VITAMIN E SUPPLEMENTATION EFFECTS ON COLOR AND LIPID STABILITY OF WHOLE AND GROUND LAMB

Crossbred wethers averaging 44.1 kg were fed a diet supplemented with 2000 IU α-tocopheryl acetate/day for 49 days. The controls received the same diet without supplement. Muscles from lambs supplemented with vitamin E contained higher concentrations of a-tocopherol than the controls (P<0.05). There were no differences between control and supplemented animals for myoglobin stabiliry of two muscle slices stored at 4C (P>0.05). Ground semimembranosus (SM)from supplemented animals exhibited higher "a" values and lower Hue angle values (P < 0.05) than meat from control animals at 6 days of storage and longer indicating enhanced color stability due to vitamin E. Vitamin E supplementation decreased lipid oxidation of ground SM at 3, 6, 9, and 12 days of storage at 4C (P < 0.05) and it partially stabilized color of ground lamb. Color stability of whole lamb slices was not affected by vitamin E supplementation.     

Comparison of Milk Mineral, Sodium Tripolyphosphate, and Vitamin E as Antioxidants in Ground Beef in 80% Oxygen Modified Atmosphere Packaging

The antioxidant effects of milk mineral (MM), sodium tripolyphosphate (STP), and vitamin E (E) were tested in raw ground beef packaged in 80% O₂ modified atmosphere packaging, and held 1, 4, 7, or 14 d at 2 °C. Two levels of each antioxidant (0.75% and 1.5% MM, 0.25% and 0.5% STP, 50 or 100 ppm E) were compared with control samples without added antioxidants. Vitamin E was mixed with mineral oil or ethanol before mixing with meat samples. Thiobarbituric acid (TBA) values were highest (P < 0.05) in controls without antioxidants, and samples with added vitamin E. Lowest TBA values (<0.5) were in samples treated with 0.75% or 1.5% milk mineral. All ground beef samples maintained redness (a* > 10) through 4 d of storage. By day 7, ground beef treatments with added E were brown. After 14 d, ground beef with 0.75% MM was more red (P < 0.05) than other treatments or controls. Thus, 0.75% MM has possible application to prolong red color stability and inhibit lipid oxidation in ground beef packaged in high oxygen atmospheres.     

Application of electron‐beam irradiation pasteurization of ground beef,from steers fed vitamin E fortified diets: microbial and chemical effects

The effects of vitamin E supplementation of diets and electron‐beam irradiation (EBI) processing of ground beef patties on microbial and chemical qualities were investigated during 21 days of storage at 4 °C. Oxidative damage to lipids induced by EBI in ground beef patties containing different fat contents was first determined at 3 day intervals throughout a 7 day storage period at 4 °C. Significantly (P ≤ 0.05) higher values for thiobarbituric acid reactive substances (TBARS) were detected in beef patties of higher fat content (ie at 17 and 30%), which was further enhanced by irradiation at 5 kGy. Since lipid oxidation proceeded to a greater extent in beef patties with higher fat levels, ground beef patties of 30% fat were prepared from steers fed basal (diet I) or basal + 500 IU (diet II) of the antioxidant (vitamin E) supplemented diets. Plasma vitamin E concentrations in cattle fed diets I and II were 1.58 ± 0.42 µg ml^?1 and 2.49 ± 0.40 µg ml^?1 respectively. Patties were processed with three doses (2, 5, or 10 kGy) of EBI and compared with non‐irradiated patties. Microbial indices monitored at 3 day intervals included total aerobic plate count, psychrotrophic counts, and total coliform and Escherichia coli counts. Bacterial growth in ground beef patties stored at 4 °C was significantly (P ≤ 0.05) reduced by EBI at 2 kGy dose. Complete inhibition of bacteria occurred at 5 kGy or higher (P ≤ 0.05) dosage of EBI over 21 days of storage at 4 °C. Quality indices monitored at 3 day intervals throughout a 21 day storage (4 °C) study involving 30% fat ground beef patties made from steers fed vitamin E supplemented diets I and II included TBARS and colour. Results indicated that irradiation at the highest dosages was associated with higher (P ≤ 0.05) TBARS values, which in turn corresponded to lower linoleic acid content. With all three levels of irradiation, Hunter a values of beef patties decreased (P ≤ 0.05) significantly. Lipid oxidation was significantly (P ≤ 0.05) retarded in stored beef patties derived from cattle fed vitamin E (diet II). Copyright © 2003 Society of Chemical Industry     

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.     

