lipid oxidation (TBARS). Response surface models for predicting the effects of temperature, storage time and modified atmosphere composition on colour stability and lipid oxidation were developed. Temperature and time were found to be the most important factors for retaining meat colour and minimizing lipid oxidation. However, the oxygen content also had a significant effect on both quality parameters. A stable interval of maintaining a good meat colour was found between 55 and 80% O 2. Response surface modelling was found to be very promising for modelling of chemical quality changes in meat stored under different conditions, but the large biological differences between animals may complicate the development of generally valid models.

Colour stability of beef from different Spanish native cattle breeds stored under vacuum and modified atmosphere

Beef steaks from five Spanish cattle breeds were submitted to three packaging conditions: (a) 15 days under vacuum, (b) 15 days under modified atmosphere (MAP) (60% O 2, 30% CO 2 and 10% N 2), and (c) 10 days under vacuum plus 5 days more under MAP. CIE L ∗a ∗b ∗ coordinates, chroma (C ∗) and hue (H ∗), relative concentration of myoglobin, oxymyoglobin and metmyoglobin at the meat surface and sensory evaluation of colour were determined 0, 5, 10 and 15 days after packaging. Beef under MAP showed higher lightness (L ∗) and hue (H ∗) and lower redness (a ∗) and chroma (C ∗) than beef under vacuum. Colour of beef under MAP was not acceptable after 15 days of storage, due to the high metmyoglobin concentration. Yellowness (b ∗) was the indicator of differences due to ageing and differences in colour between breeds were related to L ∗, a ∗ and H ∗ values. Packaging conditions had a greater effect on beef colour than breed, but breed differences might change with packaging atmosphere. Both packaging and breed are major factors in packaged beef quality.

Effect of dietary vitamin E supplementation on the colour and lipid stability of fresh, frozen and vacuum-packaged beef

The effects of dietary vitamin E supplementation on tissue α-tocopherol (α-Toc) levels and on the susceptibility of fresh, frozen and vacuum-packaged beef to lipid oxidation and colour deterioration were investigated. Friesian cattle were fed diets containing 20 (basal, n=5) or 2000 (supplemented, n=5) IU (α-tocopheryl acetate/kg feed/day for approximately 50 days prior to slaughter. α-Toc levels were higher ( p < 0.05) in muscles from supplemented animals than from those on a basal diet. Significant differences in α-Toc levels were also observed between muscles from different treatment groups, the order of the supplemented group was: M. psoas major (PM) > M. longissimus dorsi (LD) > M. gluteus medius (GM) ( p < 0.05), and in the basal group the order was: PM > GM > LD ( p < 0.05). Supplemented fresh, frozen and vacuum packed beef showed greater colour and lipid oxidative stability than meat from the basal group after 7 days retail display at 4°C ( p < 0.05). Thus, dietary (α-Toc supplementation appeared to retard metmyoglobin and TBARS formation in LD, GM and PM and increased the colour shelf life of these muscles.

Colour stability of six beef muscles stored in a modified atmosphere mother pack system with oxygen scavengers

Summary The effect of O2 scavengers on the colour stability of beef in retail overwrap trays within a modified atmosphere mother pack (CO2/N2) was assessed. Steaks from six muscles, namely Longissimus dorsi, Psoas major, Semimembranosus, Gluteus medius, Semitendinosus and Biceps femoris were examined. After storage for 2, 4 or 6 weeks mother packs were opened and steak colour was monitored during 96 h of retail display. Redness of all muscles stored with O2 scavengers was superior to that of steaks stored without O2 scavengers at all storage times. Hue angle results indicated some metmyoglobin formation in all muscles during storage. Comparisons were made between steaks stored with O2 scavengers and fresh steaks. Shelf‐life values were calculated using the reflectance difference method (R630–R580). O2 scavengers did not affect weight loss from the stored steaks.

Effect of vitamin E on α-tocopherol concentration in different tissues and oxidative stability of bull beef

