Antimicrobial effects of three herbs (Brassica juncea, Forsythia suspensa, and Inula britannica) on membrane permeability and apoptosis in Salmonella.

AIMS: This study aimed synergistic effects of three herbs in Salmonella via increased membrane permeability and apoptosis. METHODS AND RESULTS: Using high-performance liquid chromatography, four types of phenylethyl glycosides and a lignan were detected in the herb mixture (Brassica juncea, Forsythia suspensa, and Inula britannica). During treatment with the herb mixture (1×, 2×, or 4× the MIC), viable cells decreased to 1·87 log CFU per ml (Salmonella Gallinarum) and 2·33 log CFU per ml (Salmonella Enteritidis) after 12 h of incubation according to inhibition of tricarboxylic acid cycle (P < 0·01). In addition, N-phenyl-1-naphthylamine uptake increased from 229·00 to 249·67 AU in S. Gallinarum and from 232·00 to 250·67 AU in S. Enteritidis (P < 0·05), whereas membrane potential decreased from 8855·00 to 3763·25 AU and from 8703·67 to 4300·38 AU, respectively. Apoptotic Salmonella cells were observed by confocal laser scanning microscopy and flow cytometry. Transmission electron microscopy observations with negative staining showed protein leakage from damaged Salmonella. CONCLUSIONS: These results showed the synergistic effect of the three herbs against avian pathogenic Salmonella induced by membrane damage and apoptosis. SIGNIFICANCE AND IMPACT OF THE STUDY: Salmonella causes enormous economic losses in the poultry industry. These results indicated that potency of natural antimicrobial agents due to apoptosis in Salmonella.

Anti-elastase and anti-hyaluronidase activity of phosvitin isolated from hen egg yolk.

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 IC50 value of phosvitin was 31.6 µg/ml and 1,270 µg/ml against elastase and hyaluronidase, respectively. The analysis of elastase and hyaluronidase kinetics indicated that the apparent Michaelis constant (appKm) was increased by phosvitin but the Vmax value was not affected.4. In conclusion, phosvitin exhibited competitive inhibitory activity against elastase and hyaluronidase. Thus, phosvitin could be used as a natural anti-aging agent in the cosmetics industry.

Characterization of cottage cheese using Weissella cibaria D30: Physicochemical, antioxidant, and antilisterial properties.

This study aimed to evaluate the potential of Weissella cibaria D30 as an adjunct culture in cottage cheese, including an assessment of antioxidant, antilisterial, and compositional parameters. Cottage cheese samples were manufactured using a commercial starter culture and probiotic strains Lactobacillus rhamnosus GG (GG) or W. cibaria D30 (W) and without probiotic (control). Samples were stored at 4 ± 1°C for 28 d. Bacterial cell counts (log cfu/g) of control, GG, and W samples were counted at 0, 7, 14, 21, and 28 d. Counts of W. cibaria D30 in the W samples remained at 6.85 log cfu/g after 28 d. Total solids, fat, protein, ash, and pH were measured and no significant differences were observed in compositional parameters or pH after 28 d of storage in all cheeses except those inoculated to Listeria monocytogenes. To measure the antilisterial effect, Listeria monocytogenes was inoculated into the cottage cheese samples and bacterial cell counts were obtained at 0, 6, 12, 24, 48, 72, 96, 120, and 144 h. Listeria monocytogenes counts were less than the analytical limit of detection (<10 cfu/g) in the inoculated GG and W samples, whereas the counts of L. monocytogenes in the inoculated control sample remained at 3.0 log cfu/g after 144 h. We used the DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)] radical scavenging activity assays to assess antioxidant activity: GG and W samples exhibited significant increases in antioxidant activity compared with the control sample. These results indicate that W. cibaria D30 has potential as an adjunct culture in the dairy industry.

Short communication: Antioxidative and antibacterial activities on Staphylococcus aureus and Escherichia coli O157:H4 in milk with added ginseng marc extract fermented by Lactobacillus plantarum KCCM 11613P.

