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This work aimed to evaluate and compare the meat quality of chicken raised by traditional confinement (CR) and integrated (FR) conditions. Eighty chickens (40 for each group) were slaughtered, and parts yield, chemical composition, and meat quality parameters were measured. There was no significant difference in parts yield. Protein content in the breast of the CR group was significantly (P < 0.05) higher than that of the FR group. The ash content of chicken thighs in the FR group was significantly higher than in the CR group. The cooked chicken breast from the FR group was significantly more tender than that from the CR group. The TBARS values ofbreast and thigh meats on the sixth day after grindingdid not differ between CR and FR groups. However, the chickens raised in the FR had better appearance (color), fatty acids composition, and tenderness perspective than those in the CR system. All these results indicated that the plant-animal integrated system is a good alternative to the traditional confinement production system that can enhance farm diversity, land use efficiency, and sustainability of farm agriculture.

Ovotransferrin (OTF), an egg protein known as transferrin family protein, possess strong antimicrobial and antioxidant activity. This is because OTF has two iron binding sites, so it has a strong metal chelating ability. The present study aimed to evaluate the improved immune-enhancing activities of OTF hydrolysates produced using bromelain, pancreatin, and papain. The effects of OTF hydrolysates on the production and secretion of pro-inflammatory mediators in RAW 264.7 macrophages were confirmed. The production of nitric oxide (NO) was evaluated using Griess reagent and the expression of inducible nitric oxide synthase (iNOS) were evaluated using quantitative real-time polymerase chain reaction (PCR). And the production of pro-inflammatory cytokines (tumor necrosis factor [TNF]-α and interleukin [IL]-6) and the phagocytic activity of macrophages were evaluated using an ELISA assay and neutral red uptake assay, respectively. All OTF hydrolysates enhanced NO production by increasing iNOS mRNA expression. Treating RAW 264.7 macrophages with OTF hydrolysates increased the production of pro-inflammatory cytokines and the phagocytic activity. The production of NO and pro-inflammatory cytokines induced by OTF hydrolysates was inhibited by the addition of specific mitogen-activated protein kinase (MAPK) inhibitors. In conclusion, results indicated that all OTF hydrolysates activated RAW 264.7 macrophages by activating MAPK signaling pathway.

Normally, preslaughter acute heat stress could accelerate postmortem glycolysis and impair chicken breast (pectoralis major muscle) quality. However, previous studies indicated that it might be different when the acute heat stress temperature rises to an extreme range (above 35 °C). Therefore, this study’s objectives were to compare the pH decline, glycolytic enzyme activity, and AMP-activated protein kinase (AMPK) phosphorylation at early postmortem among three extreme acute heat stress temperature settings: a control group (36 °C) and two experimental groups (38 °C and 40 °C). Although the temperature did not affect glycogen phosphorylase a and pyruvate kinase activity, there was a decrease in pH decline rate, phosphofructokinase-1 activity, and phospho-AMPK-α[Thr172] within 4 h postmortem when temperature increased from 36 to 40 °C. Temperature also affected hexokinase activity, with the 36 °C-group having the highest activity. The results of the current study, for the first time, indicated that postmortem metabolic rate in chicken breast muscle could be changed by acute heat stress temperature setting at extreme range.

Bioactive peptides have great potentials as nutraceutical and pharmaceutical agents that can improve human health. The objectives of this research were to produce functional peptides from ovotransferrin, a major egg white protein, using single enzyme treatments, and to analyze the properties of the hydrolysates produced. Lyophilized ovotransferrin was dissolved in distilled water at 20 mg/mL, treated with protease, elastase, papain, trypsin, or α-chymotrypsin at 1% (w/v) level of substrate, and incubated for 0–24 h at the optimal temperature of each enzyme (protease 55°C, papain 37°C, elastase 25°C, trypsin 37°C, α-chymotrypsin 37°C). The hydrolysates were tested for antioxidant, metal-chelating, and antimicrobial activities. Protease, papain, trypsin, and α-chymotrypsin hydrolyzed ovotransferrin relatively well after 3 h of incubation, but it took 24 h with elastase to reach a similar degree of hydrolysis. The hydrolysates obtained after 3 h of incubation with protease, papain, trypsin, α-chymotrypsin, and after 24 h with elastase were selected as the best products to analyze their functional properties. None of the hydrolysates exhibited antioxidant properties in the oil emulsion nor antimicrobial property at 20 mg/mL concentration. However, ovotransferrin with α-chymotrypsin and with elastase had higher Fe3+-chelating activities (1.06±0.88%, 1.25±0.24%) than the native ovotransferrin (0.46±0.60%). Overall, the results indicated that the single-enzyme treatments of ovotransferrin were not effective to produce peptides with antioxidant, antimicrobial, or Fe3+-chelating activity. Further research on the effects of enzyme combinations may be needed.

With emerging trends in the food and pharmaceutical industries, potential applications of egg-derived bioactive compounds were recognized. Ovotransferrin is a major egg white functional protein responsible for multiple bioactivities. The objectives of this review are to provide scientific evidence of the functional properties of chicken ovotransferrin and its derived peptides and to identify future research approaches and applications. Various easy, economical, and non-toxic methods have been reported to produce ovotransferrin with high yield and purity, and chemical and enzymatic approaches have been employed to release bioactive peptides. The native ovotransferrin is known to have antimicrobial, antioxidant, anticancer, and immunomodulatory activities. The peptides produced from ovotransferrin also are reported to have antioxidant, antimicrobial, antihypertensive, and anticancer properties. However, little or no application of these compounds in the food and pharmaceutical areas is available yet. Therefore, the practical application of OTF in nutraceutical and pharmaceutical areas are among the emerging areas of research.

