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Four antioxidant treatments (none, 0.05% ascorbic acid, 0.01% α-tocopherol+0.01% sesamol, and 0.05% ascorbic acid+0.01% α-tocopherol+0.01% sesamol) were applied to ground beef using either mixing or spraying method. The meat samples were placed on Styrofoam trays, irradiated at 0 or 2.5 kGy, and then stored for 7 d at 4° C. Color, lipid oxidation, and volatiles were determined at 0, 3, and 7 d of storage. Irradiation increased lipid oxidation of ground beef with control and ascorbic acid treatments after 3 days of storage. α-Tocopherol+sesamol and ascorbic acid+α- tocopherol+sesamol treatments were effective in slowing down lipid oxidation in ground beef during storage regardless of application methods, but mixing was better than spraying method. Ascorbic acid was the most effective in maintaining redness of ground beef followed by ascorbic acid+α-tocopherol+sesamol. Beef sprayed with antioxidants produced more hydrocarbons and alcohols than mixing application, but ascorbic acid+α-tocopherol+sesamol treatment was effective in reducing the amount of volatiles produced by irradiation. Therefore, mixing was better than spraying method in preventing lipid oxidation and maintaining color of irradiated ground beef.

Release of volatiles in oil emulsion systems containing various fat contents was determined using purge-and-trap dynamic headspace/gas chromatography. Oil emulsions were prepared using 0, 0.5, 1, 2, 4, or 8% oil, and a standard mixture was prepared using hydrocarbons, aldehydes, ketones, and alcohols. Fat content in oil emulsions reduced the volatility of added volatile standards, and the amount of volatiles released from oil emulsion correlated negatively with fat content (r 2 = 0.92 in total volatiles). Among these tested, the volatilization of ketones was least influenced by fat content. The release of nonpolar hydrocarbons was not influenced but polar compounds (aldehydes, ketones, and alcohols) were greatly influenced by water.

The Egg Safety Action Plan released in 1999 raised many questions concerning egg temperature used in the risk assessment model. Therefore, a national study by researchers in California, Connecticut, Georgia, Iowa, Illinois, North Carolina, Pennsylvania, and Texas was initiated to determine the internal and external temperature sequence of eggs from oviposition through distribution. Researchers gathered data from commercial egg production, processing, and distribution facilities. The experimental design was a mixed model with random effects for season and a fixed effect for duration of the transport period (long or short haul). It was determined that processors used refrigerated transport trucks (REFER) as short-term storage (STS) in both the winter and summer. Therefore, this summary of data obtained from REFER also examines the impact of their use as STS. Egg temperature data were recorded for specific loads of eggs during transport to point of resale or distribution to retailers. To standardize data comparisons between loads, they were segregated between long and short hauls. The summer egg temperatures were higher in the STS and during delivery. Egg temperature was not significantly reduced during the STS phase. Egg temperature decreases were less (P < 0.0001) during short delivery hauls 0.6 degrees C than during long hauls 7.8 degrees C. There was a significant season x delivery interaction (P < 0.05) for the change in the temperature differences between the egg and ambient temperature indicated as the cooling potential. This indicated that the ambient temperature during long winter deliveries had the potential to increase egg temperature. The REFER used as STS did not appreciably reduce internal egg temperature. These data suggest that the season of year affects the temperature of eggs during transport. Eggs are appreciably cooled on the truck, during the delivery phase, which was contrary to the original supposition that egg temperatures would remain static during refrigerated transport. These data indicate that refrigerated transport should be a component in future assessments of egg safety.

Ground beef, pork, and chicken thigh meats were irradiated at 0 or 5.0kGy before and after cooking and then stored at -40°C in oxygen permeable bags. The pH, lipid oxidation, volatiles, and carbon monoxide production of the meat were determined at 0 and 6months of storage. The pH values of raw meats from different animal species were different (5.36-6.25) and were significantly increased by cooking, irradiation, and storage (p0.05). Irradiation had no effect on the TBARS values of ground beef and pork, but significantly increased the TBARS of chicken thigh meat. Cooking, whether it was done before or after irradiation, caused significant increase in TBARS and was most significant in chicken and pork. The numbers of volatiles analyzed by GC/MS were higher in irradiated meats than the non-irradiated ones regardless of meat source. Sulfur-containing compounds were newly produced or increased by irradiation, but dimethyl disulfide and dimethyl trisulfide were not detected in the non-irradiated meats regardless of cooking treatment. Irradiation time, whether done before or after cooking, had little effect on the TBARS, volatiles, and carbon monoxide production in the meat.

The D10-values of L. monocytogenes in breast rolls and hams were 0.52 and 0.47 kGy, respectively. For breast rolls, the log10 reductions of L. monocytogenes following irradiation at 1.0 and 2.5 kGy were 1.5 and 4.7, respectively, while 2.0 and 5.5 for hams. The log10 reductions of APC in breast rolls following 1.0 and 2.0-kGy irradiation were 2.9 and 5.2 while that of hams was < 10 CFU/cm2 after 1.0- and 2.0-kGy irradiation. In 2.0 kGy-irradiated hams, L. Monocytogenes grew to 4.82 log10 CFU/cm2 after 28 d storage at 4 °C, while APC increased to 2.98 log10 CFU/cm2, respectively. In breast rolls after 14 d storage, APC in 1.0 kGy-irradiated samples increased to 7.53 log10 CFU/cm2; and APC increased to 2.63 and 4.68 log10 CFU/cm2 for 2.0 kGy-irradiated breast rolls after 14 and 28 d storage. However, during the storage of breast rolls, L. monocytogenes grew slowly or even stopped to grow in both non-irradiated and irradiated breast rolls due to the competitive inhibition of natural flora in breast rolls. Irradiation greatly reduced L. monocytogenes and APC in turkey hams and breast rolls. However, at least 2.5 kGy irradiation is needed to achieve a 5-log reduction of L. monocytogenes in turkey hams and breast rolls. Some cells survived irradiation and grew during storage after lag phase. To control L. monocytogenes contamination in RTE turkey hams and breast rolls during storage, additional barriers, such as adding preservatives, are necessary in order to ensure the microbial safety of products following low-dose irradiation.

