• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 1998.10a
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• pp.83-106
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• 1998

This study was conducted to investigate the probiotics(acid and bile resistance, fermentation properties, viability, cholesterol assimilation, antimicrobial activity, antimutagenicity, and immunoactivation) of the strains of bifidobacteria isolated from healthy Koreans and to investigate the effects of oral administration of Bifidobacterium longum A-2 on the fecal microflora, ${\beta}-glucuronidase$ activity, pH values, Ammonia concentration. The experimental results are summarized as follows: The probiotics were tested for 23 strains including three commer챠al strains as controls. Compared to other strains, strains of A-2 and A-9 showed more acid resistance whereas A-2, A-5, A-13, A-14, A-18 and A-22 showed excellent bile resistances. The properties of bifidobacteria during fermentation were tested. Strains of A-1, A-2, A-3, A-4, A-6, and A-23 resulted in less than pH 4.5 and titratable acidity over 0.90 after 24 hr of fermentation. When the strains of A-2 was grown with glucose, maltose, and fructooligosaccharide, the acetic acid production were higher than with sorbitol and mannitol. The storage stability of the strains of A-2 and A-22 were tesed, indicating the strain A-2 was more stable over 10 days of storage at both $4^{\circ}C$ and $20^{\circ}C$ than A-22. The strains of A-8, A-10, A-11, A-12 and A-20 assimilated more than 30% of cholesterol included in the media. The strains of A-1 and A-2 showed antimicrobial activity against Sta. aureus. The antimutagenicity of the strains were also tested, showing that the mutation was suppressed more by three strains(A-2, A-12, and A-23). In addition, strain A-5 improved immunological activity(phagocytosis, $TNF-{\alpha}$, IL-6) more than other strains. In the effects of oral administration of Bif. longum A-2, the number of fecal bifidobacteria was siginificantly increased(p<0.01) and the level of fecal ${\beta}-glucuronidase$ also was siginificantly reduced(p<0.05). However there were no siginificant differences in the level of Lαctobacilli, Enterobacteriaceae, Clostridium perfringens, pH and ammonia by the administration. The results suggested that Bif. longum A-2 may be met the criteria for probiotics culture.

• Journal of the Korean Society of Groundwater Environment
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• v.7 no.3
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• pp.103-115
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• 2000

The formation of brown-colored precipitates is one of the serious problems frequently encountered in the development and supply of groundwater in Korea, because by it the water exceeds the drinking water standard in terms of color. taste. turbidity and dissolved iron concentration and of often results in scaling problem within the water supplying system. In groundwaters from the Pajoo area, brown precipitates are typically formed in a few hours after pumping-out. In this paper we examine the process of the brown precipitates' formation using the equilibrium thermodynamic and kinetic approaches, in order to understand the origin and geochemical pathway of the generation of turbidity in groundwater. The results of this study are used to suggest not only the proper pumping technique to minimize the formation of precipitates but also the optimal design of water treatment methods to improve the water quality. The bed-rock groundwater in the Pajoo area belongs to the Ca-$HCO_3$type that was evolved through water/rock (gneiss) interaction. Based on SEM-EDS and XRD analyses, the precipitates are identified as an amorphous, Fe-bearing oxides or hydroxides. By the use of multi-step filtration with pore sizes of 6, 4, 1, 0.45 and 0.2 $\mu\textrm{m}$, the precipitates mostly fall in the colloidal size (1 to 0.45 $\mu\textrm{m}$) but are concentrated (about 81%) in the range of 1 to 6 $\mu\textrm{m}$in teams of mass (weight) distribution. Large amounts of dissolved iron were possibly originated from dissolution of clinochlore in cataclasite which contains high amounts of Fe (up to 3 wt.%). The calculation of saturation index (using a computer code PHREEQC), as well as the examination of pH-Eh stability relations, also indicate that the final precipitates are Fe-oxy-hydroxide that is formed by the change of water chemistry (mainly, oxidation) due to the exposure to oxygen during the pumping-out of Fe(II)-bearing, reduced groundwater. After pumping-out, the groundwater shows the progressive decreases of pH, DO and alkalinity with elapsed time. However, turbidity increases and then decreases with time. The decrease of dissolved Fe concentration as a function of elapsed time after pumping-out is expressed as a regression equation Fe(II)=10.l exp(-0.0009t). The oxidation reaction due to the influx of free oxygen during the pumping and storage of groundwater results in the formation of brown precipitates, which is dependent on time, $Po_2$and pH. In order to obtain drinkable water quality, therefore, the precipitates should be removed by filtering after the stepwise storage and aeration in tanks with sufficient volume for sufficient time. Particle size distribution data also suggest that step-wise filtration would be cost-effective. To minimize the scaling within wells, the continued (if possible) pumping within the optimum pumping rate is recommended because this technique will be most effective for minimizing the mixing between deep Fe(II)-rich water and shallow $O_2$-rich water. The simultaneous pumping of shallow $O_2$-rich water in different wells is also recommended.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.5
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• pp.353-360
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• 1984