The formation of biofilms on the enamel surface of teeth by Streptococcus mutans is an important step in dental plaque formation, demineralization, and early caries because the biofilm is where other bacteria involved in dental caries attach, grow, and proliferate. The objectives of this study were to determine the effect of phosvitin (PSV) on the biofilm formation, exopolysaccharides (EPS) production, adherence activity of S. mutans, and the expression of genes related to the compounds essential for biofilm formation (quorum-sensing inducers and components of biofilm matrix) by S. mutans. PSV significantly reduced the biofilm-forming activity of S. mutans and increased the degradation of preformed biofilms by S. mutans. PSV inhibited the adherence activity of S. mutans by 31.9%-33.6%, and the production of EPS by 62%-65% depending upon the strains and the amount of PSV added. The expressions of genes regulating the production of EPS and the quorum-sensing-inducers (gtfA, gtfD, ftf, relA, vicR, brpA, and comDE) in all S. mutans strains were down-regulated by PSV, but gtfB was down-regulated only in S. mutans KCTC 5316. Therefore, the anti-biofilm-forming activity of PSV was accomplished through the inhibition of biofilm formation, adherence activity, and the production of quorum-sensing inducers and EPS by S. mutans.

In this study, ovalbumin (OVA) hydrolysates were prepared using various proteolytic enzymes and the anti-inflammatory activities of the hydrolysates were determined. Also, the potential application of OVA as a functional food material was discussed. The effect of OVA hydrolysates on the inhibition of nitric oxide (NO) production was evaluated via the Griess reaction, and their effects on the expression of inducible NO synthase (inducible nitric oxide synthase, iNOS) were assessed using the quantitative real-time PCR and Western blotting. To determine the mechanism by which OVA hydrolysates activate macrophages, pathways associated with the mitogen-activated protein kinase (MAPK) signaling were evaluated. When the OVA hydrolysates were added to RAW 264.7 cells without lipopolysaccharide (LPS) stimulation, they did not affect the production of NO. However, both the OVA-Protex 6L hydrolysate (OHPT) and OVA-trypsin hydrolysate (OHT) inhibited NO production dose-dependently in LPS- stimulated RAW 264.7 cells. Especially, OHT showed a strong NO-inhibitory activity (62.35% at 2 mg/mL) and suppressed iNOS production and the mRNA expression for iNOS (p

High-purity Fab fragment and immunoglobulin Y (IgY) were prepared to evaluate their anti-inflammatory activity in the lipopolysaccharide (LPS)-induced Raw 264.7 macrophage system. Compared with IgY, the Fab fragment possessed a greater potency in inhibiting the inflammation by nitric oxide (NO)/inducible nitric oxide synthase (iNOS) and prostaglandin-E2 (PGE2)/cyclooxygenase-2 (COX-2) pathways. The Fab fragment attenuated the levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-10 (IL-10) to 38.07 ± 1.86-48.39 ± 11.33 pg/mL (63.1-71.0% inhibition), 31.59 ± 3.91-38.08 ± 4.44 pg/mL (72.4-77.1% inhibition), and 20.62 ± 0.46-21.91 ± 0.65 pg/mL (50-53% inhibition), respectively. Additionally, the Fab fragment significantly inhibited the translocation of nuclear transcription factor-κB (NF-κB) p65 and the phosphorylation of mitogen-activated protein kinase (MAPK) proteins, including ERK1/2 (41.5/33.2%), JNK1/2 (44.2/39.6%), and p38 (42.2%). The Fab fragment could be internalized into cells, and the pretreatment of RAW 264.7 macrophages with the Fab fragment reduced the mRNA expression of the Toll-like receptor (TLR4, 32.7-44.4% inhibition) and αVβ3 integrin (76.1% inhibition). In conclusion, Fab fragments regulated the TLR4 and αVβ3 integrin-mediated inflammatory processes by blocking the NF-κB and MAPKs pathways in the LPS-induced RAW 264.7 macrophage system.

The effect of high-temperature and mild-pressure (HTMP) pretreatment on the enzymatic hydrolysis of phosvitin and the structural characteristics of the phosphopeptides produced were analyzed using tandem mass spectrometry. The HTMP pretreatment hydrolyzed phosvitin at random sites and helped the subsequent enzyme hydrolysis of the peptides produced. With the HTMP pretreatment alone, 154 peptides were produced, while the use of trypsin, Protex 6L, and Multifect 14L in combination with the pretreatment produced 252, 280, and 164 peptides, respectively. The use of two enzyme combinations (trypsin + Protex 6L and trypsin + Multifect 14L) helped the hydrolysis further. The number of phosphopeptides produced increased when the modifications within the same amino acid sequences were considered. This study indicated that HTMP pretreatment was a breakthrough method to improve the enzymatic hydrolysis of phosvitin that enabled an easy production of phosvitin phosphopeptides for their subsequent functional characterizations.

Grapefruit and lemon were exposed to phytosanitary irradiation doses of 0, 0.4, and 1 kGy, and then electronic-sensing screening of irradiation status and identification of radiation-induced ESR markers were conducted during 20 days storage. Codex standard photostimulated luminescence measurement (PSL(1)) was not a reliable indicator of irradiation status. Electronic tongue and electronic nose, however, showed potential as screening tools for discriminating irradiated fruits from non-irradiated counterparts based on principal component analysis of taste attributes and flavor patterns. Calibrated PSL approach clearly distinguished irradiated from non-irradiated samples based on the PSL ratio (PSL(2)/PSL(1)). Verification of irradiation status by electron spin resonance spectroscopy revealed clear paramagnetic centers from both irradiated fruits samples and ethanol-vacuum drying pretreatment improved radiation-induced ESR signal detection; not prominent enough in 0.4 kGy-irradiated commodities during 20 days of storage. Peel parts of both fruits showed high limonene which proportionally increased with irradiation doses (p

