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Phosvitin (PV) from egg yolk is an excellent substrate for the production of phosphopeptides, which have a strong calcium chelating capacity and promoting calcium absorption and bone mineralization. This study investigated the effect of PV hydrolysates produced using a effective preparation method (high temperature (121°C) and mild pressure (0.1 MPa), HTMP) or HTMP pretreatment and trypsin hydrolysis combination (HTMP-PV18) on the physiology of an osteoblast MC3T3-E1 cells line. The proliferation, apoptosis, and differentiation of MC3T3-E1 cells were analyzed using the CCK-8, flow cytometry, and RT-PCR reactions, respectively. Both the HTMP-PV and HTMP-PV18 increased the proliferation, and inhibited the apoptosis of MC3T3-E1 cells significantly. The HTMP-PV increased the proliferation of MC3T3-E1 cells by 147.12 ± 2.11% and the HTMP-PV18 by 136.43 ± 4.51%. In addition, the HTMP-PV and HTMP-PV18 effectively promoted the expression of genes related to the OPG/RANKL signaling channel during cell differentiation. This indicated that both the HTMP-PV and HTMP-PV18 have the potential to promote bone mineralization by improving the proliferation and differentiation of osteoblastic cells.

Egg yolk phosvitin is one of the most phosphorylated proteins in nature, and the extraordinarily high concentration of phosphate groups in its structure provides a strong metal-binding ability. Phosvitin is known to possess various functional activities, including metal-chelating, antioxidant, emulsifying, antimicrobial, and cytotoxic activities. However, little is known about the immune-enhancing activity of phosvitin. The objective of this study was to evaluate the immune-enhancing activity of phosvitin in murine RAW 264.7 macrophages. Griess reagents and quantitative real-time PCR were used to determine the effect of phosvitin (at 12.5, 25, 50, and 100 μg/mL) on the levels of pro-inflammatory mediators NO and inducible nitric oxide synthase (iNOS), cytokines TNF-α and IL-1β in RAW 264.7 macrophages. The effect of phosvitin on the phagocytic activity of RAW 264.7 macrophages was also measured using the Neutral-Red Uptake method. Lipopolysaccharides was used as a positive control. Phosvitin significantly (P 0.05) increased the production of NO in RAW 264.7 macrophages in a dose-dependent manner, but did not show any cytotoxicity. The amounts of NO produced were 3.47, 7.12, 10.23, and 14.57 μM in 12.5 to 100 μg/mL range of phosvitin (control: 0.46 μM). Compared with the untreated group, phosvitin treatment at a 100 μg/mL level increased the production of NO by 31.67 times. Phosvitin also significantly increased the mRNA expression of the RAW 264.7 macrophages: 100 μg/mL of phosvitin treatment increased the expression of mRNA for iNOS, TNF-α, and IL-1β by 46.25, 9.09, and 85.18 times of the control, respectively. The phagocytic activity of RAW 264.7 macrophages was also increased significantly by phosvitin treatment. These results demonstrated that phosvitin dramatically improved the immune functions RAW 264.7 macrophages by enhancing the production of immune mediators and increasing phagocytic activity. Therefore, phosvitin has a potential to be used as an immune-enhancing agent by food or nutraceutical industries.

Heat stress is one of the most important environmental stressors for the poultry industry in the world. Reduced growth rate, low feed efficiency, impaired immunological responses, changes in intestinal microflora, and deterioration of meat quality are the consequences of acute or chronic heat stress. In terms of meat quality, 3 primary mechanisms have been suggested to explain this phenomenon: 1) rapid drop in pH during and after slaughter due to the glycogen conversion to increase in lactic acid accumulation especially when the muscle temperature is high, a combination of high temperature and low pH that facilitates the denaturation of sarcoplasmic proteins resulting in lower water-holding capacity of muscle; 2) acceleration of panting to dissipate body heat, which increases CO2 exhalation and pH drop in blood, initiates metabolic acidosis in skeletal muscle. Increase in panting is also associated with a high release of corticosteroid hormones; 3) the reactive oxygen species produced by heat stress increases the oxidative stress in the birds, which can damage the structure and functions of the enzymes that regulate sarcoplasmic calcium levels in muscles. Overall, these changes in the muscle cells accentuate energy expenditure due to constant muscle contractions. This review discusses the scientific evidence about how heat stress affects the quality of chicken meat through the acid/base status, oxidative reactions, and changes in hormonal secretions.

An experiment was conducted to determine the effects of adding vitamins E and C to diets containing 3.5% refined soy oil (SO), recycled soy oil (RSO), or acidulated soy oil soapstocks (ASS) on 1) fatty acid (FA) profile, and cholesterol, triglyceride (TG) and α-tocopherol (α-T) concentrations of yolk, and 2) the oxidation status of serum and yolk. Twelve dietary treatments, using 3 oil sources, 2 levels of vitamin E (0 vs. 250 mg/kg), and 2 levels of vitamin C (0 vs. 250 mg/kg), were prepared. A total of 300 W36 Hy-line laying hens, from 44 to 56 weeks of age, were placed in 60 cages (5 birds/cage) and 5 cages were randomly assigned to one of the 12 diets. Blood samples and eggs were collected after 84 d on trial. No interactions among main effects were found for any of the traits studied. Oil sources had little effects on the FA profile of the yolk, except for C18:3 that was higher (P-value of < 0.01) in the hens fed SO than those fed RSO or ASS. Vitamin E supplementation significantly (P-value of < 0.05) increased the concentration of C16:0, C18:0, and C16:1 but decreased that of C18:2 and C22:6n3 in the yolk. Vitamin C supplementation significantly (P-value of < 0.05) increased C18:0 and C18:3 concentrations in the yolk but decreased the n6 to n3 FA ratio. The concentrations of cholesterol and triglyceride in serum and yolk were not affected by dietary treatment but α-tocopherol concentration increased (P-value of < 0.01) by the dietary vitamin E. Compared with the hens fed the SO diets, malondialdehyde (MDA) concentration in serum was higher with RSO diet but lower with ASS diet. Vitamin E and vitamin C supplementation decreased (P-value of < 0.05) serum MDA. Yolk FA profile was affected not only by the FA profile of the oil source used in diet, but also by the supplementation of vitamin E and C. The results showed that triglyceride profile, but not cholesterol content, of egg was affected by fatty acid profile of the supplemental oil and the vitamin C and E supplementations.

Egg white contains many functionally important proteins: ovalbumin (54%), ovotransferrin (12%), ovomucoid (11%), ovoglobulin (G2 and G3, 8%), ovomucin (3.5%), and lysozyme (3.5%) are major proteins, while ovoinhibitors, ovomacroglobulin, ovoglycoprotein, ovoflavoprotein, thiamine-binding proteins, and avidin are minor proteins present in egg white. These proteins, as well as the peptides derived from the proteins, have been recognized for their functional importance as antioxidant, antimicrobial, metal-chelating, anti-viral, anti-tumour, and angiotensin-converting enzyme (ACE)-inhibitory activities. Among the functional properties of the peptides, antioxidant and antimicrobial activities are important characteristics for food processing while other properties such as ACE-inhibitory activity of the peptides can have important health-related functionalities. Bioactive peptides can be produced from egg white proteins by enzyme hydrolysis, chemical treatments, or thermal treatments at different pH conditions. The effective functional peptides produced from egg white proteins are usually smaller than 2 kDa in molecular size. However, these peptides are known for their beneficial activities in vitro only, and little work has been done to prove their beneficial effects in vivo. Therefore, further studies are needed to see if the bioactive peptides derived from egg white proteins are helpful for humans in the future.

Ovalbumin is the predominant protein in egg white and is widely used in cell culture. However, it also can be used to produce peptides with various functional properties. The objectives of this study were to hydrolyze ovalbumin using various enzyme, incubation time, and temperature combinations, and to compare the functional properties of the hydrolysates. Ovalbumin (20 mg/mL) was hydrolyzed with 1% of pepsin, trypsin, α-chymotrypsin, papain, and alcalase, singly or in combination at 37°C, and then the enzymes were inactivated at 100°C for 15 min. Hydrolyzing ovalbumin with pepsin (OAPe), pepsin + papain (OAPePa), pepsin + alcalase (OAPeAl), alcalase + trypsin (OAAlTr), and α-chymotrypsin (OACh) was also effective in producing peptides from ovalbumin, and the peptides produced had strong iron- and copper-binding capacities and antioxidant capability. However, the best treatment of all was the OAAlTr treatment, which showed the highest iron-chelating and antioxidant activities among the enzyme treatments (P < 0.05). Electrospray-ionization mass spectrometry (MS/MS) analysis identified numerous peptides (

A study was conducted to develop a simple sequential separation protocol to separate phosvitin and IgY from egg yolk without using organic solvents. Egg yolk was diluted with 2 volumes of distilled water (DW), homogenized, and centrifuged. The precipitant was collected and homogenized with 4 volumes of 10% NaCl (wt/vol) in 0.05 N NaOH solution to extract phosvitin. The pH of the homogenate was adjusted to 4.0 and the precipitate was removed by centrifugation. The supernatant was collected and then heat-treated at 70°C for 30 min and centrifuged to remove impurities. The supernatant containing phosvitin was collected, had salts removed, and was concentrated and then freeze-dried. The supernatant from the centrifugation of diluted egg yolk was diluted again with 3 volumes of DW, and the precipitate was removed by centrifugation. The resulting supernatant was concentrated using ultrafiltration and then IgY was precipitated using 20% saturated (NH4)2 SO4 + 15% NaCl (wt/vol). The precipitant was collected after centrifugation at 3,400 × g for 30 min at 4°C and dissolved with DW, had salts removed, and then was freeze-dried. The purity of separated phosvitin and IgY was checked using SDS-PAGE and the proteins were verified using Western blotting. The purity of phosvitin and IgY was 97.2 and 98.7%, and the yield was 98.7 and 80.9%, respectively. The ELISA results indicated that the activities of separated IgY and phosvitin were 96.3 and 98.3%, respectively. This study proved that both phosvitin and IgY can be separated in sequence from egg yolk without using an organic solvent. Also, the method is very simple and has a high potential for scale-up processing.

