• Culinary science and hospitality research
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• v.9 no.4
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• pp.81-97
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• 2003

The purpose of this study was to evaluate hazard factors in the steps of production, holding and assembly and service of jabchae that were served by contracted management in school meal foodservice. And method of control with the Hazard Analysis Critical Control Point (HACCP)program was suggested. The hazard factors in jabchae product had come from the temperature, time, growth of microbiological equipment and utensils. Almost of raw materials, prepreparation and storage, cooking, holding, serving established the critical control point. It has shown that the microbiological quality of raw materials for jabchae was a little inferior at the time of receiving based on the total plate count(10$^3$∼10 $^{5}$ ), coliform(0∼10$^3$). However microbiological quality become acceptable level by washing and a few disinfection method. Microbiological growth has increased in 3hr at room temperature up to 5.1${\times}$10$^2$ after preparation of jobchae. In conclusion, it is extremly important to reduce hoiding and serving time and to avoid treating food within the danger zone for food safeness. In addition, the prevention of cross-contamination during mixing the ingredients with improper equipment and with insanitary treatments by workers was also important to keep the food safe in this foodservice facility.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.1
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• pp.75-80
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• 2002

The growth inhibition by nisin-Producing lactococci against Bacillus subtilis and its application to doenjang fermentation were investigated. Lactococcus lactis subsp. lactis IFO 12007, L. lactis subsp. lactis ATCC 7962 and L. lactis subsp. lactis ATCC 11454 were used as nisin-producing lactococci. All of three strain rapidly proliferated to more than 10$^{9}$ CFU/g in steamed soybeans. Only L. lactis subsp. lactis IFO 12007 was in steamed soybean without any pH decrease. In spite of the mild decrease in pH, the growth of B. subtilis was completely inhibited; no living cells were detected in a soybean sample inoculated with 10$^{6}$ CFU/g and incubated for 24 to 72h. The L. lactis subsp. lactis IFO 12007 was applied to doenjang fermentation as a starter culture. It produced high nisin activity in steamed soybean, resulting in the complete growth inhibition of B. subtilis, which had been inoculated at the beginning of the meju fermentation, throughout the process of doenjang production. Over-acidification, which is undesirable for doenjang quality, was successfully prevented simply by adding salt which killed the salt-intolerant L. lactis subsp. lactis IFO 12007. Furthermore, the nisin activity in doenjang disappeared with aging.

• Journal of Korean Society for Atmospheric Environment
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• v.32 no.3
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• pp.320-328
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• 2016

Among biogenic volatile organic compounds (BVOCs) in the natural ecosystem, monoterpenes, along with isoprene, play important roles in atmospheric chemistry and make significant impacts on air pollution and climate change, especially due to their contribution to secondary organic aerosol production and photochemical ozone formation. It is essential to measure monoterpene concentrations accurately for understanding their oxidation processes, emission processes and estimation, and interactions between biosphere and atmosphere. Thus, traceable calibration standards are crucial for the accurate measurement of monoterpenes at ambient levels. However, there are limited information about developing calibrations standards for monoterpenes in pressured cylinders. This study describes about developing primary standard gas mixtures (PSMs) for monoterpenes at about 2 nmol/mol, near ambient levels. The micro-gravimetric method was applied to prepare monoterpene (${\alpha}$-pinene, 3-carene, R-(+)-limonene, 1,8-cineole) PSMs at $10{\mu}mol/mol$ and then the PSMs were further diluted to 2 nmol/mol level. To select an optimal cylinder for the development of monoterpene PSMs, three different kinds of cylinders were used for the preparation and were evaluated for uncertainty sources including long-term stability. Results showed that aluminum cylinders with a special internal surface treatment (Experis) had little adsorption loss on the cylinder internal surface and good long-term stability compared to two other cylinder types with no treatment and a special treatment (Aculife). Results from uncertainty estimation suggested that monoterpene PSMs can be prepared in pressured cylinders with a special treatment (Experis) at 2 nmol/mol level with an uncertainty of less than 4%.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.2
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• pp.198-202
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• 1997