Ginseng marc, a by-product of the extraction of fresh ginseng, is known to have bioactive compounds, but is frequently discarded as agriculture waste. The objectives of our study were to assess the antioxidative activity of fermented ginseng marc extract using Lactobacillus plantarum KCCM 11613P and to evaluate antibacterial activity of fermented milk with added ginseng marc extract during fermentation. After 24 h of fermentation of ginseng marc extract, the viable cell number was increased to 7.7 ± 0.1 log cfu/mL, and the pH and total titratable acidity were 4.2 ± 0.4 and 0.6% lactic acid, respectively. The total phenolic and flavonoid contents of fermented ginseng marc extract increased by 32.4 and 23.3%, respectively. Higher antioxidative activity of fermented ginseng marc extract was obtained in the ß-carotene bleaching, ferric-reducing ability of plasma, and ferric thiocyanate assays than the 1,1-diphenyl-2-picrylhydrazy assay. However, the 1,1-diphenyl-2-picrylhydrazy scavenging effect decreased due to lowered pH. During production of fermented milk with ginseng, inhibition rate of Staphylococcus aureus and Escherichia coli were 9.7 and 2.3%, respectively. The present study shows the possibilities of Lactobacillus plantarum KCCM 11613P used as a fermentation strain and ginseng marc used as a functional supplement in milk.

Short communication: Physicochemical and antioxidant properties of Cheddar-type cheese fortified with Inula britannica extract.

Cheddar-type cheese was fortified with the antioxidant Inula britannica flower extract (IBE). Cheddar-type cheeses manufactured with varying concentrations of IBE (0, 0.25, 0.5, 0.75, and 1% wt/vol) were analyzed during storage at 4°C, 0, 1, 2, and 3 wk after production. Higher IBE concentrations resulted in higher protein and ash contents, with a concomitant decrease in pH, total solid, and fat content relative to the unfortified control cheese. The total phenolic content also increased with IBE concentration, but decreased over longer storage periods. The antioxidant activities of the cheeses, determined as 2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging activity and ferric thiocyanate assay results, increased proportionally to the total phenolic content. The highest antioxidant effect was observed in the 1% IBE-fortified cheese, showing 79 and 86% antioxidant effects in the DPPH and ferric thiocyanate assays, respectively. At the 1-wk time point, the 5 cheese preparations underwent sensory evaluation for odor, taste, texture, color, and overall quality, determined using a descriptive analysis by a trained panel (n=20). The addition of IBE resulted in some increases in extract odor and taste. Overall, IBE showed good potential as an antioxidant supplement for dairy products.

Short communication: Physicochemical and antioxidant properties of milk supplemented with red ginseng extract.

This study investigated the effect of red ginseng extract (RGE) on the physicochemical properties, sensory test, and antioxidant activity of milk. The milk samples with RGE added at 0.5, 1, 1.5, and 2% were analyzed during storage at 4°C. The physicochemical properties included composition of milk, pH, titratable acidity, and color. The antioxidant activity of milk samples was determined using the 2,2-diphenyl-1-picrylhydrazyl method, ß-carotene bleaching assay, and ferric thiocyanate assay. An increase in the amount of RGE in milk resulted in an increase of lactose and total solids content, titratable acidity, and a* and b* values, whereas fat and protein contents remained unchanged. Also, pH and L* value decreased. The antioxidant activity of milk samples supplemented with RGE was higher than that of the control sample. Sensory evaluation was performed using a quantitative descriptive analysis. Two types of samples were used: (1) sterilized milk fortified with RGE (0.5, 1, 1.5, and 2%) and (2) 2% RGE, 2% RGE with oligosaccharide, and 2% RGE with oligosaccharide and cyclodextrin. The addition of oligosaccharide and cyclodextrin could effect an increase of sweetness, a decrease of bitterness and flavor of RGE, and aftertaste. Therefore, milk supplemented with RGE could be useful as a functional food.

Short communication: antiviral activity of subcritical water extract of Brassica juncea against influenza virus A/H1N1 in nonfat milk.

