• Journal of Microbiology and Biotechnology
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• v.33 no.1
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• pp.106-113
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• 2023

The supply of microbiological risk-free water is essential to keep food safety and public hygiene. And removal, inactivation, and destruction of microorganisms in drinking water are key for ensuring safety in the food industry. Ultraviolet-C (UV-C) irradiation is an attractive method for efficient disinfection of water without generating toxicity and adversely affecting human health. In this study, the disinfection efficiencies of UV-C irradiation on Shigella flexneri (Gram negative) and Listeria monocytogenes (Gram positive) at various concentrations in drinking water were evaluated using a water purifier. Their morphological and physiological characteristics after UV-C irradiation were observed using fluorescence microscopy and flow cytometry combined with live/dead staining. UV-C irradiation (254 nm wavelength, irradiation dose: 40 mJ/cm²) at a water flow velocity of 3.4 L/min showed disinfection ability on both bacteria up to 10⁸ CFU/4 L. And flow cytometric analysis showed different physiological shift between S. flexneri and L. monocytogenes after UV-C irradiation, but no significant shift of morphology in both bacteria. In addition, each bacterium revealed different characteristics with time-course observation after UV-C irradiation: L. monocytogenes dramatically changed its physiological feature and seemed to reach maximum damage at 4 h and then recovered, whereas S. flexneri seemed to gradually die over time. This study revealed that UV-C irradiation of water purifiers is effective in disinfecting microbial contaminants in drinking water and provides basic information on bacterial features/responses after UV-C irradiation.

• Food Science and Biotechnology
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• v.18 no.2
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• pp.456-462
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• 2009

In comparison to processed wheat flour products, there is no established method for determining the water absorption of rye flour. The aim of this study was to work out a method using the Planetary mixer P 600 for the determination of water absorption (WA) and the rheological properties in rye dough made from rye flours of 4 different types (I-IV). In the correlation analysis showed that WA had positive correlation with ash, beginning of gelatinization, $125-160{\mu}m$ particles, sedimentation values at 20 and 25 min, bread yield, pH, and total titratable acidity, but had negative correlation with initial viscosity, gelatinization maximum, viscosities on swelling at 25, 28, and $31^{\circ}C$. The WA determined by the Planetary mixer P 600 agreed well with the experimental baking tests.

• Journal of Korean Society on Water Environment
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• v.36 no.2
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• pp.148-152
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• 2020

The quantitative accuracy of dry rehydratable film method was compared with the standard culture method to analyze the applicability of dry rehydratable film in the total aerobic bacteria test for water. The materials used in this study were 500 cases of water and were tested according to the Korean official test method for drinking water. The mean value of the total aerobic bacteria in plate count agar(PCA) and MC-Media Pad AC(MAC) were 2.6 ± 1.1 Log cfu/mL and 2.6 ± 1.2 Log cfu/mL. The p value and correlation coefficient(R²) were 0.933 and 0.9985 between the PCA and MAC, respectively, indicating no significant difference and very high correlation. According to the water types, the p value and R² were 0.887 and 0.9911 in the PCA and MAC. In the purified water, the p value was 0.973 and R² was 0.9934 in the PCA and MAC of other water. In each type of water, there were no significant differences between the PCA and MAC, and the correlation was very high. Thus, it is suggested that the MAC would be available for total aerobic bacteria test for water.

• Journal of the Korean Society of Food Culture
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• v.32 no.2
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• pp.135-143
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• 2017

This study evaluated the quality characteristics of semi-dried noodles prepared with different water contents (wet noodles; 32, 24, 22, 20%, dry noodles; 12%). The drying process was carried out in a drying chamber at $13{\sim}18^{\circ}C$ temperature and 75~95% humidity. The proximate composition of Korean wheat flour was as follows: water $22.1{\pm}3.64%$, protein $8.6{\pm}0.13%$, fat $1.3{\pm}0.10%$, ash $0.7{\pm}0.02%$, carbohydrates $67.3{\pm}0.10%$. As water contents decreased, both L and b values significantly decreased before cooking of noodles, whereas L, a, and b values were not significantly different after cooking of noodles. Weight, water absorption, and volume of cooked noodles significantly increased as water content decreased, whereas turbidity of soup was not significantly different. Cutting hardness before cooking of noodles significantly increased as water content decreased. Sections of noodles after cooking by SEM (scanning electron microscopy) showed roughness and fewer round starch particles as water content decreased. For overall preferences according to the sensory evaluation, noodles prepared with different water contents were not significantly different. According to the results, semidried noodles have development potential to complement the disadvantages of both wet noodles and dry noodles.

• The Korean Journal of Food And Nutrition
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• v.19 no.4
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• pp.515-525
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• 2006

Survey was done to total 250 people to analyze characteristics of water quality in 5 widely used mineral water springs-(Teajosan(a), Leechungmukong(b), Onju(c), Yeongin(d), Crown(e))-in Chung-nam area and local mineral water usage. And the content of mineral and physico-chemical properties were compared in 5 sites. The largest users of mineral water spring was $40{\sim}50's$ of ages. Among those mineral water spring users, 52.5% had regular dietary habit and 32% showed improvement in lift habit after using mineral water spring. The mineral water spring users were engaged in student, housewife, professional, self-employed, etc. Those who were highly interested in health were likely to use mineral spring water more often regardless of age and occupation. Five mineral water springs differed in contents of mineral. The average content of minerals was $Ca\;28.5mg/{\ell},\;K\;1.5mg/{\ell},\;Mg\;5.3mg/{\ell},\;Na\;14.3mg/{\ell}$. 'K index' was an indicator of healthy water, and 'O index' was an indicator of tasty water. According to K indek and O index, waters of a b, c and e area were classified as 'tasty and healthy water', and water of e area had the highest values in both K and O index d area was classified as 'tasty water.'

