• Food Science and Preservation
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• v.20 no.5
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• pp.699-704
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• 2013

Buckwheat Soksungjang (BS) is a bealmijang manufactured with buckwheat and soybeans. We manufactured BS using Bacillus subtilis HJ18-4 (HJ18-4), which has high enzyme activities and antibacterial effects. HJ18-4 was inoculated in a different process during the BS manufacturing, which was the meju-making time (Treat 1), and the salt water time was added (Treat 2). The physiochemical and microbial characteristics of the BS were analyzed. As a result, the total aerobic counts (7~8 log CFU/mL) in the BS increased after 15 days of fermentation. Especially, Treat 1 showed higher total aerobic counts and amino-type nitrogen (65.38~202.52 mg%) than Treat 2. During the BS fermentation, the reduction of the sugar contents and the enzyme (protease and amylase) activities decreased. In the relative quantitative expression level of PlcR, Treat 1 did not show toxin gene expressions at the end of the fermentation on Day 23. Treat 1 showed suitable B. cereus physiochemical quality characteristics and inhibition effects. When the modified-form type of fermented soybean paste was manufactured with a single starter, it could not reproduce the natural fermentation quality. These results suggest that the addition of a starter (HJ18-4) in the Meju manufacturing process could enhance the quality characteristics of the manufactured BS via natural fermentation and by suppressing B. cereus.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.24 no.1
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• pp.1-11
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• 2018

In this study, pro-oxidant($d2w^{(R)}$) and rPP/ZnO nanocomposite flexible films for food packaging were prepared, and their mechanical and antimicrobial properties were investigated. As a result, the carbonyl index and hydroxyl index increased with exposured time to heat and UV rays. Surface analysis showed that the addition of zinc oxide improved the dispersibility and compatibility of the polymer, so that the surface of the composite film was smooth and the zinc oxide particles were smaller than the compared film. And it kept the physical properties by heat and UV ray blocking effect, and it worked to reduce decomposition. In the antimicrobial activity test, the microbial reduction rate was 3 logs or more at the use concentration of zinc oxide. The tensile strength was increased and the elongation was decreased. Oxidative degradability of multi-layered film in UV exposured for 72 hours, the molecular weight of the film decreased by 75.6%, 1,294 g/mol Mn and 5,920 g/mol Mw. In the safety analysis of food packaging materials, we obtained that are in standard of polypropylene, a food contact material of domestic law.

• Korean Journal of Agricultural Science
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• v.34 no.1
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• pp.67-75
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• 2007

The effect of irradiation on the quality characteristics of pale-soft-exudative (PSE) pork was studied. The pork loin with severe PSE appearance was selected by meat grader,irradiated at 0 and 4.5 kGy, and meat quality characteristics including pH, color, lipid oxidation development, microbial and sensory quality were analyzed during 2 weeks of storage at $4^{\circ}C$. The pH values of non-irradiated and 4.5 kGy-irradiated PSE raw pork loin was not different. Hunter color $a^*$-value, which represents redness of meat surface showed significant increase (P<0.05) in irradiated PSE pork loin. This higher Hunter color $a^*$-value maintained during 2 weeks of storage. By 4.5 kGy of irradiation, approximately 2 log reduction of total aerobic bacterial counts was achieved during 2 weeks of storage when compared with non-irradiated control. Sensory panelists prefer the color of irradiated PSE meat than that of non-irradiated control because of redness. From the results, it is possible to use an irradiation technology to improve not only microbiological safety but also the color of meat which has severe defect such as PSE.

• Membrane Journal
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• v.26 no.3
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• pp.205-211
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• 2016

Performance of pyrophyllite-based ceramic membranes newly developed were investigated. Membrane fouling caused by microbial suspensions taken from a full-scaled MBR system at domestic wastewater treatment plant was observed at different airflow rate and distance between each membrane. For the pyrophyllite support, pore size was about $1.0{\mu}m$, but surface coating with $Al_2O_3$ solution decreased the pore size with the reduction of the pure water permeability. With the MLSS taken from the full-scaled MBR system (6 g/L), the fouling rate was decreased by increasing airflow rate under $20L/m^2{\cdot}hr$ of setpoint flux. However, the effectiveness of the airflow rate on the fouling control depends strongly upon the gap between each membrane. At fixed airflow rate, the fouling rate was decreased by increasing the gap between each pyrophyllite membrane. Nevertheless, further increasing the membrane distance from 3.5 to 5.4 cm resulted in higher fouling rate. Similar result was observed with the $Al_2O_3$ coated-pyrophyllite membrane. Nevertheless, the fouling rate was lower with the coated membrane than that observed with the uncoated pyrophyllite support. Regardless of surface coating, the suspended solids were removed almost completely and the surface coating on the pyrophyllite support improved organic rejection with PEG solution (MW : 8000 kDa) tested.