Effects of reducing agents on premature browning in ground beef

This study was performed to investigate the effects of food-grade reducing agents on counteracting premature browning (PMB) and to determine the relative heat stability of different redox states of bovine myoglobin (Mb). Sodium erythorbate (SE), erythorbic acid (EA), sodium ascorbate (SA), ascorbic acid (AA) and ascorbyl palmitate (AP) were added to ground beef (15% fat) at a concentration of 2.3 mM; patties were prepared and stored at 4 °C and at −18 °C. Surface redness (a* values), lipid oxidation and total reducing activity (TRA) were measured on raw beef, and a* values recorded from cooked internal surfaces. Bovine Mb was purified from biceps femoris muscle and heat capacity was measured using differential scanning calorimetry. All reducing agents decreased lipid oxidation and increased TRA relative to controls (p < 0.05). In general, SE and SA were more effective at maintaining red color in cooked ground beef patties than other reducing agents (p < 0.05). The temperature at peak heat capacity, T_m, of metmyoglobin appeared lower than that of oxymyoglobin and deoxymyoglobin. Reducing agents can maintain Mb in the reduced state, and their addition to ground beef may be one method of preventing PMB.     

Retardation by Glandless Cottonseed Flour of Lipid Oxidation and Discoloration in Raw Ground Beef Containing Salt

Salt (NaCl) was added to raw ground beef at levels of 0, 0.5, 1, 2 or 3% of the weight of the meat and defatted glandless cottonseed flour (GCF) was added at 0 or 3% levels. Patties were made with these mixes and stored for 3 or 6 days at 4°C or for 30 or 60 days at –20°C. Lipid oxidation (TBA values) in samples stored at 4° and –20°C and discoloration in samples stored at 4°C were determined. In samples made with salt only, TBA values within each storage period for each storage temperature increased with increasing salt levels up to 2%; increasing salt from 2 to 3% decreased TBA values. GCF markedly reduced TBA values at each salt level. Discoloration of samples stored at 4°C was also decreased by GCF.     

Effects of pyruvate on lipid oxidation and ground beef color

Our overall objective was to better understand the effects of added pyruvate on enhanced beef color stability. The 2 possible mechanisms assessed were the role of pyruvate in lipid oxidation and direct interaction between pyruvate and beef myoglobin. Microsomes were incubated with pyruvate at pH 5.6, 25 °C, and lipid oxidation was measured hourly for 3 h. Bovine oxymyoglobin at pH 5.6 was incubated with pyruvate and used to quantify both redox stability (metmyoglobin formation) and pyruvate-myoglobin adduction using mass spectrometry analysis. Surface color and lipid oxidation were measured on ground beef patties stored for 6 d in polyvinyl chloride over-wrap (PVC) or high oxygen. Addition of pyruvate to microsomes decreased lipid oxidation compared with controls (P < 0.05). Conversely, no effect on myoglobin was observed (no changes in redox stability and no peaks corresponding to pyruvate were observed; P > 0.05). However, pyruvate increased color stability and decreased lipid oxidation of ground beef patties packaged in PVC and high oxygen. Pyruvate decreased nitric oxide metmyoglobin-reducing capacity and oxygen consumption of patties compared with controls (P < 0.05). This research suggests that pyruvate may improve beef color stability primarily through its antioxidant effect on lipids. Practical Application: Discoloration of meat often results in significant revenue loss. This study suggests that pyruvate can improve the color stability of patties packaged in high oxygen and PVC primarily through its antioxidant effect on lipids.     

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.     

Storage Stability of Ground Pork Containing Meat from an Advanced Meat Recovery System

Pork trim-finely textured (PTFT), generated by advanced meat recovery which mechanically removes meat from bones under pressure, has properties that may cause shelf-life instability. Lipid oxidation, microbial growth and pH of retail displayed fresh ground pork patties were not affected (P>0.05) by addition of up to 15% PTFT. Ground pork with 15% PTFT and 3.3% sodium lactate (NaL) stored in chubs at–2.2°C for 14 days was ground and modified atmosphere packaged (MAP) or overwrapped (OW) and retail displayed for 4 days. Lipid oxidation increased (P<0.05) due to PTFT incorporation but was reduced by NaL. MAP and/or NaL reduced microbial counts and lipid oxidation. MAP maintained redness (a*) and prevented metmyoglobin formation.     

