• Korean Journal of Food Science and Technology
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• v.24 no.4
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• pp.353-360
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• 1992

This study was carried out to investigate the changes of quality in yogurt during delivery and storage. To do this, microbiological, physico-chemical and sensory properties in stirred yogurt were studied at different temperatures $(10^{\circ}C$ & $20^{\circ}C)$ and shakings (100 rpm & 200 rpm for 30 min). Titratable acidity and TCA soluble nitrogen in yogurt were increased in accordance with increase of temperature and time, while pH, lactose and lactic acid bacteria tended to be decreased. Interestingly enough, shaking conditions almost did not influence these studies. In sensory evaluation it showed that acidity was strong and sweetness was weak as increasing the storage temperature and time, but there were no significant differences until 10 days at $10^{\circ}C$ and 3 days at $20^{\circ}C$. Off-flavor was developed after 12 days at $10^{\circ}C$ with only 200 rpm shaking and after 6 days at $20^{\circ}C$ in both shaking conditions. These yogurts were not suitable for consumer. Viscosity in the yogurt became high as the temperature and time were increased. Viscosity was lower in yogurt shaked at 200 rpm than in non-shaked yogurt. Finally, this study indicates that temperature and shaking during delivery of yogurt may be critical in keeping quality of yogurt.

• Journal of dental hygiene science
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• v.10 no.5
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• pp.373-378
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• 2010

To test the effects of representative fluoride vanishes-1.23% APF gel and 5% NaF Fluoride Varnish-on the surface structure of pit and fissure sealant, this study classified samples of pit and fissure sealant into five groups: Group I deposited in distilled water for ten minutes, Group II treated with APF gel for one minute, Group III treated with APF gel for four minutes, Group IV treated with Fluoride Varnish for one minute, and Group V treated with Fluoride Varnish for four minutes. An abrasion test was carried out to measure changes in weight, along with observation of the surface structure by using an optical microscope, consequently drawing the following conclusions. 1. The results of the abrasion test using pit and fissure sealant, Concise, showed that Group III had the reduction in weight more increased than Group I and that Group V had less reduction in weight (p<0.05); the results of the abrasion test using Eco-S showed Group III had the reduction in weight more increased than Group I and that Group V had less reduction in weight (p<0.05). 2. The results of observation using an optical microscope showed that application of APF gel made the filler remarkable due to loss of substrate and that Group III treated with APF gel for four minutes had the toughest surface, followed by Group II treated with APF gel for one minute, Group I deposited in distilled water for ten minutes, Group IV treated with Fluoride Varnish for one minute, and Group V treated with Fluoride Varnish for four minutes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.3
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• pp.576-581
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• 2004

Foxtail Millet Yakju were treated with heat ($65^{\circ}C$/15 min) or high hydrostatic pressure ($25^{\circ}C$ (RT) and $65^{\circ}C$ (HT)/400 MPa/10 min), and stored for 64 days at l$0^{\circ}C$, $25^{\circ}C$ and 37$^{\circ}C$. Changes in microbial counts, enzyme activity and quality of Yakju during storage were measured. Total viable cells were about 10$^2$ CFU/mL, and remained almost constant during storage at l$0^{\circ}C$ and $25^{\circ}C$, while decreased significantly at 37$^{\circ}C$, and undetected after 55 days of storage in heat- and pressure(RT)-treated, but after 25 days in pressure(HT)-treated Yakju. Lactic acid bacteria and yeast in heat- and pressure-treated Yakju were not detected during storage. The relative activities of a -amylase in heat- and pressure(RT)-treated were more than 100%, while those in pressure(HT)-treated were less than 40% during storage of 64 days at l$0^{\circ}C$. However, at $25^{\circ}C$ and 37$^{\circ}C$ the relative activities in untreated and pressure(RT)-treated were decreased greatly and then reached at the point of the activities of heat- and pressure(HT)-treated. The relative activities of glucoamylase in untreated and pressure(RT)-treated were decreased as the increase of the storage temperature during storage, while those in heat- and pressure(HT)-treated increased slightly as the increase of storage period at 1$0^{\circ}C$ and $25^{\circ}C$, and had no change at 37$^{\circ}C$. pH in heat- and pressure-treated had almost no change. Turbidity and reducing sugar in heat- and pressure-treated increased as the increase of storage temperature during storage.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.4
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• pp.555-559
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• 2012