2-Thiobarbituric acid-reactive substances (TBARS) values of raw pork, and chicken breast and thigh meats did not change during a 7-d storage period. Low free iron content and high ferric ion reducing capacity (FRC) were responsible for the low TBARS values in those meats during storage. TBARS values of raw beef loin, however, significantly increased during 7-d storage because of high free iron content and high lipoxygenase-like activities by ferrylmyoglobin. The TBARS values of cooked meat increased significantly with storage. Heat-stable FRC was detected in all cooked meat and was responsible for the increase of TBARS in cooked meat during storage. The rate of TBARS increases and the amounts of nonheme iron and heat-stable FRC in cooked beef loin were higher than those in cooked pork loin and chicken breast. In spite of lower amounts of nonheme iron and heat-stable FRC, cooked chicken thigh showed similar levels of TBARS to cooked beef loin after 7-d storage because of its high PUFA content. The total amount of PUFA in meat, most of which were present in triglycerides, influenced the development of lipid peroxidation only in the presence of sufficient amounts of free irons in cooked meat. This indicated that the content of free ionic iron, myoglobin, and ferric ion reducing capacity (FRC) were the primary determinants for the different susceptibility of raw meats to lipid peroxidation. In cooked meat, the contents of free ionic iron and heat-stable FRC played a key role on the development of lipid peroxidation. PUFA was important for lipid oxidation in cooked meat only when sufficient amount of free iron was present.

The color of egg yolk was not influenced but the viscosity of egg white was dramatically lowered and became watery by irradiation. The foam capacity and foam stability of egg white were significantly decreased due to protein oxidation by irradiation. However, the texture characteristics of egg white were not changed by irradiation, indicating that irradiation may not alter the thermal characteristics of egg white proteins. Sulfur volatiles were generated by irradiation but disappeared during storage under aerobic conditions. Because egg white became watery, irradiation may not be advisable for table eggs, but may be useful for pasteurizing liquid egg white or liquid whole egg without significant deterioration of their quality and functionality. Especially, the dramatic decrease in the viscosity of egg white by irradiation will improve flow of liquid egg white or liquid whole egg, which could be highly useful for egg processing. Therefore, further studies on egg irradiation should be focused on liquid eggs rather than table egg.

Irradiation of ground beef under aerobic conditions oxidized myoglobin and drastically reduced color a*-values. Under vacuum or non-oxygen conditions, however, irradiation did not influence the redness of ground beef. Also, the red color of ground beef was maintained even after the irradiated beef was exposed to aerobic conditions. Vacuum-packaged irradiated ground beef had lower metmyoglobin content and lower oxidation-reduction potential than the aerobically packaged ones. Irradiating ground beef under vacuum-packaging conditions was also advantageous in preventing lipid oxidation and aldehydes production. Vacuum-packaged irradiated beef, however, produced high levels of sulfur volatiles during irradiation and maintained their levels during storage, which resulted in the production of characteristic irradiation off-odor. Double-packaging (V3/A3: vacuum-packaging during irradiation and the first 3 days of storage and then aerobic-packaging for the remaining 3 days) was an effective alternative in maintaining original beef color (red), and minimizing lipid oxidation and irradiation off-odor. The levels of off-odor volatiles in double-packaged irradiated ground beef were comparable to that of aerobically packaged ones, and the degree of lipid oxidation and color changes were close to those of vacuum-packaged ones. Ascorbic acid at 200 ppm level was not effective in preventing color changes and lipid oxidation in irradiated ground beef under aerobic conditions, but was helpful in minimizing quality changes in doublepackaged irradiated ground beef. This suggested that preventing oxygen contact from meat during irradiation and early storage period (V3/A3 double-packaging) and doublepackaging+ascorbic acid combination are excellent strategies to prevent off-odor production and color changes in irradiated ground beef. Developing methods that can prevent quality changes of irradiated beef is important for the implication of irradiation, which will improve the safety of beef.

Seven different pH conditions, ranging from pH 5.5 to 8.0, were used to determine the effects of pH on the heme-complex-forming reactions of myoglobin, hemoglobin, and cytochrome c with selected ligands. Each 1 mg/mL myoglobin, 1 mg/mL hemoglobin, and .5 mg/mL of cytochrome c was dissolved in a citrate-phosphate, phosphate, or Tris-HCl solution, depending on the pH desired. An appropriate amount of each reactant was dissolved in the pigment solutions, and SDS was added to provide denaturation conditions. The solutions were reduced with sodium hydrosulfite and their absorption spectra were scanned from 600 to 500 nm with a spectrophotometer. A high pH (> 6.4) was favorable for the heme-complex-forming reactions of myoglobin and hemoglobin with most of the ligands except pyridine. At pH 6.1 to 6.4, added proteins and nicotinamide started to form heme complexes with myoglobin and hemoglobin; with pyridine, heme complexes were formed at a lower pH ( The heme-complex-forming reactions of cytochrome c with ligands were barely affected by pH of the solutions. Unlike reactions with myoglobin and hemoglobin, a high pH was not always favorable for heme complex and cytochrome c reactions. In meat with a high ultimate pH such as turkey breast meat, the heme complex can be a very important factor in cooked meat color. The pH of turkey breast meat can be increased to approximately 6.4 by added phosphates, and the pH range of 6.1 to 6.4 was very critical in this research for heme complex formation of myoglobin and hemoglobin with naturally present ligands such as histidine, cysteine, methionine, nicotinamide, and solubilized proteins.

