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Contamination of poultry with pathogenic bacteria contributes to human foodborne disease, causes damage to industry brand names, and has a significant economic impact on the food industry in the form of both damage to industry brand names and losses associated with recalls. Irradiation is a safe and effective means of decontaminating poultry products, but the maximum dose strengths allowed negatively impact poultry sensory quality characteristics. The 1st objective of this study was to investigate the potential interactive inhibitory effects of natural antimicrobials as components of a vacuum-marination in addition to various dose levels of irradiation. Tartaric acid (TA) at 2 levels and grape seed (GS) and green tea (GT) extracts were combined, vacuum-infused into chicken breast fillets, and irradiated at 1, 2, and 3 kGy by electron beam irradiation. The 2nd objective was to use a consumer test group to evaluate TA and plant extract infusion into chicken breast fillets with and without irradiation at 2 kGy on overall impression, flavor, texture, appearance, and tenderness. The results showed that samples vacuum-infused with TA at 37.5 and 75.0 mM and irradiated at 1 kGy significantly reduced Listeria monocytogenes ( L.m.) levels by 2 and 3 log CFU/g compared to the control after 12 d of refrigerated storage. Vacuum-infusion of TA at 37.5 and 75.0 mM at 2 and 3 kGy irradiation, reduced L.m. to near nondetectable levels. The addition of TA and GS and GT to chicken breast fillets with and without irradiation did not significantly impact consumer preference, tenderness, appearance, or flavor. The addition of tartaric acid and natural plant extracts to chicken marinades could contribute to the prevention of L.m. contamination. [ABSTRACT FROM AUTHOR]

Boneless, skinless chicken breasts were infused with grape seed extract (GSE), green tea extract (GTE), tertiary butylhydroxyquinone and a combination of GTE and GSE. Samples were irradiated and their physicochemical properties were assessed over 9 months of frozen storage (− 20C). Irradiation did not affect pH or water-holding capacity. The effect of irradiation on the lightness value, L*, varied depending on storage time and infusion treatment. Irradiation increased redness (P < 0.05) except for samples infused with GTE (3,000 ppm). Irradiation increased maximum shear force, chewiness and hardness (P < 0.05) of cooked samples. Infusion of plant extracts increased lightness and decreased redness (P < 0.05), hardness and maximum shear force. The extent of lipid oxidation in all samples was determined by thiobarbituric acid reactive substances (TBARS) and carbonyl content methods. Irradiation increased both TBARS and carbonyl content in both raw and cooked chicken. Infusion with plant extracts decreased TBARS and carbonyl content compared with controls. PRACTICAL APPLICATIONS Although irradiation is considered a safe and effective means of ensuring the microbial safety of processed meat products, some physicochemical changes occur in the meat after irradiation that negatively affect the preservation of meat quality. Changes such as lipid oxidation and subsequent rancidity can possibly be inhibited with the use of antioxidants. Because of consumer preference for natural versus synthetic additives, natural products that have antioxidant activity could find application in products receiving irradiation treatments. It is the purpose of this study to ascertain the effect of processing with natural antioxidants found in green tea (GTE) and grape seed (GSE) extracts, which contain phenolic compounds such as catechin, epigallocatechin, epigallocatechin-gallate in GTE and procyanidins in GSE, on the physicochemical changes associated with irradiation of raw and cooked boneless/skinless chicken breasts. This preservation technology may find wide application in the meat processing industry as a means of reducing irradiation-induced quality deterioration. [ABSTRACT FROM AUTHOR]

