Effect of dietary vitamin E and irradiation on lipid oxidation, color, and volatiles of fresh and previously frozen turkey breast patties

Turkey breast meat patties, prepared from the turkeys fed diets containing 0, 50, 100, or 200 IU of dl-α-tocopheryl acetate (TA) per kg diet from 84 to 112 days of age, were aerobically packaged and irradiated at 0, 1.5, or 2.5 kGy. When dietary TA was increased from 0 to 200 IU/kg diet, plasma and muscle vitamin E levels increased by 5- and 4-fold, respectively. Dietary TA at 100 IU/kg diet significantly improved the storage stability of turkey breast, and it was more distinct in irradiated than nonirradiated meats. Both irradiation and dietary TA increased a*-values of turkey breast meat, but irradiation had a stronger impact. The redness of meat decreased during the 7-day storage, but irradiated meat maintained redder color than nonirradiated. Irradiated meat produced more sulfur volatiles and aldehydes than nonirradiated meats, and dietary TA effectively reduced these compounds during storage. The effects of dietary TA on the reduction of off-odor volatiles were more distinct in previously frozen-stored meats than in fresh meats.     

Effect of muscle type, packaging, and irradiation on lipid oxidation, volatile production, and color in raw pork patties

Effects of packaging and irradiation combinations on lipid oxidation, off-flavor, and color changes of raw patties prepared from three pork muscles were studied. Patties were prepared from each of the ground L. dorsi (L. thoracis and lumborum), psoas, and R. femoris muscles of pig, packaged either in oxygen permeable polyethylene bags or impermeable nylon/polyethylene bags, irradiated with an electron beam at 0 or 4.5 kGy dose, and then stored up to two weeks at 4 °C. Lipid 8 oxidation and color of the patties were determined after 0, 3, 7, and 14 days of storage, and volatiles 24 hr after irradiation. Irradiation and high fat content accelerated the lipid oxidation in raw meat during storage. Oxygen availability during storage, however, was more important than irradiation on the lipid oxidation and color values of raw patties. Irradiated meat produced more volatiles than nonirradiated patties, and the proportion of volatiles varied by the packaging-irradiation conditions of patties. Irradiation produced many unidentified volatiles that could be responsible for the off-odor in irradiated raw meat. No single volatile components but total volatiles, however, could be used to predict lipid oxidation status of raw meat.     

Cholesterol oxidation products in irradiated raw meat with different packaging and storage time

The effect of irradiation and packaging conditions on the formation of cholesterol oxidation products (COPs) as well as lipid oxidation products was determined in raw turkey leg, beef, and pork loin meat during 7 days of storage. Ground turkey leg, beef, and pork loin muscles were prepared as patties. The patties were individually packaged either in oxygen-permeable or impermeable bags, irradiated at 0 or 4.5 kGy using a Linear Accelerator, and stored at 4°C. The COPs such as 7-hydroxycholesterol, 7β-hydroxycholesterol, and 7-ketocholesterol were detected in fresh raw meats at 0 day at the level of 10.9 to 49.2 μg/g lipid. After 7 days of storage, other COPs such as epoxides, 20-hyroxycholesterol, and choletanetriol were formed in mainly aerobically packaged and irradiated raw meats. Packaging effect was more crucial on the cholesterol and lipid oxidation than irradiation. In aerobically packaged and irradiated meats, turkey leg muscles had higher COPs value than beef or pork did. COPs and thiobarbituric acid reactive substances (TBARS) values had a strongly positive correlation in turkey leg and pork. But, cholesterol oxidation in beef proceeded in irradiated and aerobically stored samples despite of its low level of TBARS value.     