Egg yolk phosvitin is one of the most phosphorylated proteins in nature, and thus has a strong metal-binding ability. The objective of this study was to evaluate the cytotoxic and antigenotoxic activities of phosvitin in vitro. Using the 3-[4,5-dimethythiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay, the cytotoxicity of phosvitin was evaluated in human cancer cell lines of various tissue origins, including the cervix (HeLa), breast (MCF-7), stomach (AGS), lung (A549 and SK-MES-1), liver (HepG2), and larynx (Hep-2). The growth of all cancer cell lines was inhibited in a dose-dependent manner by phosvitin. Among the cancer cell lines tested, MCF-7 and SK-MES-1 were the least sensitive and HeLa, AGS, and HepG2 were the most sensitive to phosvitin. The 50% inhibition of cell viability values of phosvitin were 5.38, 11.57, 4.78, 6.98, 11.82, 3.93, and 9.97 mg/mL for HeLa, MCF-7, AGS, A549, SK-MES-1, HepG2, and Hep-2, respectively. The protective effects of phosvitin against DNA damage in human leukocytes indicated that phosvitin showed protective effects against the oxidative stress-induced DNA damages in human leukocytes. These results suggested that phosvitin has a high potential to be used as an anticancer agent for humans.

Egg white contains many functionally important proteins. Ovalbumin (54%), ovotransferrin (12%), ovomucoid (11%), ovomucin (3.5%), and lysozyme (3.5%) are among the major proteins that have high potentials for industrial applications if separated. The separation methods for these proteins from egg white have been developed since early 1900, but preparation methods of these proteins for commercial applications are still under development. Simplicity and scalability of the methods, use of nontoxic chemicals for the separation, and sequential separation for multiple proteins are very important criteria for the commercial production and application of these proteins. The separated proteins can be used in food and pharmaceutical industry as is or after modifications with enzymes. Ovotransferrin is used as a metal transporter, antimicrobial, or anticancer agent, whereas lysozyme is mainly used as a food preservative. Ovalbumin is widely used as a nutrient supplement and ovomucin as a tumor suppression agent. Ovomucoid is the major egg allergen but can inhibit the growth of tumors, and thus can be used as an anticancer agent. Hydrolyzed peptides from these proteins showed very good angiotensin I converting enzyme inhibitory, anticancer, metal binding, and antioxidant activities. Therefore, separation of egg white proteins and the productions of bioactive peptides from egg white proteins are emerging areas with many new applications.

Reduction of foodborne illnesses and deaths by improving the safety of poultry products is one of the priority areas in the United States, and developing and implementing effective food processing technologies can be very effective to accomplish that goal. Irradiation is an effective processing technology for eliminating pathogens in poultry meat. Addition of antimicrobial agents during processing can be another approach to control pathogens in poultry products. However, the adoption of irradiation technology by the meat industry is limited because of quality and health concerns about irradiated meat products. Irradiation produces a characteristic aroma as well as alters meat flavor and color that significantly affect consumer acceptance. The generation of a pink color in cooked poultry and off-odor in poultry by irradiation is a critical issue because consumers associate the presence of a pink color in cooked poultry breast meat as contaminated or undercooked, and off-odor in raw meat and off-flavor in cooked meat with undesirable chemical reactions. As a result, the meat industry has difficulties in using irradiation to achieve its food safety benefits. Antimicrobials such as sodium lactate, sodium diacetate, and potassium benzoate are extensively used to extend the shelf-life and ensure the safety of meat products. However, the use of these antimicrobial agents alone cannot guarantee the safety of poultry products. It is known that some of the herbs, spices, and antimicrobials commonly used in meat processing can have synergistic effects with irradiation in controlling pathogens in meat. Also, the addition of spices or herbs in irradiated meat improves the quality of irradiated poultry by reducing lipid oxidation and production of off-odor volatiles or masking off-flavor. Therefore, combinations of irradiation with these additives can accomplish better pathogen reduction in meat products than using them alone even at lower levels of antimicrobials/herbs and irradiation doses. Effects of irradiation and additive combinations on the pathogen reduction and quality of poultry meat will be discussed in detail.

The objective of this study was to determine the effects of feeding high concentrations of corn distillers dried grains with solubles (DDGS) on chemical composition and selected nutrient content of egg yolk. Four isocaloric diets were formulated to contain 0, 17, 35, or 50% corn DDGS. A total of two hundred forty 54-wk-old Single-Comb White Leghorn laying hens were randomly allotted to 2 birds per cage with 3 consecutive cages representing an experimental unit (EU). Each EU was randomly assigned to 1 of 4 dietary treatments according to a completely randomized design. Hens were fed for a 24-wk experimental period after transition feeding to gradually increase corn DDGS inclusion over a 4-wk period. Two sets of experimental diets were formulated to meet or exceed the NRC nutrient recommendations for laying hens. Each diet formula was fed for 12 wk. Chemical composition and nutritional components in egg yolk were measured every 2 wk. The results showed that egg yolk from hens fed a DDGS-containing diet tended to have higher fat content and lower protein content. Total polyunsaturated fatty acids were significantly increased by the DDGS diet. The contents of choline and cholesterol were initially higher in the 50% DDGS treatment group, but were not different in the later period, especially during the last 4 wk. Lutein content increased linearly as DDGS level increased. The results indicated that feeding a high level of DDGS can increase the content of lutein and polyunsaturated fatty acids in egg yolk, but may not affect the content of cholesterol and choline.

The objective of this study was to evaluate the effect of irradiation on lipid/protein oxidation, color changes, and off-odor volatiles production in uncured and cured cooked turkey meat products. Uncured cooked turkey breast meat and cured commercial turkey breast rolls and ham were prepared and irradiated at 0, 1.5, 3.0, and 4.5 kGy using a linear accelerator. The results showed that irradiation had little effects on lipid oxidation of cured cooked turkey products, but accelerated lipid oxidation in uncured cooked turkey breast meat (P < 0.05). Protein oxidation was increased both in cured and uncured meats (P < 0.05), but more in cured cooked meat by irradiation. The redness of uncured cooked turkey was increased (P < 0.05), but the redness of cured cooked turkey meat was faded by irradiation (P < 0.05). Irradiated cured cooked turkey meat products produced less off-odor volatile compounds (dimethyl disulfide, 3-methyl/2-methyl-butananl, and hexanal) than irradiated uncured cooked meat products due to various additives in the cured meat products. Our results suggested that irradiation resulted in different chemical reactions to pigments in uncured and cured cooked turkey meat products, but cured cooked turkey meat products have a higher tolerance to odor deterioration than uncured cooked turkey meat products.

The objective of this study was to deter- mine the effect of nisin and selected meat additives (salt, lactate, lactate-diacetate combination, and poly- phosphate) on the antimicrobial activities of ovotrans- ferrin (OTF) against the growth of Listeria monocyto- genes. A Bioscreen C turbidometer (Oy Growth Curves AB Ltd., Helsinki, Finland) was used to evaluate the effect of various concentrations of nisin and individual meat additives on the antilisterial activity of OTF in brain heart infusion (BHI) broth. The concentrations of OTF, meat additives, nisin, and their combinations that proved most inhibitory to L. monocytogenes were selected and their antilisterial effects were tested us- ing frankfurters. Frankfurters were inoculated with L. monocytogenes (~6.0 log10 cfu/frankfurter); treated with OTF, meat additives, and nisin singly or in com- bination; and held under vacuum at 4, 10, or 25°C. At 40 mg/mL, OTF strongly suppressed (3.46 log at 4 h and 2.59 log at 12 h) the growth of L. monocytogenes in BHI broth compared with the control. A combina- tion of OTF (40 mg/mL) and nisin (1,000 IU) inhibited the growth of L. monocytogenes in BHI and in frank- furters held at 25°C below the detection limit (1 cfu/ mL) at 12 h. However, the antimicrobial effect of OTF (40 mg/mL) alone was not observed in frankfurters at all temperatures used in this study. Nisin (1,000 IU), OTF (40 mg/mL), and nisin (1,000 IU) combination completely inhibited the growth of L. monocytogenes in frankfurters at all temperatures during 3 d. Salt at 0.5 and 1%, lactate at 0.78 and 1.56%, and lactate (1.56%) + diacetate (0.01%) did not alter the inhibitory effect of OTF against the pathogen in BHI, but salt at 2% or polyphosphate at 0.05% negated the growth inhibitory effect of OTF against L. monocytogenes. This study demonstrated that combination of OTF and nisin was effective in controlling L. monocytogenes.

