• Journal of Food Hygiene and Safety
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• v.33 no.3
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• pp.168-175
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• 2018

The use of microwave-assisted extraction and an acid-base clean-up process to determine the amount of methylmercury (MeHg) in marine products was suggested in order to improve the complicated sample preparation process. The optimal conditions for microwave-assisted extraction was developed by using a 10% NaCl solution as an extraction solution, setting the extraction temperature at $50^{\circ}C$, and holding for 15 minutes to extract the MeHg in marine products. A NaOH solution was selected as a clean-up substitute instead of L-cysteine solution. Overall, 670 samples of marine products were analyzed for total mercury (Hg). Detection levels were in the range of $0.0006{\sim}0.3801{\mu}g/kg$. MeHg was analyzed and compared using the current food code and the proposed method for 49 samples which contained above 0.1 mg/kg of Hg. Detection ranges of methylmercury followed by the Korea Food Code and the proposed method were $75.25(ND{\sim}516.93){\mu}g/kg$ and $142.07(100.14{\sim}244.55){\mu}g/kg$, respectively. The total analytical time of proposed method was reduced by more than 25% compared with the current food code method.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.2
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• pp.261-266
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• 2009

All of the subjects of the investigation (n=141) were schools that have food services under direct management. The number of students who get food services at the schools were $1,001{\sim}1,500$ students with 46.8% investigation. In school food services, fried foods were highly preferred and the biggest merits of fried foods were (in order of highest importance) 'improvement of food services satisfaction'> 'source of calories supply'> 'easiness of cooking process'. Service frequency of fried food were in the order of 'twice a week'> 'three times a week'> 'once a week', and for the factors to decide service frequency of fried food, 'preference leaning on fried food', and 'excessive fat intake' were the most considered. The most considered factors in the case of choosing fried food were 'preference' and 'calories and nutritional value'. For the cautious steps during the frying process, 'keeping after frying' was picked the most, and the reasons were 'lack of containers to keep in appropriate temperature and quality' and 'time consuming'. For preference and service frequency of ingredients in fried foods, 'chicken' and 'pork' were very high. As the result, it was analyzed that preference by ingredients matched service in school lunches by using a ranking test. Total cooking and processing time of fried foods required in school lunches were approximately $237{\pm}99$ minutes ${\sim}291{\pm}141$ minutes which showed total required time was about same no matter what ingredients were used. As the result of comparing and analyzing the processes, vegetables took less thawing and frying time, but the processing time for vegetables was more complicated since handling time before frying was longer compared to meat. In the important management process by the main groups of fried foods, the frying process was the most cautious cooking process in the category of meat or fish and shellfish used as ingredients. In addition, if vegetables were used as ingredients, storing it after frying was the process that needed the most care.

• Food Science and Preservation
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• v.14 no.6
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• pp.662-668
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• 2007

Studies have shown that onions exhibit a wide variety of health-promoting properties. The health benefits by the onion have been attributed to its ability to scavenge free radicals, to reduce blood lipids, to lower blood pressure, and to inhibit platelet aggregation. This study was performed to investigate whether onion extract supplementation would affect the blood markers of ethanol-induced fatty liver in rats. Initially, male Sprague-Dawley rats were housed singly in a room of controlled temperature and lighting and had free access to a nutritionally adequate AIN-93G and deionized water. The rats were trained for meal feeding to prevent a decline in food intake, as inevitably observed following an ethanol feeding. After the training period, rats were weight-matched and assigned to the following three groups: 1) a control group, fed the AIN-93G diet alone (control); 2) an ethanol group, fed the AIN-93G diet with ethanol at 4 g/day/kg body weight (ethanol); and 3) an onion group, fed the AIN-93G diet with ethanol plus supplemental freeze-dried onion powder at 500 mg/day/rat (ethanol + onion). All three group were meal-fed 7.0 g of their respective diets at 0900 h and 7.5 g at 1600 h for 28 days. At 0, 2, and 4 wk, blood was collected via the orbital sinus and organs were collected following overnight food deprivation. Both control and experimental groups continually gained weight throughout the study. No significant differences in the weights of the liver, kidneys, heart, spleen, and testis were observed. However, the serum level of triglycerides was significantly increased by ethanol but significantly decreased by onion extract. The activities of serum glutamate oxaloacetate transaminase (GOT), glutamate pyruvate transaminase (GPT) at 4 wk were significantly increased by ethanol feeding but were significantly decreased by onion supplementation. However, no differences among groups were observed in the serum levels of alkaline phosphatase, gamma-glutamyl transpeptidase, bilirubin, and protein. These results provide that onion extract favorably affect alcoholic fatty liver by decreasing the serum concentration of triglyceride and the activities of GOT and GPT.