Subcritical water extract (SWE) of Brassica juncea was studied for antiviral effects against influenza virus A/H1N1 and for the possibility of application as a nonfat milk supplement for use as an "antiviral food." At maximum nontoxic concentrations, SWE had higher antiviral activity against influenza virus A/H1N1 than n-hexane, ethanol, or hot water (80°C) extracts. Addition of 0.5mg/mL of B. juncea SWE to culture medium led to 50.35% cell viability (% antiviral activity) for Madin-Darby canine kidney cells infected with influenza virus A/H1N1. Nonfat milk supplemented with 0.28mg/mL of B. juncea SWE showed 39.62% antiviral activity against influenza virus A/H1N1. Thus, the use of B. juncea SWE as a food supplement might aid in protection from influenza viral infection.

Investigation on antibacterial and antioxidant activities, phenolic and flavonoid contents of some thai edible plants as an alternative for antibiotics.

This study was aimed to examine the antibacterial and antioxidative properties of seven edible plants from Thailand to develop alternative antibiotics as feed additives. The plants include Citrus aurantifolia Swingle (Lime) fruits and its leaves, Sesbania grandiflora L. (Agati sesbania) leaves, Piper sarmentosum Roxb (Wild betal) leaves, Curcuma domestica Valeton (Turmeric) roots, Morinda citrifolia L. (Beach mulberry) leaves, Cassia siamea britt (Siamea cassia) leaves, and Cocos nucifera L. (Coconut) peels. The plants were extracted by methanol, n-hexane, chloroform, ethyl acetate, butanol and water. Antibacterial activities with minimum inhibitory concentration (MIC) were determined by agar diffusion assay against Escherichia coli, Burkholderia sp., Haemopilus somnus, Haemopilus parasuis, and Clostridium perfringens that were considered pathogenic strains in livestock infection. Methanol extracts of C. aurantifolia Swingle fruits and leaves showed the broadest spectrum of antibacterial activities except for C. perfringens. Butanol extract of S. grandiflora L. leaves showed the strongest activity against Burkholderia sp. with MIC, 135 µg/mL. P. sarmentosum Roxb leaves showed antibacterial activities against E. coli, Burkholderia sp. and H. parasuis. Ethyl acetate and water extracts from C. domesitca Valeton roots showed MIC of 306 µg/mL and 183 µg/mL, respectively against only C. perfringens. Antioxidative activity was determined by 2-diphenyl-2-picryl hydrazyl photometric assay. The methanol extracts of C. aurantifolia Swingle fruits and P. sarmentosum Roxb leaves showed the highest antioxidant activity among all the extracts with 3.46 mg/mL and 2.70 mg/mL effective concentration 50% (EC50) values, respectively. Total contents of phenolics and flavonoids were measured from the plant extracts. Methanol extracts of S. grandiflora L. and chloroform extracts of C. domestica Valeton were found to have the highest amount of total phenolics, 41.7 and 47.8 µg/mL, respectively. Flavonoid content of methanol extracts in S. grandiflora L. T was 22.5 µg/mL and the highest among plant extracts tested. These results indicated that C. aurantifolia Swingle, S. grandiflora L., P. sarmentosum Roxb, and C. domestica Valeton have antibacterial and antioxidant activities and can be used as alternative antibiotics or potential feed additives for the control of animal pathogenic bacteria.

Short communication: Bacteriocin KC24 produced by Lactococcus lactis KC24 from kimchi and its antilisterial effect in UHT milk.

The severity of Listeria monocytogenes infections emphasizes the need for prevention or elimination of the pathogen from dairy products. Lactococcus lactis KC24, isolated from kimchi, exhibited an antimicrobial effect against food pathogens, including L. monocytogenes ATCC 15313. Lactococcus lactis KC24 was cultured in a 5-L jar fermenter at 35°C, and bacteriocin activity was maximal at 4 h of incubation and persisted for 20 h. Bacteriocin KC24 was inactivated by protease XIV, indicating that it has a proteinaceous nature. Bacteriocin activity was maintained at pH 3.0 to 9.0 and at temperatures of 50 to 121°C. The mode of inhibition against L. monocytogenes ATCC 15313 was shown to involve a bactericidal effect by treatment with 100 and 200 arbitrary units (AU)/mL of bacteriocin KC24. To test the activity of bacteriocin KC24 in a food product, bacteriocin KC24 and nisin (100 and 200 AU/mL) with 4 log cfu/mL of a mixed culture of L. monocytogenes (ATCC 15313, ScottA, H7962, and H7762) were applied to UHT milk. Compared with the control, treatment with bacteriocin KC24 completely inhibited the growth of L. monocytogenes and resulted in no detectable L. monocytogenes after 14 d at 4°C, whereas nisin moderately inhibited L. monocytogenes, resulting in a final concentration after 14 d at 4°C higher than the initial inoculum. Bacteriocin KC24 may prove useful in improving the safety of dairy products.