This study was designed to evaluate the effects of dietary treatment, packaging, and irradiation singly or in combination on the oxidative stability of broiler chicken thigh meat. A total of 120 four-week-old chickens were divided into 12 pens (10 birds/pen), and 4 pens of broilers were randomly assigned to a control oxidized diet (5% oxidized oil) or an antioxidant-added diet [500 IU of vitamin E + 200 mg/kg of butylated hydroxyanisole (BHA)] and fed for 2 wk. After slaughter, thigh meats were separated, ground, packaged in either oxygen-permeable or oxygen-impermeable vacuum bags, and irradiated at 0 or 3 kGy. Lipid oxidation (TBA-reactive substances), protein oxidation (carbonyl), and color of the meat were measured at 1, 4, and 7 d of refrigerated storage. The lipid and protein oxidation of thigh meats from birds fed the diet supplemented with antioxidants (vitamin E + BHA) was significantly lower than the lipid and protein oxidation of birds fed the control diet, whereas the lipid and protein oxidation of broilers fed the oxidized oil diet was higher than that of birds fed the control diet. Vacuum packaging slowed, but irradiation accelerated, the lipid and protein oxidation of thigh meat during storage. Dietary antioxidants (vitamin E + BHA) and irradiation treatments showed a stronger effect on lipid oxidation than on protein oxidation. A significant correlation between lipid and protein oxidation in meat was found during storage. Dietary supplementation of vitamin E + BHA and the irradiation treatment increased the lightness and redness of thigh meat, respectively. It is suggested that appropriate use of dietary antioxidants in combination with packaging could be effective in minimizing oxidative changes in irradiated raw chicken thigh meat.

To develop a method that can maintain egg freshness during practical storage conditions, eggs were coated with chitosan and stored with or without dry ice. The physicochemical and microbiological qualities of eggs were evaluated during 14 d of storage at 4 and 23°C without dry ice and at 23°C with dry ice. The combination of chitosan coating and dry ice significantly inhibited a Haugh unit decrease during storage at 23°C. No difference in functional properties, such as foaming ability, foam stability, and viscosity, among treatments was observed, but chitosan coating and storage with dry ice decreased the rate of pH increase and moisture loss in albumen at d 7 and 14. The eggs treated with chitosan coating and storage with dry ice had a significantly lower number of Salmonella Typhimurium inoculated on the egg surface than did control eggs during storage at 23°C. Results revealed that the combination of chitosan coating and storage with dry ice limited the moisture loss, CO2 emission, and pH increase, which helped maintaining the freshness of eggs. Microbial growth was also inhibited during storage at 23°C.

The aim of this study was to evaluate the effect of EDTA, lysozyme, or the combination of EDTA and lysozyme on the antibacterial activity of ovotransferrin against Escherichia coli O157:H7. Ovotransferrin solutions (20 mg/mL) containing 100 mM NaHCO3 (OS) with added EDTA (2.0 or 2.5 mg/mL), lysozyme (1.0, 1.5, or 2.0 mg/mL), or both were prepared. The antibacterial activities of OS, OSE (OS + EDTA), or OSL (OS + lysozyme) against E. coli O157:H7 in model systems were investigated by turbidity and viability tests. In addition, OSE, OSL, or OSEL (OS + EDTA + lysozyme) was applied to irradiated pork chops and commercial hams to determine whether the solutions had antibacterial activity on meat products. The effect of the initial cell population on the antibacterial activity of OSE, OSL, and OSEL was determined. Ethylenediaminetetraacetate at 2 mg/mL plus OS induced a reduction of approximately 3 to 4 log in viable E. coli O157:H7 cells in brain heart infusion broth media, and 1 mg/mL of lysozyme plus OS resulted in a reduction of approximately 0.5 to 1.0 log during a 36-h incubation at 35°C. However, neither OSE nor OSEL showed a significant antibacterial effect on pork chops and hams during storage at 10°C. The initial cell number in media did not affect the antibacterial activity of OSE or OSEL against E. coli O157:H7. This study demonstrates that combinations of ovotransferrin, NaHCO3, and EDTA have the potential to control E. coli O157:H7.

The objective of this study was to determine the effect of antimicrobials on the survival and proliferation of Listeria monocytogenes in turkey breast rolls following electron-beam irradiation. Six antimicrobial additive treatments that include no preservatives (control), 0.1% potassium benzoate (PB), 2% sodium lactate (SL), 0.1% potassium benzoate plus 2% sodium lactate (PB + SL), 2% sodium lactate plus 0.1% sodium diacetate (SL + SDA), and 0.1% potassium benzoate, 2% sodium lactate, and 0.1% sodium diacetate (PB + SL + SDA) were used. Sliced turkey breast rolls were artificially inoculated with approximately 10(6) cfu/cm(2) of 5-strain L. monocytogenes cocktails, then vacuum-packaged and irradiated at 0, 1.0, 1.5, 2.0, or 2.5 kGy. The radiation dose (kGy) that results in 90% reduction of viable cells for breast rolls, D(10) value, with various additive treatments ranged from 0.56 to 0.58 kGy. Adding PB (0.1%) or SL (2%) in turkey rolls failed to prevent L. monocytogenes from growing during refrigerated storage. In turkey rolls added with 2 (PB + SL or SL + SDA) or 3 (PB + SL + SDA) antimicrobial combinations had 2 or 3 wk of lag phases before L. monocytogenes growth, respectively. Irradiating turkey rolls, which were added with PB + SL or SL + SDA, at 1.0 kGy was effective in suppressing the growth of L. monocytogenes for about 6 wk when stored at 4 degrees C. No growth of L. monocytogenes after irradiation occurred during 42 d of storage for 2.0 kGy irradiated breast rolls formulated with 0.1% PB + 2% SL, 2% SL + 0.1% SDA or 0.1% PB + 2% SL + 0.1% SDA, and 1.0 kGy irradiated turkey breast with 0.1% PB + 2% SL + 0.1% SDA. Sensory panelists found that low-dose irradiation (1.0 kGy) had no effect on the sensory characteristics of ready-to-eat turkey breast rolls. Including SL + SDA had slightly negative effect for nonirradiated turkey breast rolls, but the sensory characteristics of 1.0 kGy irradiated turkey roll containing SL + SDA was not significantly different from the others receiving 1.0 kGy irradiation. For microbial safety, PB + SL and SL + SDA antimicrobial treatments combined with 1.0 kGy or 2.0 kGy irradiation are a promising technology.

The influence of NaHCO(3) and citric acid on the antibacterial activity of apo-ovotransferrin in model systems and ham was investigated. The antibacterial activity of 20 mg/mL of ovotransferrin solution with added NaHCO(3) (0, 25, 50, or 100 mM) or citric acid (0.25 or 0.5%) was evaluated against Escherichia coli O157:H7 and Listeria monocytogenes in brain heart infusion broth. The antimicrobial activity of ovotransferrin saturated with Fe(2+) or Zn(2+) against both pathogens was also measured. In addition, ovotransferrin solutions containing either 100 mM NaHCO(3) or 0.5% citric acid were applied to commercial hams inoculated with E. coli O157:H7 or L. monocytogenes and stored at 4 degrees C for 4 wk. The antimicrobial activity of ovotransferrin increased as the concentration of added NaHCO(3) increased. Sodium bicarbonate (100 mM) significantly improved the antibacterial activity of ovotransferrin against E. coli O157:H7 and L. monocytogenes. Citric acid (0.5%) combined with ovotransferrin resulted in a synergistic antibacterial effect against E. coli O157:H7, and L. monocytogenes was susceptible to 0.5% citric acid alone. Sodium bicarbonate diminished the strong antibacterial activity of ovotransferrin + citric acid against E. coli O157:H7, and use of sodium citrate instead of citric acid did not produce any antibacterial activity against the pathogens. The antimicrobial activity of ovotransferrin increased significantly under acidic conditions. The Zn-bound ovotransferrin prevented the growth of L. monocytogenes as detected in the apo-ovotransferrin combined with 100 mM NaHCO(3) treatment, but Fe-bound ovotransferrin had little or no inhibitory activity against E. coli O157:H7 and L. monocytogenes. Ovotransferrin + 100 mM NaHCO(3) did not exhibit any antibacterial activity against the 2 pathogens in commercial hams, whereas ovotransferrin + 0.5% citric acid suppressed the growth of L. monocytogenes in irradiated hams. In conclusion, combinations of ovotransferrin with NaHCO(3), citric acid, or Zn(2+) enhanced the antibacterial activity of ovotransferrin against E. coli and L. monocytogenes, but there are some limitations as discussed for applying ovotransferrin to meat or meat products.

