Color Characteristics of Irradiated Aerobically Packaged Pork, Beef, and Turkey

Color changes in irradiated meat were species-dependent. Irradiated pork and beef became less red as a result of irradiation and display time. The redness values of turkey increased after irradiation but decreased during display time. The yellowness of the irradiated samples, for all species, increased as a result of irradiation and display. Visual evaluation of irradiated pork and beef indicated an increase in brownness, whereas turkey increased in redness as dose increased. The surface color of irradiated pork became less uniform than unirradiated pork. Reflectance spectra indicated that irradiation induced a metmyoglobin-like pigment in pork and beef, whereas the pigment in turkey was unchanged.     

Color, Oxidation-Reduction Potential, and Gas Production of Irradiated Meats from Different Animal Species

ABSTRACT: Turkey breasts, pork loins, and beef loins were aerobically or vacuum-packaged and electron beamirradiated at 3 kGy. Irradiation increased the redness of turkey breast regardless of packaging or storage. Irradiation drastically decreased the redness of aerobically packaged beef loin. Irradiated meats produced higher amounts of CO and CH₄ than nonirradiated. The oxidation-reduction potential (ORP) of meats decreased after irradiation, but increased during the storage. Little differences in CO and ORP values among the irradiated meats from different species were detected. This indicated that CO and ORP were not the only factors involved in the color changes of beef loin by irradiation.     

Effect of low dose gamma radiation on lipids in five different meats

Five types of meats were irradiated by gamma radiation up to a dose of 10 kGy. The m. longissimus dorsi from pork, lamb and beef was irradiated as well as turkey leg and turkey breast muscle. After irradiation, the lipids were extracted from the muscles to ascertain the effect of irradiation. Peroxide and iodine values along with malonaldehyde concentration were used to assess any damage made to the lipids, and to note any significant differences in these compounds due to the type of muscle tissue. Peroxide and iodine values showed that at low irradiation dose, <10 kGy, there was no significant change in any of the meat lipids. Malonaldehyde concentration changed significantly at the micromolar level due to irradiation dose, but only in turkey breast muscle.     

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.     

电子束辐照进口冷冻牛腩的剂量分布及感官特性研究

目的 确认电子束辐照冷冻牛腩的剂量分布特性,研究不同剂量电子束辐照对冷冻牛腩的杀菌效果及辐照后产品色泽、风味、质构等感官指标的变化,为冷冻牛腩辐照杀菌的工艺设定和质量控制提供技术参考依据。方法 对不同厚度的冷冻牛腩块分别用8 kGy进行单面及双面电子束辐照,检测其内部剂量分布,确定辐照适宜的产品厚度,在此基础上用0 kGy、2 kGy、4 kGy不同剂量对商品包装（1 kg/袋,最大厚度不超过8 cm）的冷冻牛腩进行电子束双面辐照,检测菌落总数、霉菌和酵母、大肠菌群,同时利用色差仪、电子鼻、质构仪检测冷冻牛腩及其熟制品的色泽、风味、质构等感官指标。结果 单面电子束辐照冷冻牛腩的内部剂量呈先上升后下降趋势,快速下降发生在3.5~5 cm深度区域,产品厚度3.5 cm时剂量不均匀度为1.57。双面辐照可增加电子束穿透深度,8.1cm厚度双面辐照的剂量不均匀度为1.62。冷冻牛腩中菌落总数、霉菌和酵母、大肠菌群均有检出,电子束辐照可显著降低冷冻牛腩微生物水平,商品包装的冷冻牛腩经2 kGy电子束双面辐照后无大肠菌群检出,菌落总数、霉菌和酵母分别较未辐照处理降低98.8%和89.2%。电子束辐照对冷冻牛腩及其熟制品风味、质构无不良影响,4 kGy处理显著还提高了冷冻牛腩回复性,但电子束辐照导致冷冻牛腩色泽参数a值和b值显著下降,且剂量越高下降幅度越大。电子束辐照对色泽的影响程度在冷冻牛腩熟制后降低,2 kGy处理的b值显著高于未辐照处理,其它各处理的a值、b值与未辐照处理均无显著差异。结论 8.1cm厚度冷冻牛腩电子束双面辐照的剂量不均匀度为1.62,冷冻牛腩2 kGy双面辐照后无大肠菌群检出,菌落总数显著降低,风味、质构无不良变化,但色泽参数a、b值显著下降,产品红色消退,熟制可以降低辐照对色泽的不良影响。     

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.     