The objective of this study was to use transmission electron microscopy to investigate the morphological changes that occurred in Listeria monocytogenes cells treated with grape seed extract (GSE), green tea extract (GTE), nisin, and combinations of nisin with either GSE or GTE. The test solutions were prepared with (i) 1% GSE, 1% GTE, 6,400 IU of nisin, and the combination of these dilutions with nisin or with (ii) the pure major phenolic constituents of GSE (0.02% epicatechin plus 0.02% catechin) or GTE (0.02% epicatechin plus 0.02% caffeic acid) and their combinations with 6,400 IU of nisin in tryptic soy broth with 0.6% yeast extract (TSBYE). Test solutions were inoculated with L. monocytogenes at approximately 106 CFU/ ml and incubated for 3 or 24 h at 37°C. After 3 h of incubation, cells were harvested and evaluated under a transmission electron microscope (JEOL-100 CX) operating at 80 kV (50,000x). Microscopic examination revealed an altered cell membrane and condensed cytoplasm when L. monocytogenes cells were exposed to a combination of nisin with either GSE or GTE or to pure compounds of the major phenolic constituents in combination. After 24 h of incubation at 37°C, the combinations of nisin with GSE and nisin with GTE reduced the L. monocytogenes population to undetectable levels and 3.7 log CFU/ml, respectively. These observations indicate that the combination of nisin with either GSE or GTE had a synergistic effect, and the combinations of nisin with the major phenolic constituents were most likely associated with the L. monocytogenes cell damage during inactivation in TSBYE at 37°C. [ABSTRACT FROM AUTHOR]

The effectiveness of whey protein isolate (WPI) coatings incorporated with grape seed extract (GSE), nisin (N), malic acid (MA), and ethylenediamine tetraacetic acid (EDTA) and their combinations to inhibit the growth of Listeria monocytogenes, E. coli O157:H7, and Salmonella typhimurium were evaluated in a turkey frankfurter system through surface inoculation (approximately 106 CFU/g) of pathogens. The inoculated frankfurters were dipped into WPI film forming solutions both with and without the addition of antimicrobial agents (GSE, MA, or N and EDTA, or combinations). Samples were stored at 4 °C for 28 d. The L. monocytogenes population (5.5 log/g) decreased to 2.3 log/g after 28 d at 4 °C in the samples containing nisin (6000 IU/g) combined with GSE (0.5%) and MA (1.0%). The S. typhimurium population (6.0 log/g) was decreased to approximately 1 log cycles after 28 d at 4 °C in the samples coated with WPI containing a combination of N, MA, GSE, and EDTA. The E. coli O157:H7 population (6.15 log/g) was decreased by 4.6 log cycles after 28 d in samples containing WPI coating incorporated with N, MA, and EDTA. These findings demonstrated that the use of an edible film coating containing nisin, organic acids, and natural extracts is a promising means of controlling the growth and recontamination of L. monocytogenes, S. typhimurium, and E. coli O157:H7 in ready-to-eat poultry products. [ABSTRACT FROM AUTHOR]

Recontamination of cooked ready-to-eat (RTE) chicken and beef products with Listeria monocytogenes has been a major safety concern. Natural antimicrobials in combinations can be an alternative approach for controlling L. monocytogenes. Therefore, the objectives of this study were to evaluate the inhibitory activities against L. monocytogenes of nisin (6,400 IU/ml), grape seed extract (GSE; 1%), and the combination of nisin and GSE both in tryptic soy broth with 0.6% yeast extract (TSBYE) and on the surface of full-fat turkey frankfurters. TSBYE was incubated at 37°C for 72 h and turkey frankfurters at 4 or 10°C for 28 days. Inocula were 6.7 or 5 log CFU per ml or g for TSBYE or frankfurters, respectively. After 72 h in TSBYE, nisin alone did not show any inhibitory activity against L. monocytogenes. The combination of nisin and GSE gave the greatest inhibitory activity in both TSBYE and on turkey frankfurters with reductions of L. monocytogenes populations to undetectable levels after 15 h and 21 days, respectively. This combination of two natural antimicrobials has the potential to control the growth and recontamination of L. monocytogenes on RTE meat products. [ABSTRACT FROM AUTHOR]