Effects of Dietary Functional Ingredients and Irradiation on the Quality of Cooked Turkey Breast Meat during Storage

ABSTRACT:  Patties were prepared using the breast meat from 15-wk-old turkeys fed one of the 8 dietary treatments [Con, control; VE, 200 IU/kg vitamin E; Se, 0.3 mg/kg selenium; CLA, 2.5% conjugated linoleic acids; VE + Se, 200 IU/kg vitamin E + 0.3 mg/kg selenium; VE + CLA, 200 IU/kg vitamin E + 2.5% CLA; Se + CLA, 0.3 mg/kg selenium + 2.5% CLA; VE + Se + CLA, 200 IU/kg vitamin E + 0.3 mg/kg selenium + 2.5% CLA] for 4 wk. Patties were vacuum-packaged in oxygen-impermeable bags, and then irradiated with 0 or 1.5 kGy. Irradiated breast meats were cooked and vacuum-packaged or aerobically packaged, and the quality of meat was evaluated after 0 and 7 d of storage at 4 °C. Dietary VE + Se, VE + CLA, Se + CLA, and VE + Se + CLA treatments reduced lipid oxidation of cooked irradiated (1.5 kGy) turkey breast meat by 24%, 29%, 26%, and 40%, respectively, compared to that of the control after 7 d of storage under aerobic conditions. Dietary treatments had no influences on the color of nonirradiated cooked turkey breast. However, dietary VE and Se decreased the internal a * value of irradiated meats in vacuum packaging at days 0 and 7, and the effect was even greater when VE and Se were combined with CLA. Dietary VE, Se, and CLA combinations significantly reduced the production of volatiles, especially those related to lipid oxidation. Dietary VE + Se, VE + CLA, and VE + Se + CLA reduced the difference in sulfur-containing compounds between irradiated and nonirradiated meat. Aerobic packaging was more effective than vacuum packaging in reducing sulfur-containing compounds. Therefore, dietary VE, Se, and CLA combinations plus aerobic packaging were effective in reducing the odor problems induced by irradiation.     

Combination of aerobic and vacuum packaging to control lipid oxidation and off-odor volatiles of irradiated raw turkey breast

Effects of the combination of aerobic and anaerobic packaging on color, lipid oxidation, and volatile production were determined to establish a modified packaging method to control quality changes in irradiated raw turkey meat. Lipid oxidation was the major problem with aerobically packaged irradiated turkey breast, while retaining characteristic irradiation off-odor volatiles such as dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide was the concern for vacuum-packaged breast during the 10-day refrigerated storage. Vacuum packaging of aerobically packaged irradiated turkey breast meat at 1 or 3 days of storage lowered the amounts of S-volatiles and lipid oxidation products compared with vacuum- and aerobically packaged meats, respectively. Irradiation increased the a-value of raw turkey breast, but exposing the irradiated meat to aerobic conditions alleviated the intensity of redness.     

Packaging Cooked Turkey Meat Patties while Hot Reduces Lipid Oxidation

Elimination of oxygen by “hot packaging” reduced the 2-thiobarbituric acid reactive substances (TBARS) value of meat patties by about 50% in control and myoglobin added, and between 30-40% in ferrous iron added turkey patties, as compared with “cold packaging.” The TBARS values of hot and cold vacuum packaged patties were significantly lower than those of loosely packaged patties after 1 wk refrigerated storage. Most lipid oxidation in meat patties occurred at day 0, and only small changes in TBARS values were observed after 1 wk storage. Although the prooxidants in meat were major factors in promotion of lipid oxidation of cooked meat, hot packaging minimized their effects.     

Addition of Antioxidant to Improve Quality and Sensory Characteristics of Irradiated Pork Patties

The effects of added antioxidants on the oxidative quality changes of irradiated pork patties were studied. Lipid oxidation (TBARS) was not a concern, even in aerobically packaged irradiated pork patties when antioxidants were added. Irradiation produced sulfur compounds, such as dimethyl sulfide and dimethyl disulfide, responsible for irradiation off‐odor. The addition of gallate + tocopherol or sesamol + tocopherol was effective in reducing the sulfur volatiles, but had no effect on the redness of irradiated raw pork patties. Aerobic packaging was highly effective in reducing sulfur volatiles and off‐odor from irradiated meat during storage. Antioxidants had little effect on the sensory characteristics and consumer acceptance of irradiated pork, and consumers did not consider the red color of irradiated raw pork as a quality defect.     

