• Journal of Dairy Science and Biotechnology
• /
• v.29 no.2
• /
• pp.37-42
• /
• 2011

The changes in pH, titratable acidity, chromaticity, total count, coliform group and organoleptic properties of the whole market milks (UHT, LTLT) that sold currently on the domestic market were stored after their production at 0, 10, 20, 30 and $40^{\circ}C$ to predict their quality during distribution, and examined prior to the analysis on the correlation of their quality properties and organoleptic preference level and discovery of optimal quality indicator. The investigation of correlation between pH, acidity and preference level of milks depending on respective storage temperature showed significant correlation (p<0.01) for the milk stored at 10, 20, 30 and $40^{\circ}C$, and the higher temperature was directly proportional to the higher correlation coefficient. The correlation between total count and preference level for LTLT milk stored at 0, 10, 20, 30 and $40^{\circ}C$ showed high correlation coefficient at every high temperature condition respectively as R=0.81, R=0.91, R=0.96, R=0.90 & R=0.99, and the correlation coefficients were also significant level for the UHT milk irrespective of their storage temperature except $0^{\circ}C$. Accordingly, the changes in total colonies turned out to be suitable to be the quality indicator for the quality prediction of the milk on the distribution.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.36 no.1
• /
• pp.93-99
• /
• 2007

The study was carried out to prepare spaghetti sauce with oyster (SSO) and the food components characteristics of the SSO were also compared to those of commercial spaghetti sauces (CSS). The optimal addition ratio of oyster for preparing SSO was 11% based on 100 g of SSO according to the results of organic acid content, Hunter color value, viscosity, and sensory evaluation. The reasonable $F_0$ value for the keeping storage of SSO was about 4 min. The proximate composition of SSO prepared under the optimal processing condition was 71.2% moisture, 2.8% protein, 6.9% crude lipid, and 3.2% crude ash. The results of sensory evaluation suggested that the quality of SSO was superior to that of CSS. However, there was no significant difference (p<0.05) in sensory evaluation on color between CSS and SSO. The total amino acid content (2,532.2 mg/100 g) of SSO was higher than that of CCS (2,305.7 mg/100 g). The contents of calcium and phosphorus of SSO were 25.7 mg/100 g and 48.7 mg/100 g, respectively. The calcium content/phosphorus content showed a suitable ratio for absorbing calcium. The total free amino content and the taste value were 1,040.2 mg/100 g and 151.26, respectively. The major taste-active amino acids were glutamic acid and aspartic acid.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.18 no.4
• /
• pp.352-362
• /
• 1985

In succession to the previous paper, the present study was directed to investigate the optimal processing conditions of meat paste products with mackerel. To improve the gel forming ability of meat paste, washing conditions with water and alkaline solution, setting time and temperature, and heating temperature were controlled, and the influences of the freshness of raw mackerel and mixing ratios of ordinary and dark muscle on the qualities of meat paste products were discussed. The most effective condition for the keeping freshness of raw mackerel meat among different storage conditions was the forozen storage at $-20^{\circ}C$, followed by the storage at $-3^{\circ}C$ and ice storages, and this relation was coincided with the effect for maintaining of gel forming ability among above conditions, but there was no effect on keeping freshness of raw mackerel in the storage at $25^{\circ}C$. Gel strength of meat washed with tap water decreased with washing time, particularly, the meat washed three times showed higher gel strength than the meat washed more than 5 times. And the removal ratios of water soluble protein were $60\%$ in the meat washed three times and $90\%$ in the meat washed nine times. Washing effect of raw mackerel meat with alkaline solution was great at pH $6.5{\sim}7.0$ of meat paste yielding the highest gel strength in the meat washed with $0.5\%$ sodium bicarbonate solution. Gel strength of meat paste product decreased with the increase of mixing ratios of ordinary and dark muscle in the raw meat. In the setting conditions of meat paste examined, 15 hours at $5^{\circ}C$ and 2 hours at $30^{\circ}C$. The most suitable temperature for gel forming in heating conditions was $90^{\circ}C$, fellowed by $100^{\circ}C\;and\;80^{\circ}C$.

