• Korean Journal of Medicinal Crop Science
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• v.8 no.3
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• pp.225-233
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• 2000

There was not noticeable differences in decreasing blood alcohol concentrations between Korea and China-produced Hovenia dulcis $T_{HUNB}$, showing only 1-2 % higher decreasing rate for Korea-produced seed extracts than those from China. It was also found that the blood alcohol decreasing ability was greatly enhanced by partitioning the crude extracts produced from both places. The both extracts (crude and partitioned) accelerated the reducing rate of blood alcohol concentrations down to 1-2 hours, compared to that of control (taking only ethanol). The crude extracts from imported seeds seemed to have slightly better effect on improving in vivo ADH and ALDH activities than domestic ones; however, not for partitioned extracts. It was interesting that the partitioned extracts from both countries enhanced ADH enzyme activity up to 60% than the crude, compared to the control, while ALDH activity was not much affected by the partitioned extracts. It was also confirmed that both ADH and ALDH activities were well balanced in controlling blood alcohol concentration maintaining 28-29% of enzyme activities in vivo. The extracts proved to have better effect on enhancing ALDH activity than ADH activity, which is one of possible explanation that Hovenia dulcis $T_{HUNB}$ can effectively relieve the hangover by fast decreasing acetaldehyde concentration in the liver and blood. GST activity was also increased in the range of 120 to 300% by adding crude or partitioned extracts from both countries; however, there was no difference in enhancing GST activity between the extracts from two countries. The extracts showed competitive inhibition with GST activity, showing the reduction of enzyme activity at higher than 0. 6 (g/L) of the imported extracts.

• Journal of Life Science
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• v.25 no.7
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• pp.795-800
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• 2015

Oyster is a nutritionally good food ingredient. Also, oyster is used to make source for taste and flavor. This study tried to investigate optimal condition of hydrolysis of oyster and oyster cooking drip for better amino acid content to make good taste and flavor. And then this study characterized hydrolysate of oyster and oyster cooking drip. Enzymes are Acalase, Flavourzyme, Neutrase, and Protamax. The optimal condition for the highest enzyme activity is given by the company. Under the best condition of each enzymes, they react with the homogenized oyster and oyster cooking drip for 0.5, 1.0, 1.5, 2, 4, 6 hr. The degree of oysters’ hydrolysis is 13.2±0.1%. But, in the case of using enzyme, the rate of hydrolysis sharply increased as time went on during 2 hr. After 8 hr, the rate is 36.9~40.5%. Protamax showed 27.4±0.4% of hydrolysis rate in 2 hr. And the degree of oyster cooking drop hydrolysis is 42.7±0.1%. The highest of hydrolysate concentration is 72.1±0.1% using protamax. In the case of oyster, it has a similar tendency of all enzymes. Otherwise, the hydrolysate of oyster cooking drip had a difference among the enzymes. Composition of free amino acid of hydrolysate using protamax was investigated how much time showed highest rate of hydrolysis to find best amino acid composition. Hydrolysis using Protamax during 6 hr is selected for best condition.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.1
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• pp.132-138
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• 1998

To improve functional properties and enhance application of FPC in food industry, modified salmon FPC with enzyme treatment was produced and its general properties were investigated. Salmon FPC has over $84\%$ of protein and less than $0.18\%$ of lipid. Solubilities of FPC extracted with IPA and ethanol were very poor as less than $3\%$ in every pH range. In case of enzyme : substrate ratio of 1 : 100, degree of hydrolysis significantly increased until 4 hours and then slightly increased. No considerable differences were observed in general components of hydrolysates. Results of SDS-PAGE showed one unique band in each case and their molecular weight was less than 6,500. The flow properties of hydrolysates showed newtonian flow. Whiteness of hydrolysates were higher than that of salmon FPC as $5\~7$. There was no significant differences in the amount of peptide, but that of free amino acid slightly increased from 0.17 to 0.21 mg/ml.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.4
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• pp.398-406
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• 1992

In order to develop a new flavourant using the fish skin gelatin, the proteolytic renditions for the gelatin hydrolysate of the alkali (B-type) and Alcalase (E-type) pretreated flounder (Limanda aspera) skin gelatin were investigated, and some physical properties, molecular weight and amino acid compositions of the hydrolysates were, also, compared with each other. The proteolytic conditions of the gelatins (B-type and E-type) by trypsin were as follows : reaction temperature, 55$^{\circ}C$ : pH, 9.0 : enzyme concentration, 0.1% : re-action time, 4hrs for B-type and 1 hr for E-type. The degrees of hydrolysis of the B-type and E-type gelatin un-der the renditions stated above were 63% and 82%, respectively. The rnajor molecular weights of the hydrolysates were 15,000 dalton for B-type and 12,400 dalton for E-type. Among the amino acids in the hydrolysates, glycine, alanine, proline, hydroxyproline and serine having a sweet taste were responsible for 57% of the total amino acid. But valine, leucine, phenylalanine, tyrosine, methionine, arginine and histidine having a bitter taste were only 18%.