The aim of this study was to evaluate the effects of different irradiation doses (0–4.5 kGy) on the quality of raw ground beef. The results showed a significant increase in lipid oxidation and protein oxidation after irradiation, and color fading was observed only at 4.5 kGy irradiation. The increasing spermidine did not trigger any food safety panic button in irradiated raw ground beef, but this issue should be taken into consideration in irradiated cured meat products. Electronic tongue detected higher saltiness in irradiated meat due to increased drip loss by irradiation. Due to the synergistic effect of saltiness on umami, an unexpected increase in umami taste was observed at 4.5 kGy. Dimethyl disulfide produced from the sulfur-containing amino acids, the major irradiation processing biomarker, was only detected at 4.5 kGy irradiation. Thus, electron beam irradiation

A series of different eggshell membrane (ESM) and chitosan (CS) blend films (ESM/CS) were prepared for wound-care dressing. The appearance, transparency and microstructure of the films were characterized. Several wound care-related properties such as the film integrity in solution, pH, protein (BSA) and wound fluid absorption capacity as well as the antibacterial property of ESM/CS films were evaluated. The blend films were more stable than CS film after 95 h of incubation in solution. The integrity of the blend films improved significantly at the cost of a small insignificant decrease in wound fluid absorption capacity. Besides, the blend films provided an acidic environment (pH = 5.86) for wound healing. The swelling properties of ESM contributed significantly to the increase of BSA absorption capacity of the blend films (from 46.57 mg/g of CS film to 61.07 mg/g of blend film) and helped absorb more nutrients to promote the proliferation and migration of fibroblasts. Addition of CS to ESM also enhanced the antibacterial activity of the films significantly. The results indicated that the EMS/CS blend films with 0.01 g ESM/mL CS solution showed the highest high potential to be used as a wound-care dressing for humans as well as animals.

The study explored a new odor control method using Low-density polyethylene (LDPE) and Triacetyl- β-cyclodextrin (TA-β-CD) functionalized fiber mat. The odor control system was prepared using an electrospinning process. Based on the image obtained from a scanning electron microscope (SEM), the fiber diameter of the pure LDPE and TA-β-CD loaded LDPE fibers were found about 1.31–4.92 μm, depending on the TA-β-CD concentration. The presence of TA-β-CD in the fibered film mat was verified using FTIR. Hydrophobicity of the fiber mat was measured by water contact angle (WCA). The result indicates a slight inverse relationship between WCA and TA-β-CD concentration after 5% loading. Finally, the odors absorbing effectiveness of this system was examined using GC–MS. Three target sulfur odor compounds, including dimethyl disulfide (DMDS), dimethyl sulfide (DMS), and carbon disulfide (CDS), were effectively removed using the TA-β-CD functionalized LDPE fiber mat. Especially, the reduction of DMDS was up to 90.33%. The result suggested that tailoring electrospun LDPE and TA-β-CD fiber mat has a strong potential to be used as an active packaging material to develop the off-odor removal system for food or healthcare packaging application.

Phosvitin is an excellent source for phosphopeptide production, but it is highly resistant to enzymatic hydrolysis. The high-temperature and mild pressure (HTMP) pretreatment hydrolyzed phosvitin at random sites and helped the subsequent enzyme hydrolysis of the peptides produced. With the HTMP pretreatment alone, 154 peptides were produced while the use of trypsin, Protex 6L, and Multifect 14L in combination with pretreatment produced 252, 280, and 164 peptides, respectively. The use of two enzyme combinations (Trypsin + Protex 6L and trypsin + Multifect 14L) helped the hydrolysis further. The number of phosphopeptides produced increased when the modifications within the same amino acid sequences were considered. This study indicated that HTMP pretreatment was a breakthrough method to improve the enzymatic hydrolysis of phosvitin that enabled an easy production of phosvitin phosphopeptides (PPPs) for their subsequent functional characterizations.

A study was conducted to develop non-dairy creamer analogs/mimics using egg white, egg yolk, soy protein, and their combinations, and their nutrient content, shelf-life, and flavor acceptability were compared. The amounts of oleic and linoleic acid content increased as the amount of yolk increased in the formula, but the increases of polyunsaturated fatty acids were < 0.5% of total fat. The addition of egg yolk to the formula increased choline and lutein content in the products, but the amounts were < 0.4 mg/g for choline and 4 mg/g for lutein. The lutein in the products continued to decrease over the storage time, and only about 15-20% of the 0-month amounts were left after 3 months of storage. Although the TBARS values of the spray-dried non-dairy creamer analogs/mimics increased as storage time increased, the values were still low. Yellowness, darkness, and egg flavor/odor of the non-dairy creamer analogs/mimics increased as the amount of egg yolk in the formula increased. The overall acceptability of the non-dairy creamer analogs/mimics was closely related to the intensity of egg flavor/odor, but storage improved their overall acceptance because most of the off-odor volatiles disappeared during the storage. Water temperature was the most important parameter in dissolving spray-dried non-dairy creamer analogs/mimics, and 55-75oC was the optimal water temperature conditions to dissolve them. Higher amounts of yolk and soy protein combinations in place of egg white reduced the cost of the products significantly and those products contained better and balanced nutrients than the commercial coffee creamers. However, off-flavor and solubility were two important issues in the products.

The objective of this study was to elucidate the relationships among lipid/protein oxidation, color changes, off-taste, and off-odor in irradiated raw beef. The raw beef round eye was prepared and irradiated at 0, 1.5, 3.0, and 4.5 kGy using a linear accelerator. Significant increases in lipid oxidation and protein oxidation were found in irradiated raw beef, while significant decreases were observed in the color values (L*-, a*-, and b*-value). The degradation of nucleotides can contribute to the taste changes (increase in sourness and decrease in umami taste) in the irradiated raw beef, which was further confirmed by the electronic tongue data. The sulfur volatiles (e.g.: dimethyl disulfide) from the sulfur-containing amino acids increased significantly after irradiation, indicating these are closely related to the off-odor of irradiated beef.