• Food Science and Preservation
• /
• v.10 no.4
• /
• pp.476-481
• /
• 2003

As its high functional properties to be used as medicine or food, the cultivation of Agaricus mushroom has been expanded and iぉ commercialization required better storage methods that can extend its functional and nutritional value for longer period. We selected drying as the most plausible method to meet such requirement, and several drying conditions were investigated to locate the optimum drying condition that can be used to keep the quality of mushroom. Drying temperature of 50$^{\circ}C$, 60$^{\circ}C$, 100$^{\circ}C$ were selected to trace the drying time required to achieve the moisture content of mushrooms less than 10%. The drying temperature at 50$^{\circ}C$ required 29 hrs of drying time, while 100$^{\circ}C$ required only 10 hrs of drying tune. However, their quality characteristics on the following categories, on the degree of browning and color were investigated to find the optimum drying condition. In addition, sensory evaluation was conducted to evaluate the quality of dried mushrooms produced by each drying condition. The browning of the mushroom was evidently increased as the higher drying temperature was used and 50$^{\circ}C$ drying produced the most desirable quality of all in pileus or stipe. The aeon of browning intensified by drying temperature was comparable to the result of whiteness index value, which resulted lower L values as drying temperature increased. and the 50$^{\circ}C$ drying resulted the most highest L values among all drying samples. As the browning and whiteness results implied, the sensory evaluation result gathered from the present research indicated that the 50$^{\circ}C$ drying was the most favorable drying condition by scoring the most highest average scores on flavors, color, appearance, and overall acceptability conducted by the 10 evaluation panels.

• The Korean Journal of Pesticide Science
• /
• v.15 no.1
• /
• pp.55-60
• /
• 2011

To work out quality control methods of environmental-friendly organic materials (EFOMs), the reason and basis for EFOM-selection and farmer's favorite formulation type of EFOMs, etc were investigated on farmers who had been practicing environmental-friendly agriculture. EFOMs used were soil amendments, control agents of plant diseases and insect pests, plant growth promotion formulations, in turns. In EFOMs application time, 22.7% of farmers sprayed EFOMs without delay after they were bought, in other hand, 77.3% of farmers used EFOMs which had been bought and stored for some period. Microbial density on seventeen environmental-friendly microbial formulates (EFMFs) including microbial pesticides, a microbial fertilizer, and environmental-friendly organic materials was investigated at different storing temperature and shelf life. When the microbial density of EFMFs was investigated without delay after they were bought, all used microbial pesticides and a microbial fertilizer was confirmed to be optimal for the certified density but two of environmental-friendly organic materials was confirmed not to be optimal. When microbial density of 17 EFMFs were investigated after storing them for six months at $4^{\circ}C$, only one of 9 microbial pesticides was confirmed not to be optimal, the other hand four of seven environmental-friendly organic materials not to be optimal, which each of their microbial density was less than the certified density. Population dynamics of microbial agents was much more influenced in fluctuated temperature (room temperature) than in static temperature condition ($5^{\circ}C$ and $25^{\circ}C$). Shelf life of microbial agents according to microbial formulation type were high in granule type, liquid wettable type and liquid type in turns.

• The Korean Journal of Food And Nutrition
• /
• v.10 no.4
• /
• pp.514-520
• /
• 1997

The study was carried out to investigate the changes of quality and to determine the optimal shelf-life of fried soybean curd under low temperature(8$\pm$2$^{\circ}C$) and room temperature(25-3$0^{\circ}C$), respectively. The quality criteria for fried soybean were acid value, peroxide value, fatty acid composition and microbial concentration, et al. The initial moisture content of fried soybean curd was 41.9%, it was rapidly decreased to 29.6% until the second days under low temperature. The pH value was 5.7 and 5.8 at the ninth days under 8$\pm$2$^{\circ}C$ and the sixth days under 25-3$0^{\circ}C$, respectively. Also, the acid value rised remarkly to 10.65 at the fifth days and the peroxide value was 12.20 at the sixth days under room temperature. The viable cell counts were 1.0$\times$1.0 at the initial storage, but they were increased to 6.1$\times$105 over at the second days of room temperature. Moreover, the mold colony counts were in 2.0$\times$10-6.0$\times$103 and 2.0$\times$10=8.5$\times$107 during all storage days under 8$\pm$2$^{\circ}C$ and 25-3$0^{\circ}C$, respectively.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.19 no.1
• /
• pp.94-131
• /
• 2007