Manures contain a variety of pathogenic microorganisms that pose a risk to human or animal. On-farm contaminations through contaminated manure were considered likely sources of the pathogen for several outbreak. Pathogenic microorganisms may survive in low numbers during the composting process and subsequently regrow to high levels under favorable conditions. The objective of this study was to investigate effect of temperature on survival of Salmonella enterica and Staphylococcus aureus in livestock manure compost. Commercial livestock manure compost (manure 60%, sawdust 40%) was inoculated with S. enterica and S. aureus. Compost was incubated at four different temperatures (10, 25, 35, and $55^{\circ}C$) for 20 weeks. Samples were taken every week during incubation depending on the given conditions. S. enterica persisted for up to 1 day in livestock manure compost at $55^{\circ}C$, over 140 days at $10^{\circ}C$, 140 days at $25^{\circ}C$, and 70 days at $35^{\circ}C$, respectively. S. aureus persisted for up to 1 day in livestock manure compost at $55^{\circ}C$ and 90 days at $10^{\circ}C$, 70 days at $25^{\circ}C$, and 40 days at $35^{\circ}C$, respectively. The results indicate that S. enterica and S. aureus persisted longer under low temperature condition. S. enterica survived longer than S. aureus at three different temperatures (10, 25, and $35^{\circ}C$). This study will provide useful and practical guidelines to applicators of soil in deciding appropriate handling and time frames for land application of livestock manure compost for sustainable agriculture. Results from these studies provide useful information in identifying manure handling practices to reduce the risk of S. enterica and S. aureus transmission to fresh produce.

• Korean Journal of Food Science and Technology
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• v.25 no.2
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• pp.98-104
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• 1993

In order to improve qualities of kochujang, various fruit juices such as apple, orange, pineapple and grape were added to the raw material of kochujang instead of the part of water. It was apparent in the kochujang with pineapple juice that organic acids originated from fruit juices increased titrable acidity and decreased pH. Free sugars and organic acids in the kochujang that was fermented during three months were degraded or might be used by microorganism after ten months of fermentation. Kochujang with grape juice showed relatively dark color, which had a good agreement with the changes of Hunter a-value. Sensory evaluation test about tastes, flavor and color showed that the kochujang with pineapple juice was preferred to others.

• Journal of the Korean GEO-environmental Society
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• v.11 no.11
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• pp.27-36
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• 2010

This study was conducted to evaluate physicochemical parameters; temperature, pH, C/N ratio, water content, organic contents and volume in a pilot-scale(capacity : $100m^3$) ultra thermophilic aerobic composting. There were three types input: municipal wasted sludge, livestock manure and slurry, and food waste produced in Jung-Eb city. Each target material was carried out by the first fermentation(organic waste + seed culture) and the second one(organic waste + seed culture + recycle compost), respectively. During composting, only with supply of air and mixing, the temperature increased $90{\sim}105^{\circ}C$ after every mixing in both periods. The changes of pH, $O_2$, $CO_2$ and $NH_3$ represented typical organic decomposition pattern by microorganisms. Also, all other physicochemical parameters of ultra thermophilic aerobic composting process showed similar or better performance than these of general aerobic composting. Heavy metal concentration of fermented compost adapted to compost fertilizer regulation standard in the heavy metal and hazardous analysis.

• Korean Journal of Microbiology
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• v.35 no.4
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• pp.307-314
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• 1999

This study was aimed at the investigation of the possibility of the addition of lactic acid bacteria as "starter"for the preparation of radish juice. Forty strains of lactic acid bacteria were isolated from dongchimi that was fermented by a traditional method. The isolates were assorted into 5groups, Leuconostoc mesenteroides subsp. mesenteroides (J-9), Lacobacillus brevis (J-12), Lactobacillus fermentum (J-7), Lactobacillus sake (J-20), and Lactobacillus plantarum (J-39). Leuconostoc mesenteroides was predominated in the sample of dongchimi with frequency of 52.5%. Each of the strain, which exhibited the beat growth in the species, was selected in the 5species, and investigation of the fermentation characteristcis was carried out. The fermentation were performed for 9 days at 25${\circ}C$ after the inoculation of 0.3% ($10^{6}$ cfu/㎖) to each ultra-filtrated radish juice. The pH, total acidity, content of non-volatile organic acids were examined during the fermentation period. Lactobacillus plantarum showed the highest growth rate and the growth rate of Lactobacillus sake was the lowest. The pH (6.3-6.36) and total acidity (0.09-1.0 %) fo the ultrafiltrated radish juice before fermentation were changed to 3.2-4.3 and 0.65-1.2% after 9days, respectively. The changes of the pH and total acidity were related with the growth of the lactic acid bacteria; the better growth of lactic acid bacteria, the more rapid decrease of pH and increase of the total acidity. when the amount of non-volatile organic acids were estimated during fermentation, citric acid, malic acid, malonic acid, and succinic acid were decreased in all cases. However, the content of lactic acid increased with the progression of fermentation. L. mesenteroides (J-9), L. brevis (J-12) and L. fermentum (J-7) were chosen for the candidates of the starter for the lactic fermentation of radish juice based on the biochemical analysis and sensory evaluation.