Volatile profiles, lipid oxidation and sensory characteristics of irradiated meat from different animal species

Irradiated meats produced more volatiles and higher 2-thiobarbituric acid reactive substances (TBARS) than nonirradiated regardless of animal species. Irradiation not only produced many new volatiles not found in nonirradiated meats but also increased the amounts of some volatiles found in nonirradiated meats. The amounts of volatiles in aerobically packaged irradiated meats decreased with storage while those of nonirradiated meats increased. TBARS values were the highest in beef loin, followed by turkey breast and pork loin regardless of irradiation, packaging, and storage time. TBARS of meats showed positive correlation with total volatiles, but preference scores between irradiated and nonirradiated were similar.     

LIPID AND CHOLESTEROL OXIDATION,COLOR CHANGES,AND VOLATILE PRODUCTION IN IRRADIATED RAW PORK BATTERS WITH DIFFERENT FAT CONTENT1

An emulsion-type product was prepared to determine the effect of irradiation on lipid and cholesterol oxidation, color change, and volatile production in raw pork with different fat contents. Lipid oxidation increased with an increase in fat content or irradiation dose. Irradiated batters had higher cholesterol oxides than nonirradiated, and the major cholesterol oxides formed in irradiated pork batters were 7α- and 7β-hydroxycholesterol. Hunter color a- and b-values of raw pork batters were decreased by irradiation regardless of fat content. Irradiation increased the amount ofvolatiles significantly. Although lipid oxidation of high fat products (10 and 15% fat) was higher than that of low fat products (4%), high fat products did not always produce greater amount of volatiles. In summary, irradiation increased lipid and cholesterol oxidation, volatiles production and had detrimental effects on the color of raw pork batters under aerobic condition.     

Effect of irradiation on the quality of turkey ham during storage

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 <0.05) 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.     

Lipid Oxidation, Volatiles, and Color Changes in Irradiated Raw Turkey Breast During Frozen Storage

ABSTRACT: Raw turkey breasts were aerobically or vacuum-packaged, irradiated with a linear accelerator, and frozen for 0, 1.5, or 3 mo. Lipid oxidation, volatiles, color values, gas production, and oxidation-reduction potential of the samples were determined. Irradiation produced off-odor volatiles associated with lipid oxidation and sulfur-volatiles; the off-odor was much higher in aerobic packaging. Volatiles increased with irradiation dose, aerobic packaging, and storage time. Irradiation increased stable pink color with both aerobic and vacuum-packaging. Irradiation increased the production of carbon monoxide (CO) and reducing property, indicating that CO-myoglobin could be responsible for the pink color. Lipid oxidation and color changes were not related in irradiated frozen turkey.     

Gamma Irradiation Effects on Thiamin and Riboflavin in Beef, Lamb, Pork, and Turkey

A study was made of the loss of thiamin and riboflavin due to gamma irradiation of beef, lamb and pork longissimus dorsi, turkey breast and leg muscles. Thiamin losses averaged 11%/kiloGray (kGy) and riboflavin losses 2.5%kGy above three kGy. The rate of loss of thiamin in beef was higher than that in lamb, pork and turkey leg, but not turkey breast. with losses of 16%/kGy in beef and 8%/kGy in lamb. The rate of thiamin loss was not related to sulfhydryl, protein, moisture, fat or water content, pH or reducing capacity by redox titration. Loss of riboflavin was not different among species. Any detriment from such slight losses would seem to be more than compensated by the advantage of controlling bacteriological contamination by irradiation processing.     

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.     

辐照对猪肉火腿肠风味与品质的影响

分别以1、3、5、7、9 kGy剂量辐照处理火腿肠,然后对其辐照异味强度、脂质氧化、挥发性风味化合物、色差等指标进行检测,分析辐照对火腿肠风味及颜色品质的影响。结果发现,辐照处理可以显著促进火腿肠中脂质的氧化(P0.05),使得红度值(a~*)相比对照组显著降低(P0.05),但是对亮度值(L~*)和黄度值(b~*)影响不显著(P0.05)。随着辐照剂量加大,火腿肠的辐照异味明显增强,1~5 kGy范围内辐照异味不明显,当辐照剂量增加到7 k Gy时,火腿肠产生明显的令消费者不能接受的辐照异味。挥发性含硫化合物、2-丁烯、戊烷、1-戊烯、辛烷、己烷以及醛类化合物含量与对照组相比显著增多(P0.05),且与辐照剂量呈正相关。二硫化碳、二甲基二硫醚、2-甲基丙醛、3-甲基丁醛、己醛、丁烯和二甲苯是火腿肠辐照后产生的最主要挥发性化合物。结果表明,火腿肠经辐照处理后风味和色泽会发生劣变,特别是5 kGy以上的辐照剂量,并且这些品质变化与火腿肠中脂质的氧化密切相关。     

End-point Temperature (EPT) Affects N-Acetyl-β-D-Glucosaminidase Activity in Beef, Pork and Turkey

End-point tempcraturc (EPT) affected N-acetyl-β-D-glucosaminidase (NAGasc) activity in nonfrozcn and previously frozen cores and ground sampics of beef, pork, turkey breast and ground turkey leg muscle tissue. There was little loss of NAGase activity when heating the products to 40°C; however, as EPT increased from 40–70°C, them was (Pc0.05) loss of activity. At 70°C 90% of activity was lost in beef, 98% in pork, and 93 to 98% in turkey. Inactivation temperature values, IT50, (50% inactivation) were: beef, 59.8°C; pork, 53.4°C; turkey breast, 55.6°C; and turkey leg, 56.6°C.     