Measurement of Oxidation-Related Changes in Proteins of Freeze-Dried Meats

A new methodology for detection of lipid oxidation in freeze-dried meats, using myoglobin, has been developed. Fresh, cold beef was ground, freeze-dried and stored aerobically at 37°C. Samples, taken at different time intervals, were reconstituted and “meat extract” obtained. Extent of myoglobin insolubilization was determined by absorbance intensity at isobestic point (525 nm). Oxidation of oxymyoglobin to metmyoglobin in meat extract was quantified by measuring α peak intensity of metmyoglobin at 630 nm. Myoglobin polymerization was determined by isolation of myoglobin dimers and monomers from meat extract using gel filtration chromatography. Dimer/monomer ratio was calculated from Soret band absorption intensity at 409 – 415 nm. The three myoglobin-based oxidative indicators correlate well with each other and can be used to detect extent of lipid oxidation in freeze-dried meat products.     

Hematological Status of Rats Fed Oxidized Beef Lipids

Hemoglobin, hematocrit, total iron binding capacity, and erythrocyte thiobarbituric acid (TBA) numbers were measured in blood from rats given a diet containing 52.7% cooked ground beef which was fed as freshly cooked beef (control), or after refrigerated storage (5°C) for 1, 3 or 8 days. Rats were maintained on the experimental diets for 6 wk. As the level of oxidation increased in the meat, erythrocyte TBA numbers also increased and were significantly different among groups. There was a drop in the erythrocyte TBA numbers for rats consuming beef stored for 8 days, suggesting that a level of rancidity was reached that was adequate to induce synthesis of enzymes that metabolize free radicals such as catalase, glutathione peroxidase, and superoxide dismutase.     

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 wheat sprout powder incorporation on lipid oxidation and physicochemical properties of beef patties

The aim of this study was to determine the effects of incorporation of wheat sprout flours (WSF) on lipid oxidation and some quality characteristics of beef patties. Two wheat sprout flour samples (WSF1 and WSF2) were obtained by germination, drying and milling of two different wheat varieties. The beef patties were stored at +4 °C for 6 days or at ?18 °C for 180 days and analysed for their proximate composition, pH, sensory properties, colour parameters and lipid oxidation. TBA formation in WSF‐added patties was reduced approximately by as much as 20% when compared to that of the control at the 180th day of the storage, while favourable results were detectable in the storage period at +4 °C. Again, up to 4% WSF1 or WSF2 incorporation gave acceptable sensorial scores to the beef patties. As a conclusion, it was confirmed that WSF could be incorporated into beef patties to improve their quality parameters and retard lipid peroxidation.     

Microbiological, Sensory and Chemical Characteristics of Vacuum-Packaged Ground Beef Patties Treated with Salts of Organic Acids

Vacuum-packaged ground beef patties containing sodium lactate (NaL), sodium propionate (NaP), sodium acetate (NaA) and sodium citrate (NaC) at various levels and combinations were stored up to 28 days at 4°C. Addition of sodium lactate alone or in combination with sodium propionate increased shelf life of the patties by decreasing microbiological growth and decreasing negative flavor notes associated with lipid oxidation. Lean color also was improved by addition of sodium lactate alone or in combination with sodium propionate. Lipid oxidation by TBA was only slightly affected by treatment addition or storage.     

Effect of dietary vitamin E on pigment and lipid stability of frozen beef: A kinetic analysis

The effect of vitamin E supplementation on pigment and lipid stability was evaluated with beef wrapped in high or low oxygen permeability films and stored in the dark or under constant illumination at -20°C. Dietary vitamin E supplementation improved pigment and lipid stability in both cases. Illumination increased metmyoglobin accumulation but did not affect lipid oxidation rate in both control and supplemented beef. A predisplay dark storage period of 30 days delayed metmyoglobin accumulation during subsequent display. Kinetic analysis showed that vitamin E supplementation stabilized the oxymyoglobin complex by enhancing the deoxymyoglobin oxygenation rate and by decreasing oxymyoglobin autoxidation rate.     