Screening for cytotoxic activity of ovotransferrin and its enzyme hydrolysates.

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.

Antioxidant effects of ovotransferrin and its hydrolysates.

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.

Influence of nisin and selected meat additives on the antimicrobial effect of ovotransferrin against Listeria monocytogenes.

The objective of this study was to determine the effect of nisin and selected meat additives (salt, lactate, lactate-diacetate combination, and polyphosphate) on the antimicrobial activities of ovotransferrin (OTF) against the growth of Listeria monocytogenes. 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 using frankfurters. Frankfurters were inoculated with L. monocytogenes (~6.0 log(10) cfu/frankfurter); treated with OTF, meat additives, and nisin singly or in combination; 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 combination of OTF (40 mg/mL) and nisin (1,000 IU) inhibited the growth of L. monocytogenes in BHI and in frankfurters 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.

In vitro antimicrobial effect and in vivo preventive and therapeutic effects of partially purified lantibiotic lacticin NK34 against infection by Staphylococcus species isolated from bovine mastitis.

Lantibiotics are small (<5 kDa), polycyclic peptides produced by gram-positive bacteria; they are also known as gram-positive bacteriocins. The high antimicrobial activity of lacticins and the continuing appearance of antibiotic-resistant bacteria in recent years have resulted in a renewed interest in lantibiotics. A partially purified form of lacticin NK34 (a Lactococcus lactis product isolated from the Korean fermented fish jeotgal) was tested to determine its antimicrobial effects against Staphylococcus aureus (n=20) and coagulase-negative Staphylococcus (CNS, n=20) strains isolated from the raw milk of cows with subclinical bovine mastitis in the present study. The spot-on-lawn assay was used to identify the 2 strains from each group with the greatest lacticin NK34 susceptibility, and the minimal lethal dose (MLD) was measured in ICR (imprinting control region) mice. The preventive and therapeutic effects of lacticin NK34 on the mouse infection model were determined for the first time. Lacticin NK34 demonstrated antimicrobial effects in 14 of 20 (70%) S. aureus indicator strains and in 18 of 20 (90%) CNS strains. Staphylococcus aureus 69 and S. simulans 55 demonstrated the greatest susceptibility to lacticin NK34 in the spot-on-lawn assay. The S. aureus 69 MLD was measured at 1.53 x 10(9) cfu/mouse, whereas the S. simulans 55 MLD was 3.59 x 10(9) cfu/mouse. Mice infected experimentally with S. aureus 69 MLD or S. simulans 55 MLD were treated with lacticin NK34. Treated mice demonstrated an 80% survival rate (48 of 60 mice) compared with a survival rate of 7.5% (3 of 40 mice) in control mice treated with distilled water. These data suggest that lacticin NK34 might be useful in the control of bovine mastitis and systemic bacterial infection.

Anticancer and immunomodulatory activity of egg proteins and peptides: a review.

Eggs are widely recognized as a highly nutritious food source that offer specific health benefits for humans. Eggs contain all of the proteins, lipids, vitamins, minerals, and growth factors necessary for embryonic development. In particular, egg white and yolk proteins are considered functional food substances because they possess biological activities such as antimicrobial, antioxidant, metal-chelating, antihypertensive, anticancer, and immunomodulatory activities. Peptides produced via processes such as enzymatic hydrolysis, fermentation by microorganisms, and some chemical and physical treatments of egg proteins have been shown to enhance the functional properties and solubility of these peptides. Peptide activity is strongly related to amino acid sequence, composition, and length. At present, cancer remains among the leading causes of mortality worldwide, and therefore research aimed at developing new treatments for cancer immunotherapy is of great interest. The present review focuses primarily on the anticancer and immunomodulatory activities of egg proteins and their peptides and provides some insight into their underlying mechanisms of action. A number of egg proteins and peptides have been reported to induce apoptosis in cancer cells, protect against DNA damage, decrease the invasion ability of cancer cells, and exhibit cytotoxic and antimutagenic activity in various cancer cell lines. Furthermore, egg proteins and peptides can stimulate or suppress pro- or anti-inflammatory cytokines, as well as affect the production of inflammatory mediators in a variety of cell lines. In addition, the composition of eggs and the processes of egg proteins and peptides production will be discussed.