Heme-complex-forming ligands and their effects on color were studied in cooked turkey breast meat. Twenty-four ground meat samples were prepared with combinations of two levels of pigments [0 or .4 mg of myoglobin (Mb) and .4 mg of hemoglobin (Hb) per gram meat weight], two levels of NaCl (0 or 2.5%), and six ligands. Each combination of ingredients was dissolved in distilled water (15%, meat weight) prior to mixing with the meat samples. Each meat sample was hand mixed in a 250-mL beaker, covered with aluminum foil, and cooked to an internal temperature of 75 C in a water bath. Among the ligands, pyridine, nicotinamide, and histidine formed heme complexes with added pigments. Pyridine produced the highest a values (redness), followed by nicotinamide, histidine, and the control, respectively. Although the added BSA was expected to produce a pink color, it did not have any effect on the redness of the meat. The effect of the added salt appeared as great as that of the added pigments by apparently providing solubilized proteins to form heme complexes in the meat. The b and L values of the meat were usually decreased because of added nicotinamide or histidine. The added pigments and salt also generally decreased the b and L values of the turkey breast meat. Total pigment and extractable pigment increased when heme pigments were added. No relationships were observed between the redness and the total pigment or between the a value and the extractable pigment.

The heme-complex-forming reactions of myoglobin, hemoglobin, and cytochrome c with various concentrations of reactants were studied. Each 1 mg/mL of myoglobin and hemoglobin as well as each .5 mg/mL of cytochrome c was dissolved in. 1 M phosphate buffer solution, pH 6.5; and several concentrations of ligands were added. A 10% SDS solution was used to prepare a final concentration of. 1% SDS for denaturing pigments. The pigment solutions were reduced with sodium hydrosulfite, and their absorption spectra were scanned from 600 nm to 500 nm with a spectrophotometer. Among those ligands studied, pyridine and nicotinamide formed heme-complexes most effectively with all three pigments. Albumin, bovine serum albumin (BSA), and gammaglobulin were also quite effective in complex formation with myoglobin and hemoglobin at high concentrations, but were not as effective as pyridine and nicotinamide. Histidine, cysteine, and methionine also made heme-complexes with hemoglobin at high concentrations. With cytochrome c, the complex-forming reactions of nicotinic acid, histidine, and BSA were as effective as those of pyridine and nicotinamide in high concentrations. The complex-forming-reaction of gammaglobulin was lower than that of other proteins with myoglobin and cytochrome c. Thiouracil exhibited some reaction with hemoglobin and myoglobin at high concentrations, but did not react with cytochrome c. Some complex-forming reaction was observed with cytochrome c at 20 mg/mL of cysteine and methionine. Aspartic acid, glycine, cysteine, and nicotinamide adenine dinucleotide (NADH) showed no reaction with any of the three pigments under the conditions studied. The color of the heme-complex was orange-red to pink; in some cases, the color intensity was increased by about three times that of the control. Although the heme-complex forming reactions of myoglobin, hemoglobin, and cytochrome c with pyridine were the strongest, pyridine is not present in meat. Therefore, the authors concluded that histidine, cysteine, and methionine, or their side-chains from the solubilized proteins and vitamin B6 derivatives, are very important factors in the pinkness of cooked meat.

Beef rounds aged for one, two, or three weeks after slaughtering were ground added with 0.05% ascorbic acid+0.01% α-tocopherol or 0.05% ascorbic acid+0.01% α-tocopherol+0.01% sesamol, placed on Styrofoam trays and wrapped with oxygen-permeable plastic film, and treated with electron beam irradiation at 0 or 2.5kGy. The meat samples were displayed under fluorescent light for 7d at 4°C. Color, lipid oxidation, volatile analysis, oxidation-reduction potential (ORP) and carbon monoxide (CO) production were determined at 0, 3, and 7d of storage. Irradiation increased lipid oxidation of ground beef regardless of their aging time and storage period. As aging time increased lipid oxidation increased. Adding sesamol increased the effectiveness of ascorbate and tocopherol combination in reducing lipid oxidation especially as aging and storage time increased. The redness of beef were decreased by irradiation and adding ascorbic acid and α-tocopherol before irradiation was effective in maintaining the redness of irradiated ground beef over the storage period. The combination of ascorbic acid+α-tocopherol to ground beef was more effective in reducing ORP than adding sesamol. Irradiation increased CO production from all ground beef regardless of aging time or additives treatments. Volatile sulfur compounds produced by irradiation at Day 0 disappeared over the storage period. Alcohol greatly increased in all nonirradiated beef, but volatiles aldehydes only in irradiated control beef. Antioxidant treatments were effective in reducing aldehydes in ground beef during storage.