The effect of electron beam irradiation on the survival and growth of Listeria monocytogenes and natural microflora in oven-roasted turkey breast rolls and turkey hams was evaluated. Slices of turkey breast rolls and hams were inoculated with a 5-strain mixture of L. monocytogenes to achieve 10 6 to 10 7 cfu/ cm 2 ; vacuum-packaged; irradiated at 0 (control), 1.0, 1.5, 2.0, or 2.5 kGy; and stored at 4°C for up to 28 d. Numbers of naturally occurring bacteria on sliced turkey hams and breast rolls were 2.72 and 6.22 log 10 cfu/ cm 2 , respectively. The values of the radiation dose that results in 90% reduction of viable L. monocytogenes in breast rolls and hams were 0.52 and 0.47 kGy, respectively. For breast rolls, the log 10 reductions of L. monocytogenes after irradiation at 1.0 and 2.5 kGy were 1.5 and 4.7, respectively, whereas they were 2.0 and 5.5 for hams. The log 10 reductions of aerobic plate count (APC) in breast rolls after 1.0 and 2.0 kGy of irradiation were 2.9 and 5.2, whereas that of hams was

The objective of this study was to develop a simple and economical protocol for separating ovotransferrin from egg white. Egg white was separated from the yolk and diluted with the same volume of distilled water. To prevent denaturation during the separation process, ovotransferrin in 2×-diluted egg white was converted to its holo-form by adding 20 mM FeCl3·6H2 O solution (0.25 to 3 mL/100 mL). The pH of egg white was adjusted to pH 7.0, 8.0, or 9.0, and NaHCO3 and NaCl were added to 50 mM and 0.15 M, respectively (final concentrations) to facilitate iron binding to ovotransferrin. The iron-bound ovotransferrin was separated from the egg white using different concentrations of ethanol (30 to 50%). Ethanol at 43% (final concentration) and pH at 9.0 were the best conditions for separating iron-bound ovotransferrin from 2×-diluted egg white solution. Almost all egg white proteins including ovalbumin were precipitated at 43% ethanol, but most of the iron-bound ovotransferrin remained in the supernatant. Holo-ovotransferrin in the 43% ethanol solution started to precipitate as the concentration of ethanol increased, but the optimal condition for precipitating ovotransferrin was when the ethanol concentration reached 59% (final). The precipitated holo-ovotransferrin was dissolved with distilled water, and AG1-X2 ion exchange resin (at 3× iron content in ovotransferrin) was used to remove iron bound to ovotransferrin after pH adjustment to 4.7 using 500 mM citric acid. The apo-ovotransferrin obtained using this protocol was >80% in purity and around 99% in yield. The protocol developed is simple, economical, and appropriate for a large-scale production of ovotransferrin from egg white. Also, the isolated ovotransferrin can be applied in human foods, because the only solvent used in this process is ethanol. Furthermore, the AG1-X2 ion exchange resin and ethanol used in this process can be regenerated and recovered.

The Egg Safety Action Plan released in 1999 raised questions concerning egg temperature used in the risk assessment model. Therefore, a national study was initiated to determine the internal and external temperature sequence of eggs from oviposition through distribution. Researchers gathered data from commercial egg production, shell egg processing, and distribution facilities. The experimental design was a mixed model with 2 random effects for season and geographic region and a fixed effect for operation type (inline or offline). For this report, internal and external egg temperature data were recorded at specific points during shell egg processing in the winter and summer months. In addition, internal egg temperatures were recorded in pre- and postshell egg processing cooler areas. There was a significant season x geographic region interaction (P0.05) for both surface and internal temperatures. Egg temperatures were lower in the winter vs. summer, but eggs gained in temperature from the accumulator to the postshell egg processing cooler. During shell egg processing, summer egg surface and internal temperatures were greater (P0.05) than during the winter. When examining the effect of shell egg processing time and conditions, it was found that 2.4 and 3.8 degrees C were added to egg surface temperatures, and 3.3 and 6.0 degrees C were added to internal temperatures in the summer and winter, respectively. Internal egg temperatures were higher (P0.05) in the preshell egg processing cooler area during the summer vs. winter, and internal egg temperatures were higher (P0.05) in the summer when eggs were (3/4) cool (temperature change required to meet USDA-Agricultural Marketing Service storage regulation of 7.2 degrees C) in the postshell egg processing area. However, the cooling rate was not different (P0.05) for eggs in the postshell egg processing cooler area in the summer vs. winter. Therefore, these data suggest that season of year and geographic location can affect the temperature of eggs during shell egg processing and should be a component in future assessments of egg safety.

The objective of this study was to develop an economical, simple, and large-scale separation method for IgY from egg yolk. Egg yolk diluted with 9 volumes of cold water was centrifuged after adjusting the pH to 5.0. The supernatant was added with 0.01% charcoal or 0.01% carrageenan and centrifuged at 2,800 x g for 30 min. The supernatant was filtered through a Whatman no. 1 filter paper and then the filtrate was concentrated to 20% original volume using ultrafiltration. The concentrated solution was further purified using either cation exchange chromatography or ammonium sulfate precipitation. For the cation exchange chromatography method, the concentrated sample was loaded onto a column equilibrated with 20 mM citrate-phosphate buffer at pH 4.8 and eluted with 200 mM citrate-phosphate buffer at pH 6.4. For the ammonium sulfate precipitation method, the concentrated sample was twice precipitated with 40% ammonium sulfate solution at pH 9.0. The yield and purity of IgY were determined by ELISA and electrophoresis. The yield of IgY from the cation exchange chromatography method was 30 to 40%, whereas that of the ammonium sulfate precipitation was 70 to 80%. The purity of IgY from the ammonium sulfate method was higher than that of the cation exchange chromatography. The cation exchange chromatography could handle only a small amount of samples, whereas the ammonium sulfate precipitation could handle a large volume of samples. This suggests that ammonium sulfate precipitation was a more efficient and useful purification method than cation exchange chromatography for the large-scale preparation of IgY from egg yolk.

Ovomucoid is well known as a "trypsin inhibitor" and is considered to be the main food allergen in egg. However, the negative functions of ovomucoid can be eliminated if the protein is cut into small peptides. The objectives of this study were to hydrolyze ovomucoid using various enzyme combinations, and compare the functional properties of the hydrolysates. Purified ovomucoid was dissolved in distilled water (20 mg/mL) and treated with 1% of pepsin, α-chymotrypsin, papain, and alcalase, singly or in combinations. Sodium sodium dodecyl sulfate-polyacrylamide (SDS-PAGE) results of the hydrolysates indicated that pepsin (OMP), alcalase (OMAl), alcalase+trypsin (OMAlTr), and alcalase+papain (OMAlPa) treatments best hydrolyzed the ovomucoid, and the 4 treatments were selected to determine their functional characteristics. Among the 4 enzyme treatments, hydrolysate from OMAlTr showed the highest iron-chelating and antioxidant activities, while OMP showed higher ACE-inhibitory activity, but lower Fe-chelating activity than the other treatments. However, no difference in the copper-chelating activity among the treatments was found. MS/MS analysis identified numerous peptides from the hydrolysates of OMAlPa and OMAlTr, and majority of the peptides produced were

The objective of this study was to evaluate the effect of dietary functional ingredients vitamin E (VE), Se, and conjugated linoleic acid (CLA), alone or in combination, on the quality of irradiated turkey breast meat. A total of 480 male turkeys (11-wk-old, raised on a cornsoybean basal diet) were randomly allotted to 32 pens and fed 1 of 8 experimental diets (4 pens/treatment) supplemented with none (control), 200 IU/kg of VE (VE), 0.3 ppm Se (Se), 2.5% CLA (CLA), 200 IU/kg of VE + 0.3 ppm Se (VE + Se), 200 IU/kg of VE + 2.5% CLA (VE + CLA), 2.5% CLA + 0.3 ppm Se (CLA + Se), 200 IU/kg of VE + 0.3 ppm Se + 2.5% CLA (VE + Se + CLA) for 4 wk. At 15 wk of age, all birds were slaughtered, and breast muscles of 8 birds from each pen were separated, pooled, and ground. Patties were prepared using the ground meat, aerobically packaged, and irradiated at 0 or 1.5 kGy absorbed dose. Lipid oxidation, color, and volatiles of the patties were measured after 0, 7, and 12 d of storage at 4 degrees C. The content of VE and Se and fatty acid composition of lipids were also determined. Dietary supplementation of VE and CLA increased their concentrations in turkey breast. Dietary CLA decreased monounsaturated and non-CLA polyunsaturated fatty acids content in meat. Irradiation increased (P0.05) Hunter color redness value of turkey breast and accelerated lipid oxidation, regardless of dietary treatments. However, dietary VE, Se, and CLA, alone and in combinations, decreased (P0.05) lipid oxidation in meat caused by both irradiation and storage. It was concluded that dietary supplementation of VE, Se, and CLA, alone and in combination, improved the storage stability of irradiated turkey breast meat.

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 PB + SL; 0.49 kGy for ham with SL+SDA; and 0.48 kGy for ham with PB + SL + SDA (PSS). Addition of SL + SDA or PB + SL in combination with 1.0 kGy of irradiation was effective in suppressing the growth of L. monocytogenes for about 6 wk when stored at 4 degrees C, whereas 2.0 kGy of irradiation was listeriostatic. Ham irradiated with 1 kGy in combination with PSS was listeriostatic throughout storage. SL increased firmness of turkey hams, and sensory panelists noted that the saltiness was a little higher in products containing SL, but its overall impact on quality was minimal. Amounts of benzene were detected in irradiated hams with PB, showing PB was not fit as an antimicrobial ingredient for irradiated foods. In conclusion, 2% SL and 0.1% SDA in combination with low-dose irradiation were effective in ensuring the safety of ready-to-eat meat products against L. monocytogenes.