Antioxidant Efficacy of Oleoresin Rosemary and Sodium Tripolyphosphate in Restructured Pork Steaks

Thiobarbituric acid (TBA) analysis, sensory evaluation and hexanal content (frozen storage only) monitored lipid oxidation. STPP significantly (P<0.01) reduced lipid oxidation in cooked steaks during refrigerated storage (ε4°C) for 8 days, and in raw steaks stored at ? 30°C for 8 mo. Lipid stability was not enhanced by OR/STPP treatments compared to STPP treatments. Water-soluble OR/STPP did not result in significantly (P>0.05) greater lipid stability than oil-soluble OR/STPP treatments. Hexanal content significantly (P<0.01) increased after 8 mo frozen storage.     

Fat content and ascorbic acid infusion influence microbial and physicochemical qualities of electron beam irradiated beef patties

The effects of fat content and post-slaughter ascorbic acid (AA) infusion on microbial and physicochemical qualities of beef patties processed by electron beam irradiation were investigated in a 4 °C storage trial. Beef muscles from AA-infused or control animals were ground and mixed with tallow to achieve a final fat content of 4%, 17% and 30%, respectively. Beef patties were irradiated at 5 and 10 kGy with a linear electron beam accelerator. Non-irradiated and non-infused ground beef patties served as a control. The addition of fat significantly (p<0.05) increased aerobic, total coliform, E. coli, and psychrotrophic bacteria counts in beef patties during storage. Irradiation at both dosages exerted a pasteurization effect on psychrotrophic bacteria for up to 7 days of storage. No viable aerobic, total coliform, or E. coli bacteria were detected in any irradiated beef patties during storage. Physicochemical changes caused by lipid oxidation and surface discoloration of beef patties were significantly (p<0.05) increased by both the addition of fat and irradiation processing. Beef patties made from AA-infused animals did not alter bacterial counts. Instead, post-slaughter infusion of AA exerted a pro-oxidant effect in the beef patties that led to a significant (p<0.0.5) increase in lipid oxidation and surface discoloration of stored patties.     

Hot Processed Raw Materials and Fat Level Affect Physical and Sensory Characteristics of Ground Beef

Sixteen treatment combinations of ground beef were evaluated (two lean types, four fat types, and two fat levels) to determine the characteristics of ground beef produced from hot fat and prerigor lean (HL). Half of each batch was immediately made into patties and the remaining chub pack stored (2°C). Fat type had no (P>0.05) effect on appearance or sensory characteristics of patties; however, all prerigor fat treatments and HL reduced (P<0.05) cooking loss. Fat smearing was greater (P<0.05) in HL patties, but no (P>0.05) difference was detected after chub pack storing (2°C). The HL improved (P<0.05) tenderness in stored ground beef.     

Influence of Polyphosphate on Storage Stability of Restructured Beef and Pork Nuggets

Influence of polyphosphate on sensory and chemical characteristics of battered and breaded, cooked, restructured beef and pork nuggets was evaluated over 20 wk storage. Beef and pork nuggets manufactured with polyphosphate had lower (P<0.05) initial thiobarbituric acid (TBA) values than those manufactured without polyphosphate (controls); and values remained lower (P<0.05) than control treatments over 20 wk of storage. Sensory panelists detected less (P<0.05) off-flavor in pork nuggets manufactured with polyphosphate than nuggets in control treatments. Detection of off-flavor in pork nugget control treatments may be attributed to higher TBA values (increased lipid oxidation) in the pork product. Addition of polyphosphate protected nuggets from lipid oxidation and subsequent off-flavor development.     

Thiobarbituric Acid Values and Glutathione Perioxidase Activity in Meat from Chickens Fed a Selenium-Supplemented Diet

Selenium glutathione peroxidase (SeGSHpx) was assayed in breast and leg muscle from chickens fed a basal (0.09 ppm Se) and a Se-supplemented (0.31 ppm Se) diet. The same muscles were ground and made into 50g patties and stored 4 days at 4° C. TBA values were determined on the stored patties. SeGSHpx activity was higher (p < 0.05) in muscles from the Se-supplemented chickens than in muscles from the non-Se supplemented birds. The higher SeGSHpx activity was accompanied by lower (p < 0.05) TBA numbers in the stored chicken patties.