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 2004 and 2005 has been done. Focus has been put on current status of research in the aspect of heating, cooling, air-conditioning, ventilation, sanitation and building environment. The conclusions are as follows. (1) Most of fundamental studies on fluid flow were related with heat transportation of facilities. Drop formation and rivulet flow on solid surfaces were interesting topics related with condensation augmentation. Research on micro environment considering flow, heat, humidity was also interesting for comfortable living environment. It can be extended considering biological aspects. Development of fans and blowers of high performance and low noise were continuing topics. Well developed CFD and flow visualization(PIV, PTV and LDV methods) technologies were widely applied for developing facilities and their systems. (2) The research trends of the previous two yews are surveyed as groups of natural convection, forced convection, electronic cooling, heat transfer enhancement, frosting and defrosting, thermal properties, etc. New research topics introduced include natural convection heat transfer enhancement using nanofluid, supercritical cooling performance or oil miscibility of $CO_2$, enthalpy heat exchanger for heat recovery, heat transfer enhancement in a plate heat exchanger using fluid resonance. (3) The literature for the last two years($2004{\sim}2005$) is reviewed in the areas of heat pump, ice and water storage, cycle analysis and reused energy including geothermal, solar and unused energy). The research on cycle analysis and experiments for $CO_2$ was extensively carried out to replace the Ozone depleting and global warming refrigerants such as HFC and HCFC refrigerants. From the year of 2005, the Gas Engine Heat Pump(GHP) has been paid attention from the viewpoint of the gas cooling application. The heat pipe was focused on the performance improvement by the parametric analysis and the heat recovery applications. The storage systems were studied on the performance enhancement of the storage tank and cost analysis for heating and cooling applications. In the area of unused energy, the hybrid systems were extensively introduced and the life cycle cost analysis(LCCA) for the unused energy systems was also intensively carried out. (4) Recent studies of various refrigeration and air-conditioning systems have focused on the system performance and efficiency enhancement. Heat transfer characteristics during evaporation and condensation are investigated for several tube shapes and of alternative refrigerants including carbon dioxide. Efficiency of various compressors and expansion devices are also dealt with for better modeling and, in particular, performance improvement. Thermoelectric module and cooling systems are analyzed theoretically and experimentally. (5) According to the review of recent studies on ventilation systems, an appropriate ventilation systems including machenical and natural are required to satisfied the level of IAQ. Also, an recent studies on air-conditioning and absorption refrigeration systems, it has mainly focused on distribution and dehumidification of indoor air to improve the performance were carried out. (6) Based on a review of recent studies on indoor environment and building service systems, it is noticed that research issues have mainly focused on optimal thermal comfort, improvement of indoor air Quality and many innovative systems such as air-barrier type perimeter-less system with UFAC, radiant floor heating and cooling system and etc. New approaches are highlighted for improving indoor environmental condition as well as minimizing energy consumption, various activities of building control and operation strategy and energy performance analysis for economic evaluation.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.31 no.5
• /
• pp.770-774
• /
• 2002

The effect of mixing ratio of materials and their retort processing conditions on the physical properties and preference of oyster porridge were investigated. Rice gave adequate viscosity (about 800 cp) to the porridge as it was used 10～12% level and half of it was ground. Potato starch, waxy corn starch, and Perfectamyl AC showed small variation in viscosity unrelated to the temperature, that was a good condition for high quality porridge. Especially, waxy corn starch had a good property for retort porridge because its viscosity was maintained high during the processing and decreased to preferable one after processing. Purity CSC, modified starch gave gum-like texture and didn't cause water-separation much after freezing and thawing treatment of the porridge. Therefore, it was good for enhancing the physical property of the porridge as a co-additive of waxy corn starch when it was used at quarter level of waxy corn starch. Xanthan gum increased dispersibility of materials and it was useful for stabilizing physical quality of the porridge without affecting preference when it was used below 0.2% concentration. As a result, the optimal material-mixing ratio was determined as rice 10% (50% of it was ground), waxy corn starch 1.5%, Purity CSC 0.5%, xmthan gum 0.2%, salt 0.3%, and water 87.5%. Oyster's porridge, retort processed with this recipe, showed stable physical property after 6 month storage at room temperature.