The objective of the study was to examine the effect of vitamin E on α-tocopherol concentration in different tissues and oxidative stability of bull beef. In a 2 (length of vitamin E supplementation; 80 or 120 days)×3 (level of vitamin E supplementation; control, 600 or 2000 mg/animal/day) factorial experiment, 66 German Fleckvieh bulls (starting weight at 568±23 and 530±20 kg, respectively, for the two groups on the length of supplementation) were given 2.6 kg concentrate per day together with maize silage ad libitum up to the same mean slaughter weight of 641±29 kg. At slaughter, the intramuscular fat contents of the M. longissimus thoracis (MLT) and the M. semitendinosus (MST) were low, with mean values of 1.60 and 1.14%, respectively. The α-tocopherol concentrations in the serum, liver, kidney fat and muscle tissues increased with level and duration of supplementation. However, MLT and MST reached only mean α-tocopherol contents of 1.11 (600 mg–80 days) to 2.79 mg/kg (2000 mg–120 days), and 1.48 (600 mg–80 days) to 3.56 mg/kg (2000 mg–120 days) in vitamin E-supplemented animals in comparison with 0.56 and 0.65 mg/kg in controls, respectively. The level of vitamin E supplementation had a much clearer effect on the α-tocopherol concentrations in the tissues than did the duration of supplementation. The intensity of redness of the muscle tissue remained relatively constant in the supplemented groups up to a storage time of 7–9 days, arrived after 10 days of ageing time, whilst significant darkening of the meat was observed in the controls after 4 days. Vitamin E supplementation also resulted in a delay in the increase of metmyoglobin in the pigment fraction, in a reduction of fat oxidation and in a tendency for reduced drip loss. Duration of vitamin E supplementation tended to have a clearer effect than level of supplementation on meat colour and oxidative stability of bull beef.

The effect of dietary vitamin E and controlled atmosphere packaging on the storage life of beef

The effects of dietary vitamin E upon colour, bacteriology and case life of beef was examined following extended storage of longissimus thoracis (LT) muscle in vacuum or in anoxic atmospheres containing 100% CO2 The diets of treated steers were supplemented with 1000 IU of vitamin E animal−1 d−1 for 100 d. Animals were slaughtered in a research abattoir and after 24 h of postmortem aging the LT muscles were removed and assignedto a packaging treatment for storage for up to 11 wk at 2 °C. Rib-eye steaks were cut and displayed under simulated retail conditions to give a surface temperature of 6 °C after storage intervals of 0, 3, 6, 9 and 11 wk. Feeding treatment had no effect (P &gt; 0.05) upon standard carcass and muscle quality traits or bacterial growth but increased carcass α-tocopherol levels from 2.89 µg g−1 in control animals to 5.18 µg g−1 in carcasses supplemented with vitamin E (P &lt; 0.0001). The α-tocopherol concentration in LT muscles was unaffected (P &gt; 0.05) by storage time for up to 11 wk in either packaging treatment. Dietary vitamin E increased a* values and reduced metmyoglobin accumulation after LT storage for up to 11 wk irrespective of package atmosphere. However, dietary vitamin E had no significant effect (P &gt; 0.05) on the colour case life of steaks derived from the LT muscle after vacuum storage for 3 to 11 wk. Contrarily, vitamin E acted synergistically with the CO2 packaging treatment to produce an increase in colour case life from 2.7 (control) to 5.4 d (vitamin E) after 6 wk of LT storage and from 2.4 (control) to 4.0 d (vitamin E) after 9 wk of LT storage (P &lt; 0.0001). In combination with anoxic, CO2 packaging, dietary vitamin E may play a role in assuring beef colour stability following extended periods of storage necessary for fresh beef export. Key words: Vitamin E, packaging, beef storage

Color coordinates for assessment of dietary vitamin E effects on beef color stability.

Color stability was investigated in longissimus lumborum (LL), semimembranosus (SM), and gluteus medius (GM) muscles from Holstein steers fed diets including doses of alpha-tocopheryl acetate that were 0 (EO), 250 (E250), 500 (E500), and 2,000 (E2000) mg.steer-1.d-1 for 42 or 126 d. Longissimus lumborum was aged for 14, 28, and 56 d and GM and SM were aged for 14 d. Effects of vitamin E dose on retention of redness (a*), yellowness (b*), color saturation (chroma), and proportions of redness and yellowness (hue angle) following an aging period of 14 d were E2000 > E500 = E250 > EO (P < .01). Effectiveness of dose duration on the color parameters was 126 d > 42 d (P < .01). Dietary vitamin E supplementation stabilized redness and color saturation, decreased yellowness, and extended color display life of fresh beef. A technique for estimation of color display life based on hue angle measurements of fresh beef is described. Color display life estimates based on hue angle measurements were more consistent with vitamin E supplementation effects on metmyoglobin percentage and hue angle than were estimates obtained from the metmyoglobin threshold method. Color display life across LL, SM, and GM stored until d 14 and then displayed under simulated retail conditions was extended (P < .01) 2.0 (E250) to 5.0 d (E2000). Coefficients of determination for regressions of color display life on muscle alpha-tocopherol concentration were .81, .64, and .63 in LL, SM, and GM muscles aged 14 d, respectively. Supplementation of 500 mg of alpha-tocopheryl acetate per steer daily improved (P < .01) the mean color display life of these three muscles by 2.3 d, or 100%.

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

ABSTRACTLongissimus 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 &gt; 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.