PROCESSING AND PRODUCTS

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1 PROCESSING AND PRODUCTS Use of Double Packaging and Antioxidant Combinations to Improve Color, Lipid Oxidation, and Volatiles of Raw and Cooked Turkey Breast Patties 1 K. C. Nam and D. U. Ahn 2 Department of Animal Science, Iowa State University, Ames, Iowa ABSTRACT The effects of antioxidants and double radiated control. aerobically packaged meat packaging combinations on color, lipid oxidation, and volatiles production in irradiated raw and cooked turkey breast were determined. Ground meat was treated with antioxidants (none, sesamol + α-tocopherol, or gallate + α- tocopherol), and patties were prepared. The patties were packaged under vacuum, packaged aerobically, or double packaged (vacuum for 7 d then aerobic for 3 d) and electron beam irradiated at 3 kgy. Color, 2-thiobarbituric acid-reactive substances (TBARS), and volatile profiles of the samples were determined at 0 and 10 d and after cooking. had accelerated lipid oxidation and aldehyde production at 10 d and after cooking. Gallate + α-tocopherol alone with double packaging was effective in reducing the red color of irradiated meat at 10 d and after cooking. Considerable amounts of off-odor volatiles were reduced by double packaging and antioxidant treatment. Sulfur volatiles were evaporated during the aerobic period of double packaging, and lipid oxidation was prevented by the antioxidants and vacuum condition of double packaging. These beneficial effects of double packaging and antioxidants were more critical in irradiated cooked meat. Therefore, vacuum-packaged patties had great the combined use of antioxidants and double pack- amounts of sulfur volatiles (dimethyl sulfide and dimethyl disulfide) and increased red color during refrigerated storage and after cooking compared with the noniraging would be a useful method to control the oxidative quality changes of irradiated raw and cooked turkey breast. (Key words: antioxidant, double packaging, irradiated turkey, lipid oxidation, volatiles) 2003 Poultry Science 82: INTRODUCTION Although irradiating is the best method to ensure the microbiological safety of raw meat (Lambert et al., 1991), it caused a few radiolytic meat quality defects. pork and poultry meat accelerate lipid oxidation (Katusin-Razem et al., 1992; Ahn et al., 2000a), produce a characteristic off-odor (Patterson and Stevenson 1995; Du et al., 2000; Ahn et al., 2001), and develop a pink color (Lynch et al., 1991; Nanke et al., 1998; Nam and Ahn, 2002a). Jo and Ahn (2000) elucidated that sulfur volatiles produced by radiolytic degradation of sulfur amino acids are responsible for the irradiation off-odor, and Nam and Ahn (2002a) characterized the pink color in irradiated turkey breast as the complex of heme pigment and radiolytic carbon monoxide. The primary and 2003 Poultry Science Association, Inc. Received for publication February 13, Accepted for publication December 18, Journal Paper No. J of the Iowa Agriculture and Home Economics Experiment Station, Ames, IA Project No. 3706, and supported by NRI. 2 To whom correspondence should be addressed: duahn@iastate.edu. secondary reactions of free radicals generated by irradiation with meat components are believed to be the main cause of these quality changes. Woods and Pikaev (1994) and Ahn et al. (1997) reported that antioxidants reduce oxidative quality deterioration of irradiated meat by quenching free radicals. Nam and Ahn (2002b) showed that gallate or sesamol combined with α-tocopherol decreases production of sulfur volatiles as well as lipid oxidation in irradiated pork patties. Packaging is also a critical factor influencing the quality of irradiated meat. Under vacuum conditions, almost all sulfur volatiles generated by irradiation are retained in meat (Ahn et al., 2000b; Ahn et al., 2001; Nam et al., 2001), and the intensity of pink color in irradiated meat increases during storage (Luchsinger et al., 1996; Nam and Ahn, 2002a). Under aerobic conditions, almost all sulfur volatiles generated by irradiation disappear, and pink color intensity decreases after a few days of storage. Lipid oxidation in irradiated meat during storage was Abbreviation Key: a* = redness; b* = yellowness; CO-Mb = carbon monoxide-myoglobin; L* = lightness; TBARS, 2-thiobarbituric acid reactive substances. 850

