Incidence,Antibiotic Susceptibility,and Toxin Profiles of Bacillus cereus sensu lato Isolated from Korean Fermented Soybean Products

Korean fermented soybean products, such as doenjang, kochujang, ssamjang, and cho‐kochujang, can harbor foodborne pathogens such as Bacillus cereus sensu lato (B. cereus sensu lato). The aim of this study was to characterize the toxin gene profiles, biochemical characteristics, and antibiotic resistance patterns of B. cereus sensu lato strains isolated from Korean fermented soybean products. Eighty‐eight samples of Korean fermented soybean products purchased from retails in Seoul were tested. Thirteen of 26 doenjang samples, 13 of 23 kochujang samples, 16 of 30 ssamjang samples, and 5 of 9 cho‐kochujang samples were positive for B. cereus sensu lato strains. The contamination level of all positive samples did not exceed 4 log CFU/g of food (maximum levels of Korea Food Code). Eighty‐seven B. cereus sensu lato strains were isolated from 47 positive samples, and all isolates carried at least one enterotoxin gene. The detection rates of hblCDA, nheABC, cytK, and entFM enterotoxin genes among all isolates were 34.5%, 98.9%, 57.5%, and 100%, respectively. Fifteen strains (17.2%) harbored the emetic toxin gene. Most strains tested positive for salicin fermentation (62.1%), starch hydrolysis (66.7%), hemolysis (98.9%), motility test (100%), and lecithinase production (96.6%). The B. cereus sensu lato strains were highly resistant to β‐lactam antibiotics such as ampicillin, penicillin, cefepime, imipenem, and oxacillin. Although B. cereus sensu lato levels in Korean fermented soybean products did not exceed the maximum levels permitted in South Korea (<10⁴ CFU/g), these results indicate that the bacterial isolates have the potential to cause diarrheal or emetic gastrointestinal diseases.     

Hypnotic effect of GABA from rice germ and/or tryptophan in a mouse model of pentothal-induced sleep

γ-Aminobutyric acid (GABA), a primary inhibitory neurotransmitter, and tryptophan (Trp), a substrate for melatonin, are found in functional foods and exert hypnotic effects. The hypnotic effects of 3 doses of GABA and a combined-preparation of GABA and Trp (GABA+Trp) were investigated in mice. Hypnotic activity was evaluated using pentothal-induced sleep time testing. Treatments included low, middle, and high doses of GABA and GABA+Trp. Low doses of GABA (low-GABA) and low-GABA+Trp reduced sleep latency and significantly (p<0.05) prolonged the sleep time induced by pentothal, compared with controls, although the melatonin concentration in the serum was not affected. On the other hand, the adenosine A1 receptor (AA1R) immunoreactivity in the suprachiasmatic nucleus of the hypothalamus was significantly (p<0.05) increased after administration of low-GABA and/or low-GABA+Trp, compared to controls. Low doses of GABA and/or Trp cause hypnotic effects that may be related to AA1R activation.     

Comparison of the effects of commercial whey protein and native whey protein on muscle strength and muscle protein synthesis in rats

Food Science and Biotechnology - Commercial whey protein (CWP) is generally produced in the cheese making process with heat treatment. Recently, native whey protein (NWP) can be obtained through...     

Characterisation of jellyfish protein films with added transglutaminase and wasabi extract

The physical, optical, antimicrobial and antioxidant properties of jellyfish protein (JFP) films with added transglutaminase (TGase) and wasabi extract (WE) were studied. Among the plasticisers, 30% sorbitol was the most desirable. The optimal physical properties of the JFP films were obtained when 15 U transglutaminase g^?1 JFP was added. The incorporation of WE affected the physical properties of the JFP films. The tensile strength (21.68–35.25 MPa), elongation at break (10.85–13.25%) and Young's modulus (920.18–1278.9 MPa) of the films increased as WE concentration increased from 0.5% to 1.5%. The thermal gravimetric analysis results revealed that the thermal stability of the JFP films increased with increasing concentrations of WE. The inhibition zones against Escherichia coli O157:H7 and Listeria monocytogenes and antioxidant activity also increased as the concentration of WE increased. Thus, antimicrobial and antioxidant JFP films could be prepared by the addition of WE.     