As an effort to expand the utilization of mackerel which has been thought disadvantageous to processors due to the defects in bloody dark color of meat, high content of lipid, and low stability of protein, and to develope a new type of product, so called, preservative fish meat paste, the processing method was studied in which dielectric heating was applied by means of cooking, pasteurization, dehydration, and control of water activity. The principle of this method is based on that dielectric heating can initiate a rapid dispersion or displacement of moisture in the meat tissue so that the level of water acivity can be controlled by dehydration with hot air meanwhile the product is cooked, pasteurized, and texturized. And the product is finally heated with electric heaters and vacuum sealed to stabilize water activity and storage stability. In present paper, a formula for preparing the fish meat-stach paste, the conditions of dielectric heating and dehydration, shape and size of the product, and other parameters were tested to optimize the process operation. A formula of the fish meat-starch paste to provide proper textural properties and water activity was $10\%$ starch, $1.5\%$ salt, $3\%$ soybean, $0.6\%$ MSG, $2\%$ sucrose, and $3\%$ sorbitol against the weight of fish meat. A proper shape and size of the product to avoid foaming and case hardening during heating was sliced disc of 8 cm $diameter{\times}0.8$ cm thickness or $10{\times}10$ cm square plate with 1.0 cm thickness. The disc shape was recommended because it resulted more uniform heating, minimum foaming and case hardening. And it was also advantageous that disc was simply provided when the fish meat disc was stuffed in the same, solidified in boiling water for 2 to 3 minutes, and sliced. Condition of dielectric heating was critical to decide the levels of sterility, water activity, and textural property of the product. The temperature at the center of the meat disc slices was raised up to $95^{\circ}C$ in 1.5 minutes so that continuous exposure to microwave caused expanded tissue and hardening ending up with a higher water content. Heating for 5 to 6 minutes was adequate to yield the final water activity of 0.86 to 0.83(35 to $40\%$ moisture). It is important, however, that heating had to be done periodically, for instance, in the manner of 2.0, 1.5, 1.5, and 1.0 minute to give enough time to displace or evaporate moisture from the meat tissue. The product was dehydrated for 2 to 3 minutes by hot air of $60^{\circ}C$, 3 to 5m/sec and finally exposed to electric heaters for 5 to 6 minutes until the surface was roasted deep brown. These conditions of heating and dehydration resulted in a complete reduction of total plate count from an initial count of $5.3{\times}10^6/g$ to less than $3{\times}10^2/g$. General composition of the product was $40.1\%$ moisture, $20.8\%$ protein, $17.4\%$ lipid, $16.2\%$ carbohydrate, and $5.5\%$ ash. Textural properties revealed folding test AA, hardness 42, cohesiveness 0.53, toughness 4.6, and elasticity 0.8.

• Journal of the Korean Society of Food Culture
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• v.7 no.3
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• pp.259-270
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• 1992

The changes in life style today appear many ways. Many housewives turn away from home preparation of the time consuming traditional foods, such as 'Andong sikhe'. The importance, however, of succeeding the traditional cuisines is getting appreciated widely nowadays. This study aimed to investigate the preparation of Andong sikhe by use of pure culture inoculation and the improvement of storage stability by the addition of stabilizers to the product. Lactobacillus delbreuckii was selected for the pure culture inoculation in the fermentation. The changes in chemical composition such as total acidity, sugar content, amino acid and various forms of nitrogen during fermentation were determined. The changes in pH of the product, the enzyme activities and the population of lactic acid bacteria were also followed in the process of fermentation. The Lactobacillus dominated in the beginning of the fermentation but the Streptococcus out numbered the former as the fermentation proceeded. The crude protein content increased up to the 4th day of fermentation but slowly decreased there after. The pH of the product rapidly decreased to 4.2 by the 2nd day of fermentation. The total acidity reached to the 0.38% by the 2nd day of fermentation and kept on increasing slowly during the fermentation. The free sugar consisted of 6 kinds including maltose and one unknown sugar. The amino form nitrogen increased up to 38.5mg% at the 2nd day of fermentation and the product tasted best at this time. The ammonia form nitrogen, water soluble and salt soluble protein decreased during fermentation. Proline and aspartic acid were the two major free amino acids. The free methionine increased while the free lysine decreased in the process of fermentation. The major amino acids of water soluble and salt soluble protein were glutamic acid and aspartic acid. The arginine content of salt soluble protein increased as the fermentation proceeded. Linoleic, palmitic and oleic acid were the three major fatty acids and occupy 90% or more of the total fatty acids. The activities of acid protease and liquefying amylase reached to the maximum at the 4th day of fermentation while those of saccharogenic amylase and lipase reached to the peak at the 2nd day of fermentation.