2 ANTIOXIDANT AND DOUBLE PACKAGING ON IRRADIATED TURKEY MEAT QUALITY 851 TABLE 1. Packaging, irradiation, and antioxidant treatments used in this study Irradiation Antioxidant Treatment (kgy) (100 ppm each) Packaging method -vacuum packaged 0 Not added Vacuum for 10 d -vacuum packaged 3 Not added Vacuum for 10 d -aerobic packaged 3 Not added Aerobic for 10 d -double packaged 3 Not added Vacuum for 7 d then aerobic for 3 d -double packaged/s+e 1 3 Sesamol, α-tocopherol Vacuum for 7 d then aerobic for 3 d -double packaged/g+e 2 3 Gallate, α-tocopherol Vacuum for 7 d then aerobic for 3 d 1 Sesamol (100 ppm) and α-tocopherol (100 ppm) added. 2 Gallic acid (100 ppm) and α-tocopherol (100 ppm) added. accelerated only under aerobic conditions (Katusin-Razem et al., 1992; Ahn et al., 2000b). Therefore, exposing irradiated meat to aerobic conditions for a limited period of time could lower irradiation off-odor odor and decrease pink color intensity, and subsequent storage under vacuum could minimize lipid oxidation. Addition of antioxidants thus can prevent quality deterioration of irradiated double-packaged meat during storage. The objective of this study was to determine the effects of double packaging and antioxidant combinations on color, lipid oxidation, and volatiles of irradiated raw turkey breast during refrigerated storage and after cooking. Treatments MATERIALS AND METHODS A total of 36 male Large White turkeys (16 wk old) were slaughtered, and then carcasses were chilled in ice waterfor3handdrainedinacoldroom.breast muscles were deboned from the carcasses 24 h after slaughter. Skin and visible fat were removed. Breast meats from six birds were pooled from and used as a replication. Meats for each replication were ground through a 3-mm plate, and four replications were prepared. Six different treatments were prepared using antioxidant, packaging method, and irradiation conditions (Table 1). Vitamin E + sesamol and vitamin E + gallate combinations were used in this study, because these antioxidant combinations were most effective in reducing lipid oxidation and off-odor volatiles in irradiated turkey meat (Nam and Ahn, 2002b). Sesamol 3 (3,4-methylenedioxyphenol) plus α-tocopherol 4 or gallate 3 (3,4,5-trihydroxybenzoic acid) plus α-tocopherol was mixed with the ground turkey meat each at 100 ppm (final 200 ppm) using a bowl mixer 5 (Model KSM 90). The mixed meat samples were ground again through a 3-mm plate to ensure uniform 3 Sigma Chemical Co., St. Louis, MO. 4 Aldrich Chemical Co., Milwaukee, WI. 5 Kitchen Aid, Inc., St. Joseph, MI. 6 Koch, Kansas City, MO. 7 Associated Bag Company, Milwaukee, WI. 8 Thomson CSF Linac, Saint-Aubin, France. 9 Bruker Instruments Inc., Billerica, MA. 10 Hunter Associated Labs, Inc., Reston, VA. distribution of the added antioxidants. Other treatments without antioxidants were also put through the same mixing process to provide the same preparation conditions as antioxidant-added treatments. About 50 g of turkey breast patties was prepared from each treatment and then individually vacuum packaged in high oxygen-barrier bags 6 (nylon-polyethylene, 9.3 ml O 2 /m 2 per24hat0 C), aerobically packaged in polyethylene oxygen-permeable bags 7 (polyethylene, 2 mil), or double packaged. For double packaging, aerobically packaged patties were repackaged in oxygen-impermeable vacuum bags. The packaged patties were irradiated at 2.5 kgy using a linear accelerator 8 (Circe IIIR) with 10 MeV of energy, 10 kw of power, and 86.2 kgy/min of average dose rate. To confirm the target dose, two alanine dosimeters per cart were attached to the top and bottom surfaces of the sample and were read using a 104 Electron Paramagnetic Resonance instrument 9 (EMS-104). vacuum-packaged patties were prepared as a control. The outer vacuum bags of double-packaged meat were removed after 7 d of storage at 4 C toexposethe samples under aerobic conditions. Color, lipid oxidation, and volatile compounds of the irradiated raw meats were determined at 0 and 10 d of refrigerated storage. Part of the raw meat stored for 10 d was cooked in a 90 C water bath (cooked in bag) to an internal temperature of 75 C. The surface and internal colors, lipid oxidation, and volatiles of the cooked meat were determined after cooling the meat to room temperature. Color Measurement The CIE color values were measured on the surface of sample using a LabScan color meter 10 that had been calibrated against black and white reference tiles covered with the same packaging materials as used for the samples. The CIE lightness (L*), redness (a*), and yellowness (b*) values were obtained using an illuminant A (light source) with an area view of 0.25 inch and a port size of 0.40 inch. Two random locations of both top and bottom surfaces of the samples were measured. For the internal color of cooked meat, the patties were horizontally dissected, and the internal central locations were measured.