Effect of kimchi powder level and drying methods on quality characteristics of breakfast sausage.

This study was conducted to determine the effect of the addition of kimchi powder on the quality characteristics of meat batter and breakfast sausage. Breakfast sausages were supplemented with freeze dried kimchi powder (FKP) or hot air dried kimchi powder (HKP) at levels of 1% (FKP-1 and HKP-1) or 2% (FKP-2 and HKP-2). The emulsion stability, cooking yield, and apparent viscosity in meat batters improved with increments of kimchi powder (p<0.05). Increased levels of kimchi powder in breakfast sausage decreased the L(∗) value, pH, and springiness, and increased the a(∗) value, b(∗) value, hardness, chewiness, and gumminess (p<0.05). Sensory evaluations indicated that a higher overall acceptability was attained when the kimchi powder was added to breakfast sausage at a level of 2%.

In vitro cytotoxic and ACE-inhibitory activities of promod 278P hydrolysate of ovotransferrin from chicken egg white.

Peptides released from egg proteins via enzymatic hydrolysis show various bioactivities such as antimicrobial, antioxidant, antihypertensive, and immunomodulatory properties. The objective of this study was to investigate the cytotoxic and Angiotensin Converting Enzyme (ACE)-inhibitory activities of ovotransferrin and its promod 278P enzyme hydrolysate. Ovotransferrin from egg white was hydrolyzed using promod 278P at 45°C for 3 hours. Using the MTT assay, the cytotoxicity of ovotransferrin and promod 278P hydrolysate of ovotransferrin were evaluated in human cancer cell lines of various tissue origins. The ACE-inhibitory activity was determined using the cleavage of a chromogenic substrate -Hip-His-Leu. The promod 278P hydrolysate of ovotransferrin showed a potent cytotoxicity (>90%) at 20 mg/mL in all cancer cell lines tested, but ovotransferrin did not. The IC50 value of the promod 278P hydrolysate of ovotransferrin against 5 different cancer cells were 10.05 ± 1.55, 3.45 ± 0.94, 4.43 ± 1.87, 4.92 ± 0.63, and 10.43 ± 3.91 mg/mL for MCF-7, HeLa, HepG2, HT-29, and LoVo cells, respectively. The promod 278P hydrolysate of ovotransferrin showed a strong ACE-inhibiting activity: at 10 mg/mL level, the hydrolysate showed 76.82 ± 1.28% inhibition to ACE-inhibitory activity, and 73.33 ± 2.56%, 56.85 ± 1.84%, 50.32 ± 3.71%, 17.30 ± 0.13%, and 4.52 ± 6.83% inhibitory activity at 5, 2.5, 1.25, 0.625, and 0.3125 mg/mL level, respectively. The IC50 value of the promod 278P hydrolysate of ovotransferrin was 1.53 ± 0.20 mg/mL. However, ovotransferrin did not show any inhibitory effect to angiotensin-converting enzyme activity. This result indicated that the promod 278P hydrolysate of ovotransferrin has a great potential as an anticancer and antihypertension agent for humans, but the information on the peptides responsible for the functional activities is not available yet.

Immune-enhancing activity of phosvitin by stimulating the production of pro-inflammatory mediator.

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-1ß 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-1ß 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.

Effects of thawing temperature on the physicochemical properties of pre-rigor frozen chicken breast and leg muscles.