Addition of tea catechins and vitamin C on sensory evaluation, colour and lipid stability during chilled storage in cooked or raw beef and chicken patties

The effects of addition of tea catechins (TC) and vitamin C (VC) on sensory evaluation, colour and lipid stability in cooked or raw beef and chicken meat patties during refrigerated storage were studied. Fresh beef striploin and chicken breast muscles were minced, following removal of external fat and connective tissue. Following mincing, beef and chicken were assigned to one of the following five treatments: control (meat treated with no antioxidant); TC200, meat plus 200 mg TC/kg muscle; TC400, meat plus 400 mg TC/kg muscle; VC200, meat plus 200 mg VC/kg muscle, VC400, meat plus 400 mg VC/kg muscle. Sodium chloride (1%) was added to all samples. Patties (125 g portions), formed from the above-treated minced meat, were oven cooked, cooled, and packaged in 30% CO₂:70% N₂. Fresh raw beef and chicken patties were packaged in 80% O₂:20% CO₂. All samples were stored for up to 7 days under fluorescent lighting at 4 °C. Sensory parameters (colour, flavour, taste, tenderness and overall acceptability) were evaluated on cooked beef and chicken patties after 1, 3 and 6 days of storage. Surface colour (Hunter L, a and b values), and lipid oxidation (2-thiobarbituric acid reactive substances) were measured on days 1, 3 and 6 of storage for cooked meats and on days 2 and 7 for raw beef and chicken. Tea catechins addition (200 or 400 mg/kg) to minced meat caused (P < 0.05) discolouration in cooked beef and chicken meat patties and significantly reduced (P < 0.001) lipid oxidation in cooked or raw beef patties compared to the control. Beef, either raw or cooked, was more susceptible (P < 0.01) to oxidation compared to chicken. Raw meat stored in high oxygen conditions was more susceptible to lipid oxidation than cooked meat stored in anaerobic conditions. Tea catechins treatments (TC200 and TC400) inhibited (P < 0.05) lipid oxidation in raw beef to a greater extent than vitamin C treatments (VC200 and VC400). These results indicate that tea catechins are potent natural antioxidants and exhibit greater antioxidant efficacy compared to vitamin C.     

Effect of Double-packaging and Acid Combination on the Quality of Irradiated Raw Turkey Pattie

ABSTRACT: Effects of double-packageing (combinational use of vacuum and aerobic packaging conditions) and acid (citric or ascorbic acid) combinations on color, lipid oxidation and volatiles of irradiated raw turkey breast were determined. Acid did not affect the a-values but increased the L-values of meat after irradiation. Citric acid promoted lipid oxidation of irradiated turkey meat, whereas ascorbic acid had an antioxidant effect. The amounts of total volatile and dimethyl sulfide in doubly packaged turkey meat were 35 to 56% and 58 to 73% lower than those of the irradiated vacuum-packageed control, respectively, and dimethyl disulfide and dimethyl trisulfide were not found in double-packageed meat. The combination sequence of aerobic/anaerobic packaging was not a critical factor in the production of off-odor volatiles of irradiated turkey.     

Packaging and Irradiation Effects on Lipid Oxidation and Volatiles in Pork Patties

Raw-meat patties were prepared from three pork muscles, irradiated in different packaging environments, and stored for 0 or 3 days before cooking. Lipid oxidation by-products were formed in the raw meat during storage and the baseline lipid oxidation data of raw meat was used to measure the progression of lipid oxidation after cooking. Thiobarbituric acid-reactive substances (TBARS) and volatiles data indicated that preventing oxygen exposure after cooking was more important for cooked meat quality than packaging, irradiation, or storage conditions of raw meat. Propanal, pentanal, hexanal, 1 -pentanol, and total volatiles correlated highly (P < 0.01) with TBARS values of cooked meat. Hexanal and total volatiles represented the lipid oxidation status better than any other individual volatile components.     