• Korean Journal of Food Science and Technology
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• v.39 no.4
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• pp.438-446
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• 2007

The fermented soybean product, cheonggukjang, is favored by many people, partly due to its bio-functional ingredients. Since the fermentation process of cheonggukjang is mediated by enzymes, including proteases, produced by microbes, analysis of the proteome profile changes in cheonggukjang during fermentation would provide us with valuable information for fermentation optimization, as well as a better understanding of the formation mechanisms of the bio-functional substances. The soluble proteins from cheonggukjang were prepared by a phenol/chloroform extraction method, in order to remove interfering molecules for high resolution 2-D gel analysis. Proteomic analysis of the cheonggukjang different fermentation periods suggested that most of the soluble soy proteins were degraded into smaller forms within 20hr, and many microbial proteins, such as mucilage proteins, dominated the soluble protein fraction. The proteomic profile of cheonggukjang was very different from natto, in terms of the 2-D gel protein profile. Among the separated protein spots on the 2-D gels, 50 proteins from each gel were analyzed by MALDI-TOF MS and PMF for protein identification. Due to database limitations with regard to soy proteins and microbial proteins, identification of the changed proteins during fermentation was restricted to 9 proteins for cheonggukjang and 15 for natto. From de novo sequencing of the proteins by a tandem MS/MS, as well as by database searches using BLASTP, a limited number of proteins were identified with low reliability. However, the 2-D gel analysis of proteins, including protein preparation methods, remains a valuable tool to analyze complex mixtures of proteins entirely. Also, for intensive mass spectrometric analysis, it is also advisable to focus on a few of the interestingly changed proteins in cheonggukjang.

• Korean Journal of Food Science and Technology
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• v.36 no.5
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• pp.837-841
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• 2004

Changes in total aerobic bacteria (TAB), lactic acid bacteria (LAB), rod- and coccal-shaped lactic acid bacteria (R- and C-LAB), pH, and total acidity were investigated during fermentation of radish with new fermentation base at $20^{\circ}C$ for up to 16 days. New fermentation base was prepared by pre-fermenting a mixture of rice bran and rice water (1 : 0.1, w/v) at $20^{\circ}C$ for 7 days. Initially, radish showed 5.41, 4.23, 4.57, and 3.1 log CFU/g, and base showed 6.68, 6.60, 5.95, and 5.6 log CFU/mL for TAB, LAB, R-LAB, and C-LAB, respectively. Initial pH and total acidity of radish were $6.6^{\circ}C$ and 0.09%, and those of base were 5.76 and 0.36%, respectively, Counts of LAB (4.23 to 8.33 Bog Cpu/g, 6.6 to 9.7 log CFU/mL), R-LAB (4.57 to 7.15 log CFU/g, 5.95 to 8.5 log CFU/mL), and C-LAB (3.1 to 7.5 log CFU/g, 5.6 to 8.6 log CFU/mL) of radish and base respectively increased during initial fermentation period, then remained constant during late fermentation period, and far 4 days after fermentation, pH values (6.6 to 4.19, 5.76 to 4.57) drastically decreased and thereafter slowly decreased. Total acidities of radish and base (0.09 to 0.63%, 0.36 to 0.63%, respectively) drastically increased far 7 days after fermentation and increased slightly thereafter.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.3
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• pp.335-342
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• 2011

The purpose of this study was to investigate the effects of mugwort powder on the quality characteristics and antioxidant activity of Maejakgwa. Maejakgwa were prepared with mugwort powder at levels 0%, 1%, 3% and 5% ($60{\pm}1^{\circ}C$, 14 days). The lightness, redness, and yellowness values of Maejakgwa significantly reduced depending on mugwort powder. The hardness of Maejakgwa was decreased with the increase of storage period and increased with the increase of mugwort powder. In the sensory evaluations, the Maejakgwa prepared with 3% added mugwort powder received higher acceptance scores for the properties of color, taste, hardness, crispiness, adhesiveness and overall acceptability. As the mugwort powder content increased, acid value and peroxide value were decreased. With the increase of storage period, acid value and peroxide value of all sample increased but growth rate of these values decreased with the addition of the mugwort powder. DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity was improved significantly via the addition of mugwort powder and decreased as storage period increased. During storage period, Maejakgwa with mugwort powder showed a stronger antimicrobial effect in yeasts and molds than in total aerobic bacteria. Coliform bacteria were not detected in all samples. Also the antimicrobial activity was increased with the addition of the mugwort powder and decreased as storage period increased. The results show that addition of the mugwort powder to foods with fat such as Maejakgwa would be a useful way to enhance the antioxidant quality, sensory characteristics and shelf life.