Raw and cooked breast patties from turkeys fed 8 different diets [control; 200 IU/kg of vitamin E (VE); 0.3 mg/kg of Se; 2.5% conjugated linoleic acids (CLA); 200 IU/kg of VE + 0.3 mg/kg of Se; 200 IU/kg of VE + 2.5% CLA; 0.3 mg/kg of Se + 2.5% CLA; and 200 IU/kg of VE + 0.3 mg/kg of Se + 2.5% CLA] were treated with 2 irradiation doses (0 and 1.5 kGy) and 2 packaging methods (vacuum and aerobic). Raw and cooked samples from 32 treatments were tested by 8 trained sensory panelists for turkey aroma and irradiation off-aroma. Based on the sensory scores, the 3 dietary treatments producing the most and the least off-aroma were selected and used for a consumer acceptance study. Sensory results of raw meat showed that turkey aroma was intense in aerobically packaged meat, whereas irradiation off-aroma was intense with vacuum packaging. Raw meats from dietary treatments containing CLA (CLA, VE + CLA, Se + CLA, VE + Se + CLA) had greater turkey aroma scores, whereas those containing VE (VE and VE + Se) had lower scores than the control. Dietary treatments containing VE (VE, VE + Se, VE + Se + CLA) significantly lowered (P < 0.05) irradiation off-aroma in raw turkey breast meat, whereas CLA increased it, especially when the meats were packaged aerobically. In cooked meat, however, irradiation and packaging had no effect on turkey meat aroma and irradiation off-aroma. Cooked meat from turkeys supplemented with VE (VE and VE + Se) had less (P < 0.05) irradiation off-odor than other dietary treatments. Dietary CLA increased the irradiation off-aroma in cooked meat, which could not be reduced, even when VE and Se were combined in the diet. Irradiation off-aroma of raw meat was not pleasant for most consumers, and dietary supplementation of VE and VE + Se improved consumer acceptance of irradiated raw meat. For cooked meat samples, consumers preferred both color and flavor of irradiated meat to nonirradiated meat.

Shell eggs were irradiated and the physico-chemical, and functional properties of egg yolk and white were determined. The color of egg yolk was not affected, but the viscosity of egg white was dramatically lowered and became watery by irradiation. The foam capacity and foam stability of egg white were significantly decreased due to protein oxidation by irradiation. However, the texture characteristics of egg white were not changed by irradiation, indicating that irradiation may not alter the thermal characteristics of egg white proteins. Sulfur volatiles were generated by irradiation but disappeared during storage under aerobic conditions. Because egg white became watery, irradiation may not be advisable for table eggs but may be useful for pasteurizing liquid egg white or liquid whole egg without significant deterioration of their quality and functionality. In particular, the dramatic decrease in the viscosity of egg white by irradiation will improve flow of liquid egg white or liquid whole egg, which could be highly useful for egg processing.

The effects of adding 1%, 2% and 3% plum extract on the quality characteristics of vacuum-packaged, irradiated ready-to-eat turkey breast rolls were determined. Turkey breast rolls were sliced, packaged and irradiated at 0 or 3 kGy using a Linear Accelerator. Lipid oxidation, volatile profiles, color, texture, proximate analysis and sensory characteristics of sliced turkey breast rolls were determined at 0 and 7 days of storage. Addition of plum extract had no detectable effect on the proximate analysis of turkey breast rolls. Plum extract increased a* and b* values, and decreased L* value of turkey breast rolls due to the original color of plum extract. Addition of >2% plum extract to turkey breast rolls was effective in controlling lipid oxidation of irradiated meat and the production of aldehydes (hexanal, heptanal, octanal, and nonanal) in non-irradiated meat at Day 0. Texture of turkey breast rolls was not influenced, but juiciness was increased by plum extract. Therefore, addition of 3% or higher of plum extract is recommended to improve mouth-feel and antioxidant effect in irradiated turkey breast rolls. However, the color of turkey breast rolls with 3% plum extract was dark and might not be appealing to consumers.

Irradiation is an effective technology in eliminating Listeria monocytogenes, but it induces quality changes in meat products at or above specific radiation doses. To minimize irradiation-induced quality changes, only low irradiation doses are recommended. However, low-dose irradiation provides a chance for some pathogens to survive and proliferate during prolonged storage. To solve this problem, antimicrobial ingredients [2% sodium lactate (SL), 0.1% sodium diacetate (SDA), 0.1% potassium benzoate (PB)] and low-dose irradiation were combined and tested for their effects on the growth of L. monocytogenes and meat quality. The log10 reductions of L. monocytogenes in hams following exposure to 1.0 to 2.5 kGy of irradiation ranged from 2.0 to 5.0. The D10 values were 0.52 kGy for control ham or ham with PB, SL, or (

An Iowa grain processor attempted to alter the typical 12-h preharvest fasting period by giving broilers cornstarch derivative pellets and water for 6 h followed by 6 h of no feed or water. After slaughter, plant food inspectors determined that livers from the treatment group were lighter in color than normal, and consequently a significant number of chicken carcasses were condemned for human consumption. The study reported herein was conducted to determine the effects of fasting or 3 feeding programs applied before processing on liver color, liver lipids, and liver glycogen of broilers. Dietary treatment groups consisted of 1) full-fed control broilers, 2) fasted broilers, 3) maltodextrin-fed broilers, and 4) and chickens given maltodextrin and methionine. Full-fed chickens had lighter liver coloration than chickens without access to feed for 6 or 12 h immediately prior to slaughter (P < 0.05). Lightness values for livers from full-fed control chickens (L* = 54.41) were 38% higher than those for livers from fasted broilers (L* = 39.30). Lighter liver colors in full-fed broilers were associated with higher hepatic lipid concentrations (6.38%) and more total liver lipid (4.96 g/liver) than was found in broilers without feed for 12 h. In contrast, darker livers from fasted broilers had lower levels of lipid (4.42%) and less total lipid (2.68 g/liver) than the full-fed broilers. Feeding maltodextrin pellets resulted in liver colors that were lighter (P < 0.05) than those found in fasted chickens but darker (P < 0.05) than livers from full-fed broilers. If carbohydrate supplements are fed prior to slaughter, producers should notify processing plant officials so that inspectors do not interpret light livers as an abnormal physiological state.