3 852 NAM AND AHN TABLE 2. CIE color values of irradiated turkey breast patties treated by different packaging and antioxidants during the 10 d of storage and after cooking Double packaging 2 Storage 1 packaging packaging packaging None S+E 3 G+E 4 SEM L* value 0 d abz az ay ay bz by d bz ay ay ay bz by 0.37 Cooked 5 (surface) ax ax ax ax ax bx 0.31 Cooked (inside) y x x x y x 0.81 SEM a* value 0 d 4.42 cz 7.95 ay 7.15 bx 7.74 axy 6.95 by 6.74 bx d 4.67 dz 7.89 ay 5.66 cy 6.98 by 4.68 dz 5.63 cy 0.11 Cooked 5 (surface) 5.96 by 7.53 ay 3.99 cz 6.20 bz 5.55 bz 4.51 cz 0.21 Cooked (inside) 7.50 cx ax 5.58 dy 8.62 bx 7.51 cx 5.75 dy 0.23 SEM b* value 0 d 9.63 aby 9.79 az 9.62 abz 9.14 bz 8.58 cz 8.59 cz d 9.18 dy 9.55 cdz ay by by 9.86 cy 0.18 Cooked 5 (surface) abx ax bx ax abx bx 0.50 Cooked (inside) abx aby ax ax abx bx 0.33 SEM a d Different letters within a row are significantly different (P < 0.05); n = 4. x z Different letters within a column with same color value are significantly different (P < 0.05). 1 L* = lightness; a* = redness; b* = yellowness. 2 Vacuum packaged for 7 d then aerobically packaged for 3 d. 3 Sesamol (100 ppm) and α-tocopherol (100 ppm) added. 4 Gallic acid (100 ppm) and α-tocopherol (100 ppm) added. 5 Cooked by internal temperature (75 C) after 10 d of storage. Analysis of 2-Thiobarbituric Acid Reactive Substance Values Lipid oxidation was determined by analysis of 2-thiobarbituric acid reactive substances (TBARS) (Ahn et al., 1998). Each meat sample (5 g) was placed in a 50-mL test tube and homogenized with 15 ml of deionized, distilled water using a Brinkman Polytron 11 (Type PT 10/35) for 15 s at high speed. The meat homogenate (1 ml) was transferred to a disposable test tube ( mm), and butylated hydroxytoluene (7.2%, 50 µl) and thiobarbituric acid-trichloroacetic acid [20 mm thiobarbituric acid and 15% (wt/vol) trichloroacetic acid] solution (2 ml) were added. The mixture was vortexed and then incubated in a 90 C water bath for 15 min to develop color. After cooling for 10 min in cold water, the samples were vortexed and centrifuged at 3,000 g for 15 min at 5 C. The absorbance of the resulting upper layer was read at 531 nm against a blank prepared with 1 ml deionized, distilled water and 2 ml thiobarbituric acid-trichloroacetic acid solution. The amounts of TBARS were expressed as milligrams of malonedialdehyde per kilogram of meat. 11 Brinkman Instrument, Inc., Westbury, NY. 12 Takmar-Dohrmann, Cincinnati, OH. 13 Hewlett-Packard Co., Wilmington, DE. 14 J & W Scientific, Folsom, CA. Analysis of Volatile Profiles A purge-and-trap apparatus 12 (Precept II and Purge & Trap Concentrator 3000) connected to a gas chromatograph-mass spectrometer 13 was used to analyze volatiles produced (Ahn et al., 2001). Each minced meat sample (3 g) was placed in a 40-mL sample vial, and the vials were flushed with helium gas (40 psi) for 5 s. Samples were held in a refrigerated (4 C) sample-holding tray before analysis, and the maximum holding time was lessthan6htominimize oxidative changes (Ahn et al., 1999). The meat sample was purged with helium gas (40 ml/min) for 13 min at 40 C. Volatiles were trapped using a Tenax column 14 and desorbed for 2 min at 225 C, focused in a cryofocusing module ( 90 C), and then thermally desorbed into a column for 30 s at 225 C. An HP-624 column 13 (7.5 m 0.25 mm i.d., 1.4 µm nominal), an HP-1 column 13 (52.5 m 0.25 mm i.d., 0.25 µm nominal), and an HP-Wax column 13 (7.5 m 0.25 mm i.d., 0.25 µm nominal) were connected using zero dead-volume column connectors. 14 Ramped oven temperature was used to improve volatile separation. The initial oven temperature of 0 C was held for 2.50 min. After that, the oven temperature was increased to 15 C at 2.5 C/min, increased to 45 C at5 C/min, increased to 110 C at20 C/min, increased to 210 C at10 C/min, and then held for 4.5 min. Constant column pressure at 20.5 psi was maintained. The ionization potential of the mass selective detector 13 (Model 5973) was 70 ev, and