The current study was designed to determine if dietary vitamin E influenced either the gut clearance or levels of peripheral blood CD4+ and CD8+ T lymphocytes in adult turkeys experimentally infected with Listeria monocytogenes. Turkeys were fed vitamin E (0, 100, or 200 IU) from day of hatch to time of necropsy. After 6 wk on the experimental diet, turkeys were orally inoculated with L. monocytogenes (approximately 10(9) cfu). To monitor infection status, cloacal swabs were taken on selected days post-inoculation (DPI). At necropsy, samples of viscera, including liver, spleen, cecum, duodenum, ileum, and colon were collected and cultured for L. monocytogenes. In experiments 1 and 2, recovery of L. monocytogenes from cloacal swabs, tissues, and intestines from turkeys fed vitamin E was generally lower than that from turkeys fed the control diet, although these differences were not statistically significant. When data from both trials were combined, L. monocytogenes was cultured less frequently from cloacal swabs of the vitamin E-treated group (200 IU) on 2 and 3 DPI, when compared to controls (0 IU, P < 0.01). There were no changes in virulence characteristics of L. monocytogenes cells, as measured by in vitro killing of Ped-2E9 cells, recovered from cloacal swabs or tissues of experimentally infected turkeys fed the control or a vitamin E treatment diet. Flow cytometric analysis indicated that CD4+ and CD8+ peripheral blood T lymphocytes were elevated at 6 and 8 DPI in infected turkeys given 200 IU vitamin E.

The effects of double packaging on lipid oxidation, color, and volatile production were determined to establish a modified packaging method to improve quality changes in irradiated raw turkey meat. Sliced raw turkey breast and thigh meats were aerobically, vacuum- or double (vacuum and aerobic)-packaged, electron beam irradiated at 2.5 kGy, and then stored under refrigerated temperature. For the double-packaged samples, the outer vacuum bags were removed after 5, 7, or 9 d of refrigerated storage. 2-Thiobarbituric acid-reactive substances (TBARS) values, volatile compounds, and color values of the samples were determined after 10 d of storage. Irradiation and aerobic packaging promoted production of aldehydes (propanal and hexanal) related to lipid oxidation in turkey breast and thigh meats. Vacuum-packaged irradiated samples retained S-volatile compounds (methanethiol, dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide), mainly responsible for the irradiation off-odor, during storage. Exposure of double-packaged irradiated turkey meats to aerobic conditions by removing outer vacuum bags a few days before the test was effective in controlling both lipid oxidation-dependent (aldehydes) and radiolytic off-odor (S-compounds) volatiles. The a* values of raw turkey breast and thigh meats increased by irradiation regardless of packaging conditions. The a* value of double-packaged meats was lower than that of the vacuum-packaged meats but was not significant. Thus, the use of double-packaging alone was not enough to reduce the pink color of irradiated raw turkey meat. When lipid oxidation and irradiation off-odor should be minimized without any additional additives, however, double packaging is an excellent method to be used for turkey meats.

We investigated the effect of dietary conjugated linoleic acid (CLA) along with n-3 polyunsaturated fatty acid (n-3 PUFA) on yolk fatty acid composition and volatile compounds in eggs that were raw (RA), hard-boiled (HB), or hard-boiled, irradiated (HBI, 2.5 kGy). Single Comb White Leghorn laying hens (n = 40) were randomly assigned to one of the four experimental diets containing 0, 0.5, 1.0, or 2.0% CLA. Menhaden oil was used as the source of n-3 PUFA. Eggs collected after 6 wk of feeding were analyzed for fatty acids and volatile compounds. The content of docosahexaenoic acid (C22:6 n-3) was reduced (P0.05) in eggs from hens fed the 2.0% CLA diet. Eggs from hens fed 0.5% CLA incorporated the highest concentration of docosahexaenoic acid (P0.05) with a concomitant reduction in arachidonic acid (P0.05). The yolk contents of cis-9 trans-11 CLA and trans-10 cis-12 CLA increased linearly (P0.05) as the dietary CLA supply increased. Total monounsaturates were reduced (P0.05) with an increase in saturates in yolk. No difference was observed in the total PUFA content of eggs. Total volatiles were reduced in RA eggs from 1.0 and 2.0% CLA diets. 2-Propanone, hexane, and methyl cyclopentane were the major volatiles in RA eggs and were reduced by dietary CLA at 1.0 and 2.0%. Acetaldehyde, pentane, propanol, acetic acid methyl ester, acetic acid ethyl ester, propionic acid methyl ester, 2-methylmethyl propionic acid, 2-propanone, and octane were the major volatiles in HB eggs and were reduced by 2.0% CLA (P0.05). No difference was observed in the acetaldehyde, pentane, propanol, acetic acid ethyl ester, octane, or total volatile content of HBI eggs.

A total of 450 1-d-old male broiler chicks were fed a corn-soy-flax meal-based diet (control), two cultivars of sorghum-Ruby Red (low tannin content) and Valpo Red (high tannin content)–were used at 10% level. Birds were slaughtered at the end of 42-d feeding trial. Boneless, skinless breast and thigh muscles were separated and ground to make patties. Half of the breast and thigh meat patties were individually packaged in zipper bags, and 2-TBA-reactive substances (TBARS) and colors of the patties were determined after 0 and 7 d of storage at 4 C. The other half was cooked and vacuum-packaged. The vacuum-packaged patties were used to determine time-dependent volatile production and oxidative change during 12-h holding time before analyses. Thigh meat from broilers fed the Valpo Red cultivar produced lower TBARS than that from control at Day 0. The amounts of aldehydes and sulfur compounds of cooked breast meats were lower from chickens fed the Valpo Red cultivar than those fed the control or Ruby Red cultivar. Dietary Valpo Red cultivar improved the oxidative stability of breast meat 8 and 12 h after cooking. Dietary sorghum slightly improved the color a* stability of raw thigh meat patties. This result indicated that feeding sorghum to broilers could improve some measures of the storage stability of broiler meat, but sorghum with high tannin content was more effective than that with low tannin content.

The effects of antioxidants on the flavor and color of electron-beam-irradiated turkey sausages were studied. Sausages were prepared from turkey thigh meat, NaCl (2.0%), phosphate (0.5%), water (10%), and one of five antioxidant treatments (none, vitamin E, sesamol, rosemary extract, or gallic acid at 0.02%). Sausages were stuffed and cooked in an 85 C smokehouse to an internal temperature of 74 C, then chilled and sliced to 1.5-cm thickness, and vacuum-packaged. Packaged sausages were randomly divided into three groups and irradiated at 0, 1.5 or 3.0 kGy, using an electron beam. Volatiles, color, 2-TBA-reactive substances values, and sensory characteristics were analyzed. The antioxidant effect of sesamol was the highest, followed by vitamin E and gallic acid; rosemary extract had the weakest antioxidant effect. Irradiation induced red color in sausages, but addition of gallic acid, rosemary extract, or sesamol reduced it. Gallic acid was very effective in lowering the redness of irradiated and nonirradiated sausages. The redness (a*) values of sausages with added gallic acid that were irradiated at 0, 1.5, and 3.0 kGy were 1.49,2.03, and 2.29, respectively, whereas those of control sausages under the same irradiation conditions were 2.58, 2.81, and 3.25, respectively. The reduction of redness in irradiated sausages by antioxidants was not related to CO, because antioxidants had no effect on CO production by irradiation. The amount of total volatiles was decreased significantly by antioxidants, but antioxidants had minimal effect on the off-flavor of turkey sausages induced by irradiation.

Two experiments were conducted to evaluate the effects of drinking water temperature (Tw) on laying hens subjected to warm cyclic air temperature (Ta) conditions. Each experiment consisted of a 1-wk acclimation under thermoneutrality (TN) (Ta = Tw = 21 C), a 4-wk heat exposure or treatment period, and a 2-wk recovery under TN. Each experiment involved 24 individually caged hens at the initial age of 29 wk (Experiment 1) or 30 wk (Experiment 2). In Experiment 1, Tw of 18 or 27 C was provided to 12 birds per Tw regimen under a diurnal Ta of 27 to 35 C (daily mean of 31 C). In Experiment 2, Tw of 15, 19, 23, or 27 C was provided to six birds per Tw regimen under a diurnal Ta of 27 to 38 C (daily mean of 32.5 C). Experiment 1 showed that Tw of 18 C enhanced hourly and daily feed and water intake during the first 2 wk of heat exposure, as compared with Tw of 27 C. Experiment 2 showed that daily feed and water intake were greatest for hens in the 23 C Tw regimen and least for hens in the coolest or warmest Tw regimens. Reduction in daily feed intake with increase in daily mean Ta ranged from 2.0 to approximately 3.2 g/C-day (first week of heat exposure) to 1.1 to approximately 1.9 g/C-day (fourth week of heat exposure). Water to feed intake ratio was 1.8 to approximately 2.0 during acclimation and recovery, but increased to 3.0 to approximately 3.4 during heat exposure. Internal egg quality parameters were in general unaffected by Tw. The two warmer Tw regimens in Experiment 2 had less reduction in egg size than did the two cooler Tw. In both experiments, hens displayed anticipatory increase in feed and water intake 2 to 3 h prior to lights-off. However, the stimulus of lights-on did not elicit a strong return to feed and water consumption as typically seen in broilers. The results revealed the potential existence of an optimal Tw range (near 23 C) for heat-chal lenged laying hens. Larger-scale tests are warranted to further verify the findings.