Low-dose irradiation (1.6 kGy) of commercially- produced cured, sliced ham and frankfurters resulted in off-odors and off-flavors following the irradiation treatment. Lipid oxidation was not affected by irradiation but gas chromatography/mass spectrometry analysis showed that several new volatile compounds were produced in the products by irradiation processing. These included heptane, trans-1-butyl-2- methylcyclopropanone, 2-octene toluene and 2- butanone. Changes in odor and flavor of irradiated ham and frankfurters resulting from production of volatile compounds must be controlled before irradiation will be accepted by the industry or by consumers as a means of improved the microbial safety of these products.

Adding 2% SL increased the hardness, springiness, cohesiveness, chewiness, and resilience of breast rolls. The color a* and b*values of turkey rolls with 2% SL added were significantly lower than those of the control, and this difference was maintained after irradiation and during storage. Breast rolls containing antimicrobials had more lipid oxidation than control. Irradiation promoted the formation of dimethyl disulfide and dimethyl trisulfide. Adding PB in breast rolls greatly increased the formation of benzene during irradiation. It also implies that certain spices or foods containing high amounts of phenolic compounds may not be suitable for irradiation. The combination of SL and SDA has a strong potential as an antimicrobial treatment for RTE meats, but low-dose irradiation (

The influence of temperature abuse on the quality of irradiated pork loins was investigated. Pork loins were obtained directly from a local packing plant, sliced and vacuum-packaged. Pork loins were randomly separated into 3 groups, sliced, and assigned to receive 0, 1.5, or 2.5 kGy electron-beam irradiation. Then, each chop was further cut into three equal pieces and assigned to three temperature treatments: Trt I was placed in a refrigerator directly after irradiation; Trt II was left at room temperature for 3 h before refrigeration; and Trt III was exposed at room temperature for 1 h three consecutive days with intermittent storage at 4 C between exposures. Before irradiation, each loin pieces were vacuum-packaged. Color, 2-thiobarbituric acid reactive substances (TBARS), and volatiles were measured after 0, 14, 28 and 42 days of storage, and water-holding capacity and sensory characteristics of the loins were measured after 0, 14 and 28 days of storage. Temperature abuse had no significant effect on color, oxidation, and volatiles of irradiated pork loins. However, temperature abuse improved water-holding capacity of meat, which could be caused by the accelerated hydrolysis of muscle proteins at higher temperature. Irradiation increased redness, sulfur contents in volatiles and offodor of pork loin. Off-odor and redness induced by irradiation sustained during storage. Among sulfur compounds, the content of dimethyl disulfide decreased gradually while the level of thiourea remained relatively constant. Irradiation also increased water loss, which might be related to the structural damage in membrane during irradiation. This study shows that temperature abuse has little effect on the quality of irradiated pork. 2004 Elsevier Ltd. All rights reserved.

The productions of CO in all samples were irradiationdose dependent. Glycine, asparagine, and glutamine were the major sources of CO production among amino acids, and glyceraldehydes, pyruvate, and α -ketoglutarate were the major sources of CO among glycolysis intermediates. Phosphatidyl choline, phosphatidyl ethanolamine, and lysophosphatidyl choline produced the greatest amounts of CO among the phospholipids. The amounts of CO produced from these sources were significant, and the production of gas compounds via radiolytic degradation appears to be closely related to the structure of molecules.

Lipid oxidation, color, volatiles, and sensory evaluation of double-packaged pork loin were determined to establish a modified packaging method that can improve the quality of irradiated pork loins. Vacuum-packaged irradiated samples produced dimethyl sulfide and dimethyl disulfide responsible for irradiation off-odor, whereas lipid oxidation was promoted under aerobic conditions. Exposing doublepackaged irradiated pork to aerobic conditions for 1 to 3 d was effective in controlling both lipid oxidation and irradiation off-odor, regardless of packaging sequence. Sensory panels could distinguish the decrease in irradiation off-odor intensities by modifying packaging method. However, carbon monoxide-heme pigments, responsible for the increased redness by irradiation, were not effectively controlled by double packaging alone.

The amounts of dimethyl disulfide and dimethyl trisulfide decreased as sample holding time in an autosampler (4 °C) before purge increased, whereas those of aldehdyes increased as holding time increased due to lipid oxidation. Helium flush of sample vials before sample loading on an autosampler retarded lipid oxidation and minimized the changes of sulfur volatiles in raw meat, but was not enough to prevent oxidative changes in cooked meat. Although DH/GC-MS is a powerful method for automatic analysis of volatiles in meat samples, the number of samples that can be loaded in an autosampler at a time should be limited within the range that can permit reasonable repeatabilities for target volatile compounds.

Influence of irradiation and storage on the quality of ready-to-eat (RTE) turkey breast rolls was investigated. Commercial oven roasted turkey breast rolls purchased from local stores were sliced and vacuum packaged. The sliced samples were randomly divided into 3 groups and irradiated at 0, 1.0, or 2.0 kGy using a linear accelerator. Color, 2-TBA-reactive substances (TBARS), sensory characteristics, and volatiles were evaluated at 0, 7, and 14 d of storage. Irradiation increased color a* value of turkey breast rolls. Irradiation and storage did not influence TBARS values. Sensory evaluation showed that irradiation significantly increased sulfury flavor. Because a dramatic increase in sulfur compounds was detected in irradiated samples, the sulfury flavor should be due to the sulfur compounds formed during irradiation. Irradiation also increased the amounts of acetylaldehyde, 2-methyl butanal, 3-methyl butanal, benzene, and toluene. It was concluded that irradiation significantly influenced the odor and flavor of RTE turkey breast rolls under vacuum packaging conditions. Therefore, strategies to prevent negative changes in the quality of irradiated RTE turkey breast rolls are needed.

