• Microbiology and Biotechnology Letters
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• v.42 no.1
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• pp.58-66
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• 2014

In the course of study for a use for non-edible parts of broccoli (Brassica oleracea L), and the development of processed food utilizing these parts, edible floret and non-edible stalk were extracted with ethanol and different organic solvent fractions were prepared. With 10 different extracts and fractions, their useful components and various biological activities, such as antioxidant, antimicrobial and anti-proliferation activity, were investigated. The stalk has more abundant water soluble carbohydrate when compared with the floret, and floret has higher hexane-soluble pigments. Analysis of total flavonoid and total polyphenol contents showed that the floret has 1.5~1.99 times higher concentrations than the stalk. Among the fractions, ethylacetate (EA) fractions have the highest amount of total flavonoid and total polyphenol. The stalk and floret possessed 9.45 and 42.01 mg-total flavonoid/g, respectively. In the antioxidation activity assay, the EA fraction of floret showed strong radical scavenging activity and reducing power, while the n-hexane fraction of the stalk exhibited nitrite scavenging activity. In the antimicrobial activity assay, the EA fraction of floret showed a strong and broad-range of antibacterial activity, irrespective of gram positive or gram negative bacteria. In a while, the hexane and EA fractions revealed anti-proliferative effects against the human colorectal cancer cell HCT-116. Strong anti-proliferative activities were found in the hexane fraction of stalk (18.4% of cell viability), and the n-butanol fraction of floret (6.9% of cell viability). Our results suggest that the further study of the characterization of active fractions and the identification of active components from different parts of broccoli are needed to develop functional foods or novel plant-derived medicines.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.3
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• pp.386-395
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• 2016

To develop a functional fermentation food from Rubus coreanus Miquel (Bokbunja) and chlorella mixtures, optimal lactic acid fermentation conditions were established, and quality properties based on physicochemical evaluation such as chemical compositions, free sugars, organic acids, and antibacterial activities were investigated. Regarding optimal fermentation strain selection, formation of lactic acid was best in Lactobacillus plantarum among the experimental strains (10 kinds), and the optimal fermentation temperature was $37^{\circ}C$. In addition, overall acceptability in the sensory evaluation was highest in the 5% chlorella mixture sample. Therefore, quality properties of the prepared sample under the established optimal fermentation conditions were investigated. Moisture, total sugar (dry basis), crude fiber (dry basis), and pH of fermented Rubus coreanus Miquel juice (RCM) with 5% chlorella mixture (RCM-C5) were reduced by 4.90%, 14.15%, and 0.32%, respectively, as compared with non-fermented RCM. Meanwhile, crude protein, crude fat, and crude ash (dry basis) of RCM-C5 were elevated by 13.75%, 0.18%, and 0.73%, respectively, as compared with RCM. The yellowness (b value) of color values was greater in RCM-C5 compared to RCM. The free sugar and organic acid contents of RCM-C5 were elevated by 0.97% and 616.30 mg%, respectively, as compared with RCM. In addition, the gram positive bacterium Staphylococcus aureus was elevated by 5.83% while gram negative bacteria Escherichia coli and Salmonella Typhimurium were elevated by 2.94% and 4.67%, respectively, as compared with RCM. In conclusion, the quality properties of RCM and chlorella lactic acid fermentation mixtures were improved compared with the general RCM product. Consequently, it is possible to apply fermented RCM as a functional fermentation food.

• Microbiology and Biotechnology Letters
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• v.41 no.3
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• pp.358-366
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• 2013

The aim of this study was to evaluate the antimicrobial activities of Glycyrrhiza uralensis and Glycyrrhiza glabra extracts with various countries of origin. Three samples of licorice with various origins (Korea, China, and Uzbekistan) were evaluated for their antimicrobial activities against six skin microflora. The bioassay applied for determining the antimicrobial effects included the disc diffusion assay, minimum inhibitory concentration, and challenge test. The ethyl acetate fractions of G. uralensis and G. glabra extracts showed significant antimicrobial activities against two gram-positive (Bacillus subtilis, Propionibacterium acnes) and two gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria. These samples had much more intensive antimicrobial activities than synthetic preservatives on B. subtilis, P. acnes, and P. aeruginosa, especially. Korean licorice showed the highest antimicrobial activity amongst the samples tested. In view of the observed inhibitory features of these G. uralensis and G. glabra extracts, it is suggested that they could be used as natural antiseptics against bacterial contamination in cosmetics and foods, instead of the common synthetic preservatives currently employed.