The effect of irradiation on thiobarbituric acid reactive substances (TBARS) and volatile compounds in raw and cooked nonirradiated and irradiated chicken breast meat infused with green tea and grape seed extracts was investigated. Chicken breast meat was vacuum in- fused with green tea extract (3,000 ppm), grape seed extract (3,000 ppm), or their combination (at a total of 6,000 ppm), irradiated with an electron beam, and stored at 5°C for 12 d. The targeted irradiation dosage was 3.0 kGy and the average absorbed dosage was 3.12 kGy. Values of TBARS and volatile compound contents of raw and cooked chicken meat were determined during the 12-d storage period. Thiobarbituric acid reactive substances values ranged from 15.5 to 71.4 mg of malondialdehyde/kg for nonirradiated raw chicken and 17.3 to 80.1 mg of malondialdehyde/kg for irradiated raw chicken. Values for cooked chicken ranged from 31.4 to 386.2 and 38.4 to 504.1 mg of malondialdehyde/kg for nonirradiated and irradiated chicken, respectively. Irradiation increased TBARS and hexanal values of controls and meat infused with plant extracts. Hexanal had the highest intensity of volatiles followed by pentanal and other volatiles. Cooking the samples significantly (P < 0.05) increased the amounts of TBARS and volatiles. Addition of plant extracts decreased the amount of TBARS as well as hexanal and pentanal values. Although irradiation increases lipid oxidation, infusion of chicken meat with plant extracts could reduce lipid oxidation caused by irradiation. [ABSTRACT FROM AUTHOR]

The effects of hydrophobicity/hydrophilicity of edible films against Listeria monocytogenes strain V7 by various nisin concentrations (4.0 -- 160 IU/film disk) and pH values ranging from 2.0 to 8.0 were determined and the mechanical properties and water vapor permeability of films prepared with or without nisin were compared. Surface hydrophobicities (446, 282, 232 and 142, respectively) of whey protein isolates, soy protein isolates, egg albumen and wheat gluten were determined. As the nisin concentration increased, the amount of inhibition progressively increased in all tested films. Using nisin, edible films with higher hydrophobicity values of 280 to 450 units under an acidic environment exerted a greater inhibitory effect against L monocytogenes. Different interactions of nisin with the proteins of the different films resulted in variation in the mechanical properties and water vapor permeabilities of the films tested. [ABSTRACT FROM AUTHOR]

Rice proteins were extracted from defatted rice flour. Turbidity measurement of supernatants revealed isoelectric points of albumin (pH 4.1), globulin (pH 4.3 and pH 7.9), and glutelin (pH 4.8), at which they were precipitated with 82.3 to 93.2% recovery efficiency. Prolamin did not aggregate and precipitate upon pH adjustment, but was precipitated by acetone. Denaturation temperatures (73.3, 78.9, and 82.2 °C) as well as enthalpy values (2.88, 3.14, and 3.79 J/g), of albumin, globulin, and glutelin were different. Prolamin did not show any thermographic denaturation peak. Heat-denaturation of globulin and glutelin resulted in progressive increases in their surface hydrophobicities. Measurement of surface hydrophobicity would be an effective parameter to evaluate rice protein denaturation. [ABSTRACT FROM AUTHOR]

The article focuses on the study about the properties of bipolymers from cross-linking whey protein isolate and soybean 11S globulin. The study involves the determination of the electrophoretic pattern, solubility, emulsification, hydrophobicity and foaming properties of the biopolymers. Results show that biopolymer solubility was greater than 90 percent at pH 3 and below, and at pH 7 and below.

BSTRACT: Functional properties of protein isolates prepared from 3 cowpea varieties and 2 soybean varieties in each of 2 y were determined. Both cowpea protein isolate (CPI) and soy protein isolate (SPI) showed a u-shaped curve for solubility with the minimum solubility occurring at pH 4.5. The CPI had lower emulsifying activity than SPI but was similar in stability. Foaming capacity and foaming stability ranged from 58.6 to 60.2 mL and 63.7 to 64.4 min for CPI and from 31.9 to 33.0 mL and 43.4 to 45.0 min for SPI, respectively. Gels were formed at 70 °C for 40 min and 30 min for CPI (12%) and SPI (10%), respectively. The CPI needs modification to enhance functional properties for potential application in food products. [ABSTRACT FROM AUTHOR]