4 ANTIOXIDANT AND DOUBLE PACKAGING ON IRRADIATED TURKEY MEAT QUALITY 853 TABLE 3. 2-Thiobarbituric acid reactive substance values of irradiated turkey breast patties treated by different packaging and antioxidants during 10 d of storage and after cooking Double packaging 1 Storage packaging packaging packaging None S+E 2 G+E 3 SEM (mg MDA 4 /kg meat) 0 d 0.66 by 0.84 ay 0.91 ay 0.83 ay 0.42 dy 0.55 c d 0.72 cy 0.84 cy 2.18 ax 1.61 by 0.53 cx 0.53 c 0.09 Cooked dx 1.67 cx 2.37 ax 2.09 bx 0.54 ex 0.64 e 0.07 SEM a e Different letters within a row are significantly different (P < 0.05); n = 4. x,y Different letters within a column are significantly different (P < 0.05). 1 Vacuum packaged for 7 d then aerobically packaged for 3 d. 2 Sesamol (100 ppm) and α-tocopherol (100 ppm) added. 3 Gallic acid (100 ppm) and α-tocopherol (100 ppm) added. 4 Malonedialdehyde. 5 Cooked by internal temperature (75 C) after 10 d of storage. the scan range was 18.1 to 350 m/z. Identification of volatiles was achieved by comparing mass spectral data of samples with those of the Wiley library. 13 Standards, when available, were used to confirm the identification by the mass selective detector. The area of each peak was integrated using the ChemStation, 13 and the total peak area (pa s 10 4 ) was reported as an indicator of volatiles generated from the sample. Statistical Analysis A completely randomized design was used to determine the effects of double packaging and antioxidant combinations on color, lipid oxidation, and volatile profiles of the irradiated samples during storage. Data were analyzed by the general linear models procedure using SAS software (SAS Institute, 1995). Student-Newman- Keul s multiple-range test was used to compare the mean values of treatments. Mean values and SEM were reported at P < RESULTS AND DISCUSSION Color Changes turkey breast had higher a* values than nonirradiated meat (Table 2). Antioxidants lowered the L* value of vacuum-packaged irradiated meat by about 2 U and a* value by 1 U. The a* value of aerobically packaged irradiated meat was lower than that of vacuum-packaged meat but was still higher than the nonirradiated control. Nam and Ahn (2002a) attributed the increased red color in irradiated turkey meat to the formation of carbon monoxide-myoglobin (CO-Mb) complexes. The CO-Mb complex is more stable than oxymyoglobin because of the strong binding of CO to the iron-porphyrin site on the myoglobin molecule (Sorheim et al., 1999). The increased redness of vacuum-packaged turkey breast by irradiation was stable even after 10 d of refrigerated storage. However, the redness of aerobically or double-packaged meat decreased significantly. This finding indicated that exposing irradiated meat to aerobic conditions was effective in reducing CO-heme pigment complex formation. Furthermore, the combination of antioxidants with double packaging showed a synergistic effect in reducing the redness of irradiated meat; the presence of oxygen should accelerate the dissociation of CO-Mb, whereas antioxidants should inhibit radiolytic generation of CO. Grant