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Beers are made of malted barley, hop, yeast, and water where the barley malt is the main ingredient. There are two types of barleys, two-row and six-row barley. Two-row barley is principally used in large-scale beer brewing, whereas six-row barley is incorporated in small scale brewing (e.g., microbrewery). In this study, beers were prepared from five varieties of Korean barley1 two-row barley and 4 six-row barley, through malting, mashing, and fermentation processes. Beer fermentation parameters, namely alcohol and diacetyl contents, turbidity, foam stability, free amino nitrogen (FAN), yeast viability, color, and sensory properties were kinetically studied. From a practical point of view, the beer made of Dahyang, one of the six-row barley malts, showed the highest sensory preferences.

The bacteriocin-producing lactic acid bacteria Enterococcus faecium DB1 was isolated from Korean traditional gajami sikhae. Culture conditions were optimized by response surface methodology (RSM) to maximize bacteriocin DB1 production. E. faecium DB1 displayed the highest bacteriocin activity when grown in modified MRS medium containing sucrose, rather than glucose, as a carbon source. The effects of temperature, initial pH, and sucrose concentration were tested to determine the optimum conditions for maximum bacteriocin production by E. faecium DB1. A central composite design was used to control the three variables in the experiment. RSM revealed that the optimum values for bacteriocin production were 27.66 g/L sucrose, temperature of 34.37 C, and an initial pH of 6.54. A 2.08-fold increase in bacteriocin production was obtained with sucrose-containing MRS medium compared to production in standard MRS medium.

A DF01 strain that inhibits tyramine-producing Lactobacillus curvatus KFRI 166 was isolated from Dongchimi, a tradi-tional Korean fermented vegetable, and identified as Lactobacillus brevis by biochemical analysis and reverse transcriptasesequencing of 16S rRNA. The antimicrobial compound produced by L. brevis DF01 was secreted at a maximum level of640 AU/mL in late exponential phase in MRS broth, and its activity remained constant during stationary phase. The activityof bacteriocin DF01 was totally inactivated by α-chymotrypsin, pronase E, proteinase K, trypsin, and α-amylase, but not bycatalase, which indicates the compound was glycoprotein in nature. The activity was not affected by pH changes rangingfrom 2 to 12 or heat treatment (60, 80, and 100°C for 30 min), but was reduced after autoclaving. Bacteriocin DF01 hadbacteriolytic activity and a molecular weight of approximately 8.2 kDa, as shown by tricine-SDS-PAGE analysis. There-fore, bacteriocin DF01 can be used in the manufacture of fermented meat products due to its inhibition of tyramine-produc-ing L. curvatus and non-inhibition of L. sake, which is used as a starter culture for meat fermentation.Key words: amylase-sensitive bacteriocin, Lactobacillus brevis, dongchimi

Objectives. To investigate the potential association of tumor necrosis factor-α T-857C polymorphism with susceptibility to the five common malignant tumors. Materials and Methods. A comprehensive search of PubMed/Medline, Embase, and Web of Science databases was performed up to November 2015. Pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated to assess the strength of the association. Subgroup analysis, heterogeneity analyses, and publication bias were also texted in the meta-analysis. Results. A total of twenty-two publications involving 5215 cases and 6755 controls were recruited. Overall, the meta-analysis revealed an increased risk between the TNF-α T-857C polymorphism and gastric cancer susceptibility in T versus C model, heterozygote genetic model, and dominant genetic model. An increased risk between the TNF-α T-857C polymorphism and hepatocellular cancer susceptibility in homozygote genetic model and recessive genetic model was also found. No significant association was found between the TNF-α T-857C polymorphism and colorectal cancer, cervical cancer, and prostate cancer. Conclusions. Our meta-analyses suggest that TNF-α T-857C polymorphism may be associated with increased risk of gastric cancer and hepatocellular cancer development. Therefore, the TNF-α T-857C polymorphism could be considered as one possible risk factor of gastric cancer and hepatocellular cancer according to our study.

The feasibility of using six-row barley, which is produced more often than two-row barley (malting barley) in Korea, for beer brewing was studied. Beer was brewed from one variety of two-row barley (Jinyang, malting barley) and four varieties of six-row barley (Jasujungchal and Hinchalssal which are unhulled; Dahyang and Samgwangchal which are hulled). Using principal component analysis of the material properties in malting, mashing and fermentation, and the sensory properties of beer, the barley was categorized into three groups: group 1 (Jinyang and Dahyang), group 2 (Samgwangchal and Hinchalssal) and group 3 (Jasujungchal). Group 1 was distinctive for extract (dry basis), Brix and carbonation; group 2 was characterized by alcohol, foam stability and sour odour; and group 3 was characterized by malt protein and sour taste. The brewing qualities of group 1 were superior to those of the other groups. Among the Korean six-row barley varieties, Dahyang was found to be the most suitable for beer production. Copyright © 2014 The Institute of Brewing & Distilling

The development of an anisotropic theory of continuum damage mechanics for fatigue failure is described. The fatigue damage evolution model is based on earlier publications of the author on the anisotropic ductile damage and uniaxial fatigue damage theories. A more general damage characteristic tensor capable of characterizing micro-crack growth on the maximum shear plane as well as on the plane normal to the maximum tensile stress is formulated. The validity of the damage model proposed is verified by comparing the predicted and measured number of cycles to failure for RS50 steel and excellent agreement has been achieved.