Jangkimchi is a kind of Kimchi which is made with soy-sauce instead of salt. Occasionally, when sugar is added to Jangkimchi for condiment, the kimchi juice becomes viscous. In this study. the nature of the viscous material and the condition for producing viscous property in Kimchi juice were investigated. HPLC analysis showed that the viscous material in Jangkimchi is polysaccharide composed of glucose. Sucrose was more effective in forming viscous juice than glucose and the viscosity increased with the addition of sucrose up to 10%. Soy-sauce also played a role in increasing the viscosity of Kimchi juice compared with salt. Aerobic fermentation condition was found to be another factor to make the juice viscous. The population of Leuconostoc mesenteroides, well-known producer of viscous dextran was not different in the Kimchi juice prepared with the addition of sucrose from that without sucrose, which implys that the Jangkimchi preparation methods such as addition of sucrose and soy-sauce would do some effects on the production of viscous material in Jangkimchi.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.5
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• pp.667-672
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• 2003

Low-fat, precooked high quality Wanjajun was prepared by treating natural antioxidant herbs and hydrocolloids for quantity production of cook/chill system in foodservice. The proposed Wanjajun was formulated under the consideration of flavor and fat level. Wanjajun was prepared with hydrocolloid such as sodium alginate, car-boxymethyl cellulose (CMC), carrageenan and xanthan gum. Cooking yield, fat retention and water holding capacity of Wanjajun containing hydrocolloidal gums were higher than those of control. L-value of raw product was low in comparison with cooked product, but a-value was higher than that of other cooked product. Colors of raw and cooked products were not different among five kinds of products. pH value of cooked product was higher than that of raw product pH range of cooked products revealed to 6.10~6.23. There was no considerable change in pH value during storage. The coliform group and Staphylococus aureus were not detected during storage. Total bacteria1 counts were close to microbial guidelines for safe condition. Hardness, springness, cohesiveness, gumminess and brittleness of low-fat products were generally lower than those of control product. Hardness, gumminess and brittleness of reheated products were higher than those of preheated products. Flavor, tenderness, juiciness and overall quality were not different between precooked and reheated products. Textural characteristics of products were superior in the order of sodium alginate, xanthan gum, CMC, carrageenan and control product.

• Nuclear Engineering and Technology
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• v.22 no.2
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• pp.101-107
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• 1990

The PIXE (Proton Induced X-ray Emission) method is applied to the quantitative analysis of trace elements in tap water, red wine, urine and old black powder samples. Sample irradiations are performed with a 1.202 MeV proton beam from the SNU 1.5-MV Tandem Van de Graaff accelerator, and measurements of X-ray spectra are made by the Si(Li) spectrometer To increase the sensitivity of analysis tap water is preconcentrated by evaporation method. As an internal standard, Ni powder is mixed with black powder sample and yttrium solution is added to the other samples. The analyses of the PIXE spectra are carried out by using the AXIL (Analytical X-ray Analysis by Iterative Least-squares) computer code, in which the routine for least-squares method is based on the Marquardt algorithm. The elements such as Mg, Al, Si, Ti, Fe and Zn are analyzed at sub-ppm levels in the tap water sample. In the red wine sample prepared without preconcentration. the element Ti is detected in the amount of 3ppm. In conclusion, the PIXE method is proved to be appropriate for the analysis of liquid samples by relative measurements using the internal standard. and is expected to be improved by the use of evaluated X-ray production cross-sections and the development of sample preparation techniques.

• Microbiology and Biotechnology Letters
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• v.39 no.4
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• pp.357-363
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• 2011

This study focus was primarily the development of liquid starters for Aspergillus oryzae and Aspergillus niger prepared with wheat bran as a low cost culture medium. For the preparation of the liquid media wheat bran was added at rates of 0, 5, 10, 15 and 20% and the Aspergillus sp. strains were then inoculated to these prepared broths. The results indicated that the more that wheat bran was contained in the medium, the more mycelia was produced for A. oryzae and A. niger. The highest enzyme activities were obtained with a 10~15% adding rate of wheat bran for both strains. Changes in the enzyme activities of the liquid starters during various incubation times (0, 24, 48, 72 and 96 hrs), indicated that the highest enzyme activities were seen between 48 and 72 hrs of culture. In addition, a comparative study was carried out on the production of enzymes using wheat as a substrate in nuruk, with liquid starter made from fermented agents according to the same concentrations used with the wheat bran. The pH, acidity, amino acidity, reducing sugar content and enzyme activity (${\alpha}$-amylase, glucoamylase, acidic protease) of wheat nuruk made with liquid starter were compared with those of wheat nuruk made with solid starter. The results suggest that the liquid starter is superior in both cases.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.11
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• pp.2085-2095
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• 2000