Although a dynamic headspace/gas chromatography-mass spectrometry (DH/GC-MS) method is an effective tool for determining volatiles of irradiated turkey meat, the profile of volatiles may be changeable depending upon the availability of oxygen in the sample vial and sample holding time before purge. The objective of this study was to evaluate the effects of helium flushing and sample holding time before purge on the volatiles profiles of irradiated raw and cooked turkey breast meat. Vacuum-packaged turkey breasts were irradiated at 2.5 kGy, and the volatiles of irradiated raw and cooked samples were analyzed using a DH/GC-MS with different holding times up to 280 min. The amounts of dimethyl disulfide and dimethyl trisulfide decreased as sample holding time in an autosampler (4 degrees C) before purge increased, whereas those of aldehdyes increased as holding time increased due to lipid oxidation. Helium flush of sample vials before sample loading on an autosampler retarded lipid oxidation and minimized the changes of sulfur volatiles in raw meat but was not enough to prevent oxidative changes in cooked meat. Although DH/GC-MS is a convenient method for automatic analysis of volatiles in meat samples, the number of samples that can be loaded in an autosampler at a time should be limited within the range that can permit reasonable repeatabilities for target volatile compounds.

The antioxidant effect of far-infrared-treated rice hull (FRH) extracts in irradiated turkey breast meat was compared with that of sesamol and rosemary oleoresin. FRH significantly decreased TBARS values and volatile aldehydes (hexanal, pentanal, and propanal) and was effective in reducing the production of dimethyl disulfide responsible for irradiation off-odor in irradiated raw and cooked turkey meat during aerobic storage. The antioxidant activity of FRH (0.1%, w/w) was as effective as that of rosemary oleoresin (0.1%). However, the addition of FRH increased red and yellow color intensities and produced an off-odor characteristic to rice hull in raw and cooked meat, and cannot be used in meat without further refining process to remove off-color and off-odor compounds.

Effect of electron-beam irradiation on the quality of ready-to-eat (RTE) turkey ham was studied.Turkey hams were purchased from local stores and sliced into 0.5 cmthick pieces and vacuum packaged.The ham samples were randomly separated into three groups and irradiated at 0, 1, or 2 kGy, and stored at 4°C for up to 14 d.Volatiles, color, TBARS values and sensory characteristics were determined. Irradiation had little effects on color and TBARS values of RTE turkey hams. Sensory analysis indicated that sulfury odor increased as irradiation dose increased, and the contents of sulfur compounds in irradiated RTE turkey hams were higher than those in nonirradiated samples.Irradiation increased (P < 0.05) the production of acetaldehyde, which could be related to a metal-like flavor in irradiated hams. However, overall quality changes in RTE turkey hams by irradiation up to 2 kGy were minor.

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-d 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.

To understand the mechanisms of off-odor production in irradiated meat, the volatile compounds produced from individual fatty acids by irradiation were identified. Nonirradiated oil emulsions prepared with polyunsaturated fatty acids (PUFAs) produced many volatile compounds, but the amounts of volatiles generally decreased after irradiation. Although volatile profiles of fatty acid emulsions were changed by irradiation, the odor characteristics and intensity between irradiated and nonirradiated fatty acid emulsions were not different. Thiobarbituric acid-reactive substances (TBARS) values indicated that irradiation accelerated lipid oxidation during subsequent storage, but the volatiles produced by lipid oxidation were not the major contributors of off-odor in irradiated samples.

Dietary CLA treatment reduced color a*- and b*-values of cooked chicken breast rolls. Sensory panels rated the color of cooked chicken rolls with CLA treatments darker than the control. The production of CO in cooked chicken rolls increased dramatically after irradiation and was correlated with the increased redness of cooked chicken rolls after irradiation. Irradiation greatly increased volatile production and induced a metallic off-flavor in chicken rolls. The hardness of chicken rolls increased and juiciness decreased as the dietary level of CLA increased, and consumer preferred the color of cooked chicken rolls after irradiation to the nonirradiated ones. Although dietary CLA was somewhat positive in reducing pinkness, but negatively influenced to the eating quality of irradiated cooked chicken rolls.

Irradiated vacuum-packaged patties had great amounts of sulfur volatiles (dimethyl sulfide and dimethyl disulfide) and increased red color during the refrigerated storage and after cooking compared with the nonirradiated control. Irradiated aerobically packaged meat 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, the combined use of antioxidants and double packaging would be a useful method to control the oxidative quality changes of irradiated raw and cooked turkey breast.

Irradiation significantly decreased the redness of ground beef, and the visible color of beef changed from a bright red to a green/brown depending on the age of meat. Addition of ascorbic acid prevented color changes in irradiated beef, and the effect of ascorbic acid became greater as the age of meat or storage time after irradiation increased. The ground beef added with ascorbic acid had significantly lower ORP than control, and the low ORP of meat helped maintaining the heme pigments in reduced form. During the aerobic storage, the S-volatiles disappeared while volatile aldehydes significantly increased in irradiated beef. Addition of ascorbic acid at 0.1% or sesamol + α-tocopherol at each 0.01% level to ground beef prior to irradiation were effective in reducing lipid oxidation and S-volatiles. As storage time increased, however, the antioxidant effect of sesamol + tocopherol in irradiated ground beef was superior to that of ascorbic acid.

Antioxidants had no effect on the production of sulfur compounds, color change, and off-odor intensity of irradiated turkey breast meat, but addition of sesamol tocopherol or gallate tocopherol was effective in reducing thiobarbituric acid-reactive substance values and aldehydes, especially under aerobic con- ditions. Consumers preferred the color of irradiated raw and cooked meat to nonirradiated meat because the pink color of irradiated meat looked fresher. The packaging method was more important than the antioxidant treat- ment in reducing irradiation off-odor because S-compounds produced by irradiation easily volatilized under aerobic packaging conditions. Therefore, the combined use of aerobic packaging and antioxidants is recom- mended to improve consumer acceptance of irradiated poultry meat.