• Applied Biological Chemistry
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• v.26 no.1
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• pp.35-40
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• 1983

The inhibitory activity of 20 Lactic strains from Kimchi was tested against Escherichia coli and other microorganisms. Of the lactic strains investigated, A7 (Pediococcus cerevisiae) and C4(Leuconostoc spp.) were the most effective in restricting the growth of test organisms. The mixed culture inoculation of each selected lactic strain and Escherichia coli resulted in a drastic reduction in the plate count of Escherichia coli after 24 hours. Similar results were obtained when Staphylococcus aureus and Bacillus cereus were used as test organisms. For all test organisms, the presence of A7 caused a higher death rate constant than that of C4. Addition of catalase in the mixed culture did not prevent inhibition, suggesting that hydrogen peroxide did not cause the inhibition. The filtrate of A7 culture added to Escherichia coli showed identical inhibitory action, however heat treatment of filtrate at $80^{\circ}C$ 30min. destroyed the inhibitory activity. A7 filtrate treated with trypsin substantially lost the inhibitory effect, but not by pepsin. The results imply that the protein-like compound(s) is the principal inhibitor produced by this lactic strain.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.7
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• pp.915-920
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• 2007

Rice flour milled from spray-washed rice was stored at $5^{\circ}C$, $20^{\circ}C$, and $35^{\circ}C$ for 4 months and changes in flour properties during the storage were investigated. Moisture content of rice flour tended to decrease during the storage, and the reduction in the moisture content was higher at higher storage temperature. Compared to dry-milled rice flour, lightness of the rice flour milled from spray-washed rice was slightly higher and tended to increase slightly during the storage. Rapid Visco-Aanlyzer (RVA) peak viscosity of rice flour milled from spray-washed rice was higher throughout the storage period, compared to dry-milled rice flour. The RVA peak viscosity was lower in the order of rice flour stored at $5^{\circ}C$, $20^{\circ}C$, and $35^{\circ}C$. Little changes in setback viscosity were observed in rice flour stored at $5^{\circ}C$ and $20^{\circ}C$, while an increase in the setback viscosity was found in rice flour stored at $35^{\circ}C$. Total bacteria count was consistently lower in the rice flour milled from spray-washed rice, suggesting that spray-washing prior to milling could lower microbial growth of rice flour during storage.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.531-540
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• 2016

The adoption of legume cover crops in no-tillage system can contribute to improve soil fertility by providing several benefits, including reduction in soil erosion, suppression of weed growth and N supply to subsequent crops. We conducted a field study to investigate the effect of cover crops and nitrogen fertilization rates on yield and nitrogen use efficiency of waxy corn (Zea mays L.) in no-tillage upland field. Two legume cover crops, hairy vetch (Vicia villosa Roth) and crimson clover (Trifolium incarnuturn L.) were mechanically terminated with roller in early June. For each cover crop treatment, nitrogen (N) fertilizer was applied at three different rates (145, 72.5 and $0kg\;N\;ha^{-1}$). The growth and yield characteristics of corn were significantly affected by the N fertilization rates in crimson clover plots, which suggest N mineralization from the cover crop residue was not sufficient. In contrast, N fertilization rates had no significant effect on growth and yield of corn in hairy vetch plots, indicating that the amount of N released from the cover crop is large enough to meet most of the N requirement of corn. However, the application of N fertilizer in hairy vetch cover plots resulted in slight increase of crop yield, though not statically significant, and high levels of N concentration in corn plant tissue possibly due to luxury consumption of N. Organic residues on the soil surface in hairy vetch cover plots had substantial amounts of N after harvest, ranging from 100 to $116kg\;N\;ha^{-1}$, which is presumably retained during winter season and released by microbial mineralization in subsequent year. The highest nitrogen yield efficiency was achieved in the plot with hairy vetch cover and no N fertilizer application, followed by the plot with hairy vetch cover and $72.5kg\;N\;ha^{-1}$ fertilization rate. In conclusion, hairy vetch showed better performance in corn productivity as compared with crimson clover. In addition, it was concluded that the application of N fertilizer between 0 and $72.5kg\;N\;ha^{-1}$ in combination with hairy vetch cover crop might be most efficient for corn yield under no-tillage system with climatic and soil characteristics similar to those of the experimental site.