The ubiquitous nature of Listeria monocytogenes and its ability to grow at refrigerated temperature makes L. monocytogenes a significant threat to the safety of ready-to-eat (RTE) meat products. The contamination by L. monocytogenes in RTE meat primarily occurs during slicing and packaging after cooking. The effectiveness of post-package decontamination technology such as in-package thermal pasteurization, irradiation, and high-pressure processing are discussed. Formulating meat products with antimicrobial additives is another common approach to control L. monocytogenes in RTE meat. Irradiation is an effective technology to eliminate L. monocytogenes but can influence the quality of RTE meat products significantly. The effect of irradiation or the combination of irradiation and antimicrobials on the survival of L. monocytogenes and the quality of RTE meat is discussed.

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.

This study investigated the effects of phosvitin (PV), one of the major proteins from egg yolk, with different degree of phosphorylation on the physiology of an osteoblast (MC3T3-E1) cell line. The proliferation and differentiation of MC3T3-E1 were analyzed using the CCK-8 and the alkaline phosphatase (ALP) assay, respectively. The effect of PV on the mineralization of MC3T3-E1 was monitored using the Alizarin-red staining. PV at 100 μg/mL increased the ALP activity by 145% of the control after 7 days of incubation. PV also stimulated the proliferation and differentiation of MC3T3-E1 in a phosphorylation level-dependent manner. The RT-PCR reactions indicated that PV stimulated the expression of BMP-2 and OPG mRNA in a phosphorylation-dependent manner, but inhibited RANKL mRNA expression in MC3T3-E1. This result suggested that the phosphate groups in PV not only stimulated the proliferation and differentiation of MC3T3-E1, but also controlled the mineralization by regulating the expression of BMP-2, RANKL and OPG mRNA in the osteoblast cell.

Korean citrus fruits (Jinjihyang and Chunggyun) were treated with electron beam (e-beam) at phytosanitary irradiation doses of 0, 0.4, and 1 kGy, and their irradiation status was screened after storage for 0, 10, and 20 days. Because of the inherent limitations of photo-stimulated luminescence (PSL), the first PSL measurement (PSL1) was not sufficient to distinguish the irradiated samples from the non-irradiated controls. The calibrated PSL approach clearly distinguished the e-beam-irradiated samples from the control based on PSL ratio (PSL2/PSL1): > 10, non-irradiated

The objective of this study was to elucidate the relationships among lipid/protein oxidation, color changes, off-taste and off-odor in irradiated raw beef round eye. Raw beef round eye was prepared and irradiated at 0, 1.5, 3.0 and 4.5 kGy using a linear accelerator. Significant increases in lipid oxidation and protein oxidation were found in irradiated raw beef round eye, while significant decreases were observed in the color values (L*-, a*-, and b*-value). The degradation of nucleotides can contribute to the taste changes (increase in sourness and decrease in umami taste) in the irradiated raw beef round eye, which was further confirmed by the electronic tongue data. The sulfur volatiles (e.g.: dimethyl disulfide) from the sulfur-containing amino acids increased significantly after irradiation, indicating these are closely related to the off-odor of irradiated beef round eye.

Lipid oxidation is the most crucial quality parameter in foods. Many methods were developed to determine the level of oxidation and antioxidant activity. This review compares the methods used to determine lipid oxidation and antioxidant capacity in foods. Lipid oxidation methods developed are based on the direct or indirect measurement of produced primary or secondary oxidation substances. Peroxide values and conjugated diene methods determine the primary oxidative products of lipid oxidation and are commonly used for plant oils and high-fat products. 2-Thiobarbituric acid-reactive substances and chromatographic methods are used to determine the secondary products of oxidation and are suitable for meat and meat-based products. The fluorometric and sensory analyses are indirect methods. The antioxidant capacity of additives is determined indirectly using the lipid oxidation methods mentioned above or directly based on the free-radical scavenging activity of the antioxidant compounds. Each lipid oxidation and antioxidant capacity methods use different approaches, and one method cannot be used for all foods. Therefore, selecting proper methods for specific foods is essential for accurately evaluating lipid oxidation or antioxidant capacity.

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.

Egg white is a good source for making functional peptides that can be used in the food industry. Ovotransferrin (OTF) is one of the major egg white proteins, with many functional properties, including antioxidant, antimicrobial and antiviral activities. However, enzymatic hydrolysis of ovotransferrin is known to further improve the functional activities of OTF. The aim of this study was to investigate the antioxidant and anticancer activities of functional peptides produced by two-step enzyme hydrolysis of OTF.; Results: OTF hydrolysates were prepared using promod 278P, thermolysin and a combination of the two enzymes. OTF and OTF hydrolysates showed strong antioxidant activities when analyzed using the DPPH assay. However, only OTF hydrolysates showed a strong free radical scavenging activity when NO- or ABTS-scavenging activity was measured. OTF hydrolysates showed stronger cytotoxic activities than the natural OTF against human cancer cell lines. Furthermore, OTF hydrolysates prepared with promod 278P + thermolysin combination showed the strongest cytotoxic activity, and their IC50 values were 0.79, 0.78, 0.92 and 0.78 mg mL-1 against AGS, LoVo, HT-29 and HeLa, respectively.; Conclusion: These results indicated that the two-step enzyme hydrolysates of OTF have great potential for use as a food ingredient with antioxidant and anticancer activities. © 2017 Society of Chemical Industry.; © 2017 Society of Chemical Industry.

