• 수산해양교육연구
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• 제28권6호
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• pp.1573-1580
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• 2016

The disease occurred in cultured eel (Anguilla japonica) in a recirculatory culture system without any separated filtration apparatus. As the pond had a high level of nitrite with $60mg/{\ell}$, 1% NaCl was added to reduce nitrite toxicity to eel. The first outbreak was observed a week after the NaCl treatment and continued for 10 days. Accumulated mortality was about 0.2-0.5%. Affected fish ranged from 150-350 g were usually anorexic and exhibited yellow colour in the skin of the abdominal region and at the base of pectoral fins, as well as in the eyes. In a few individuals with severe symptoms, the lateral skin was also yellowish. The spleen, kidney, muscle and gall bladder were yellowish and the liver was pale-yellow colour but green on the posterior part. The gall bladder was shrunken without bile. Some abnormal erythrocytes such as "tear drop" cells (dacrocyte) were observed in peripheral blood smears stained with May-Grunwald Giemsa. Hematocrit values and hemoglobin contents in the jaundiced eel were significantly lower compared with apparently heathy eel. Severe haemosiderosis accompanied by erythrophagocytosis was found in the kidney and spleen. Haemosiderin deposits were observed in macrophages of the haematopoietic tissue of the kidney and in the splenocytes. But no significant alterations were found in the hepatic cells. In this study we report the first outbreak of jaundice in cultured eel in Korea. Pathological and hematological investigations suggested that severe hemolysis may resulted in jaundice in eel although the cause of hemolytic jaundice was not identified in this study.

• 한국식품영양학회지
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• 제21권1호
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• pp.35-42
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• 2008

To develop physiological functionality of Omija extracted with water was evaluated on antioxidative activity. Omija, high acid material with pH 3.6, contain $57.5{\pm}1.03%$ of moisture, and $18.8{\pm}0.12%$ of crude fat. This material have $12.6{\pm}0.04%$ of carbohydrate and $11.1{\pm}0.07%$ of crude protein as well, but ash and crude protein contents were found less than 10%. 10 mineral contents were also found, too; K and Ca showed the highest level, then Al, Mg, Na and Mn were followed. In composition amino acid contents, glutamic acid took the largest portion, $131.7{\pm}1.3$ mg/100 g, aspartic acid $51.5{\pm}0.6%$, and other composition amino acid under 50%. In case of free sugar contents, 7 types were found. Most of them were glucose and fructose. Total phenolic compounds showed the highest level, $2,862.6{\pm}31.7$ mg/100 g. $197.8{\pm}14.6$ mg/100 g of flavonoid and $225.6{\pm}18.2$ mg/100 g were included. In terms of electron donating ability, radical scavenging ability activated as the amount of Omija extract increased. In particular, Omija extract in 1,000 ${\mu}g/m{\ell}$ demonstrated almost similar electron donating ability, $72.4{\pm}0.21%$, to BHT. It was also found that antioxidant activities of electron donating ability, SOD-like ability, hydroxyl radical scavenging ability and nitrite scavenging ability were highly promoted as Omija extract concentration increased. The nitrite scavenging ability was significant when the extract belonged to strong acid region and doping concentrations increased.

• 한국식품영양학회지
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• 제33권1호
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• pp.64-73
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• 2020

The purpose of this study was to investigate the antioxidant activity and β-glucan content of extracts extracted by varying the temperature at 30, 55 and 80℃ after hot air drying or freeze drying of Pleurotus ostreatus and Pleurotus eryngii. For the analysis antioxidant activity of each mushroom, β-glucan, total phenol, flavonoid contents, and DPPH·ABTS⁺·Nitrite assay were measured. Also, the β-glucan content, total flavonoid content and ABTS⁺ scavenging activity increased with freeze drying rather than hot air drying, and increased with increasing extraction temperature in both mushrooms. However, the total phenol and nitrite scavenging activity increased with hot air drying rather than freeze drying, and decreased with increasing temperature in both mushrooms. DPPH scavenging activity was not significant in both mushrooms, but decreased with increasing extraction temperature. Pearson's correlations between total flavonoid content and antioxidant activities were r=0.719~0.753 (p<0.01). As a result, the β-glucan content, total flavonoid content, and ABTS radical cation scavenging activity were highest during freeze drying and extraction at 80℃. And the highest total phenol content, DPPH radical scavenging activity and nitrite scavenging activity were obtained during hot air drying and extraction at 30℃.