Use of antioxidants to reduce lipid oxidation and off-odor volatiles of irradiated pork homogenates and patties

Pork homogenates and patties treated with antioxidants (200 μM, final) were irradiated with an electron beam. Lipid oxidation of the pork homogenates and patties were determined at day 0 and 5 and volatile compounds were analyzed soon after irradiation. Ionizing radiation accelerated lipid oxidation and produced S-containing volatiles in pork homogenates and patties. Addition of an antioxidant (sesamol, gallate, Trolox, or α-tocopherol) and their combinations decreased, but carnosine did not affect the production of off-odor volatiles and lipid oxidation of pork homogenates and patties by irradiation. Antioxidant combinations showed distinct beneficial reduction in lipid oxidation of aerobically packaged irradiated pork patties. The effect of antioxidant combinations in reducing sulfur volatiles of irradiated pork patties was clearer under vacuum than aerobic conditions.     

Lipid Oxidation, Volatiles and Color Changes of Irradiated Pork Patties Affected by Antioxidants

Changes were measured in TBARS, color, and volatiles of irradiated (4.5 kGy) pork patties with antioxidants (sesamol, quercetin, rutin, BHT, and rosemary oleoresin) during 7 days storage at 4°C. Irradiation accelerated lipid oxidation of raw pork during storage. However, irradiation before cooking did not influence lipid oxidation of cooked pork during storage. Sesamol, quercetin, and BHT were effective in both irradiated raw and cooked pork during 7-days storage. Rosemary oleoresin and rutin were effective only in irradiated raw pork for 3 days. Hexanal, propanal and higher boiling components were well correlated (P < 0.01) with TBARS in cooked pork. Generation of volatiles was reduced by sesamol and quercetin, but the effects of antioxidants on color changes of raw pork patties were minor and inconsistent.     

Influence of dietary conjugated linoleic acid on volatile profiles, color and lipid oxidation of irradiated raw chicken meat

Forty-eight, 27-week-old White Leghorn hens were fed a diet containing 0, 1.25, 2.5 or 5.0% conjugated linoleic acid (CLA) for 12 weeks. At the end of the 12-week feeding trial, hens were slaughtered, and boneless, skinless breast and leg meats were separated from carcasses. Meats were ground through 9 and 3-mm plates, and patties were prepared. Patties prepared from each dietary treatment were divided into two groups and either vacuum- or aerobic-packaged. Patties were irradiated at 0 or 3.0 kGy using a linear accelerator and stored at 4°C. Samples were analyzed for thiobarbituric acid reactive substances, volatile profiles, color and odor characteristics at 0 and 7 days of storage. Dietary CLA reduced the degree of lipid oxidation in raw chicken meat during storage. The content of hexanal and pentanal in raw chicken meat significantly decreased as dietary CLA level increased. Irradiation accelerated lipid oxidation in meat with aerobic packaging, but irradiation effect was not as significant as that of the packaging. Dietary CLA treatment improved the color stability of chicken patties. Color a*-value of irradiated raw chicken meat was higher than that of the nonirradiated meat. Dietary CLA decreased the content of polyunsaturated fatty acid and increased CLA in chicken muscles, which improved lipid and color stability and reduced volatile production in irradiated and nonirradiated raw chicken meat during storage.     