• Korean Journal of Poultry Science
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• v.16 no.3
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• pp.149-156
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• 1989

Two broiler experiments were carried out to determine whether supplementation of zeolite in the diet would affect broiler performance and economical efficiency. Day old male broiler chickens of Abor Acres strain were used. In the first experiment,60 birds were distributed into f groups of 10 birds each. Three groups of chickens were randomly placed on one of the following single-stage (0-6wks) experimental diets； control diet (non-supplemented) or 2% zeolite supplemented diet (supplemented to the control). In the second experiment,216 birds were distributed into 24 groups of 9 birds each. Eight groups of chickens were randomly placed on one of the 3 two-stage diet (starter；0-4wks, finisher；5-7wks)；control diet ($T_1$ , non-supplemented), 2% zeolite diet ($T_2$：isocaloric and isonitrogenous as $T_1$ ) and 2% zeolite supplemented diet ($T_3$, supplemented to the control). Birds were housed in the batteries, and feeds and water were fed ad libitum. The results of Experiment 1 showed that birds fed control diet were heavier than those fed 2% zeolite supplemented diet up to 4th wks of age. However, birds fed the latter grew more at 5th and 6th wk. Overall weight gain, feed intake and feed efficiency were not significantly different. The results of Experiment 2 showed that there were no significant differences in weight gains, feed intakes and feed efficiencies among treatments during starter, finisher to overall period. The moisture levels in excreta of the birds were significantly (P＜0.01) less when zeolite was included in the diets and those in excreta significantly (P ＜ 0.01) increased as the ambient temperature increased. Economical efficiency expressed in fed cost (won) required per kg weight gin were 346.55 (T$_3$),348.34 ($T_1$ ) and 359.85 ($T_2$).

• Korean Journal of Ecology and Environment
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• v.49 no.4
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• pp.354-374
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• 2016

This study explored spatiotemporal variability of water quality in correspondence with hydrometeorological factors in the five stations of Paldang Reservoir located in the Han River during 4 years from May 2012 to December 2015. Variability of basic water quality factors were largely related with seasonal fluctuations of hydrology. Temperature stratification occurred in the deep dam station, and prolonged hypoxia was observed during the draught year. Nitrogen nutrients were increased with decreasing inflow in which changing pattern of $NH_4$ reversed to $NO_3$ by the effect of treated wastewater effluent. Phosphorus increase was manifest during the period of high inflow or severe drought. Chl-a variation was reversely related with both flow change and AGP(algal growth potential) variations. Our study demonstrated that water quality variability in Paldang Reservoir was largely attributed to both natural and operational changes of inflow and outflow (including water intake) based on major pollution source of the treated wastewater (total amount of $472{\times}10^3m^3d^{-1}$) entering to the water system from watershed. In the process of water quality variability, meteorological (e.g., flood, typhoon, abnormal rainfall, scorching heat of summer) and hydrological factors (inflow and discharge) were likely to work dynamically with nutrients pulse, dilution, absorption, concentration and sedimentation. We underline comprehensive limnological study related to hydro-meteorolology to understand short- and long-term water quality variability in river-type large reservoir and suggest the necessity of P-free wastewater treatment for the effective measure of reducing pollution level of Paldang drinking water resource.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.160-168
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• 2021