• Journal of Animal Science and Technology
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• v.47 no.6
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• pp.1017-1024
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• 2005

This study was investigated the effect of the length of stunning time on pH, water holding capacity(WHC), cooking loss(CL), meat color and incidence rate of blood spot in broiler carcass. One-hundred and forty broiler chickens were slaughtered by three different length of stunning times(5 sec., 8 sec., 11 sec.) with the same electrical frequency(255Hz) and 50 voltage in a commercial abattoir. The WBS values and cooking loss of breast muscle were increased with increasing the stunning time, while WHC of breast muscle were decreased. Lightness(L* value) and yellowness(b* value) scores of leg muscle and skin stunned with 50V, 255Hz, 8 sec, 11 sec. were higher than those of broilers stunned with 50V, 255Hz, 5sec(P<0.05). But, there was no significant difference in color on breast and wing muscle. In subjective evaluation, frequence of the first grade had a trend of being increased by extending the stunning time. There was only a few cases of PSE chicken with 0.02%, while blood spot was observed at the highest rate for the 5 sec. treatment. TBARS indicated that a longer length of stunning resulted in a higher rate of fat oxidation. This experiment demonstrated that the length of stunning time has a significant effect on meat quality and its stability during chiller storage.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.755-762
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• 2000

Physicochemical properties of commercial sweet potato starches manufactured by 7 different companies were investigated in comparison with corn and potato starches. Crude ash and protein content varied from 0.36 to 1.02%, and from 0.04 to 0.14% based on dry weight, respectively. The protein contents were relatively smaller than that of corn or potato starch. But whiteness of the sweet potato starches was less than that of corn or potato starch. Mean diameter of the sweet potato starch granules varied from 14.23 to $21.08\;{\mu}m$ depending on the company and all sweet potato starches showed bimodal size distributions. Pasting viscosity measured by Rapid Viscoanalyzer(RVA) also showed variations among the starches of different companies. The starch from D company in Korea had the lowest pasting temperature$(74.00^{\circ}C)$ whereas the starch from a phillippine company(P) did the highest one$(80.35^{\circ}C)$. The peak viscosity of sweet potato starches was higher than that of corn starch but lower than that of potato starch. The D company starch also showed the highest peak viscosity(2283 cp) among the starches tested. Paste breakdown by hot shearing ranged from 524 cp (S company) to 1279 cp (HL company). Textural properties of the starch gels appeared significantly different among the starches of different manufacturers. The greatest hardness of the gel was $137.90\;g_{f}$ at 1 day storage whereas the lowest value was $31.53\;g_{f}$. Except the starches from 2 companies (P and S), the sweet potato starches formed very soft and weak gels. P or S company starches formed the gels similar to potato starch. Syneresis by freeze-thawing treatments appeared less for sweet potato starch gels than that for corn starch gels, but greater than that for potato starch gel. The overall properties of the sweet potato starches varied by the manufacturing companies, and ranged between those of corn and potato starches.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.3
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• pp.434-441
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• 2015

To develop dough methods for improving bread making properties of Korean wheat flour, straight dough methods (SDM) and dough and sponge methods (DSM) were applied. The bread making properties such as weight of bread, specific volume, baking loss, crumb color, and texture were analyzed. In comparison of flour properties between Korean wheat flour and imported wheat flour by Farinograph, Korean wheat flour showed less gluten network form ability than imported wheat flour. The dough making method affected bread quality such as weight of bread, specific volume, and baking loss. SDM had a more desirable effect on bread quality. Crumb color was lighter in bread made with Korean wheat flour compared to imported wheat flour, whereas dough making method did not affect crumb color. In consumer acceptance analysis, bread made by DSM showed higher consumer acceptance than that made by SDM. Regarding physicochemical changes during storage, bread made by SDM using Korean wheat flour showed higher chewiness, brittleness, and hardness than that made by imported wheat flour. However, bread made by DSM showed similar chewiness as bread made by SDM using imported wheat flour. The bread making properties of bread made by DSM is improved versus that of bread made with Korean wheat flour.