The effects of dietary oregano essential oil and α-tocopheryl acetate on lipid oxidation in raw and cooked turkey during refrigerated storage

The effects of dietary oregano essential oil and α-tocopheryl acetate supplementation on the susceptibility of raw and cooked turkey breast and thigh meat to lipid oxidation during refrigerated storage for 9 days were examined. Thirty 12-week-old turkeys were divided into five groups and fed a basal diet containing 30 mg α-tocopheryl acetate kg(-1) feed as control, or basal diet plus 200 mg α-tocopheryl acetate kg(-1), or basal diet plus 100 mg oregano oil kg(-1), or basal diet plus 200 mg oregano oil kg(-1), or basal diet plus 100 mg oregano oil and 100 mg α-tocopheryl acetate kg(-1), for 4 weeks prior to slaughter. Lipid oxidation was assessed by monitoring malondialdehyde formation in raw and cooked meat at 0, 3, 6 and 9 days of refrigerated storage, through use of a third-order derivative spectrophotometric method. Results showed that all dietary treatments significantly (P<0.05) increased the stability of both raw and cooked turkey meat to lipid oxidation compared with the control. Oregano oil at 200 mg kg(-1) was significantly (P<0.05) more effective in delaying lipid oxidation compared to the level of 100 mg kg(-1), equivalent to α-tocopheryl acetate at 200 mg kg(-1), but inferior (P<0.05) to oregano oil plus α-tocopheryl acetate at 100 mg kg(-1) each, which in turn was superior (P<0.05) to all dietary treatments, indicating a synergistic effect. Thigh muscle was more susceptible to oxidation compared with breast muscle in all treatments, although it contained α-tocopherol at significantly (P<0.05) higher levels.     

Effect of Antioxidants on the Production of Off-Odor Volatiles and Lipid Oxidation in Irradiated Turkey Breast Meat and Meat Homogenates

The addition of gallate, sesamol, trolox, and tocopherol was effective, but sesamol, sesamol + tocopherol, and gallate + tocopherol were among the most effective antioxidants in reducing thiobarbituric acid reactive substances, volatile production, and off‐odor intensity in turkey breast homogenates. Also, these 3 antioxidant treatments were effective in controlling lipid oxidation and off‐odor intensity in both vacuum and aerobically packaged patties. However, aerobic packaging was better than antioxidant treatments in reducing off‐odor intensity of irradiated turkey patties. Antioxidants had no effect on redness, but increased lightness and yellowness of irradiated turkey breast. It was concluded that a combination of antioxidant and aerobic packaging was more useful than antioxidant and vacuum packaging in controlling off‐odor problems in irradiated raw turkey meat.     

Effect of irradiation and packaging conditions after cooking on the formation of cholesterol and lipid oxidation products in meats during storage

The effect of irradiation and packaging conditions on the content of cholesterol oxidation products (COPs) and lipid oxidation in cooked turkey, beef, and pork during storage was studied. Ground turkey leg, beef, and pork were cooked, packaged either in oxygen-permeable or oxygen-impermeable bags, and irradiated at 0 or 4.5 kGy. Lipid oxidation and COPs were determined after 0 and 7 days of storage at 4°C. Packaging of cooked meat was more important than irradiation in developing COPs and lipid oxidation in cooked meats during storage. 7-Hydroxycholesterol, 7β-hydroxycholesterol, β-epoxide, and 7-ketocholesterol were among the major COPs formed in cooked turkey, beef, and pork after storage, and their amounts increased dramatically during the 7-day storage in aerobic conditions. Irradiation had no significant effect on the amounts of any of the COPs found in cooked turkey and beef, but increased (P<0.05) the amounts of - plus 7β-hydroxycholesterol, β-epoxide, 7-ketocholesterol, and total COPs in aerobically packaged cooked pork. The amounts of COPs and lipid oxidation products (TBARS) closely related to the proportion of polyunsaturated fatty acids in meat. The results indicated that the composition of fats in meat is important on the oxidation rates of lipids and cholesterol, and packaging is far more important than irradiation in the formation of COPs and lipid oxidation in cooked meat.     