• International Journal of Concrete Structures and Materials
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• 제5권1호
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• pp.65-73
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• 2011

Corrosion of steel bars embedded in concrete admixed with 0%, 2% and 4% calcium nitrite (CN), having compressive strengths of 20 and 46 MPa was investigated. Reinforced concrete specimens were immersed in 3% NaCl solutions for 1, 7 and 15 days where 0.4A external current was applied to accelerate the chemical reactions. Corrosion rate was measured by retrieving electrochemical data via potentiodynamic polarization technique. Pull-out tests of reinforced concrete specimens were then conducted to assess the corroded steel-concrete bond characteristics. Experimental results showed that corrosion rate of steel bars and steel-concrete bond strength were dependent on concrete strength, amount of CN added and accelerated corrosion period. As concrete strength increased from 20 to 46 MPa, corrosion rate of embedded steel decreased. The addition of 2% CN to concrete of 20 MPa was not effective in retarding corrosion of steel at long time of exposure. However, the combination of higher strength concrete and 2% or 4% CN appear to be a desirable approach to reduce the effect of chloride-induced corrosion of steel reinforcement. After 1 day of corrosion acceleration, specimens without CN showed higher bond strength in both concrete mixes than those with CN. After 7 and 15 days of exposure, the higher concentration of CN, the higher bond strength in both concrete mixes achieved, except for the concrete specimen of 20 MPa compressive strength with 2% CN that recorded the highest deterioration in bond strength at 15 days of exposure.

• 한국식품영양학회지
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• 제21권2호
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• pp.148-156
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• 2008

The purpose of this study was to analyze the changes in physicochemical characteristics and NDMA formation of Orostachys japonicus A. Berger according to harvest times. The results showed moisture, carbohydrate, crude fiber and crude protein contents of <$48.5{\pm}1.4%$, $38.2{\pm}1.2%$, $l5.8{\pm}0.4%$ and $13.2{\pm}0.6%$ respectively. The total mineral content was 4,817.1 mg/100 g, where Ca was highest($2,577.0{\pm}3.2$ mg/100 g), followed by K, Mg, Na, P and Fe. The composition amino acid of O. japonicus A. Berger showed high levels of glutamic acid and aspartic acid. And among the five free sugars detected, galactose and glucose were most abundant at $32.2{\pm}0.02$ mg/100 g and $25.3{\pm}0.1O$ mg/100 g, respectively. Upon comparing O. japonicus A. Berger extracts that came from plants harvested during $August{\sim}October$, total phenolic compound($2,703.l{\pm}5.2l{\sim}2,428.0{\pm}3.52$ mg/100 g) and flavonoid($634.2{\pm}2.33{\sim}1,324.6{\pm}1.87$ mg/100 g) contents were higher in the methanol extract than in the water extract. Also, within a reaction system, nitrite scavenging ability and NDMA inhibition were most effective at pH 2.5, and increased in proportion to the extract concentration. Finally, the methanol extract of O. japonicus A Berger harvested during $August{\sim}October$ had the highest nitrite scavenging and NDMA inhibition effects.