This study was designed to elucidate the mechanisms of quality changes in raw turkey breast meat by irradiation. Raw turkey breast meat was irradiated at 0 kGy, 1.5 kGy, 3.0 kGy and 4.5 kGy, and changes in quality parameters including color, lipid and protein oxidation, and off-odor volatiles were determined. Irradiation accelerated lipid and protein oxidation, and increased redness in raw turkey breast meat. However, irradiation had less effect on the volatile profiles of salt-soluble muscle extract than water-soluble muscle extract because the primary radiolytic product from water (hydroxyl radical) had higher chances to react with the water-soluble molecules nearby. The radiolytic degradation products from sulfur-containing amino acids and aldehydes from lipid oxidation were two major volatile compounds responsible for the off-odor of irradiated raw turkey breast meat. Dimethyl disulfide was found only in irradiated raw turkey breast meat, and the amount of dimethyl disulfide linearly increased as the irradiation dose increased, indicating that this compound can be used as a marker for irradiate meat.

1. Phosvitin, a major phosphoprotein found in egg yolk, has strong antioxidant activity. Activation of elastase, collagenase, and hyaluronidase by reactive oxygen species are related to the degradation of ECM and skin aging. The objective of this study was to determine the anti-elastase and anti-hyaluronidase activity of phosvitin.2. Elastase from porcine pancreas and hyaluronidase from bovine testes were used to study the inhibitory activity of phosvitin. To elucidate the mechanism of enzyme inhibition, a Lineweaver-Burk plot was constructed.3. Phosvitin inhibited elastase and hyaluronidase activity in a dose-dependent manner. The IC

Five major proteins from egg white were separated using a successive extraction/precipitation protocol. The yield and purity of the separated proteins were measured. The separated proteins were confirmed by MALDI-TOF-MS, and their structures were characterized by CD spectrum. Lysozyme was first separated using FPC 3500 resin and then ovomucin from the lysozyme-free egg white. Ammonium sulfate and citric acid were added to the resulting lysozyme- and ovomucin-free egg white solution to precipitate ovotransferrin. Ovomucoid and ovalbumin were separated from the resulting supernatant using ethanol. The separated proteins were further purified and the optimal conditions for the further purifications were suggested. The purity and yield of lysozyme, ovotransferrin, ovalbumin, and ovomucoid were higher than 90% and 77%, while those of ovomucin were about 72% and 75%, respectively. This study separated five major proteins in egg white successively using resin adsorption, pH adjustment, salt/ethanol precipitation, and ultrafiltration.

Lipid oxidation not only negatively influences the sensory characteristics but also the functional characteristics of meat. During the process, various primary and secondary by-products are formed depending upon the types of fatty acids, oxygen availability, and the presence of pro- and antioxidants. Some of the lipid oxidation products only influence the quality of meat but others are implicated to various diseases and human health. Therefore, prevention of lipid oxidation in meat is important for meat quality and for human health as well. The imbalance of oxidants and antioxidants that favors oxidants in the biological system is called oxidative stress in the body. Although the body is equipped with defense enzymes and antioxidant compounds, there are many sources of oxidants or free radicals that can destroy the oxidants/antioxidants balance. Therefore, supply of extra antioxidants through food can help maintaining the balance in favor of antioxidants and help preventing various diseases and malfunctions of our body.

This study was conducted to evaluate the effect of fermentation temperature on the volatile composition in Kimchi. Kimchi was fermented at 2 temperature conditions (4 and 20 °C). Volatile compounds of Kimchi samples were analyzed during the fermentation periods using the dynamic headspace gas chromatography-mass spectrometry method. The optimum ripening time for the Kimchi fermented at 4 °C was 35 d, and that of 20 °C was 2 d. The pH at the optimum ripening time was 4.97 and 4.41, and the titratable acidity was 0.59% and 0.76% for the Kimchi fermented at 4 and 20 °C, respectively. Forty different types of volatile compounds, including alcohol, aldehyde, ester, and sulfur compounds, were identified. The Kimchi fermented at 20 °C produced greater amounts of volatile compounds than that at 4 °C. The amounts of most volatiles increased as the fermentation time increased, but those of aldehydes decreased rapidly during both 4 and 20 °C fermentation. Organic acids, ester, and nitriles were detected only in Kimchi fermented at 20 °C. The amounts of dimethyl disulfide, methyl-2-propenyl disulfide, and di-2-propenyl disulfide produced from the Kimchi fermented at 20 °C were more than 2-times of those at 4 °C. Therefore, it is concluded that the strong pungent odor of Kimchi fermented at 20° C is probably due to the high amount of organic acids (low pH) and sulfur compounds (dimethyl disulfide, methyl-2-propenyl disulfide, and di-2-propenyl disulfide) between the 2 Kimchi.

Irradiation had little effects on the thiobarbituric acid reactive substances (TBARS) values in ready-to-eat (RTE) turkey meat products, while it increased protein oxidation at 4.5 kGy. The volatile profile analyses indicated that the amount of sulfur compounds increased linearly as doses increased in RTE turkey meat products. By correlation analysis, a positive correlation was found between benzene/ benzene derivatives and alcohols with lipid oxidation, while aldehydes, ketones and alkane, alkenes and alkynes were positively correlated with protein oxidation. Principle component analysis showed that irradiated meat samples can be discriminated by two categories of volatile compounds: Strecker degradation products and radiolytic degradation products. The cluster analysis of volatile data demonstrated that low-dose irradiation had minor effects on the volatile profile of turkey sausages (