This study was undertaken to determine the effect of different cooling systems on the performance and hair cortisol of sows under heat stress. During a 21-day experiment, a total of 40 multiparous sows (Landrace×Yorkshire; 242.84±2.89 kg) were allotted to 4 treatments, each with 10 replicates (1 sow per pen). The experimental treatments were CP (Cooling pad), AC (Air conditioner), SC (Snout cooling), and MS (Mist spray). We observed an increase in the average daily feed intake during lactation (p<0.05) in the CP and AC treatment groups. AC treatment had the highest (p<0.05) and SC treatment had the lowest (p<0.05) piglet weight at weaning. During lactation, sows administered SC and MS treatments had higher (p<0.05) hair cortisol accumulation, as compared with the AC and CP treatments. Hair cortisol accumulation in piglets during lactation was highest with MS treatment (p<0.05), and lowest after CP treatment (p<0.05). MS treatment had the highest (p<0.05), and AC treatment had the lowest (p<0.05) respiratory rate and rectal temperature during lactation. In conclusion, our results indicate that a cooling pad and air conditioning cooling system increases the productivity of a sow, as compared to snout cooling and mist spray cooling systems.

• Journal of Animal Science and Technology
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• v.45 no.2
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• pp.229-240
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• 2003

An in vitro test and a broiler feeding trial were conducted to test the effect of hydrothermal treatment of wheat bran on phytate-P degradation and it’s feeding effect on performance of broilers. Hydrothermal treatment of wheat bran was carried out at 55$^{\circ}C$ with pH 5.5 buffer solution. Phytate-P content of wheat bran decreased quadrically as the wheat bran: buffer solution ratio increased from 1:0.5 to 1:5. Phytate-P degradation was not significantly affected by incubation times above 10 min., drying temperature (55$^{\circ}C$, 65$^{\circ}C$ and 75$^{\circ}C$) or pH of the buffer solution (5.5 and 7.0). A feeding trial was conducted with 240 sex separated d-old broiler chickens (Ross$^{\circledR}$). Broilers were randomly housed to 24 cages of 10 birds each. Six cages (3 of each sex) were assigned to 4 treatments: Control-normal level of non-phytate-P (NPP); LP-low NPP treatment which had 0.1% lower NPP than Control; LPWB-LP with wheat bran which provided 475 IU of plant phytase per kg diet; LPHWB-LP with hydrothermally treated wheat bran. Results of the feeding trial showed that broilers in the LP treatment gained significantly less than other treatments in starter period (1-21d) but only male broilers for growing LP gained significantly less than Control in the grower (22-35d) and overall period. There were no significant differences in weight gain among the birds of LPWB, LPHWB and Control. Feed intake during the overall period was not significantly different between LPWB and Control but that of LP was lower than LPHWB and that of LPHWB was lower than Control. Feed/gain ratio was significantly lower in LPHWB and LP than in Control and LPWP. Mortality was highest in LPHWB. Availability of crude fat, crude ash and Ca was significantly lower in LP than other treatments. Availability of P and Zn was higher in LPWB and LPHWB than in Control and LP. Availability of P, Mg and Zn was highest in LPHWP treatment. Excretion of P was significantly lower in low NPP treatments than in Control. Serum Ca level was highest whereas serum P level was lowest in LP. Tibial crude ash content was higher in wheat bran treatments, but lower in LP than Control. However, tibial Ca content was higher in Control and LP than wheat bran treatments. Tibial P content of LP and LPWB was lower than Control. However, tibial content of Fe was highest in LP. It was concluded that wheat bran, a source of plant phytase, could be used in low NPP broiler diets to prevent the depression of performance. Reduction of P excretion can be achieved concomitantly. Hydrothermal treatment of wheat bran was effective in improving utilizability of some minerals but was not effective in improving performance of broilers.