• KSBB Journal
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• 제26권2호
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• pp.151-156
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• 2011

For the development of functional food and cosmetics using the hot water extract of Undaria pinnatifida, the concentrations of vitamin, amino acid and element and activities of antioxidant and nitrite scavenging were investigated. The results are shown as follows: Vitamin C and E concentrations were 0.301 and 0.11 mg/100 g, respectively. Mineral concentrations were an order of Ca > Mg > K > Fe. The concentrations of total amino acids were an order of Glu > Ala > Val > Leu > Gly > Pro. Total phenol concentration and DPPH radical scavenging activity were increased with the increase of the concentration of extract. Especially, when the extract concentrationwas increased from 1.0 to 10.0 mg/mL, the total phenol concentration was increased from 0.043 to 0.125 OD 725 nm. DPPH radical scavenging activity at 50 mg/mL was 70.1%. The antioxidant activity of extract was stable in range of 80 to $140^{\circ}C$ and pH 3-9. The nitrite scavenging activity was increased with the decreaseof pH and the increase of it's extract concentration. Especially, it was 83.4% at 50 mg/mL (pH 1.2). These results showed that the hot water extract of U. pinnatifida can be applied to functional food and cosmetics.

• 환경위생공학
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• 제9권1호
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• pp.76-88
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• 1994

This study was carried out to investigate contents of nitrosamine precursors such as trite and dimethylamine( DMA ) in some foods. The diazo and Cu- dithiocarbamate melt were used for determination, respectively. The major affecting factors of Nnitrosodimethylamine( NDMA ) formation such as pH, contents of DMA and NaNO$_{2}$, other chemicals, and UV- ray in beverage were investigated in vitro. The contents of nitrite in meat sausage and meat ham were 6.44 ∼ 18.66ppm and 12.85- 39.95pp% respectively, And extremely low level was detected in a certain kind of fish sausage. The contents of DMA in meat sausage meat ham and fish sausage were 3.34∼15. 85ppm, 1.20∼7.10ppm and 7.38∼12.28ppm, respectively. The optimum pH for NDMA formation in vitro was 3.0. NDMA formation was rapidly occurred at high temperature and formed above 80% within 1 hour reaction. The formation of NDMA was increased in proportion to the concentration of DMA and the square of the nitrite concentration. 0.1 M of sodium citrate, sodium tartarated and sodium taiocyanate enhanced NDMA formation. But sodium chloride did not affect. However, 0.3M of ascorbic acid, erythroid acid, ascorbic, palmitate and propy, gallate inhibited NDMA formalion approximately 78%,81%,86% and 85%, respectively. Cow milk and soybean milk inhibited 35 ∼47% of NDMA formation but orange juice and apple juice enhanced 15 ∼64% of NDMA formation. The peak in HPLC for NDMA disappeared by irradiation of UV to prior formed NDMA This result suggest that NDMA was destroyed by UV irradiation.

• Journal of Microbiology and Biotechnology
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• 제17권3호
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• pp.445-453
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• 2007

The effect of an electrochemically generated oxidation-reduction potential and electric pulse on ethanol production and growth of Saccharomyces cerevisiae ATCC 26603 was experimented and compared with effects of electron mediators (neutral red, benzyl viologen, and thionine), chemical oxidants (hydrogen peroxide and hypochlorite), chemical reductants (sulfite and nitrite), oxygen, and hydrogen. The oxidation (anodic) and reduction (cathodic) potential and electric pulse activated ethanol production and growth, and changed the total soluble protein pattern of the test strain. Neutral red electrochemically reduced activated ethanol production and growth of the test strain, but benzyl viologen and thionine did not. Nitrite inhibited ethanol production but did not influence growth of the test strain. Hydrogen peroxide, hypochlorite, and sulfite did not influence ethanol production and growth of the test strain. Hydrogen and oxygen also did not influence the growth and ethanol production. It shows that the test strain may perceive electrochemically generated oxidation-reduction potential and electric pulse as an environmental factor.