A total of 400, one day-old commercial broiler chicks were divided into five diet groups (negative control, positive control group with 55 ppm Zn-bacitracin, 15 ppm β-glucan, 30 ppm β-glucan, and 60 ppm β-glucan) and fed for six weeks. Ten broilers were allotted to each of 40 floor pens. Eight floor pens were randomly assigned to one of the 5 diets. Each diet was fed to the broilers for 6 weeks with free access to water and diet. The survival rate, growth rate, feed efficiency, and feed conversion rate of the broilers were calculated. At the end of the feeding trial, the birds were slaughtered, breast muscles deboned, and quality parameters of the breast meat during storage were determined. The high level of dietary β-glucan (60 ppm) showed better feed conversion ratio and survival rate than the negative control. The survival rate of 60 ppm β-glucan-treated group was the same as that of the antibiotic-treated group, which showed the highest survival rate among the treatments. There was no significant difference in carcass yield, water holding capacity, pH, color, and 2-thiobarbituric acid reactive substances values of chicken breast meat among the 5 treatment groups. Supplementation of 60 ppm β-glucan to broiler diet improved the survival rate and feed conversion rate of broilers to the same level as 55 ppm Zn-bacitracin group. The result indicated that use of β-glucan (60 ppm) can be a potential alternative to antibiotics to improve the survival and performance of broilers. However, dietary β-glucan showed no effects on the quality parameters of chicken breast meat.

Proteins and its constituents (amino acids) are known as the major contributors to the off-odor in irradiated meat. However, radiolytic degradation of amino acids occurred not only at side chains but also at amino- and carboxyl-groups of the α-carbon. A model system with amino acid esters was used to elucidate the mechanisms of volatile production at side chains of amino acids by irradiation. The low-molecular weight aldehydes, which contributed to the irradiation off-odor, were mainly from acidic, aliphatic and aliphatic hydroxyl group amino acid esters through the radiolysis of amino acid side chains or Strecker degradation. However, the contribution from non-sulfur amino acids was minor compared with sulfur amino acids. Among the sulfur-containing amino acids, methionine made the greatest contribution to the irradiation off-odor not only through the direct cleavage of the side chain. However, the chemical reactions of sulfur compounds with other compounds produced by irradiation also played significant roles to the off-odor of irradiated meat.

Non-sulfur amino acid monomers were used to study the mechanisms of volatile production in meat by irradiation. Irradiation not only produced many volatiles but also increased the amounts of volatiles from non-sulfur amino acid monomers. The major reaction mechanisms involved in volatile production from each group of the amino acids by irradiation differ significantly. However, we speculate that the radiolysis of amino acid side chains were the major mechanism. In addition, Strecker degradation, especially the production of aldehydes from aliphatic group amino acids, and deamination, isomerization, decarboxylation, cyclic reaction and dehydrogenation of the initial radiolytic products were also contributed to the production of volatile compounds. Each amino acid monomers produced different odor characteristics, but the intensities of odor from all non-sulfur amino acid groups were very weak. This indicated that the contribution of volatiles produced from non-sulfur amino acids was minor. If the volatile compounds from non-sulfur amino acids, especially aldehydes, interact with other volatiles compounds such as sulfur compounds, however, they can contribute to the off-odor of irradiated meat significantly.

Sulfur-containing amino acids were used to study the mechanisms of off-odor production in meat by irradiation. Irradiation not only increased the amounts of volatiles but also produced many new volatiles from sulfur-containing amino acid monomers. We speculate that the majority of the volatiles were the direct radiolytic products of the side chains, but Strecker degradation as well as deamination and decarboxylation of radiolytic products were also involved in the production of volatile compounds from sulfur amino acids. The volatile compounds produced in amino acids were not only the primary products of irradiation, but also the products of secondary chemical reactions after the primary compounds were produced. Cysteine and methionine produced odor characteristics similar to that of the irradiated meat, but the amounts of sulfur volatiles from methionine were far greater than that of cysteine. Although the present study was carried out using an amino acid model system, the information can be applied to the quality indexes of irradiated meats as well as other food products.

Ovalbumin (OVA) is the most abundant protein in egg white, but its application in food processing was limited because of its poor functional properties near isoelectric point. In this study, propylene glycol alginate (PGA) was used for the first time to form coacervate with OVA to solve this problem. The objective of this research was to investigate phase separation behavior and structural characteristic of OVA-PGA coacervates. Phase behavior transition during coacervate formation was carried out by turbidity, zeta-potential and appearance with the change of pH, NaCl concentration and protein/polysaccharide ratio R. At R = 2:1, the turbidity curve indicated that the soluble complexes and insoluble coacervate occurred at pH 4.78 (pHc) and 4.08 (pHϕ1), respectively. Specially, with increasing NaCl concentration, the turbidity decreased significantly. With increasing OVA/PGA ratio, the turbidity curve shifted to higher pH. The results of UV and fluorescence spectra demonstrated that the tertiary conformation of OVA was changed by PGA interaction. Besides, the Fourier transform infrared spectroscopy (FTIR) revealed that complexes were formed through the electrostatic interactions between the -NH3+ groups of OVA and –COO− groups of PGA. OVA-PGA coacervation resulted in structural change and improved OVA thermal stability. Consequently, these findings can make contribution to the development of OVA-PGA coacervates as the encapsulation of functional ingredients.

A separation method for ovoinhibitor from egg white without using toxic chemicals was established. After sequentially removing lysozyme, ovomucin, ovotransferrin and ovomucoid from egg white using Amberlite FPC 3500 ion exchange resin, pH adjustment, acidic ammonium sulfate and ethanol (35% final concentration, v/v) respectively, the resulting ovalbumin-rich precipitant was homogenized with 4 vol of distilled water and then centrifuged. The extraction was done twice and the extracts containing crude ovoinhibitor were pooled, concentrated using ultrafiltration and then subjected to 35% saturation ammonium sulfate (final concentration) precipitation. The precipitated ovoinhibitor was dissolved in acidic water (pH 3.0), desalted and concentrated using ultrafiltration, and then lyophilized. The product had 90.8% purity with a yield of 70.0% and its identity was confirmed by the MALDI-TOF MS/MS. The inhibitory activity of the separated ovoinhibitor showed that it maintained protease inhibitory activities against elastase, trypsin, ɑ-chymotrypsin, and subtilisin. This result indicated that the protocol was highly efficient, scalable, and environmentally friendly for the separation of ovoinhibitor from the egg white, and the ovoinhibitor separated has a great potential to be used as a functional protein.