• Korean Journal of Poultry Science
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• v.41 no.2
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• pp.135-142
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• 2014

This study was conducted to evaluate dietary effects of Marigold extract on laying performance, egg quality, oxidative stability of egg yolk and lutein transfer into chicken eggs. A total of one-hundred eighty nine 55-wk-old Hy-Line Brown layers were divided into seven groups and fed control diet or each experimental diet containing 0.1, 0.3, 0.5, 1.0, 1.5 or 2.0% Marigold extract. Egg production, egg weight and daily egg mass were not affected by dietary treatments. The yolk colors in groups fed diets containing Marigold extract were significantly higher than that of control. The Haugh unit were tended to be improved by feeding of diets containing Marigold extract although there were no significant difference in egg shell strength and thickness. The MDA (malondialdehyde) contents in groups fed diets containing Marigold extract above 0.5% were significantly reduced than that of control. After 14d of storage, the Haugh unit values in groups feed diets containing 0.3 and 1.0% Marigold extract were significantly higher than that of control (p<0.05). The concentration of lutein in egg yolk increased by feeding of Marigold extract. When 2% Marigold extract was supplemented to the diet, lutein content of egg was increased as much as 1.71 mg/60 g. These results indicated that the use of Marigold extract in layer diets was effective in egg quality and for the production of lutein fortified eggs.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.12
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• pp.1847-1855
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• 2015

Supercritical carbon dioxide ($SC-CO_2$) treatment has been becoming an important method for substituting the use of organic solvents for samples extraction prior to analysis due to its low toxicity, ease of handling, low cost of disposal etc. Freeze-dried bovine liver was treated with $SC-CO_2$ under different pressures (200, 300, and 450 bar) in order to investigate effects on physicochemical properties and reduction of microbial load. The yield of lipid extraction from bovine liver by $SC-CO_2$ treatment increased with increasing pressure, with values of 84, 86, and 90% in response to 200, 300, and 450 bar, respectively. Results of high performance liquid chromatography analysis showed that vitamin A and coenzyme $Q_{10}$ ($CoQ_{10}$), which is soluble in lipid, were almost removed from bovine liver by $SC-CO_2$ treatment. Saturated fatty acids ratio of bovine liver decreased with increasing pressure, whereas polyunsaturated fatty acids increased with increasing pressure. Total content of amino acids in bovine liver treated by $SC-CO_2$ was less than that of the control sample without treatment. The number of aerobic bacteria in bovine liver, which was stored at $5^{\circ}C$ for 5 days and freeze-dried, decreased from 6.2 to 4.2 log CFU/g by $SC-CO_2$ treatment at 100 bar for 3 h. Interestingly, coliform bacteria were not found in the bovine liver sample by $SC-CO_2$ at 100 bar for 3 h under all storage conditions. This indicates that $SC-CO_2$ treatment can effectively reduce coliform bacteria in the food matrix even at low moisture. In conclusion, freeze-dried bovine liver by proper $SC-CO_2$ treatment may be used as a potential high protein source, with increasing microbial safety and stability of lipid oxidation.

• Journal of Soil and Groundwater Environment
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• v.11 no.6
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• pp.69-75
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• 2006

Improper disposal of petroleum and spills from underground storage tanks have created large areas with highly toxic contamination of the soil and groundwater. Methyl tert-butyl ether (MTBE) is widely used as a fuel additive because of its advantageous properties of increasing the octane value and reducing carbon monoxide and hydrocarbon exhausts. However, MTBE is categorized as a possible human carcinogen. This research investigated the Modified Photo-Fenton system which is based on the Modified Fenton reaction and UV light irradiation. The Modified Fenton reaction is effective for MTBE degradation near a neutral pH, using the ferric ion complex composed of a ferric ion and environmentally friendly organic chelating agents. This research was intended to treat high concentrations of MTBE; thus, 1,000 mg/L MTBE was chosen. The objectives of this research are to find the optimal reaction conditions and to elucidate the kinetic and mechanism of MTBE degradation by the Modified Photo-Fenton reaction. Based on the results of experiments, citrate was chosen among eight chelating agents as the candidate for the Modified Photo-Fenton reaction because it has a relatively higher final pH and MTBE removal efficiency than the others, and it has a relatively low toxicity and is rapidly biodegradable. MTBE degradation was found to follow pseudo-first-order kinetics. Under the optimum conditions, [$Fe^{3+}$] : [Citrate] = 1 mM: 4 mM, 3% $H_2O_2$, 17.4 kWh/L UV dose, and initial pH 6.0, the 1000 ppm MTBE was degraded by 86.75% within 6 hours and 99.99% within 16 hours. The final pH value was 6.02. The degradation mechanism of MTBE by the Modified Photo-Fenton Reaction included two diverse pathways and tert-butyl formate (TBF) was identified to be the major degradation intermediate. Attributed to the high solubility, stability, and reactivity of the ferric-citrate complexes in the near neutral condition, this Modified Photo-Fenton reaction is a promising treatment process for high concentrations of MTBE under or near a neutral pH.