• 한국식품영양과학회지
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• 제26권1호
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• pp.45-53
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• 1997

우리나라의 대표적인 염장 가공품인 고등어를 염장하는 과정중 아질산염을 100, 500 및 100mg/kg첨가할 경우 VBN, TMAO, TMA 및 DMA와 같은 아민류와 N-nitrosamine(NA)의 생성,NA의 생성과 아질산염과의 관계 등을 구명코져 고등어 염장 중 NA의 함량 변화를 GC-TEA로 분석하였고, 동시에 조리방법이 NA의 생성에 어떤 영향을 미치는 가를 실험하였다. 고등어 염장 중 휘발성 염기 질소는 염장 중 계속해서 증가하여 염장 50일 후에는 생시료에 비해 약 23.8배의 증가를 보였다. TMAO 질소는 3.7~21.0mg%, TMA 질소는 15.0 ~20.4mg%범위였으며 , 염장 및 조리과정 중 대부분의 시료에서 TMAO 질소는 약간 감소하는 반면에 TMA 질소는 계속해서 증가하는 경향이었다. DMA 질소는 염장 중 급증하는 경향을 보여 염장 50일 후에는 생시료에 비해 약 16.0배 증가하였다. 아질산염의 첨가가 DMA 질소의 생성에는 별다른 영향을 미치지 않았으나 조리 과정 중에는 상당량의 증가를 보였다. NDMA는 대조구에서 1.0$\mu\textrm{g}$/kg 이하였으나, 100mg/kg의 아질산염 처리구에서는 8.1~14.6$\mu\textrm{g}$/kg, 500mg/kg 처리구에서는 24.5~45.5$\mu\textrm{g}$/kg, 1000mg/kg 처리구에서는 53.8~77.2$\mu\textrm{g}$/kg 범위였으며, 조리시료에서는 3.3~12.6$\mu\textrm{g}$/kg의 범위였다. 일반적으로 전자레인지와 같은 간접적인 열원을 사용하여 조리한 경우보다 가스레인지, 연탄불과 같은 직접적인 열원으로 조리한 시료에서 그 증가폭이 가장 높았다.

• 한국식품저장유통학회지
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• 제11권3호
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• pp.388-393
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• 2004

생약재의 용매별 추출액에 대한 생리활성 측정 결과 총폴리페놀 함량은 모든 생약재가 50$\%$ ethanol 추출액에서 가장 우수하였으며, 생약재 별로는 감초의 50$\%$ ethanol 추출액이 2.23$\%$로 가장 높은 함량을 나타내었다. 전자공여 작용은 감초 water 추출액이 81.81$\%$로 가장 우수하였으며, 감초, 건강는 water 추출액이 두충, 건마늘, 인삼은 50$\%$ ethanol 추출액에서 다른 용매에 비해 높은 전자공여 효과를 나타내었다. Superoxide dismutase(SOD) 유사활성은 감초의 10$\%$ ethanol추출액이 42.75$\%$로 가장 높은 활성을 나타냈었고, 전마늘, 건강은 50$\%$ ethanol 추출액이 감초, 두충, 인삼은 water 추출액이 다른 용매에 비해 우수한 것으로 나타났다. 아질산염소거작용은 pH가 증가할 수록 소거율이 크게 감소하는 것으로 나타났다. 또한 용매별 소거능은 뚜렷한 차이를 보이지 않았지만 water 추출액이 다른 두 용매 추출액에 비해 소거능이 높은 것으로 나타났다. ACE 저해작용은 건강을 제외한 생약재 추출물에서 50$\%$ ethanol 추출물이 다른 용매에 비해 우수한 효과를 나타내었으며, 건마늘의 50$\%$ ethanol 추출물이 37.16$\%$로 가장 높은 저해 활성을 나타내었다. 용매별 효과는 50$\%$ ethanol 추출액이 다른 용매에 비해 ACE저해활성이 우수한 것으로 나타났다. 따라서 생약재의 종류에 따라 다름을 알 수 있다. 또한 기능성 효과를 확인함으로써 기능성 식품의 소재로의 이용가능성을 확인하였다.