• Journal of Food Hygiene and Safety
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• v.38 no.5
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• pp.319-331
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• 2023

Aminoglycoside antibiotics, also known as aminoglycosides (AGs), are veterinary drugs effective against a wide range of gram-negative and gram-positive bacteria. Owing to their recent use in cultured meats, it has become essential to establish an analytical method for safety management. AGs are highly polar compounds, and ion-pair reagents (IPRs) are used to ensure component separation. Owing to the high possibility of potential mechanical problems resulting from IPR addition to the mobile phase, an analytical method in which IPRs are added directly to the vial was explored. In this study, methods for analyzing 10 AGs via liquid chromatography-tandem mass spectrometry (LC-MS/MS) with the addition of two IPRs were validated for selectivity, detection limit, quantitation limit, recovery, and precision. The detection limit was 0.0001-0.0038 mg/kg, the quantification limit was 0.004-0.011 mg/kg, and the linearity (R²) within the concentration range of 0.01-0.5 mg/kg was over 0.99. Recovery and precision (expressed as relative standard deviation) evaluated in the two matrices (beef and cell culture media) ranged from 70.7% to 120.6% and 0.2% to 24.7%, respectively. The validated AG analytical method was then applied to 15 meats prepared from chicken, beef, and pork, and 6 culture media and additives used in cultured meat. No AGs were detected in any of the 15 meats distributed in Korea; however, streptomycin and dihydrostreptomycin were detected at levels ranging from 695.85 to 1152.71 mg/kg and 6.35 to 11.11 mg/kg, respectively, in the culture media additives. The LC-MS/MS method coupled with direct addition of IPRs to the vial can provide useful basic data for AG analysis and safety evaluation of meats as well as culture media and additives for cultured meats.

• Restorative Dentistry and Endodontics
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• v.25 no.4
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• pp.561-574
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• 2000

Poly-P has been used to prevent decomposition of foods and has been shown to have inhibitory effect on the growth of gram positive bacteria. The purpose of this study was to evaluate the effect of poly-P on the growth of Porphyromonas endodontalis, a gram negative obligate anaerobic rod, endodontopathic bacterium. P. endodontalis ATCC 35406 was in BHI broth containing hemin and vitamin K with or without poly-P. Inhibitory effect of each poly-P which was added at the beginning(lag phase) or during(exponential phase) the culture, MIC(minimum inhibitory concentration) was determined by measuring the optical density of the bacterial cell at 540nm. Viable cell counts were measured to determined whether poly-P has a bactericidal effect. Leakage of intracellular nucleotides from P. endodontalis was determined at 260nm and morphological change of P. endodontalis was observed under the TEM(transmission electron microscope). Binding of 32P-labeled poly-P to P. endodontalis was examined. SDS-polyacrylamide gel electrophoresis and zymography were performed to observe the changes in protein and enzyme profiles of P. endodontalis, respectively. The results from this study were as follows : 1. The minimal inhibitory concentration(MIC) of poly-P to P. endodontalis appeared to be 0.04~0.05%. 2. Poly-P added to the P. endodontalis culture during the exponential phase of P. endodontalis was as much effective as poly-P added at the begining of the culture, suggesting that the antibacterial effect of poly-P is not much dependent on the initial inoculum size of P. endodontalis. 3. Poly-P are bactericidal to P. endodontalis, demonstrating the decrease of the viable cell counts. 4. Intracellular nucleotide release from the P. endodontalis, was not increased in the presence of poly-P and was not reversed by the addition of divalent cations like $Ca^{2+}$ and $Mg^{2-}$. 5. Under the TEM, it was observed that fine electro-dense materials were prominent in the poly-P grown P. endodontalis, appearing locally in the cell, and the materials were more abundant and more dispersed in the cell as the incubation time with poly-P increased. In addition, highly electron dense granules accumulated in many poly-P grown cells, most of which were atypical in their shape. 6. Binding of 32P-labeled poly-P to P. endodontalis appeared to be 32.8 and 45.5 and 53.4% at 30 minutes, 1 hours and 2 hours, respectively. 7. In the presence of poly-P. the synthesis of proteins with apparent molecular masses of 25, 27, 35, 45 was lost or drastically decreased whereas expression of a protein with an apparent molecular mass of 75 was elevated. 8. Proteolytic activity of P. endodontalis was decreased by poly-P. The overall results suggest that use of poly-P may affect the growth of P. endodontalis, and the anti-bacterial activity of poly-P seems largely bactericidal. Changes in shape, protein expression, and proteolytic activity of P. endodontalis by poly-P may be directly and indirectly attributed to the antibacterial effect of poly-P. Further studies will be needed to confirm the effect of poly-P.