• Journal of Periodontal and Implant Science
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• v.31 no.2
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• pp.401-420
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• 2001

A novel glucanhydrolase from a mutant of Lipomyces starkeyi(KSM 22)has been shown effective in hydrolysis of mutan, reduction of mutan formation by Streptococcus mutans and removal pre-formed sucrose-dependent adherent microbial film and Lipomyces starkeyi KSM 22 dextranase has been strongly bound to hydroxyapatitie. These in vitro properties of Lipomyces starkeyi KSM 22 dextranase are desirable for its application as a dental plaque control agent. This study was performed to determine oral hygiene benefits and safety of dextranase(Lipomyces starkeyi KSM 22 dextranase)-containing mouthwash in human experimental gingivitis. This 3-week clinical trial was placebo-controlled double-blind design evaluating 1U/ml dextranase mouthwash and 0.12% chlorhexidine mouthwash. A total 39 systemically healthy subjects, who had moderate levels of plaque and gingivitis were included. At baseline, 1, 2 and 3 weeks, subjects were scored for plaque(Silness and $L{\ddot{o}e$ plaque index and plaque severity index), gingivitis($L{\ddot{o}e$ and Silness gingival index), and at baseline and 3 weeks of experiment, subjects were scored for plaque(Turesky-Quingley-Hein's plaque index and plaque severity index), tooth stain(Area and severity index system by Lang et al). Additionally, oral mucosal examinations were performed and subjects questioned for adverse symptoms. Two weeks after pre-experiment examinations and a professional prophylaxis, the subjects provided with allocated mousewash and instructed to use 20-ml volumes for 30s twice dailywithout toothbrushing. All the groups showed significant increase in plaque accumulation since 1 week of experiment. During 3 weeks' period, the dextranase group showed the least increase in plaque accumulation of Silness and $L{\ddot{o}e$ plaque index, compared to the chlorhexidine and placebo groups, but chlorhexidine group showed the least increase inplaque accumulation of Turesky-Quingley-Hein's plaque index. As for gingival inflammation, all the groups showed significant increase during 3 weeks of experiment. The dextranase group also showed the least increase in gingival index score, compared to the chlorhexidine as well as the placebo groups. Whereas the tooth stain was increased significantly in the chlorhexidine group, compared to the baseline score and the placebo group since 3 weeks of mouthrinsing. It was significantly increased after 3 weeks in the dextranase group, still less severe than the chlorhexidine group. As for the oral side effect, the dextranase group showed less tongue accumulation, bad taste, compared to the chlorhexidine group. From these results, mouthrinsing with Lipomyces starkeyi KSM 22 dextranase was comparable to 0.12% chlorhexidine mouthwashin inhibition of plaque accumulation and gingival inflammation and local side effects were if anything less frequent and less intense than chlorhexidine, in human experimental gingivitis. All data had provided positive evidence for Lipomyces starkeyi KSM 22 dextranase as an antiplaque agent and suggested that further development of dextranase formulations for plaque control are warranted.

• Food Science and Preservation
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• v.22 no.5
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• pp.758-767
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• 2015

Red pepper powder sensitive to aflatoxins contamination is major ingredients of kimchi. This study was conducted to investigate the effect of lactic acid bacteria (LAB) on the changes in aflatoxin levels during kimchi fermentation. Baechu kimchi was contaminated with aflatoxins ($B_1$, $B_2$, $G_1$, and $G_2$) and inoculated with LAB (Lactobacillus plantarum and Leuconostoc mesenteroides), and the following characteristics were investigated for 8 weeks: pH, titratable acidity, salinity, microbial properties, and aflatoxin levels. The pH decreased rapidly during storage, and the titratable acidity was increased. The salinity of the samples was shown to increase from 2.30 to 2.40%. The total number of aerobic bacteria and lactic acid bacteria in kimchi inoculated with LAB was significantly higher than that of the others. Yeast and molds were detected at approximately 1~3 log CFU/g during storage. Coliforms were detected in the control after 4 weeks, whereas in other samples they were not detected until after 2 weeks. The aflatoxin levels reduced during kimchi fermentation. The average reduction rate of aflatoxin levels during kimchi fermentation was 8.39%, but in kimchi inoculated with Lac. plantarum and Leu. mesenteroides, the rate were 25.16 % and 27.86%, respectively. These results showed that aflatoxins can be removed by LAB during kimchi fermentation.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1596-1603
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• 1999

Dongchimi (Korean-style fermented radish with juice) products were frozen to prevent further acidification and softening of texture by restraining microbial growth and enzyme activity during storage. Dongchimi juice and radish were separated prior to freezing process. Dongchimi radish was frozen at $-20^{\circ}C,\;-70^{\circ}C$ and immersed in liquid nitrogen and dongchimi juice was frozen at $-20^{\circ}C\;and\;-70^{\circ}C$. Frozen dongchimi samples were thawed with ambient temperatures of $4^{\circ}C\;and\;27^{\circ}C$ and with 915 MHz-microwave, respectively. Dongchimi radish immersed in liquid nitrogen and thawed with 915 MHz-microwave showed the highest pectinesterase activity and hardness, and the lowest polygalacturonase activity and color change, indicating that this quick freezing-quick thawing method can be used for the long-term storage of dongchimi products. Dongchimi juice frozen at $-70^{\circ}C$ and thawed with 915 MHz-microwave retained its pH and titrable acidity, and showed a largest reduction in total aerobic count and lactic acid bacteria.