Red mud is generated as a by-product during the production of aluminum hydroxide from bauxite ore. In this study inorganic coagulants were prepared by leaching aluminum and iron from red mud with acids under various operating conditions. The optimum leaching efficiency of Al and Fe was obtained by contacting red mud with acids of 5M $H_2SO_4$ and 9M HCI with the ratio of 1/10(g/mL) at $85^{\circ}C$ and $25^{\circ}C$, respectively. In addition. the removal experiments of heavy metal ions($Pb^{2+}$, $Cd^{2+}$, $Cu^{2+}$, $Zn^{2+}$, $Cr^{3+}$), turbidity and phosphate phosphorus($PO_4{^{3-}}-P$) in aqueous solutions were also studied in various experimental conditions. As a result, the developed coagulants are found to show a good removal performance of heavy metal ions. turbidity and phosphate phosphorus in aqueous solutions.

• Journal of the Korean Society of Food Culture
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• v.14 no.4
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• pp.431-446
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• 1999

The purpose of this study is to examine current foodservice management practices at free congregate meal service for elderly people. Forty seven meal service centers as well as randomly selected Seoul and Kyunggido area were surveyed and interviewed and results were summarized as follows: The cost of each meal(lunch) was ranged from 1,300 won to 1,500 won and 68% of target centers were severed over 100 meals per day. Meal time for lunch begins from 10:30 am to 12:00 because great portion of elderly didn't take breakfast frequently. 52.3% of centers severed meal 5 times per week, just weekdays. 21.3% of centers employeed dietitian, 63.8% of center employeed cook. 95.7% of center were supported labor force by volunteers. Volunteer was important contribution to free meal service. Utilizing the labor force more effectively is thus a major challenge facing manager in each center. Ideal supporting system of free foodstuff, foodbank was still minor source of securing foodstuff. Most of centers(46 centers)served lunch, only one of them served breakfast and lunch. Government was the major financial sponsor, the second of them was religious organization. The large portions of financial support provided only food cost of total meal service budget. Most of center adapted self-service system. Standardized recipes were not developed and meal preparation was controlled under the experience of volunteers. Recording system of nutrition management, production control, storage and inventory control was not adapted by most of sites. It is suggested that in order to meet the change of the patterns of social and family structure, the service of the center should be offended in urban area and it is necessary to develop systematic management models for the center. It was suggested that not only financial support but also systematical support on management by the local government may be necessary to meet the goal of supply nutritionally balanced food at center.

• Journal of the Korean Institute of Gas
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• v.22 no.2
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• pp.46-51
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• 2018

Hydrogen sulfide from landfill and sewage treatment plant is a major odor component and causes many civil petitions. Rapidly developing industries release hydrogen sulfide, an odorous gas, to the atmosphere. This study aims to develop a $10{\mu}mol/mol$ concentration level hydrogen sulfide primary standard gas for odor measurement. The hydrogen sulfide gas was prepared at a nominal concentration of $10{\mu}mol/mol$ in nitrogen using the gravimetric method described in ISO 6142. Replicate standard gases were produced in 4 aluminium cylinders, and their concentrations were verified by GC-AED. The uncertainty of production was less than 0.50 %, and the variation of the 4 replicates was 0.22 %. The wall adsorption of hydrogen sulfide in cylinders was 0.10 % at 1500 psi, and the concentration was estimated to be long-term stable for one year. The relative expanded uncertainty of the preparation consistency, adsorption and long-term stability of this hydrogen sulfide standard gas was less than 1.05 % (95 % of confidence level, k=2).