Two experiments were conducted to investigate the influence of dietary conjugated linoleic acid (CLA) on the growth, body composition, abdominal fat accumulation, and meat quality in broilers. In Experiment 1, 50 broilers that were 3 wk old (total of 200 birds) were assigned to one of the four diets containing 0, 0.25, 0.5, or 1% CLA and were fed for 3 wk. In Experiment 2, 40 broilers that were 3 wk old (total of 120 birds) were assigned to one of the three diets containing 0, 2, or 3% CLA and fed for 5 wk. At the end of the 3-wk feeding trial, the average body weight of broilers for Experiment 1 was about 2.20 kg per bird for all treatments. For Experiment 2, after 5-wk feeding trial, the average body weights of birds were 4.04, 3.99, and 3.93 kg for the control, 2% CLA, and 3% CLA groups, respectively, with a non significant reduction in body weight as the levels of dietary CLA increased. There was no difference in abdominal fat weight, the total body fat, and protein content in broilers among the CLA treatments for Experiment 1. However, when the dietary CLA was increased to 2 or 3%, the total body fat content was reduced. The whole body fat content decreased from 14.2% in the control to 11.9 and 12.2% for 2 and 3% CLA, respectively. Dietary CLA at 2 and 3% levels influenced meat quality. After cooking, the breast meat from 2 or 3% dietary CLA treatment was harder and drier, and the color was a little darker than that of the control. These changes could be caused by the decreased unsaturated fatty acid content in meat after CLA feeding, which increased the melting point of the fat.

Ovotransferrin and ovomucoid were separated using 2 methods after extracting the ovotransferrin- and ovomucoid-containing fraction from egg white. Diluted egg white (2×) was added to Fe(3+) and treated with 43% ethanol (final concentration). After centrifugation, the supernatant was collected and treated with either a high-level ethanol (61% final concentration) or an acidic salt combination (2.5% ammonium sulfate and 2.5% citric acid) to separate ovotransferrin and ovomucoid. For the high-level of ethanol method, ovotransferrin was precipitated using 61% ethanol. After centrifugation, the precipitant was dissolved in 9 vol. of distilled water and the residual ethanol in the solution was removed using ultrafiltration. The supernatant, mainly containing ovomucoid, was diluted with 4 vol. of water, had ethanol removed, and was then concentrated and used as the ovomucoid fraction. For the acidic salt precipitation method, the ethanol in the supernatant was removed first. The ethanol-free solution was then concentrated and treated with a 2.5% ammonium sulfate and 2.5% citric acid combination. After centrifugation, the precipitant was used as the ovotransferrin and the supernatant as the ovomucoid fraction. The ovomucoid fraction from both of the protocols was further purified by heating at 65°C for 20 min and the impurities were removed by centrifugation. The yields of ovomucoid and ovotransferrin were >96 and >92%, respectively. The purity of ovomucoid was >89% and that of the ovotransferrin was >88%. The ELISA results confirmed that the activity of the separated ovotransferrin was >95%. Both of the protocols separated ovotransferrin and ovomucoid effectively and the methods were simple, fast, and easy to scale up.

Ovalbumin, ovotransferrin, ovomucin, and lysozyme are a few of the egg white proteins that can be used as functional components. The objective of this study was to develop a simple, sequential separation method for multiple proteins from egg white. Separated proteins are targeted for human use, and thus any toxic compounds were excluded. The methods for individual components and the sequential separation were practiced in laboratory scale first, and then tested for scale-up. Lysozyme was separated first using FPC3500 cation exchange resin and then ovomucin using isoelectric precipitation. Ovalbumin and ovotransferrin were separated from the lysozyme- and ovomucin-free egg white by precipitating ovotransferrin first using 5.0% (wt/vol) (NH4)2SO4 and 2.5% (wt/vol) citric acid combination. After centrifugation, the supernatant (S1) was used for ovalbumin separation and the precipitant was dissolved in water, and reprecipitated using 2.0% ammonium sulfate (wt/vol) and 1.5% citric acid (wt/vol) combination. The precipitant was used as ovotransferrin fraction, and the supernatant (S2) was pooled with the first supernatant (S1), desalted using ultrafiltration, and then heat-treated to remove impurities. The yield of ovomucin and ovalbumen was >98% and that of ovotransferrin and lysozyme was >82% for both laboratory and scale-up preparations. The SDS-PAGE and western blotting of the separated proteins, except for ovomucin, showed >90% purity. The ELISA results indicated that the activities of separated ovalbumin, ovotransferrin, and lysozyme were >96%. The protocol separated 4 major proteins in sequence, and the method was simple and easily scaled up.

Chicken breast fillets were equally divided into three groups. One group was vacuum packaged, cooked in a water bath (cooked-in-bag) at 82 C for 25 min, and then irradiated at 0 or 3 kGy with a linear accelerator (V-C-I). The other two groups were irradiated at 0 or 3.0 kGy in vacuum packaging (V-I-C) or aerobic packaging (A-I-C). After 3 d of storage at 4 C, the irradiated meats were cooked in a water bath (cooked-in-bag) at 82 C for 25 min. After being cooked, meats were repackaged under vacuum and stored at 4 C. Breast fillets were analyzed at 0 and 21 d after cooking and analyzed for lipid oxidation, color, and volatiles. Irradiation accelerated lipid oxidation of breast fillets. Three days of storage of raw meat in aerobic conditions after irradiation had only minor influences on lipid oxidation after cooking. However, irradiation had a significant effect on the volatile production in meat. Dimethyl disulfide, related to irradiation odor, was significantly higher in irradiated fillets than in nonirradiated fillets for V-C-I and V-I-C, whereas it was only slightly higher for A-I-C. Other volatiles, such as 3-methyl butanal and 2-methyl butanal, were also produced in significant amounts after irradiation, especially in V-C-I and V-I-C. These results showed that irradiating cooked meat induced slightly more changes in volatiles than irradiating raw meat and then cooking. The amount of dimethyl disulfide between irradiated and nonirradiated samples for A-I-C was not different, because the dimethyl disulfide produced by irradiation disappeared during the 3 d in aerobic storage before cooking. Color a* value of irradiated fillets was higher than that of nonirradiated fillets. Irradiation also induced color L* and b* value changes. After 3 d of aerobic storage after irradiation of raw meat, the influence of irradiation on color after cooking was reduced. No significant lipid oxidation occurred during storage as shown by the low values for TBA-reactive substances.

A study was conducted to determine the effects of dietary conjugated linoleic acid (CLA) and the ratio of linoleic:linolenic acid on long-chain polyunsaturated fatty acid status. Thirty-two 31-wk-old White Leghorn hens were randomly assigned to four diets containing 8.2% soy oil, 4.1% soy oil + 2.5% CLA (4.1% CLA source), 4.1% flax oil + 2.5% CLA, or 4.1% soy oil + 4.1% flax oil. Hens were fed the diets for 3 wk before eggs and tissues were collected for the study. Lipids were extracted from egg yolk and tissues, classes of egg yolk lipids were separated, and fatty acid concentrations of total lipids, triglyceride, phosphatidylethanolamine, and phosphatidylcholine were analyzed by gas chromatography. The concentrations of monounsaturated fatty acids and non-CLA polyunsaturated fatty acids were reduced after CLA feeding. The amount of arachidonic acid was decreased after CLA feeding in linoleic acid- and linolenic acid-rich diets, but amounts of eicosapentaenoic acid and docosahexaenoic acid were increased in the linolenic-rich diet, indicating that the synthesis or deposition of long-chain n-3 fatty acids was accelerated after CLA feeding. The increased docosahexaenoic acid and eicosapentaenoic acid contents in lipid may be compensation for the decreased arachidonic acid content. Dietary supplementation of linoleic acid increased n-6 fatty acid levels in lipids, whereas linolenic acid increased n-3 fatty acid levels. Results also suggest that CLA might not be elongated to synthesize long-chain fatty acids in significant amounts. The effect of CLA in reducing the level of n-6 fatty acids and promoting the level of n-3 fatty acids could be related to the biological effects of CLA.

A study was conducted to determine the effects of dietary vitamin E supplementation on the storage stability and volatiles production in irradiated cooked turkey meat. Turkeys, raised with diets containing 25, 50, 75, or 100 IU of dl-alpha-tocopheryl acetate (TA)/kg diet from 1 to 105 d of age, were fed with diets containing 25, 200, 400, or 600 IU of TA/kg diet from 105 to 122 d of age. Breast and leg meat patties were prepared, irradiated at 0 or 2.5 kGy dose, cooked to an internal temperature of 78 C, and stored in either vacuum or aerobic packaging. Thiobarbituric acid reactive substance (TBARS) values gradually decreased as the dietary TA increased and > 200 IU TA/kg diet treatments were helpful in maintaining low TBARS values in irradiated breast and leg meat patties during the 7-d storage period. With vacuum-packaging, irradiated cooked breast patties developed more oxidation than nonirradiated patties but the prooxidant effect of irradiation in cooked leg meat patties was not consistent. In aerobic-packaged cooked meat, irradiated patties had lower TBARS than nonirradiated patties in both breast and leg meat stored in oxygen permeable bags for 7 d. Propanal, pentanal, hexanal, 1-pentanol, and total volatiles were highly correlated with the TBARS values of meat. However, hexanal represented the lipid oxidation status of cooked meat better than any other volatiles component. The amount of hexanal and total volatiles in cooked breast and leg meat shows decreasing trends as dietary TA increased. In vacuum packaging, irradiated breast and leg meat had higher hexanal and total volatiles content than nonirradiated meat at both 0 and 7 d of storage. In aerobic packaging, the amount of hexanal and total volatiles greatly increased in both irradiated and nonirradiated meat patties during the 7-d storage periods. The results illustrated that the antioxidant effect of TA was not strong enough to control lipid oxidation and off-odor generation in cooked meat stored under aerobic conditions because the progress of lipid oxidation in cooked meat under aerobic condition is very rapid. However, the combination of dietary TA and vacuum packaging of cooked meat immediately after cooking could be a good strategy to minimize oxidation and volatiles production in cooked meat.