A comparison of irradiation effects on the quality of injected and uninjected pork loins was conducted. Irradiation treatments resulted in greater lipid oxidation and production of volatile compounds.However, injection treatments did not alter any of the effects of irradiation on the quality parameters measured.

The influence of temperature abuse on the quality of irradiated pork loins was investigated. Pork loins were obtained directly from a local packing plant, sliced and vacuum-packaged. Pork loins were randomly separated into 3 groups, sliced, and assigned to receive 0, 1.5, or 2.5 kGy electron-beam irradiation. Then, each chop was further cut into three equal pieces and assigned to three temperature treatments: Trt I was placed in a refrigerator directly after irradiation; Trt II was left at room temperature for 3 h before refrigeration; and Trt III was exposed at room temperature for 1 h three consecutive days with intermittent storage at 4 °C between exposures. Before irradiation, each loin pieces were vacuum-packaged. Color, 2-thiobarbituric acid reactive substances (TBARS), and volatiles were measured after 0, 14, 28 and 42 days of storage, and water-holding capacity and sensory characteristics of the loins were measured after 0, 14 and 28 days of storage. Temperature abuse had no significant effect on color, oxidation, and volatiles of irradiated pork loins. However, temperature abuse improved water-holding capacity of meat, which could be caused by the accelerated hydrolysis of muscle proteins at higher temperature. Irradiation increased redness, sulfur contents in volatiles and off-odor of pork loin. Off-odor and redness induced by irradiation sustained during storage. Among sulfur compounds, the content of dimethyl disulfide decreased gradually while the level of thiourea remained relatively constant. Irradiation also increased water loss, which might be related to the structural damage in membrane during irradiation. This study shows that temperature abuse has little effect on the quality of irradiated pork.

The effects of antioxidants and double 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 + alpha-tocopherol, or gallate + alpha-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. Irradiated vacuum-packaged patties had great amounts of sulfur volatiles (dimethyl sulfide and dimethyl disulfide) and increased red color during refrigerated storage and after cooking compared with the nonirradiated control. Irradiated aerobically packaged meat had accelerated lipid oxidation and aldehyde production at 10 d and after cooking. Gallate + alpha-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, the combined use of antioxidants and double packaging would be a useful method to control the oxidative quality changes of irradiated raw and cooked turkey breast.

Effect of electron-beam irradiation on the quality of ready-to-eat (RTE) turkey ham was studied. Turkey hams were purchased from local stores and sliced into 0.5 cm-thick pieces and vacuum packaged. The ham samples were randomly separated into three groups and irradiated at 0, 1, or 2 kGy, and stored at 4 °C for up to 14 days. Volatiles, color, TBARS values and sensory characteristics were determined to compare the effect of irradiation and storage on the quality of RTE turkey ham. Irradiation had little effects on color and TBARS values of RTE turkey hams. Sensory analysis indicated that sulfury odor increased as irradiation dose increased, and the contents of sulfur compounds in irradiated RTE turkey hams were higher (P

The objective of this study was to determine the effect of irradiation on the quality of ready-to-eat (RTE) breast rolls from turkeys fed conjugated linoleic acid (CLA). The oxidative stability of RTE turkey rolls was improved by the dietary CLA treatment. Irradiation increased the production of acetaldehyde, 3-methyl-butanal, 2-methyl-butanal, and total volatiles in turkey rolls but had little effect on other aldehydes. Irradiation also produced new volatiles, including sulfur compounds, not detected in nonirradiated turkey breast rolls. We detected significantly higher amounts of alkanes with nine or higher carbons in irradiated samples than in nonirradiated samples. Irradiation increased the redness of RTE turkey breast rolls, but the degree of redness and the amount of total volatiles decreased with storage. CLA treatment lowered the redness (a*) and increased the lightness (L*) of RTE turkey breast rolls during the entire storage period. Sensory evaluation revealed that irradiation produced off-flavor, but CLA and irradiation did not influence the texture and juiciness of RTE turkey breast rolls. Consumers did not like the off-flavor but preferred the color induced by irradiation to nonirradiated RTE turkey breast rolls.

Excessive intake of saturated fatty acids and/or linoleic acid favors the induction of an array of lipid mediators and cytokines enhancing inflammatory responses. Conversely, dietary supplementation with (n-3) fatty acids or vitamin D ameliorates inflammation and autoimmune diseases. Although it was well accepted that conjugated linoleic acid (CLA) prevented diseases with a common inflammatory pathogenesis (i.e., cancer and atherosclerosis), no studies were available on the roles of CLA in mucosal inflammation. The present study was designed to investigate the anti-inflammatory actions and molecular mechanisms underlying the regulation of colonic health by CLA. We hypothesized that colonic inflammation can be ameliorated by dietary CLA supplementation. To test this hypothesis, inflammation of the colonic mucosa was triggered by challenging pigs fed either soybean oil-supplemented or CLA-supplemented diets with an enteric bacterial pathogen (i.e., Brachyspira hyodysenteriae). Immunoregulatory cytokines and peroxisome proliferator-activated receptor-gamma (PPAR-gamma) mRNA expression were assayed in colonic lymph nodes and colon of pigs. Colonic mucosal lesions and lymphocyte subset distribution were evaluated by histology and immunohistochemistry. Supplementation of CLA in the diet before the induction of colitis decreased mucosal damage; maintained cytokine profiles (i.e., interferon-gamma and interleukin-10) and lymphocyte subset distributions (i.e., CD4+ and CD8+), resembling those of noninfected pigs; enhanced colonic expression of PPAR-gamma; and attenuated growth failure. Therefore, CLA fed preventively before the onset of enteric disease attenuated inflammatory lesion development and growth failure.