• Journal of Life Science
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• v.28 no.11
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• pp.1354-1360
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• 2018

The aim of this study was to develop a simple, environmentally friendly synthesis of silver nanoparticles (SNPs) without the use of chemical reducing agents by exploiting the extracellular synthesis of SNPs in a culture supernatant of Bacillus thuringiensis CH3. Addition of 5 mM $AgNO_3$ to the culture supernatant at a ratio of 1:1 caused a change in the maximum absorbance at 418 nm corresponding to the surface plasmon resonance of the SNPs. Synthesis of SNPs occurred within 8 hr and reached a maximum at 40-48 hr. The structural characteristics of the synthesized SNPs were investigated by various instrumental analysis. FESEM observations showed the formation of well-dispersed spherical SNPs, and the presence of silver was confirmed by EDS analysis. The X-ray diffraction spectrum indicated that the SNPs had a face-centered cubic crystal lattice. The average SNP size, calculated using DLS, was about 51.3 nm and ranged from 19 to 110 nm. The synthesized SNPs exhibited a broad spectrum of antimicrobial activity against a variety of pathogenic Gram-positive and Gram-negative bacteria and yeasts. The highest antimicrobial activity was observed against C. albicans, a human pathogenic yeast. The FESEM observations determined that the antimicrobial activity of the SNPs was due to destruction of the cell surface, cytoplasmic leakage, and finally cell lysis. This study suggests that B. thuringiensis CH3 is a potential candidate for efficient synthesis of SNPs, and that these SNPs have potential uses in a variety of pharmaceutical applications.

• Journal of Food Hygiene and Safety
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• v.13 no.2
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• pp.112-120
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• 1998

This study was performed to investigate the synergistic effect of chitosan and sorbic acid as a new food preservative. So it was performed to investigate inhibitory effect on growh of E. coli 0157:H7, gram negative pathogenic food borne disease bacteria and of S. aureus, gram positive food borne disease bacteria in chitosan, sorbic acid and combination of chitosan and sorbic acid. Minimun Inhibitory Concentration (MIC) of chitosan in E. coli 0157:H7 was 500 ppm at pH 5.0, 250 ppm at pH 5.5, 500 ppm at pH 6.0, and 2000 ppm at pH 6.5, while in Staph. aureus 31.25 ppm at pH 5.0 and 62. 5 ppm at more than pH 5.5. also, MIC of sorbic acid in E. coli 0157:H7 was 500 ppm at pH 5.0, 1500 ppm at pH 5.5, and 2000 ppm at more than pH 6.0, while in Staph. aureus 1500 ppm at pH 5.0 and more than 2000 ppm at more than pH 5.5. Due to the effect of pH in E. coli 0157:H7, MIC of combined chitosan and sorbic acid was 500 ppm of chitosan with 500 ppm of sorbic acid at pH 6.5, but 250 ppm of chitosan with 31.3 ppm of sorbic acid at pH 5.0. In Staph. aureus, there was great effect of chitosan, but neither effect of pH nor sorbic acid. When E. coli 0157:H7 were treated with 500 ppm of chitosan with 500 ppm of sorbic acid and 250 ppm of chitosan with 250 ppm of sorbic acid at pH 6.5, they were inhibited. But, they were increased at the initial concentration of bacteria at 1000 ppm of chitosan in 18 hours, at 500 ppm of chitosan in 36 hours. There was no effect of growth inhibition with sorbic acid but great effect with chitosan on Staph. aureus. The correl~tions between MICs of chitosan and sorbic acid in E. coli 0157:H7 accoding to pH were higher than those in Staph. aureus. R values in E. coli 0157:H7 were 0.95 (p<0.01), 0.99 (p<0.01), 0.97 (p<0.01), and 0.99 (p<0.01) at pH 6.5, 6.0, 5.5, and 5.0 respectively. The synergistic effect of chitosan and sorbic acid in E. coli 0157:H7 could be confirmed from the result of this experiment. Therefore, it was expected that the food preservation would increase or maintain by using sorble acid together with chitosan, natural food additive that did no harm to human body.