• Journal of Soil and Groundwater Environment
• /
• v.17 no.2
• /
• pp.15-21
• /
• 2012

MTBE (Methyl tertiary-butyl ether) has been commonly used as an octane enhancer to replace tetraethyl lead in gasoline, because MTBE increases the efficiency of combustion and decreases the emission of carbon monoxide. However, MTBE has been found in groundwater from the fuel spills and leaks in the UST (Underground Storage Tank). Fenton's oxidation, an advanced oxidation catalyzed with ferrous iron, is successful in removing MTBE in groundwater. However, Fenton's oxidation requires the continuous addition of dissolved $Fe^{2+}$. Zero-valent iron is available as a source of catalytic ferrous iron of MFO (Modified Fenton's Oxidation) and has been studied for use in PRBs (Permeable Reactive Barriers) as a reactive material. Therefore, this study investigated the condition of optimization in MFO-PRBs using waste zero-valent iron (ZVI) with the waste steel scrap to treat MTBE contaminated groundwater. Batch tests were examined to find optimal molar ratio of MTBE : $H_2O_2$ on extent to degradation of MTBE in groundwater at pH 7 with 10% waste ZVI. As the results, the ratio of optimization of MTBE to hydrogen peroxide for MFO was determined to be 1:300[mM]. The column experiment was conducted to know applicability of MFO-PRBs for MTBE remediation in groundwater. As the results of column test, MTBE was removed 87% of the initial concentration during 120days of operational period. Interestingly, MTBE was degraded not only within waste ZVI column but also within sand column. It means the aquifer may affect continuously the MTBE contaminated groundwater after throughout the waste ZVI barrier. The residual products showed acetone, TBF (Tert-butyl formate) and TBA (Tert-butyl acetate) during this test. The results of the present study showed that the recycled materials can be effectively used for not only a source of catalytic ferrous iron but also a reactive material of the MFO-PRBs to remove MTBE in groundwater.

• Microbiology and Biotechnology Letters
• /
• v.33 no.4
• /
• pp.248-254
• /
• 2005

One hundred thirty nine bacteria were isolated from rotten onions collected from main producing districts, Chang-Nyung, Eui-Ryung, and Ham-Yang in Korea. The $18\%$ (25 strains) of bacterial isolates have carboxymethylcellulase (CMCase) activity and the $53\%$ (74 strains) have polygalacturonase (PGase) activity. Thirty one among randomly selected 45 strains of PGase producing bacteria have pathogenicity to onions. The isolates were classified into Pseudomonas sp. (18 strains), Bacillus sp. (11 strains), Yers-inia sp. (7 strains), and others (9 strains) on the basis of FAMEs patterns. Eighteen strains of Pseudomonas sp. were mainly divided into three cluster in the dendrogram and only the two clusters of them showed pathogenicity to onions. CMCase and PGase activities of Pseudomonas sp. weaker than those of Bacillus sp.. However, the pathogenicity of pseudomonas sp. to soften onions was stronger than that of Bacillus sp. Inoculation of $10^{2}$ cfu of Pseudomonas sp. gives rise to softening of onions. Pseudomonas sp. was identified as Pseudomonas gladioli by biochemical and physiological characteristics. P. gladioli is the first reported bacterium as a pathogen of onion in Korea. In low temperature, P. gladioli showed better growth and higher PGase activity than those of Bacillus sp. identified as Bacillus subtilis. And pH 9.0 is optimal pH for PGase activity of B. subtilis while that of P. gladioli is pH $5.0\∼6.0$ which is the acidity of onions. Taken together, P. gladioli may be a main pathogene of onion rot during the cold storage condition.