and Patterson (1991) also reported that irradiated color could be discolored in the presence of oxygen. The color changes of irradiated meat after cooking are more of concern, because residual pink color in turkey breast meat can be considered undercooked or contaminated by consumers. The redness of meat was still higher in irradiated meat than in nonirradiated meat even after cooking, and the inside of the meat had stronger redness intensity than the surface. cooked turkey breast meat from double packaging and antioxidant combinations, however, produced significantly lower a* values than the vacuum-packaged irradiated cooked meat. Gallate plus α-tocopherol was significantly more effective in reducing the redness than sesamol plus α- tocopherol. Therefore, the gallate plus α-tocopherol in combination with double packaging can be effective in controlling off-color in irradiated raw and cooked turkey breast meat. Lipid Oxidation Both aerobic packaging and irradiation increased the lipid oxidation of turkey breast, but the presence of oxygen was a more critical factor than irradiation on lipid oxidation during storage (Table 3). Vacuum-packaged meat was more resistant to lipid oxidation than aerobically packaged meat, and the TBARS increase was proportional to the exposure time to aerobic conditions. The TBARS of meat was highest with aerobic packaging, lowest with vacuum packaging, and in the middle with

5 854 NAM AND AHN double packaging. Two antioxidant combinations were very effective in preventing lipid oxidation during storage, and the TBARS of antioxidant-treated meats were lower than even nonirradiated vacuum-packaged meat at 10 d. The antioxidant effect on lipid oxidation of turkey meat was even more distinct after cooking. The TBARS of irradiated turkey meat increased rapidly after cooking, but those with antioxidants did not. Therefore, the problem of lipid oxidation in aerobically or doublepackaged irradiated raw and cooked turkey breast could be solved by addition of sesamol + α-tocopherol or gallate + α-tocopherol. Off-Odor Volatiles of Raw Meat Irradiation generated many volatiles not found in vacuum-packaged nonirradiated turkey breast meat (Table 4). The majority of newly generated volatiles were hydrocarbons and sulfur-containing compounds, and 1- butene, toluene, dimethyl sulfide, and dimethyl disulfide were among the most distinct. S-compounds are regarded as the major volatiles responsible for the characteristic of irradiation off-odor and are different from the rancidity caused by lipid oxidation products. Ahn et al. (2000a) described the irradiation odor in raw pork as a barbecued corn-like odor. S-containing volatiles, such as 2,3-dimethyl disulfide produced by radiolytic degradation of sulfur amino acids, are responsible for the off-odor in irradiated pork, and their amounts are highly dependent upon irradiation dose (Ahn et al., 2000b). Aerobic packaging was more desirable than vacuum or double packaging in reducing the amounts of hydrocarbons and sulfur compounds. Almost all dimethyl disulfide, a main irradiation off-odor, disappeared under aerobic conditions, and aerobically packaged irradiated meat had only one-third the total volatiles of the vacuum-packaged meat. Little difference in volatile profiles between vacuum-packaged irradiated and doubly packaged irradiated meats at 0 d was found because they were both under vacuum conditions during irradiation. Antioxidant treatments lowered total volatiles in meat, and propanal was not detected when antioxidants were