Three experiments were conducted to develop a sensitive and reliable fluorometric thiobarbituric acid (TBA) reactive substances (TBARS) method to determine lipid oxidation products in meat. The first study was conducted to find the optimum sample preparation conditions for meat in the fluorometric method. The second study was to compare the original and the modified methods by using meat and blood samples. The modified fluorometric method was compared with a conventional spectrophotometric method in a third study. Four different extraction solutions (2.5 M acetic acid, 0.5 M hydrochloric acid, 0.8 M perchloric acid, and 1.4 M trichloroacetic acid) and two ratios of extraction solution to TBA (20 mM) solutions (2:1 and 1:1) were examined in the first study. Hydrochloric acid was the optimum among the four extraction solutions tested, and the ratio of extraction solution to TBA solution at 1:1 was the best for the fluorometric TBARS method in raw ground turkey. The modified fluorometric method had high recovery rates (91%, average), and the regression coefficient of the standard curve prepared with spikes was also high (r2 = 0.99). The analysis of raw meat and plasma samples indicated that the modified fluorometric method had greater sensitivity than the original method. The pH of the reaction mixture played an important role in extraction TBARS from samples, and low pH conditions were preferable to high pH conditions. The amount of lipid oxidation products in raw turkey breast meat indicated that the fluorometric method had much greater sensitivity than the spectrophotometric method. The results from the three studies showed that the modified fluorometric TBARS method was useful for the samples with low lipid oxidation products, such as fresh raw meat. The sensitivity of the modified fluorometric method also facilitates the determination of oxidation products in small quantities of samples.

Oil emulsion and raw and cooked tissue homogenates were used to determine the mechanisms of various iron forms on the catalysis of lipid peroxidation. Flax oil (0.25 g) was blended with 160 mL maleate buffer (0.1 M, pH 6.5) to prepare an oil emulsion. Raw or cooked turkey leg meat was used to prepare meat homogenates. Samples were prepared by adding iron from each of the various sources, reactive oxygen species, or enzyme (xanthine oxidase and superoxide dismutase) systems into the oil emulsion or meat homogenates. In oil emulsion and cooked-meat homogenates, ferrous iron and hemoglobin had strong prooxidant effects, but ferritin became prooxidant only when ascorbate was present. Hemoglobin and ferritin had no prooxidant effect in raw-meat homogenates. The status of heme iron and the released iron from hemoglobin had little effect on the prooxidant effect of hemoglobin in oil emulsion and cooked meat homogenate systems. The prooxidant effect of ferrous iron in oil emulsion and cooked-meat homogenates disappeared in the presence of superoxide (.O2-), H2O2, or xanthine oxidase systems. In raw-meat homogenates, however, ferrous had strong prooxidant effects even in the presence of .O2-, or H2O2. The status of free iron was the most important factor in the oxidation of oil emulsion and cooked-meat homogenates but the impact in raw-meat homogenates was small.

The objective of this study was to investigate the effects of nitric oxide (NO) on the quality of broiler chicken meat during postmortem storage. Eighteen broiler chickens were slaughtered and breast meat was randomly assigned to 1 of 3 treatments including the control group, nitric oxide synthase (NOS) inhibitor group, and NO enhancer group. The breast samples were incubated with water, NO enhancer, and NO inhibitor for 1 d and then stored at 4°C under atmospheric conditions for 4 and 7 d. Left side of breast meat was used to determine protein oxidation, lipid oxidation, water-holding capacity, and pH, whereas the right side was used for the measurement of color and drip loss. Breast meat from NO enhancer group showed the lowest water-holding capacity during refrigerated storage, whereas drip losses were not significantly (P0.05) different among 3 treatments. Lipid oxidation showed a significant difference (P0.05) only at 7 d in which NOS inhibitor group showed the highest, whereas the NO enhancer group showed the lowest levels of lipid oxidation. Carbonyl content in NO enhancer group was significantly higher than the control and NOS inhibitor treatment at 1 and 4 d of refrigerated storage. Lightness of breast meat in the NOS inhibitor group was greater, whereas redness was lower than the control and NO enhancer group at 4 and 7 d of refrigerated storage. The ultimate pH of 3 treatments was not significantly (P0.05) different from one another. These data indicate that NO could play a significant role in modulating the quality of fresh broiler breast meat during refrigerated storage.

Ovotransferrin is one of the major egg white proteins that have antimicrobial activity as well as iron binding capability. The objective of this study was to develop a simple and easy method to separate ovotransferrin without using organic solvents. Egg white was separated from yolk, added in a 1:1 ratio to distilled water (DW), and then homogenized. The ovomucin in the diluted egg white was removed by centrifugation, adjusting the pH to 4.5 to 5.0. The resulting supernatant was added to different ratios of ammonium sulfate and citric acid, and then centrifuged after holding overnight at 4°C. The precipitant, which contains ovotransferrin, was dissolved in DW, and ovotransferrin was precipitated using different ratios of ammonium sulfate and citric acid. The precipitant collected after centrifugation was dissolved with DW and subjected to ultrafiltration to remove salts and concentrate the solution. The purity of the ovotransferrin was determined using SDS-PAGE, the protein identified using Western blot, and the estimated yield calculated by weighing the ovotransferrin after freeze drying. Over 85% purity and over 83% yield were obtained from the combinations of 5.0% (wt/vol) ammonium sulfate and 2.5% (wt/vol) citric acid followed by 2.0% (wt/vol) ammonium sulfate and 1.5% (wt/vol) citric acid. Activity of the ovotransferrin showed similar activity with previously separated ovotransferrin. However, this method is simpler and more cost effective than the previous method. The isolated ovotransferrin can be used as is or after modifications for various applications such as antimicrobial treatments, anticancer treatments, and iron-supplementing agents for humans.

The aim of this study was to investigate the cytotoxic activities of ovotransferrin (OTF) from egg white and its enzyme hydrolysates (OTH). The OTF was hydrolyzed at 45°C for 3 h using neutrase, alcalase, acid (0.03 N HCl, pH 2.5), protamex, protex 6L, flavorzyme, α-chymotrypsin, trypsin, and collupulin MG. The enzyme to substrate ratio was 1:25 (wt/wt) in all experiments. Using the 3-(4,5-dimethylthizol-2-yl)-2,5-diphenylatetetrazolium bromide (MTT) assay, the cytotoxicity of OTF and OTH was evaluated in human cancer cell lines of various tissue origins, including the lung (A549 and SK-MES-1), stomach (AGS), breast (MCF-7), larynx (Hep-2), cervix (HeLa), and liver (HepG2). The growth of all cancer cell lines was inhibited by both OTF and OTH in a dose-dependent manner. In particular, OTF displayed relatively high cytotoxicity (≤60% inhibition effects) at 40 mg/mL. At lower concentrations (≤5 mg/mL), however, OTF- and OTH-mediated cytotoxic effects were not significant in all cancer cell lines tested. The MCF-7 cells were the least sensitive to all treatments among all cancer cell lines tested. The OTH-trypsin and OTH-neutrase showed a potent cytotoxicity (over 90% cytotoxicity) to HeLa cells at the 10 mg/mL level. The OTH-trypsin, OTH-protamex, OTH-protex 6L, and OTH-collupulin MG caused 95, 96, 86, and 87% growth inhibition, respectively, in AGS cells. These results indicated there are possibilities that OTF and OTH can be used as natural growth inhibitors of human cancer cell lines.

A study was conducted to determine the effect of dietary α-linolenic acid on the fatty acid compositions of egg yolk lipids, to copherols, and internal quality of raw eggs during storage and the sensory characteristics of hard-boiled eggs from six different laying hen strains. Laying hens (total 300 birds, 72 wk old) from six strains (Rhode Island Red, Barred Plymouth Rock, New Hampshire, Light Sussex, Brown Leghorn, and White Leghorn) were distributed in 12 floor pens (2 pens per strain, 25 birds per pen) with male roosters. One of the pens for each strain was fed with tallow-based control diet and another was assigned with 3% α -linolenic acid (LNA) enriched diet with 120 U of mixed to copherol/kg diet for 3 mo. Ten eggs from each pen were collected every day after 2 wk with the experimental diets, and stored in a cold room at 4 C up to 4 wk. Total lipids, fatty acid compositions, Haugh units, and tocopherols of egg yolk were determined once a week during the 4-wk storage periods. Sensory studies were also conducted using the eggs stored for 2 wk at 4 C. Dietary LNA increased the amount of n-3 fatty acids (6.5%) in total lipid, and over 70% was C18:3n3, and the rest was C22:6n3 (20 to 25%) and C22:5n3 (5 to 10%). Only minor differences in fatty acids among strains were observed. The differences and the changes in tocopherols during storage periods by strain and diet appeared randomly and lacked consistency. The amount of tocopherols in yolk and the internal quality of raw eggs were not changed during storage periods. The flavor scores of eggs from control diet were more favorable than those of eggs from LNA diet, but their differences were minor. This result indicates that laying hen strains is not an important consideration in the dietary modification of fatty acid of shell eggs.