The objective of this study was to evaluate effects of thawing temperature on the biochemical and physicochemical properties of pre-rigor frozen chicken breast and leg muscles. Breast and leg muscles from 24 broiler chickens were excised within 10min postmortem. Pre-rigor muscles were frozen at -20°C and thawed at 0 and 18°C, and pH, R-value, sarcomere length, muscle shortening, thaw and cook loss, shear force and myofibrillar fragmentation index (MFI) compared with those in pre-rigor or 2°C chilled muscles. The ultimate pH of 18°C thawed muscle was lower than that of 0°C thawed and 2°C chilled muscles. As expected, the shortening of sarcomere length and muscle length of thaw rigor muscles were more than those of chilled muscle, but there were no significant differences between chilled muscle and 0°C thawed muscle. Also, there were no significant differences in R-value (Abs 250/Abs 260) and cook loss due to thawing temperature. Samples thawed at 0°C had higher MFI and lower shear value than samples thawed at 18°C. Shear force value and MFI were not significantly different between chilled muscle and 0°C thawed muscle. By thawing at 0°C, thaw shortening was prevented, and tender meat comparable to the chilled meat was obtained.

Identification and partial characterization of lacticin BH5, a bacteriocin produced by Lactococcus lactis BH5 isolated from Kimchi.

Strain BH5 was isolated from naturally fermented Kimchi and identified as a bacteriocin producer that has bactericidal activity against Micrococcus flavus ATCC 10240. Strain BH5 was identified tentatively as Lactococcus lactis by API test. Lactococcus lactis BH5 showed a broad spectrum of activity against most of the nonpathogenic and pathogenic microorganisms tested by the modified deferred method. The activity of lacticin BH5, named tentatively as the bacteriocin produced by L. lactis BH5, was detected at the mid-log growth phase, reached its maximum during the early stationary phase, and decreased after the late stationary phase. Lacticin BH5 also showed a relatively broad spectrum of activity against nonpathogenic and pathogenic microorganisms as tested by the spot-on-lawn method. Its antimicrobial activity on sensitive indicator cells was completely destroyed by protease XIV. The inhibitory activities of lacticin BH5 were detected during treatments up to 100 degrees C for 30 min. Lacticin BH5 was very stable over a pH range of 2.0 to 9.0 and was stable with all the organic solvents examined. It demonstrated a typical bactericidal mode of inhibition against M. flavus ATCC 10240. The apparent molecular mass of lacticin BH5 was estimated to be in the region of 3 to 3.5 kDa, by the direct detection of bactericidal activity after sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

Effect of antioxidant application methods on the color, lipid oxidation, and volatiles of irradiated ground beef.

Four antioxidant treatments (none, 0.05% ascorbic acid, 0.01%alpha-tocopherol + 0.01% sesamol, and 0.05% ascorbic acid + 0.01%alpha-tocopherol + 0.01% sesamol) were applied to ground beef using either mixing or spraying method. The meat samples were placed on Styrofoam trays, irradiated at 0 or 2.5 kGy, and then stored for 7 d at 4 degrees C. Color, lipid oxidation, volatiles, oxidation-reduction potential (ORP), and carbon monoxide (CO) production were determined at 0, 3, and 7 d of storage. Irradiation increased lipid oxidation of ground beef with control and ascorbic acid treatments after 3 d of storage. alpha-Tocopherol + sesamol and ascorbic acid +alpha-tocopherol + sesamol treatments were effective in slowing down lipid oxidation in ground beef during storage regardless of application methods, but mixing was better than the spraying method. Irradiation lowered L*-value and a*-value of ground beef. Storage had no effect on lightness but redness decreased with storage. Ascorbic acid was the most effective in maintaining redness of ground beef followed by ascorbic acid +alpha-tocopherol + sesamol. Irradiation and storage reduced the b*-value of ground beef. Irradiation lowered ORP of ground beef regardless of antioxidants application methods, but ORP was lower in beef with mixing than spraying method. Beef sprayed with antioxidants produced more hydrocarbons and alcohols than the mixing application, but ascorbic acid +alpha-tocopherol + sesamol treatment was effective in reducing the amount of volatiles produced by irradiation. Therefore, mixing was better than the spraying method in preventing lipid oxidation and maintaining color of irradiated ground beef.