Antigen-binding (Fab) and crystallizable (Fc) fragments are the active components of yolk immunoglobulin (IgY), which have been widely used in the pharmaceutical field. However, the common purification methods for the Fab and Fc fragments use combinations of multi-columns are complex and time-consuming. The objective of this study was to improve the separation efficiency of the Fab and Fc fragments from the hydrolyzed IgY and increase the purity of the isolated Fab and Fc fragments. Natural IgY was hydrolyzed using papain for 6 hr and then treated with 45% saturated ammonium sulfate to remove small molecular-weight-peptides. The fraction containing Fab and Fc fragments was loaded on a DEAE-Sepharose ion exchange column and the Fab fraction was washed out first with 10 mM Tris-HCl buffer (pH 7.6). Then, the Fc fraction bound to the DEAE Sepharose was eluted with 10 mM Tris-HCl buffer (pH 7.6) containing 0.21 M NaCl. The purity of the two fragments was 88.7% and 90.1%, respectively. The results of Western blotting and MS analyses indicated that this method purified Fab and Fc fractions with high purity. This method is easy and simple compared with other methods, and the active fragments separated can be easily used.

Objective A study was conducted to develop non-dairy creamer analogs/mimics using egg white, egg yolk, soy protein and their combinations, and their nutrient content, shelf-life and flavor acceptability were compared. Methods Spray dried egg white, egg yolk, and soy protein isolate were purchased from manufacturers and used for the formulae. Results The protein contents of the non-dairy creamer analogs/mimics were about 8.5% as calculated. The amounts of oleic and linoleic acid content increased as the amount of yolk increased in the formula, but the increases of polyunsaturated fatty acids were

The major driving force for the egg consumption in the United States over the past few decades was processed egg. However, the consumption of egg through the processed egg reached the plateau in recent years because of the imbalance in the demands between the egg white and yolk products. The consumer demands for egg white products are very high while those for the egg yolk, the co-product of dried egg white, are low because of the negative perceptions on egg yolk. Two key approaches that can be used to increase the value and use of egg yolk are: (1) developing new commodity products by fractionating egg yolk and apply them in various food processing, and (2) separating functional proteins and lipids from yolk and use them as is or further develop functional peptides and functional lipids and use them as pharmaceutical, nutraceutical, and cosmeceutical agents. These approaches can diversify the use of egg yolk, which eventually will help increase the consumption of egg. This review (1) discusses the current use of egg yolk products and the development of new functional commodity products from egg yolk, (2) review the important functional components in egg yolk and overview the current separation methods and their applications, (3) discuss the production of functional peptides and lipids using the separated egg proteins and lipids, and (4) suggest the future directions for the best use of egg yolk components. Development of scale-up production methods, which is vital for the practical applications, is discussed when appropriate.; © 2019 Institute of Food Technologists®.

The dramatic improvements in the growth rate and breast muscle size and yield in broilers through the intensive genetic selection, and the improvement in nutrition and management over the past 50 years have introduced serious abnormalities that influenced the quality of breast meat. The abnormalities include pale-soft-exudative (PSE) conditions, deep pectoral muscle (DPM) myopathy, spaghetti meat (SM), white striping (WS), and woody breast (WB) that have serious negative implications to the broiler meat industry. The incidences of PSE and DPM have been known for several decades, and their prevalence, etiology and economic impact have been well discussed. However, other abnormalities such as SM, WS and WB conditions have been reported just for few years although these conditions have been known for some time. The newly emerging quality issues in broilers are mainly associated with the Pectoralis major muscles, and the incidences have been increased dramatically in some regions of the world in recent years. As high as 90% of the broilers are affected by the abnormalities, which are expected to cause from $200 million to $1 billion economic losses to the U.S. poultry industry per year. So, this review mainly discusses the histopathological characteristics and biochemical changes in the breast muscles with the emphasis on the newly emerging abnormalities (SM, WS, and WB) although other abnormalities are also discussed. The impacts of the anomalies on the nutritional, functional, mechanical and sensory quality of the meat and their implications to the poultry industry are discussed.

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.