Ascorbic acid (1), a natural antioxidant, was modified by employing transglycosylation activity of Bacillus stearothermophilus maltogenic amylase with maltotriose and acarbose as donor molecules to enhance its oxidative stability. The transglycosylation reaction with maltotriose as donor created mono- and di-glycosyl transfer products with an alpha-(1,6)-glycosidic linkage. In addition, two acarviosine-glucosyl transfer products were generated when transglycosylation was performed with acarbose as a donor. All transfer products were observed by TLC and HPLC, and purified by Q-sepharose anion exchange and Biogel P-2 gel permeation chromatographies. LC/MS and (13)C NMR analyses revealed that the structures of the transfer products were 6-O-alpha-D-glucosyl- (2) and 6-O-alpha-D-maltosyl-ascorbic acids (3) in the reaction of maltotriose, and 6-O-alpha-acarviosine-D-glucosyl- (4) and 2-O-alpha-acarviosine-D-glucosyl ascorbic acids (5) in the reaction of acarbose. The stability of the transglycosylated ascorbic acid derivatives was greatly enhanced against oxidation by Cu(2+) ion and ascorbate oxidase. Among them, compound 3 proved to be the most stable against in vitro oxidation. The antioxidant effects of glycosyl-derivatives of ascorbic acid on the lipid oxidation in cooked chicken breast meat patties indicated that they had antioxidant activities similar to that of ascorbic acid. It is suggested that the transglycosylated ascorbic acids can possibly be applied as effective antioxidants with improved stability in food, cosmetic, and other applications.

The effect of irradiation on color, lipid oxidation, and volatile production of precooked, irradiated turkey breast during frozen storage was studied. Turkey breast muscles were precooked, aerobically or vacuum-packaged, irradiated at 0, 2.5, or 5.0 kGy using a linear accelerator (electron beam), and then frozen-stored at -40 C. Lipid oxidation, volatiles, color values, gas production, and oxidation-reduction potential (ORP) of meat were determined during 3-mo storage periods. Ionizing radiation produced characteristic off-odor volatiles (dimethyldisulfide and methylthioethane) and lipid oxidation products in precooked, frozen turkey breast. The production of volatiles was accelerated by the confounding effect of high irradiation dose, aerobic packaging, and increased storage time. Volatile production and color changes in irradiated, precooked turkey breast were induced by different mechanisms. Irradiation increased pink color in precooked, vacuum-packaged turkey breast, and the pink color was stable during frozen storage. Decreased ORP and increased CO in irradiated meat indicated that denatured CO-heme pigments could be responsible for the pink color in precooked, irradiated turkey breast. Vacuum packaging was better than aerobic packaging in preventing lipid oxidation and oxidation-dependent volatile production, but pink color in precooked, irradiated turkey breast during frozen storage was maintained.

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.

Male and female emus were fed a diet rich in saturated fat (beef tallow) or a diet rich in unsaturated fat (soybean oil) until they weighed about 35 kg. Samples of subcutaneous and retroperitoneal adipose tissues and samples of six major meat cuts were taken for determination of composition. Emus fed the two different diets grew at similar rates, but the male emus had a higher percentage of carcass fat. The adipose tissue cells from males were larger than those from females. All six meat cuts averaged 2.2% fat, with the regular filet having the most and the inside and outside drums the least. Cholesterol concentration of all sizes of meat cuts averaged 32.2 mg/100 g meat. Diet did not influence cholesterol content of the rendered oil. Fan filets had the greatest concentration of cholesterol, and the inside and outside drums had the least. Source of dietary fat had no effect on fat and cholesterol content of the meats. Meat from emus fed beef tallow was more tender and juicy. Fan filets were the most tender meat, had the least intense flavor, and were the most flavorful. Untrained panelists were able to discriminate between emu meat and beef. Source of dietary fat did not influence the fatty acid compositions of the meats. As expected, the soybean oil-fed emus produced oil that was more polyunsaturated than did the tallow-fed emus.

Patties were made from pork loin, individually vacuum- or aerobic-packaged and stored either at 4 or −40°C. Refrigerated patties were irradiated at 0, 1.5, 3.0 or 4.5 kGy absorbed dose, and frozen ones were irradiated at 0, 2.5, 5.0, or 7.5 kGy. Samples were analyzed for lipid oxidation, volatile production and odor characteristics. Refrigerated samples were analyzed at 0, 1 and 2 weeks, and frozen ones after 0, 1.5 and 3 months of storage. With vacuum packaging, the lipid oxidation (TBARS) of both refrigerated and frozen patties was not influenced by irradiation and storage time except for the patties irradiated and refrigerated at 7.5 kGy. With refrigerated storage, panelists could detect irradiation odor at day 0, but not after 1 week at 4°C. With frozen storage, however, irradiation odor was detected even after 3 months of storage. With aerobic packaging, the TBARS of refrigerated pork patties increased with storage time. The TBARS of pork patties increased as irradiation dose increased at day 0, but the effect disappeared after 1 week at 4°C. Nonirradiated patties were preferred to the irradiated ones at day 0 because of the significant irradiation odor in the irradiated ones, but the off-odor disappeared after 1 week at 4°C. With frozen storage, patties irradiated at 7.5 kGy had higher TBARS than those irradiated at lower doses. Nonirradiated patties had higher preference scores than the irradiated ones for 1.5 months in frozen storage. Sulfur-containing compounds were responsible for most of the irradiation off-odor, but these volatilized quickly during storage under aerobic conditions. Overall, vacuum packaging was better than aerobic packaging for irradiation and subsequent storage of meat because it minimized oxidative changes in patties and produced minimal amounts of volatile compounds that might be responsible for irradiation off-odor during storage.