• Korean Journal of Food Science and Technology
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• v.37 no.3
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• pp.405-411
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• 2005

Chitosan, second largest biomass after cellulose on earth, has potential for use as functional food package due to its antibacterial activity. However, due to high melting temperature of chitosan, chitosan films have been made by casting method. Because gelatin has relatively low molting temperature depending upon amount of plasticizer added, it was added to chitosan to produce commercially feasible film. The objective of the current study was to determine optimum blend ratio and amount of chitosan/gelatin blend solutions against antibacterial activities for extruder resin. Gram-positive bacteria (Bacillus cereus ATCC 14579 and Listeria monocytogenes ATCC 15313) and -negative bacteria (Escherichia coli ATCC 25922 and Salmonella enteritidis IFO 3313) were used. Paper (8 mm) diffusion and optical density methods were used to evaluate effect of different blending ratio solutions on the inhibition of bacterial growth. Measured clear none size ranged from 8 mm to 18.07 mm in paper diffusion test. For B. cereus, E. coli, and S. enteritidis, addition of $50\;{\mu}L$ blend solution (chitosan/gelatin = 2/8: 0.3 mg) resulted in clear zone on paper disc. In L. monocytogenes, inhibition effect was observed with 0.6 mg chitosan (chitosan/gelatin=4/6). Minimum inhibitory concentration (MIC) values of B. cerues, L. monocytogenes, E. coli, and S. enteritidis with addition of chitosan were 0.1461, 0.2419, 0.0980, and 0.0490 mg/mL, respectively, These results indicate possibility of producing commercially feasible film with addition of optimum chitosan/gelatin amount.

• Journal of Life Science
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• v.21 no.3
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• pp.375-384
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• 2011

This study was performed to evaluate the antioxidant and antimicrobial activity of methanol extract from Rosmarinus officinalis L. and its fractions. The ethyl acetate fraction of rosemary had a higher antioxidant activity in both DPPH ($3.22\;{\mu}g/ml$) and ABTS ($5.05\;{\mu}g/ml$) compared to other extracts and fractions. Based on the results of the FRAP assay, the ethyl acetate fraction of rosemary showed a value of $5.9{\pm}0.3\;{\mu}M/{\mu}g$, and buthanol fraction and rosmarinic acid exhibited values of $4.8{\pm}0.2\;{\mu}M/{\mu}g$ and $5.1{\pm}0.1\;{\mu}M/{\mu}M$, respectively. Measurements of the antimicrobial activities of the extracts, fraction against gram positive, negative bacteria revealed that the methanol extract, hexane, ethyl acetate, and chloroform fraction of rosemary caused Staphylococcus aureus and Escherichia coli to form clear zones greater than 12 mm. Furthermore, the methanol extract and chloroform fraction showed high antibacterial activity, with inhibition zone exceeding 13 mm. The methanol extract and chloroform fraction of rosemary had broad antimicrobial spectrums and low MIC values. Therefore, methanol extracts of rosemary could serve as potential antibacterial agents to inhibit pathogen growth in food and hand sanitizers.