We studied the effectiveness of partial replacement of glycerol with citric, lactic, malic, and tartaric acids on the antimicrobial activities of nisin (205 IU/g protein)-incorporated soy protein film against Listeria monocytogenes, Escherichia coli O157:H7, and Salmonella gaminara. S. gaminara inoculated into 2.6% malic acid-incorporated films and lactic acid-incorporated films with nisin (5.7 and 3.4 log number colony-forming units (CFU)/mL, respectively) and without nisin (3.2 and 3.0 log number CFU/mL, respectively) had fewer survivors than HCl-incorporated film with and without nisin (8.6 and 7.9 log number CFU/mL, respectively). Malic acid (2.6%)-incorporated soy protein film had the fewest survivors of L. monocytogenes, S. gaminara, and E. coli O157:H7 (5.5, 3.0, and 6.8 log number CFU/mL, respectively) and has the potential to inhibit a wide spectrum of microbes in product application. [ABSTRACT FROM AUTHOR]

Edible films were prepared from solutions of soy protein with calcium salts and glucono-delta-lactone (GDL). Calcium salts cross-linking interactions with soy-protein isolate (SPI) could result in the formation of films with rigid three-dimensional structure. GDL contributed to the formation of a homogeneous film structure due to increased protein--solvent attraction. Tensile strength (TS) of calcium sulfate treated SPI film (8.6 MPa) was higher than the TS of calcium chloride treated SPI films (6.4 MPa) and the control SPI film (5.5 MPa). Puncture strength (PS) of calcium sulfate treated SPI film (9.8 MPa) was higher than the PS of calcium chloride treated SPI films (8.5 MPa) and the control SPI film (5.9 MPa). SPI film formulated with GDL had larger elongation at break (39.4%) than that of SPI control film (18.2%). Calcium salts and GDL-treated SPI films had lower water-vapor permeability than the SPI control film.

Films containing soy protein and wheat gluten were exposed to simulated farmland soil mix over a period of 30 days and monitored for degradation. The simulated farmland soil mix (topsoil/sand/Sunshine compost/vermiculite, 59:6:25:10, wt %) was mixed and stored at ambient humidity (48-55%) and temperature (20-24 degrees C); the soil mix was constantly maintained at 15% moisture by weight. Research focused on evaluating the effectiveness of gluten and cysteine additions on biodegradable behavior in the simulated farmland soil conditions. The four types of films, soy protein (S:G 1:0); soy protein with cysteine addition (S:G 1:0 + CYS); soy protein-wheat gluten (S:G 4:1); and soy protein-wheat gluten with cysteine addition (S:G 4:1 + CYS), were prepared at pH 7. 0 for degradation studies. Soy protein-gluten film rapidly degraded with 50% weight loss in about 10 days and with up to 95% weight loss in 30 days. Tensile strength and elongation of all soy protein-gluten films significantly decreased in 3 days. However, cysteine addition delayed the degradation rate of soy protein-gluten films. Soy protein-wheat gluten film disintegrated after 20 days in the simulated farmland soil environment. These results suggest that wheat gluten and cysteine addition to soy protein-based films could delay degradation rates due to their high disulfide contents.

Rice bran protein isolate (RBPI) containing approximately 92.0% protein was prepared from unstabilized and defatted rice bran using phytase and xylanase. The yield of RBPI increased from 34% to 74.6% through the use of the enzymatic treatment. Nitrogen solubilities of RBPI were 53, 8, 62, 78, 82, and 80% at pHs 2.0, 4.0, 6.0, 8.0, 10.0, and 12.0, respectively. Differential scanning calorimetry showed that RBPI had denaturation temperature of 83.4 degrees C with low endotherm (0.96 J/g of protein). RBPI had similar foaming properties in comparison to egg white. But emulsifying properties of RBPI were significantly lower than those of bovine serum albumin. The result of amino acid analysis showed that RBPI had a similar profile of essential amino acid requirements for 2-5-year-old children in comparison to that of casein and soy protein isolate.

DNA was prepared from isolated mitochondria of Acanthamoeba castellanii and was shown to behave as a single component in density gradients, on ;melting' and on renaturation. From measurements of renaturation kinetics, sedimentation coefficient and electron micrographs the genome size of the mitochondrial DNA was calculated to be about 3.4x10(7) daltons. A small proportion of the preparations could be isolated as relaxed circular molecules of mean contour length 16.2mum.