Numerous strains of lactic acid bacteria used in the fermentation of foods are known to produce bacteriocins. In general, bacteriocins are a group of proteinaceous antimicrobial substances that inhibit the growth of closely related bacteria. However, some bacteriocins produced by lactic acid bacteria (LAB) exhibit a relatively broad antimicrobial spectrum and are active against several food‐spoilage and health‐threatening microorganisms. Many investigators have reported on the use of bacteriocins as food preservative to extend the shelflife of various foods. This review decribes the research that has been conducted on bacteriocinogenic lactic acid bacteria— isolated from a wide variety of foods and in some instances of animal origin—and the characteristics of bacteriocins. Special emphasis is placed on their potentials for use as food preservative and on their physicochemical nature, antibacterial spectrum, and genetic behavior.

A continuum damage mechanics model for low-cycle fatigue is presented. The rupture time of hot rolled type RS50 steel is predicted by the damage model and compared with those measured with excellent agreement. It is shown that the proposed damage model can predict the rupture time of material more reasonably when stress variation is infinitesimal, or when the stress ratio R approaches unity.

Lactic acid bacteria (LAB) with antimicrobial activity and high exopolysaccharide (EPS) production ability isolated from sourdough were studied for their fermentation characteristics as potential new starter cultures. The values of pH, titratable acidity, and viable cell counts were 4.06+/-0.009-4.50+/- 0.015, 0.787+/-0.020%-1.172+/-0.018%, and 8.78+/-0.08-8.98+/- 0.06 log CFU/ml, respectively. In order to select probiotics with a high survival rate in the gut, isolates were tested to assess resistance against the artificial gastric acid and bile juice. Viable LAB counts were significantly (p0.05) affected by the acidity. At pH 2.0, the total declines in the initial bacterial counts were 4.52+/-0.07 log for S. thermophilus St-Body-1,7.98+/-0.03 log for E. flavescens DU-10,7.95+/-0.05 log for E. faecium DU-12, and 3.15+/- 0.06 log for L. amylovorus DU-21. Among the strains, L. amylovorus DU-21 was the only strain that had bile tolerance under simulated gastrointestinal conditions. In order to improve EPS production by L. amylovorus DU- 21, the influence of carbon source was studied. When glucose was used as a carbon source, EPS production dramatically increased to 17.19+/-0.28 g/l (p0.05). The maximum cell growth (10.012+/-0.012 log CFU/ml) and EPS production (18.71+/-0.19 g/l) were achieved when 15 g/ l of glucose was employed as the carbon source.

Staphylococcus aureus strains are important foodborne pathogens that produce various toxins. To evaluate the risk of the enterotoxins, four S. aureus strains from kinbap and two clinical samples were isolated and identified, and their expression of the enterotoxin genes were analyzed using a reverse transcription real-time PCR. Various enterotoxin genes were detected, including sea, seg, seh, sei, sen, seo, and sem, where each isolate contained one or two. When the mRNA detection of the enterotoxin genes was analyzed using a reverse transcriptase PCR, various levels of expression were found depending on the species and enterotoxin gene. Therefore, it is reasonable to suggest that the poisoning risk of S. aureus can be effectively evaluated based on the gene expression at the mRNA level.

A recombinant DNA, encoding the chimeric protein of the signal sequence for bifidobacterial α-amylase mature pediocin PA-1, was introduced into Bifidobacterium longum MG1. Biologically active pediocin PA-1 was successfully secreted from the strain and showed bactericidal activity against Listeria monocytogenes and the same molecular mass as native pediocin PA-1.

Pediocin PA-1 is a representative class IIa bacteriocin which is small and heat-stable and has a consensus motif, –YGNGV–. The plasmid pQE40PED, encoding pediocin PA-1 fused with His-tagged mouse dihydrofolate reductase (DHFR), was constructed and introduced into Escherichia coli M15 strain. The fusion protein was overexpressed in the strain after induction of isopropyl-β- d -thiogalactopyranoside (IPTG) and purified by nickel-nitrilotriacetic acid (Ni-NTA) metal affinity chromatography. For the recovery of biologically active pediocin PA-1, the purified fusion protein was cleaved by Factor Xa protease and the liberated pediocin PA-1 was finally purified by ultrafiltration with a 75% yield. The molecular mass of the purified recombinant pediocin PA-1 was the same as that of native pediocin PA-1 on an electrophoresis gel.

For rapid detection of Escherichia coli 0157:H7 and Listeria monocytogenes, simple methods for sample preparation and PCR were established and applied to a field test. To improve specificity, primer sets LP43-LP44 and C(+)-D(-) were selected for E. coli O157:H7 and L. monocytogenes, respectively. Through centrifugation and partial heat treatment after enrichment, E. coli 0157:H7 and L. monocytogenes were detected at 1 initial CFU without genomic DNA extraction in the culture and with artificially inoculated food samples including milk, chicken, ham, and pork. Based on the optimized PCR method, a feasibility test was carried out using randomly collected field samples. To remove false positives and false negatives, a PCR method using several primer sets, including the optimized primer set, and a standard culture method were used. With the PCR detection and standard culture methods, two pork samples were positive for L. monocytogenes after enrichment, indications that the PCR assay could be effectively used for rapid, sensitive, and species-specific detection of foodborne pathogens.