• Food Science and Biotechnology
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• v.17 no.1
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• pp.72-79
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• 2008

In this study, changes in the physicochemical properties and functional components of uncooked foods, including carrots, cabbage, shiitake (Lentinus edodes) and white button (Agaricus bisporus) mushrooms, sea mustard, and laver treated with electrolyzed water were investigated. No changes were observed in the primary compositions of any of the materials that were hot air- or freeze-dried after being treated with electrolyzed water. The lightness (L), redness (a), and yellowness (b) values of the carrots, shiitake, and laver were not affected by drying, while changes did occur in the cabbage (L-, a-, and b-values), mushrooms (a-value), and sea mustard (b-value) specimens that were hot air- or freeze-dried following the treatments with electrolyzed water. The dietary fiber contents of all the materials increased when they were hot air-dried. Vitamin C content decreased when the samples were treated with alkalic electrolyzed water. No changes occurred in the lectin, $\beta$-carotene, or total phenolic compound contents after the electrolyzed water treatments, suggesting that electrolyzed water could be used effectively as a pasteurization step for uncooked carrots, cabbage, shiitake and white button mushrooms, sea mustard, and laver.

• Journal of Environmental Health Sciences
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• v.27 no.4
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• pp.107-114
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• 2001

The number of covered carts selling snack foods along the streets are increasing in Korea and people enjoy eating foods at these carts. However there are only a few reports on the contamination or sanitary condition of the food carts. This study was performed to investigate the sanitary condition of food and water at the street food carts in the eight major areas of a city. Water and several kinds of food, kimbop(laver rollers) ddeokbokki(stir fried rice cake in hot pepper paste) oemuk(fish cakes) fish cake soup, and soy sauce were collected from four street carts from each of the 8 areas from June to August in 2001 The standard plate counts(SPCs) and coliform groups were examined according to the Food Code of Korea. The nufitness rates of SPCs of the samples were 0~15.6%: 15.6% in kimbop:6.3% in fish cake soup; and 3.1% in water samples SPCs were not detected in some samples. of ddeokbokki, oemuk and soy sauce. The unfitness rates of coliform groups were 0~62.5%; 46.9% in kimbop; 6.3% in ddeokbokki,;22.9% in oemuk 62.5% in fish cake soup; and 3.1% in soy sauce. Coliform groups were not detected in water sample The numbers and unfitness rates of SPCs and coliform groups showed increasing tendencies over time within a day. The higher the air temperature was the more increase of bacteriological growth was observed These results indicate that the level of bacteriological contamination of foods and water in the street carts should be monitored and strict inspection is necessary. There should be legal consequences for serving contaminated food to the public.

• Food Science and Biotechnology
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• v.14 no.1
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• pp.108-111
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• 2005

To improve water-resistance and physical properties of sodium alginate film, effects of sodium alginate and plasticizer concentrations, divalent cation types and concentrations, and immersion time of films into divalent cation solutions on sodium alginate films were evaluated, based on elongation strength (ES), elongation rate (E), water vapor permeability (WVP), and water solubility (WS). Film made from 1.5% sodium alginate solution (w/w) had low WVP and WS, which are optimal characteristics for application of film preparation. Addition of plasticizer increased E and WS. Less than 2% $CaCl_2$ addition and 15min immersion time reduced WVP, WS, and E significantly (p<0.05). Sodium alginate films treated with $CuCl_2$, and $ZnCl_2$ solutions had lower WVP and WS, whereas $MgCl_2$ had no influence on improving water resistance of films.

• Preventive Nutrition and Food Science
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• v.9 no.2
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• pp.121-125
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• 2004

Effects of chemical treatment with a citric acid solution or ozonated water on microbiological changes in lettuce and cabbage during storage were studied. Fresh lettuce and cabbage samples were cut into small pieces and treated by soaking in either ozonated water or a citric acid solution. After treatment, populations of total bacteria, yeast and mold, and E. coli were determined. Numbers of microorganisms increased during storage, but ozonated water and citric acid treatments retarded the increase in microbial growth. Among treatments, 1 % citric acid treatment was the most effective in terms of microbiological change and inhibition of polyphenoloxidase (PPO). For lettuce, citric acid treatment decreased the microbial growth overall by 1.5 log CFU/g and inhibited the PPO activity by 80%. These results indicate that chemical-treated lettuce and cabbage retained a better quality than those of the control during storage.

• Food Science and Biotechnology
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• v.18 no.3
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• pp.808-812
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• 2009

The ${\alpha}-glucosidase$ inhibitory and antioxidant effects of water chestnut (Trapa japonica Flerov.) were assessed to explore its possible use as an anti-diabetic agent. Methanol extracts of the fruit shell and meat of water chestnut were assayed for inhibitory activity against yeast ${\alpha}-glucosidase$ and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. Effect of fruit shell extract on postprandial glucose response was assessed. Compared with fruit meat, shell extract showed stronger inhibition against ${\alpha}-glucosidase$ with an $IC_{50}$ of 273 ${\mu}g/mL$. Oral administration of fruit shell extract (500 mg/kg) significantly lowered the postprandial area under the glucose response curve to starch (1 g/kg) in streptozotocin (STZ)-induced diabetic rats (p<0.01). Compared with fruit meat, shell extract showed stronger scavenging activity against DPPH, with an $IC_{50}$ of 27.1 ${\mu}g/mL$. The results indicate that the fruit shell of water chestnut was effective in controlling postprandial hyperglycemia and exerted an antioxidant effect. Therefore, water chestnut may be useful in treating diabetes.