added. After 10 d of refrigerated storage, volatile profiles of irradiated turkey breast were highly dependent upon antioxidant and packaging conditions (Table 5). Vacuum-packaged irradiated turkey breast had the greatest amounts of total and sulfur volatiles. The amount of dimethyl disulfide increased twofold compared with that at 0 d (P < 0.01), and dimethyl trisulfide was newly generated in vacuum-packaged irradiated meat. These sulfur volatiles, however, were not detected in irradi- TABLE 4. Volatile profiles of irradiated raw turkey breast patties treated by different packaging and antioxidants at 0 d Double packaging 1 Storage packaging packaging packaging None S+E 2 G+E 3 SEM (Total ion counts 10 4 ) Hydrocarbons 1-Butene 0 b 854 a 947 a 818 a 859 a 951 a 68 1-Pentene 0 c 176 ab 189 a 156 ab 123 b 147 ab 14 Pentane 431 b 854 a 1,105 a 904 a 352 b 426 b 70 2-Pentene 0 b 110 a 96 a 102 a 0 b 33 b 10 1-Hexene 0 c 115 a 99 ab 94 ab 75 ab 47 ab 14 Hexane 97 c 260 b 384 a 212 b 168 bc 180 bc 26 Benzene 0 c 196 ab 158 b 226 a 208 ab 246 a 15 1-Heptene 0 d 124 ab 155 a 127 ab 90 bc 64 c 10 Heptane 0 d 110 b 168 a 120 b 76 c 57 c 9 Toluene 0 d 560 a 365 c 432 bc 468 b 426 bc 24 4-Octene 246 b 371 a 0 d 123 c 135 c 135 c 23 Octane 418 b 658 a 119 c 246 bc 255 bc 251 bc 43 2-Octene 169 bc 644 a 0 c 397 b 480 b 408 b 10 3-Methyl-2-heptene 242 a 313 a 0 c 82 b 109 b 99 b 24 2-Octene 0 c 145 a 0 c 70 b 16 c 39 bc 11 Sulfurs Dimethyl sulfide 879 b 1,455 a 819 b 1,405 a 1,434 a 919 b 78 Carbon disulfide 246 ab 293 a 0 c 276 ab 203 b 44 c 22 Dimethyl disulfide 0 b 11,918 a 83 b 11,466 a 8,306 a 8,557 a 1,473 Aldehyde and ketone Propanal 61 b 286 a 257 a 298 a 0 b 0 b 19 2-Propanone 2,608 a 2,630 a 2,465 ab 1,555 c 1,800 c 2,158 b 105 Total 5,401 c 22,069 a 7,415 c 19,117 ab 15,162 b 15,195 b 1,483 a d Different letters within a row are significantly different (P < 0.05); n = 4. 1 Vacuum packaged for 7 d then aerobically packaged for 3 d. 2 Sesamol (100 ppm) and α-tocopherol (100 ppm) added. 3 Gallic acid (100 ppm) and α-tocopherol (100 ppm) added.

6 ANTIOXIDANT AND DOUBLE PACKAGING ON IRRADIATED TURKEY MEAT QUALITY 855 TABLE 5. Volatile profiles of irradiated raw turkey breast patties treated by different packaging and antioxidants after 10 d of refrigerated storage Double packaging 1 Storage packaging packaging packaging None S+E 2 G+E 3 SEM (Total ion counts 10 4 ) Hydrocarbons 1-Butene 0 c 930 a 111 c 419 b 366 b 366 b 52 1-Pentene 0 c 195 a 113 b 120 b 140 b 99 b 16 Pentane 684 bc 1,365 ab 2,147 a 1,532 a 354 c 571 bc Pentene 40 bc 174 a 0 c 65 b 0 c 0 c 14 1-Hexene 0 c 112 a 75 b 67 b 69 b 80 b 7 Hexane 78 c 374 b 514 a 311 b 294 b 304 b 33 Benzene 0 c 309 a 20 c 200 b 152 b 144 b 22 1-Heptene 0 c 92 b 167 a 96 b 79 b 79 b 8 Heptane 0 c 110 b 217 a 125 b 82 b 99 b 12 Toluene 0 c 537 a 178 b 214 b 172 b 213 b 24 4-Octene 228 b 490 a 0 d 74 cd 96 c 137 c 25 Octane 411 b 862 a 122 c 174 c 203 c 302 bc 53 2-Octene 193 b 451 a 0 c 59 c 59 c 85 c 17 3-Methyl-2-heptene 230 b 445 a 0 d 60 cd 76 cd 116 c 28 Sulfurs Dimethyl sulfide 1,304 b 1,990 a 140 d 831 c 676 c 546 c 85 Carbon disulfide 258 b 306 a 0 c 0 c 0 c 0 c 14 Dimethyl disulfide 0 b 22,702 a 0 b 32 b 0 b 43 b 739 Dimethyl trisulfide 0 b 554 a 0 b 0 b 0 b 0 b 16 Aldehydes and Ketones Propanal 0 b 0 b 1,966 a 600 b 0 b 0 b 14 Hexanal Propanone 1,739 b 2,116 ab 2,465 a 2,147 ab 1,962 ab 1,992 ab Butanone 0 b 0 b 107 a 0 b 0 b 0 b 5 Total 5,172 b 34,120 a 9,102 b 7,132 b 4,785 b 5,183 b 1,152 a d Different letters within a row are significantly different (P < 0.05); n = 4. 