Effect of carnosine, salt and dietary vitamin E on the oxidative stability of chicken meat

The effect of carnosine on lipid and cholesterol oxidation in salted chicken thigh meat and its relationship to dietary α-tocopherol supplementation was examined. Broilers (Cobb 500) were fed diets with a basal (30 mg kg(-1)) or supplemental (200 mg kg(-1)) level of α-tocopheryl acetate for 6 weeks. Thigh meat patties were prepared with carnosine (1.5%), salt (1%) or salt plus carnosine. Salt accelerated lipid and cholesterol oxidation following cooking and refrigerated storage. However, carnosine inhibited lipid and cholesterol oxidation in salted patties. Dietary α-tocopherol supplementation also reduced the extent of lipid and cholesterol oxidation in salted patties. The combination of carnosine and dietary α-tocopherol resulted in the greatest lipid and cholesterol stability in salted meat.     

Carbon monoxide-heme pigment is responsible for the pink color in irradiated raw turkey breast meat

Turkey breast muscles were aerobically or vacuum packaged, irradiated at 0, 2.5, or 5.0 kGy using a Linear Accelerator (electron beam), and stored at 4°C. The CIE color values, reflectance scan, oxidation-reduction potential (ORP), production of gaseous compounds, and lipid oxidation of samples were determined at 0, 1, and 2 weeks of storage. Absorption spectra of sample drips were determined at 1 week of storage. Irradiation increased the a-value of both aerobically and vacuum-packaged turkey breast, but vacuum-packaged meat had stronger intensity than the aerobically packaged. The increased redness in vacuum-packaged meat was stable during the 2 weeks of storage. The production of CO in meat, which can bind to myoglobin as a sixth ligand, was proportional to irradiation dose. The ORP was decreased by irradiation, but was increased during storage. The ORP and lipid oxidation values were lower in vacuum-packaged than those in aerobically packaged turkey breast. Therefore, increased a-values in irradiated turkey breast should be caused by the decreased ORP and heme pigment-CO ligand formation. The absorption spectra of meat drip also showed that the peak wavelengths of irradiated turkey breast were similar to that of the CO-myoglobin.     

Prevention of Lipid Oxidation in Precooked Turkey Meat Patties with Hot Packaging and Antioxidant Combinations

The effects of antioxidants or hot packaging and their combination on lipid oxidation were quite variable depending on the additives in turkey meat. The TBARS values of cooked patties were greatly affected by the degree of oxidation in the raw meat, and the effectiveness of antioxidants varied with added prooxidants. Ascorbate and free radical terminators had stronger antioxidant effects than iron chelators, and chelating iron alone could not eliminate lipid oxidation in either raw or cooked meat with added NaCl. The combination of hot packaging and antioxidants provided cooked patties with better protection from lipid oxidation than either treatment alone.     

Effect of dietary α-tocopherol supplementation and gamma-irradiation on α-tocopherol retention and lipid oxidation in cooked minced chicken

The effects of dietary α-tocopherol supplementation and gamma-irradiation on α-tocopherol retention and lipid oxidation in cooked minced chicken during refrigerated storage were studied. Minced breast and thigh meat from broilers fed diets supplemented with 100, 200 or 400 mg α-tocopheryl acetate/kg feed was irradiated at 2.5 or 4.0kGy. Cooked irradiated and unirradiated meat was stored at 4 °C for 5 days. α-Tocopherol concentrations increased with increasing dietary supplementation. Concentrations decreased during storage, but retention was not affected by irradiation. Lipid stability was determined by measuring the formation of thiobarbituric acid-reacting substances (TBARS) and cholesterol oxidation products (COPs) during storage. TBARS and COPs increased during storage and were reduced by increasing levels of dietary α-tocopheryl acetate supplementation. Irradiation accelerated TBARS formation during storage, but this was prevented by supplementation with 200 mg α-tocopheryl acetate/kg feed. Irradiation tended to increase COPs during storage, although no consistent effects were observed. In general supplementation with over 400 mg α-tocopheryl acetate/kg feed may be required to control cholesterol oxidation in minced chicken. The results suggest that, overall, irradiation had little effect on lipid stability in α-tocopherol-supplemented meat following cooking and storage.