A study was conducted to determine the effect of feeding high concentrations of corn distillers dried grains with solubles (DDGS) on egg production and the internal quality of eggs from laying hens. Four diets were formulated to contain 0, 17, 35, or 50% corn DDGS. A total of two hundred forty 54-wk-old Sin- gle-Comb White Leghorn laying hens were randomly allotted to 2 birds per cage with 3 consecutive cages representing an experimental unit (EU). Each EU was assigned to 1 of 4 dietary treatments according to a completely randomized design. Hens were fed for a 24-wk experimental period after transition feeding to gradually increase corn DDGS inclusion over a 4-wk period. Two sets of experimental diets were formulated, and each diet was fed for 12 wk. Egg production, feed consumption, egg component, yolk color, Haugh unit during storage times, and shell breaking strength were measured. Egg production, egg weight, egg mass, feed intake, and feed efficiency were adversely affected by the highest level of DDGS in the diet (50%) during the first 12-wk period. Once diets were reformulated to include an increased concentration of both lysine and methionine, differences among the dietary treat- ments were reduced, as the performance of the 50% DDGS diets was greatly improved. Over the last 6 wk of study, no differences in egg production, egg weight, and feed intake among DDGS treatments were found. The DDGS diets positively affected the internal qual- ity of eggs during storage. Improved yolk color and Haugh unit were observed as the dietary DDGS levels increased, but the increase for Haugh unit was signifi- cant only when the DDGS level was 50%. Shell weight percentage was increased in the 50% DDGS diet, but no differences in yolk and albumen percentage were observed. It was concluded that up to 50% of DDGS could be included in the layer's diet without affecting egg weight, feed intake, egg mass, feed efficiency, and egg production as long as digestible amino acids were sufficient in DDGS-added diets.

Food protein-derived peptides are important components for nutraceuticals, with many biological functions as well as substantial nutritional benefits. The aim of this study was to investigate the antioxidant effects of ovotransferrin (OTF) derived from egg white and its hydrolysates (OH) prepared by hydrolyzing either with acid or enzymes (protamex, alkalase, trypsin, neutrase, flavorzyme, maxazyme, collupulin, protex, promod 278, and α-chymotrypsin). All OH showed approximately 3.2 to 13.5 times higher superoxide anion scavenging activity than OTF, with the maximum activity found in the OH-protamex. Similar results were obtained for oxygen radical absorbance capacity assay, with the highest value in OH-α-chymotrypsin [1.6 μM trolox equivalents (TE)] and the lowest value in OTF (0.2 μM TE). However, OTF showed the most powerful 2,2-diphenyl-2-picrylhydrazyl radical scavenging activity, which reached 78.2% after 36 h of reaction. Both OTF and OH showed protective effects against the oxidative stress-induced DNA damages in human leukocytes. Overall, OTF possessed antioxidant abilities and hydrolyzation of OTF with acid or enzymes improved these abilities.

This study was aimed at determining the effect of irradiation of shell eggs on the physiochemical and functional properties of liquid egg white during storage. Color and textural parameters of irradiated liquid egg white after cooking were also determined. Shell eggs were irradiated at 0, 2.5, 5, or 10 kGy using a linear accelerator. Egg white was separated from yolk and stored in at 4°C up to 14 d. Viscosity, pH, turbidity, foaming properties, color, and volatile profile of liquid egg white, and color and texture properties of cooked egg white were determined at 0, 7, and 14 d of storage. Irradiation increased the turbidity but decreased viscosity of liquid egg white. Foaming capacity and foam stability were not affected by irradiation at lower dose (2.5 kGy), but were deteriorated at higher doses (≥5.0 kGy) of irradiation. Sulfur-containing volatiles were generated by irradiation and their amounts increased as the irradiation dose increased. However, the sulfur volatiles disappeared during storage under aerobic conditions. Lightness (L* value) and yellowness (b* value) decreased, but greenness (-a* value) increased in cooked egg white in irradiation dose-dependent manners. All textural parameters (hardness, adhesiveness, cohesiveness, chewiness, and resilience) of cooked egg white increased as the irradiation dose increased, but those changes were marginal. Our results indicated that irradiation of shell egg at lower doses (up to 2.5 kGy) had little negative impact on the physiochemical and functional properties of liquid egg white, but can improve the efficiency of egg processing due to its viscosity-lowering effect. Therefore, irradiation of shell eggs at the lower doses has high potential to be used by the egg processing industry to improve the safety of liquid egg without compromising its quality.

The concentrations of hydrocarbons, 2-alkylcyclobutanones, and sulfur volatiles in irradiated (0 and 5 kGy) chicken meat samples (raw, precooked, and irradiated-cooked) were analyzed after 0 and 6 mo of frozen storage (-40°C) under oxygen-permeable packaging conditions. Two hydrocarbons [8-heptadecene (C(17:1)) and 6,9-heptadecadiene (C(17:2))], two 2-alkylcyclobutanones (2-dodecylcyclobutanone and 2-tetradecylcyclobutanone), and dimethyl disulfide were determined as radiation-induced detection markers in the irradiated raw and cooked chicken meats. Although irradiated-cooked samples produced fewer hydrocarbons and 2-alkylcyclobutanones than precooked irradiated samples, the number of individual hydrocarbons or 2-alkylcyclobutanones was still sufficient to detect radiation treatment even after 6 mo of storage at -40°C. Among sulfur volatiles, only dimethyl disulfide was found in meat after 6 mo of storage, indicating it has potential to be used an irradiation detection marker for frozen-stored meats under oxygen-permeable packaging conditions.

The objective of this study was to develop a new protocol that could be used for large-scale separation of phosvitin from egg yolk using ethanol and salts. Yolk granules, which contain phosvitin, were precipitated after diluting egg yolk with 9 volumes of distilled water. The pH of the yolk solution was adjusted to pH 4.0 to 8.0 using 6 N HCl or NaOH, and then yolk granules containing phosvitin was separated by centrifugation at 3,220 × g for 30 min. Lipids and phospholipids were removed from the insoluble yolk granules using 85% ethanol. The optimal volumes and concentration of ethanol in removing lipids from the precipitants were determined. After centrifugation, the lipid-free precipitants were homogenized with 9 volumes of ammonium sulfate [(NH(4))(2)SO(4)] or NaCl to extract phosvitin. The optimal pH and concentration of (NH(4))(2)SO(4) or NaCl for the highest recovery rate and purity for phosvitin in final solution were determined. At pH 6.0, all the phosvitin in diluted egg yolk solution was precipitated. Among the (NH(4))(2)SO(4) and NaCl conditions tested, 10% (NH(4))(2)SO(4) or 10% NaCl at pH 4.0 yielded the greatest phosvitin extraction from the lipid-free precipitants. The recovery rates of phosvitin using (NH(4))(2)SO(4) and NaCl were 72 and 97%, respectively, and their purity was approximately 85%. Salt was removed from the extract using ultrafiltration. The salt-free phosvitin solution was concentrated using ultrafiltration, the impurities were removed by centrifugation, and the resulting solution was freeze-dried. The partially purified phosvitin was suitable for human use because ethanol was the only solvent used to remove lipids, (NH(4))(2)SO(4) or NaCl was used to extract phosvitin, and ultrafiltration was used to remove salt and concentrate the extract. The developed method was simple and suitable for a large-scale preparation of partially purified phosvitin.

The effect of iron chelators, free radical scavengers, and enzyme systems on the formation of hydroxyl radicals and the lipid peroxidation of raw turkey meat was determined. Fresh hand-deboned turkey breast and leg meat without skin or mechanically deboned turkey meat (MDTM) was homogenized with 3 vol of .1 M citrate-phosphate buffer, pH 5.5, or distilled water. Samples were prepared by adding iron chelators, free radical scavengers, or enzyme (xanthine oxidase and superoxide dismutase) systems into the meat homogenate. Free ionic iron was the critical component in the formation of 2-thiobarbituric acid reactive substances (TBARS), and chelation with strong or weak iron chelators was effective in preventing the formation of TBARS in meat, except with weak iron chelators in breast meat. Hydroxyl radical scavengers mannitol, glucose, formic acid, and dimethyl sulfoxide were not effective, but free radical terminators, ascorbate and burylated hydroxyanisol, were very effective antioxidants. Tyrosine had stronger antioxidant effects than hydroxyl radical scavengers. Superoxide dismutase (SOD) and SOD plus catalase had a weak antioxidant effect on lipid oxidation of raw turkey meat but xanthine oxidase had a strong antioxidant effect that could not be explained. The formation of TBARS in meat was mainly catalyzed by the ferryl or perferryl complex-dependent free radicals, not by the superoxide-dependent hydroxyl radicals.

The effect of free ionic iron, heme pigments, and iron chelators on lipid peroxidation were determined in raw turkey meat. Fresh hand-deboned turkey breast and leg meat (without skin) or mechanically deboned turkey meat was homogenized with citrate-phosphate buffer at pH 5.0 or pH 6.5, or distilled water. Samples were prepared by adding iron (free ionic iron, 10 μg/g meat), hemoglobin (Hb), ferritin, or transferrin into the meat homogenate with or without diethylenetriaminepentaacetic acid (DTPA). The amount of analyzable iron in meat with ferritin and transferrin added was 5 to 8 ppm higher than that of the control, but the bound iron in transferrin and ferritin had little catalytic effect on lipid oxidation. The structural iron of Hb had little effect on the content of nonheme iron and had no effect on the lipid oxidation of meat. Weak iron binders (citrate and phosphate) significantly (P