1 Vacuum packaged for 7 d then aerobically packaged for 3 d. 2 Sesamol (100 ppm) and α-tocopherol (100 ppm) added. 3 Gallic acid (100 ppm) and α-tocopherol (100 ppm) added. ated aerobically or double-packaged meat. Three days of exposure to aerobic conditions was enough for the sulfur volatiles to escape from the meat. However, aerobically packaged irradiated meat without antioxidants produced large amounts of aldehydes (propanal, hexanal) and 2-butanone at 10 d, which coincided with the result of TBARS (Table 3). Double-packaged meat had few lipid oxidation products compared with aerobically packaged meat, but antioxidant combinations significantly reduced the amount of pentane. Therefore, the combination of double packaging (vacuum for 3 d then aerobic for 7) with antioxidants in irradiated raw turkey breast was very effective in reducing total and sulfur volatiles responsible for the irradiation off-odor without any problem in lipid oxidation. Off-Odor Volatiles of Cooked Meat The beneficial effects of double packaging and antioxidant combinations on volatiles were more apparent in irradiated cooked turkey breast (Table 6). cooked turkey breast not only produced considerable amounts of sulfur volatiles but also aldehydes and ketones. Therefore, irradiated cooked meat had a characteristic irradiation off-odor and lipid oxidation-related volatiles compared with the nonirradiated cooked meat. Cooking of vacuum-packaged irradiated meat produced high amounts of sulfur volatiles, whereas cooking of aerobically packaged irradiated meat produced large amounts of aldehydes. Large amounts of propanal and hexanal were formed in irradiated cooked turkey breast, and the amount of total volatiles was greatest in aerobically packaged irradiated cooked meat. This result shows that both lipid oxidation products and irradiation off-odor were problematic when storing irradiated meat under aerobic conditions. Double packaging was more effective than vacuum packaging in reducing sulfur volatiles and lipid oxidation-dependent volatiles compared with aerobic packaging. However, the combination of antioxidant with double packaging was more effective in reducing sulfur and lipid oxidation volatiles in irradiated cooked meat. The total amounts of sulfur volatiles in double-packaged irradiated turkey meat with antioxidants were only about 5 to 7% of the irradiated vacuum-packaged cooked meat without antioxidants. Production of most aldehydes in irradiated cooked turkey breast was prevented by using antioxidants and double packaging. In conclusion, the combination of double packaging and antioxidants was highly effective in controlling lipid

7 856 NAM AND AHN TABLE 6. Volatile profiles of irradiated, cooked (internal temperature, 75 C) turkey breast patties treated by different packaging and antioxidants Double packaging 1 Storage packaging packaging packaging None S+E 2 G+E 3 SEM (Total ion counts 10 4 ) Hydrocarbons and furan 1-Butene 74 c 1,441 a 1,595 a 1,502 a 575 b 577 b 95 1-Pentene 0 d 366 ab 380 ab 436 a 174 c 240 bc 43 Pentane 1,738 c 6,527 c 30,267 a 21,607 b 1,332 c 2,443 c 2,051 2-Pentene 77 d 289 c 721 a 606 b 82 d 128 d 28 1-Hexene 0 c 199 ab 274 a 204 ab 156 b 191 ab 22 Hexane 191 d 904 c 5,192 a 2,540 b 803 c 931 c 165 Benzene 0 c 313 a 177 b 316 a 192 b 224 ab 29 1-Heptene 0 b 414 a 680 a 558 a 412 a 453 a 75 Heptane 94 c 467 c 3,602 a 1,799 b 321 c 485 c 133 Toluene 0 c 2,199 a 822 b 2,226 a 2,403 a 1,689 a Octene 253 b 510 a 129 b 294 b 313 b 251 b 56 Octane 380 d 1,219 bc 2,214 a 1,677 b 800 