Dietetic and hypocholesterolaemic action of black soy peptide in dietary obese rats

To investigate the effect of peptides from black soy (rat's eye) bean (Rhynchosia volubilis Lour.) on weight gain and lipid composition, Sprague–Dawley male rats were fed either a black soy peptide (BSP; 2, 6 or 10% of energy)‐containing diet or a casein control diet (20% of energy) enriched with 36% fat and 1% cholesterol for 28 days. Compared with the casein group, the BSP groups showed significant attenuation of body, liver and epididymal adipose tissue weight gains (P < 0.05). Moreover, rats that consumed BSP had a lower total cholesterol concentration and low‐density lipoprotein/high‐density lipoprotein (LDL/HDL) ratio in serum and a lower level of hepatic triglycerides as well as higher excretion of faeces compared with those fed only casein (P < 0.05). Molecular weights of peptides from black soy were mainly below 10 kDa, and Arg/Lys and Gly/Met ratios in BSP were five and three times of those in casein respectively. It is concluded that BSP can be a potent nutraceutical component for anti‐obesity and hypolipidaemic benefits. Copyright © 2007 Society of Chemical Industry     

Preparation and application of a flaxseed meal protein film containing lemongrass (Cymbopogon citratus) oil

Flaxseed meal protein (FMP) films were prepared, and their mechanical properties (tensile strength (TS) and elongation at break (E) values), water vapour permeability, optical properties and thermogravimetric analysis were evaluated. Briefly, 5 g FMP, 2 g fructose and 0.03 g ferulic acid were required for the optimal preparation of an FMP film. The TS and E values of the FMP film were 13.12 MPa and 61.90%, respectively. Furthermore, different amounts of lemongrass oil (LE) were incorporated into the FMP film to prepare an antimicrobial film. Wrapping pen shell adductor muscle with the FMP film containing 1.0% LE reduced the counts of inoculated Listeria monocytogenes and Escherichia coli O157:H7 compared with those in the control, after storage at 4 °C for 12 day. Consequently, packaging with FMP film containing 1.0% LE can be useful in improving the quality of pen shell adductor muscle during storage.     

Effect of cross-linking on the physicochemical and physiological properties of corn starch

Corn starch was chemically modified by cross-linking with STMP/STPP (99:1. w/w) and the physicochemical and physiological properties (in vitro and in vivo) of the cross-linked corn starch were investigated as a function of the degree of cross-linking. Cross-linking decreased the solubility, swelling factor, and paste clarity of corn starch. While the swelling factor was highly correlated with the degree of cross-linking (R² = 0.878), the X-ray diffraction patterns did not show any significant alteration in the crystallinity of corn starch. It was shown by SEM measurement that a black zone was observed on the surface of crossed-linked starch granules, which did not occur with native starch. When mice were fed the diets containing the corn starch with low (CLCS-5) and high (CLCS-12) degree of cross-linking (51.3 and 99.1%, respectively), significant effects on the final body weight, weight gain as well as perirenal weight of the mice (p < 0.05) were observed. Also, significant decreases in total lipid, triglyceride, and total cholesterol concentrations in serum were detected in CLCS-5 and CLCS-12 groups (p < 0.05). While total lipid level in the liver decreased with increasing degree of cross-linking, the triglyceride level was not affected by the supplementation with both of CLCS-5 and CLCS-12 corn starch samples.     

Concentrations and profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans in soils from Korea

Soil samples were collected from Changwon and Masan Cities, Korea, and analyzed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/DFs). Nearly all tetra- through octachlorinated PCDDs/DFs including the 17 2,3,7,8-substituted PCDDs/DFs were detected in all samples. Total concentrations of PCDDs/DFs and of 2,3,7,8-tetrachlorinated dibenzo-p-dioxin (TeCDD) equivalents (TEGs) in soils ranged from 35 to 121,400 pg/g, dry weight, and from 0.2 to 3720 pg of I-TEQ/g, respectively. On the basis of guidelines for TEQ concentrations established in Germany and the United States, 9 of 23 soil samples (39% of the total samples analyzed) could not be expected to pose human health hazards. The rest of 61% of soils need measures such as investigations of source identification, soil decontamination, and/or soil removal. Total concentrations of PCDDs/DFs were greater at or near four industrial sites, which are concerned with the steel industry, petrochemical-related industry, and industrial waste incineration, than other areas. This indicates the presence of potential source areas. Soil collected from a site 50 m from an open-burning industrial waste incinerator in an industrial complex was heavily contaminated, containing a total concentration of PCDDs/DFs of 121,400 pg/g, dry weight. PCDDs/DFs were also detected in soils from the top of a 200 m mountain indicating a wide dispersal of PCDDs/DFs by atmospheric transport from point source areas. The congener pattern and relative proportions of PCDFs in soils suggest that commercial PCB preparations such as Kanechlors may be one of the sources. The wide range of PCDD/DF isomers detected in soils from many locations also suggests a multitude of sources, in addition to commercial PCBs, such as incineration of industrial wastes such as car tires, scrap wires, plastics, papers, and emission of automobile exhaust.