Background: Sodium or potassium nitrite is widely used as a curing agent in sausages and other cured meat products. Nitrite has strong antimicrobial and antioxidant effects and generates cured meat color. Nitrite, however, can react with secondary or tertiary amines in meat to form carcinogenic, teratogenic and mutagenic N-nitroso compounds. Several findings have been suggested that high consumption of processed meat may increase the risk of cancer, and emphasized that dietary nitrosamines are positively associated with cancer. Lysozyme is one of the major egg proteins that have antimicrobial and antioxidant characteristics. Therefore, lysozyme can be used in meat processing to prevent microbial growth and oxidative degradation in meat products during storage. This study is focused on evaluating the antimicrobial and antioxidant effects of lysozyme extracted from egg white as a replacer of nitrite in a cooked Italian-type chicken sausage.Methods: Four curing treatments including 100% nitrite (control), 100% lysozyme (treatment 1), 25% nitrite + 75% lysozyme (treatment 2) and 50% nitrite + 50% lysozyme (treatment 3) were used to prepare Italian-type chicken sausage samples. Recipe was developed with 64% (w/w) meat, 17% (w/w) binder (bread crumble), 12% (w/w) ice, 4% (w/w) vegetable oil, 2% (w/w) salt, 1% (w/w) spices (chili, black pepper, cardamom). Prepared samples were cooked in an 80 °C smoke house to a core temperature of 65 °C and cooled in cold water to 20-25 °C subsequently packed in polyethylene and stored in a freezer (-18 °C). The antimicrobial effect lysozyme was tested using Escherichia coli and Salmonella. The growth of these pathogens at 0, 3 and 5 days of storage of spore inoculation was determined. The antioxidant activity of lysozyme was determined using the TBARS value during the 25 d storage period. The redness (a*), lightness (L*), and yellowness (b*) of sausages were analyzed using a Minolta color meter (CR 410, Konica Minolta Inc., Japan). The proximate composition (AOAC, 2002) of frozen (-18 °C) sausage samples and sensory properties of cooked samples were determined.Results: 50% nitrite + 50% lysozyme (treatment 3) was as effective as control (100% nitrite) in suppressing the growth of Escherichia coli, Salmonella and limiting lipid oxidation in the Italian-type chicken sausage. Treatment 3 was not significantly different from the control, for lightness (L*), redness (a*) and yellowness (b*) values (P > 0.05) but showed the best sensory characteristics among the treatments (p < 0.05). Moisture content of control sample was significantly higher (p < 0.05) than other treatments while crude protein, crude fat, crude fiber and ash content were not significantly differ each. In term of the cost, both treatment 3 and control have shown approximately equal values.Conclusion: This study demonstrated that lysozyme can be used as an effective nitrite replacer in the Italian-type chicken sausage. Replacing 50% of nitrate salt with 50% lysozyme did not show any negative effects in controlling microbial growth, preventing lipid oxidation, and color changes but improved the sensory characteristics.Keywords: Italian-type chicken sausage, nitrite, lysozyme, antimicrobial, antioxidant

The microbial distribution of raw materials and beef jerky, and the effect of nisin on the growth of Bacillus cereus inoculated in beef jerky during storage, were studied. Five strains of pathogenic B. cereus were detected in beef jerky, and identified with 99.8% agreement using API CHB 50 kit. To evaluate the effect of nisin, beef jerky was inoculated with approximately 3 Log CFU/g of B. cereus mixed culture and nisin (100 IU/g and 500 IU/g). During the storage of beef jerky without nisin, the number of mesophilic bacteria and B. cereus increased unlikely for beef jerky with nisin. B. cereus started to grow after 3 d in 100 IU nisin/g treatment, and after 21 d in 500 IU nisin/g treatment. The results suggest that nisin could be an effective approach to extend the shelf-life, and improve the microbial safety of beef jerky, during storage.

The purpose of this research was to apply mathematical models to predict the effect of kimchi powder on the growth of spoilage microflora in pork snack sticks. Kimchi powder was added to the pork sticks at concentrations of 0% (control, C), 1% (T1), 2% (T2) and 3% (T3) of total content. Microbiological analysis was performed at the end of the drying process (day 0) and after 15, 30, 45, 60 and 90 days of storage at 25C. The obtained data were applied to the Baranyi growth model. Application of up to 2% kimchi powder to pork snack sticks had no effect on the initial and maximal bacterial counts, but 3% of kimchi powder reduced the lag time (tlag) and extended the maximum specific growth rate (μmax) of total plate count, anaerobic bacteria and lactic acid bacteria significantly. Mathematical models developed on the basis of the Baranyi model were useful in predicting natural microflora in the pork snack sticks during storage. Practical Applications Many kinds of jerky have become diversified and industrialized recently and kimchi, fermented vegetable, has been known to have various antimicrobial effects. Kimchi powder-treated pork jerky has higher consumer acceptability because of its spicy taste. However, the possibility of contamination of microflora in terms of food safety can be high through manufacture and distribution in industry. The predictive model suggested in this study can be used to control the possibility of microfloral contamination in restructured pork jerky products supplemented with kimchi powder as basic information.

7.1 Food Irradiation 156 7.1.1 History of Food Irradiation 156 7.1.2 Irradiation Process 159 7.2 Microbial Decontamination of Meat by Irradiation 162 7.2.1 Factors Affecting Radiation Destruction of Micro-Organisms in Meat 163 7.2.1.1 Irradiation Dose 163 7.2.1.2 Meat Composition 163 7.2.1.3 Temperature 164 7.2.1.4 Gaseous Composition 164 7.2.1.5 Microbial Factors 165 7.2.2 Combinations of Irradiation and Other Antimicrobial Interventions 166 7.3 Quality Changes in Meat by Irradiation 167 7.3.1 Lipid Oxidation 167 7.3.2 Sources and Mechanisms of Off-Odor Production 169 7.3.2.1 Sources of Off-Odor Production in Irradiated Meat........ 169 7.3.2.2 Mechanism of Off-Odor Production in Irradiated Meat.....170 7.3.3 Color Changes in Meat by Irradiation 171 7.3.3.1 Color Changes in Irradiated Raw and Cooked Meat ...... 171 7.3.3.2 Mechanism of Color Changes in Irradiated Meat 173 7.3.4 Water Holding Capacity and Texture 175 7.3.5 Consumer Attitude and Acceptance of Irradiated Meat 175 7.3.6 Control of Quality Changes 176 7.3.6.1 Additives 176 7.3.6.2 Packaging 178 7.3.6.3 Packaging and Additive Combinations 180 7.4 Future Research Needed 180 References 181 DK3813.book Page 155 Friday, February 10, 2006 10:33 AM

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.

In this chapter, methods of meat preservation that discourage microbial growth through the creation of unfavorable environments in the meat are considered. These involve action more directly inhibitory or lethal to molds and bacteria. This chapter discusses the principles, physical and biochemical aspects, antimicrobial aspects, quality aspects, and organoleptic aspects of nonthermal technologies, including freeze dehydration, ionizing radiation, and high pressure as the tools for the storage and preservation of meat.