cd 801 cd Octene 137 c 612 a 653 a 606 a 313 b 323 b 50 3-Methyl-2-heptene 267 a 409 a 0 b 301 ab 227 ab 170 ab 61 Nonane 0 b 0 b 63 a 0 b 0 b 0 b 1 2-Ethyl furan 0 b 0 b 166 a 0 b 0 b 0 b 11 Sulfurs Dimethyl sulfide 1,008 b 2,032 a 451 d 1,005 b 689 c 588 cd 48 Carbon disulfide 419 a 339 ab 210 b 271 ab 278 ab 374 a 35 Dimethyl disulfide 0 b 17,861 a 342 b 940 b 412 b 210 b 601 Dimethyl trisulfide 0 b 1,007 a 0 b 118 b 0 b 0 b 49 Aldehydes and Ketones Propanal 233 d 2,272 c 8,637 a 5,962 b 38 d 427 d 377 Butanal 0 e 127 d 592 a 195 c 302 b 226 c 22 Pentanal 62 c 875 c 3,014 a 1,667 b 0 c 31 c 223 Hexanal 0 b 3,734 b 37,617 a 9,686 b 0 b 0 b 2,626 2-Propanone 1,770 d 2,828 bc 3,744 a 33,84 ab 2,863 bc 2,637 c Butanone 0 c 116 b 0 c 231 a 223 a 142 b 10 3-Methyl butanal 0 c 100 b 223 a 204 a 131 b 142 b 12 Total 6,706 c 47,171 b 101,773 a 58,251 b 13,046 c 13,691 c 4,889 a e Different letters within a row are significantly different (P < 0.05); n = 4. 1 Vacuum packaged for 7 d then aerobically packaged for 3 d. 2 Sesamol (100 ppm) and α-tocopherol (100 ppm) added. 3 Gallic acid (100 ppm) and α-tocopherol (100 ppm) added. oxidation and irradiation off-odor of irradiated raw and cooked turkey breast patties. REFERENCES Ahn, D. U., C. Jo, and D. G. Olson Volatile profiles of raw and cooked turkey thigh as affected by purge temperature and holding time before purge. J. Food Sci. 64: Ahn, D. U., C. Jo, and D. G. Olson. 2000a. Analysis of volatile components and the sensory characteristics of irradiated raw pork. Meat Sci. 54: Ahn, D. U., C. Jo, M. Du, D. G. Olson, and K. C. Nam. 2000b. Quality characteristics of pork patties irradiated and stored in different packaging and storage conditions. Meat Sci. 56: Ahn, D. U., K. C. Nam, M. Du, and C. Jo Volatile production in irradiated normal, pale soft exudative (PSE) and dark firm dry (DFD) pork under different packaging and storage conditions. Meat Sci. 57: Ahn, D. U., D. G. Olson, C. Jo, X. Chen, C. Wu, and J. I. Lee Effect of muscle type, packaging, and irradiation on lipid oxidation, volatile production, and color in raw pork patties. Meat Sci. 47: Ahn, D. U., J. L. Sell, M. Jeffery, C. Jo, X. Chen, C. Wu, and J. I. Lee Dietary vitamin E affects lipid oxidation and total volatiles of irradiated raw turkey meat. J. Food Sci. 62: Du, M., D. U. Ahn, K. C. Nam, and J. L. Sell Influence of dietary conjugated linolenic acid on volatile profiles, color and lipid oxidation of irradiated raw chicken meat. Meat Sci. 56: Grant, I. R., and M. F. Patterson Effect of irradiation and modified atmosphere packaging on the microbiological and sensory quality of pork stored at refrigeration temperatures. Int. J. Food Sci. Technol. 26: Jo, C., and D. U. Ahn Production of volatile compounds from irradiated oil emulsions containing amino acids or proteins. J. Food Sci. 65: Katusin-Razem, B., K. W. Mihaljevic, and D. Razem Timedependent post irradiation oxidative chemical changes in dehydrated egg products. J. Agric. Food Chem. 40: Lambert, A. D., J. P. Smith, and K. L. Dodds Shelf life extension and microbiological safety of fresh meat: A review. Food Microbiol. 8: Luchsinger, S. E., D. H. Kropf, C. M. Garcia-Zepeda, M. C. Hunt, J. L. Marsden, E. J. Rubio-Canas, C. L. Kastner, W. G. Kuecher, and T. Mata Color and oxidative rancidity of gamma and electron beam-irradiated boneless pork chops. J. Food Sci. 61: Lynch, J. A., H. J. H. MacFie, and G. C. Mead Effect of irradiation and packaging type on sensory quality of chilled-

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