Prevention of Pinking, Off-odor, and Lipid Oxidation in Irradiated Pork Loin Using Double Packaging

ABSTRACT: 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 double-packaged 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 the packaging method. However, carbon monoxide heme pigments, responsible for the increased redness by irradiation, were not effectively controlled by double packaging alone.     

Effect of vitamin E, low dose irradiation, and display time on the quality of pork

A 4×2×3 factorial experiment was designed to investigate the effect of supplemental vitamin E (0, 100, 200, and 300 mg/kg feed), irradiation and days in display on quality characteristics of aerobically packaged ground pork and vacuum packaged loin chops. Color, thiobarbituric acid reactive substances (TBARS), olfactory and sensory characteristics were evaluated. Samples held in display for 3 d were used for sensory evaluation. In the ground pork, irradiation (1.9 kGy) increased "wetdog" flavor, increased a(*) (redness) and decreased L(*) (lightness) and b(*) (yellowness) values but had no effect on TBARS. However, as display time (0, 4, and 8 days) increased; the differences in a(*) values diminished and putrefying and fishy odors were higher in non-irradiated samples than irradiated. Supplemented vitamin E had no effect on TBARS, odor, and color measures; but increased the juiciness of ground pork regardless of irradiation. Similarly, in the loin chops, irradiation (1.5 kGy) increased a(*) value and "wetdog" flavor; but decreased b(*) value regardless of vitamin E supplementation. Also, irradiation reduced putrefying, and fishy odors during longer display times. TBARS increased with increased display time but was not affected by vitamin E supplementation. These results indicate that in aerobically packaged ground pork and vacuum packaged loin chops, radiolytic odors and color changes cannot be mediated with vitamin E supplementation. Display time and irradiation are significant in determining color and odor changes.     

Lipid Oxidation and Color Stability in Restructured Meat Systems during Frozen Storage

Salt and combinations of salt with phosphates and antioxidants were investigated for their role in lipid oxidation and discoloration in restructured beef, pork, and turkey steaks during storage at - 10°C for 16 wk, 8 wk and 8 wk, respectively. Lipid oxidation and discoloration occurred simultaneously in pork and turkey, but beef color loss occurred much earlier than did lipid oxidation. Phosphates were effective in inhibiting lipid oxidation in beef (4 wk), pork (8 wk) and turkey (6 wk). Tertiary butylhydroquinone inhibited lipid oxidation in pork and turkey steaks, but, overall, neither prevented discoloration. Results indicate discoloration and lipid oxidation are interrelated, and pigment oxidation may catalyze lipid oxidation.     

Solid phase extraction (SPE) method for detection of irradiated meats

Solid phase extraction (SPE) has been proposed as an alternative to the currently used florisil column chromatography. The hydrocarbons formed from beef, pork and chicken irradiated with 0-10 kGy were determined by the SPE and quantified by GC/MS. The limit of detection for the hydrocarbons in irradiated meats was 0.5 kGy. The correlation between the irradiation dose and the concentrations of hydrocarbons in beef, pork and chicken was high that linear regression coefficients (r²) were 0.87-0.99. SPE method would be used as the rapid detection of irradiated meats.     

Acceptance and Species Identification of Turkey Steaks Prepared with Beef, Pork, Lamb, and Turkey Fat

Fabricated extruded steaks were prepared from turkey meat, salt, phosphate, and water plus 15% beef, pork, lamb, or turkey fat. The grilled samples recieved relatively high hedonic scores from a sensory panel. The flavor, juiciness, and overall quality of the samples made with pork, beef, and turkey fat were preferred significantly over the samples made with lamb fat. Panel members tended to consider all samples as being pork flavored. Beef, pork, or turkey fat could be used as the fat in a fabricated, extruded steak without affecting the relative acceptability of the cooked product.     

Effects of Ascorbic Acid and Antioxidants on the Color of Irradiated Ground Beef

Irradiation significantly decreased the redness of ground beef (P < 0.05), 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 (0.1%, wt/ wt) in ground beef prior to irradiation 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. Ground beef with added ascorbic acid had significantly lower oxidation‐reduction potential than the control (P < 0.05), and the low oxidation‐reduction potential of meat helped maintain the heme pigments in reduced form. Sesamol +α‐tocopherol had no effect in stabilizing color of irradiated beef.