• KSBB Journal
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• v.21 no.2
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• pp.140-143
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• 2006

Acid- and enzymatic hydrolysis properties of two fructans(inulin and levan) and their oligofructoses has been investigated. At pH 1, the initial fructose release rate differs and is rapidly hydrolyzed in the order of levan oligosaccharide and inulin oligosaccharide, levan, inulin. At pH 4.5, 7 and 14, no or little amount of fructose are found from four samples. At the presence of inulinase in the reaction mixture, the fructose is rapidly produced from all samples, whilst invertase treatments show low activities. The results allow the estimation of the fructose release rate in many foodstuff processing conditions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.2
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• pp.323-329
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• 1995

For the effective utilization of dark meat separated as by-product from skip-jack canning, the dark meat concentrate(DPC) was prepared by removal of extractable materials with ethanol from dried dark meat. Dark meat protein hydrolysate(DPH) was prepared by the hydrolysis of DPC with ${\alpha}-chymotrypsin$. ${\alpha}-Chymotrypsin$ hydrolysed DPC to the extend of 79% during 10hr. The solubility over a pH range 1~12 showed similar trend on the both of DPH and DPC. The highest solubility was 81% on the DPH and was 36% on the DPC at pH 3. The lowest solubility was 65% on the DPH and was 22% on the DPC at pH 7. The content of total free amino acid was higher in the DPC than in the DPH, but the content of total essential free amino acid was higher in the DPH. Especially, the contents of taurine in the DPC and DPH were much higher than those of other amino acids. The result of sensory evaluation on the fish sauce analogue showed good taste, color and odor at the supplemented level of 8g DPH per 100ml of raw solution of fish sauce analogue and didn't show signifcaint difference compared with market fish sauce(p<0.05). On the preparation of surimi gel, 2% substitution of DPH for the supplemented starch was the most appropriate level.

• Applied Chemistry for Engineering
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• v.16 no.1
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• pp.28-33
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• 2005

A resource recovery technique using sub- and supercritical water hydrolysis was applied to recover amino aicds from waste fish entrails. The effect of reaction parameters such as temperature and time necessary for the control of reaction towards optimum yield of amino acids was investigated using semi-batch and batch reactors. Results showed a maximum yield of total amino acids (137 mg/g-dry entrails) from waste fish entrails at T=$250^{\circ}C$ (P=4 MPa) and reaction time of 60 min in a batch reactor. Under supercritical conditions (e.g., T=$400^{\circ}C$, P=45 MPa), the yield decreased due to rapid decomposition compared to production rate of amino acids. As a result, the low temperature and the short reaction time were needed to produce a maximum yield of amino acids.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.3
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• pp.68-73
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• 2002

Acidogenic fermentation of primary sludge was investigated for the solution to reduce the sewage sludge and develope external carbon source for BNR process. In a viewpoint to use existing anaerobic digestion tanks, we didn't change environmental factors such as reactor configuration, temperature, pH and investigate the variation of solubilization rates, acidification rates and environmental factors which affected by the variation of HRT. The average solubilization rates were 0.0309 and $0.0204mgSCOD_{prod.}/mgICOD_{inf.}$ at a HRT of 3 and 1.5 days, respectively. The average acidification rates were 0.0068mg HAc/mg $TCOD_{inf.}$ and 0.0652mg HAc/mg $VSS_{destroyed}$ at a HRT of 3day. At a HRT of 1.5 days the average acidification rates were 0.0060mg HAc/mg $TCOD_{inf.}$ and 0.0346mg HAc/mg $VSS_{destroyed}$. For the period of experiments alkalinity and pH were properly maintained without artificial adjusting.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.1
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• pp.1-10
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• 2005

The purpose of this study was to evaluate the potential of a gamma irradiation to decompose 2,4,6-trinitrotoluene(TNT) in an aqueous solution. The decomposition reaction of TNT by gamma irradiation was a pseudo first-order kinetic over the applied initial concentrations($25{\sim}100mg/L$). The dose constant was strongly dependent on the initial TNT concentration. The removal of TNT was more efficient at pH below 3 and at pH above 11 than at neutral pH(pH 5-9). The required irradiation dose to remove over 99% of TNT was 40, 80 and 10 kGy, individually at pH 2, 7 and 13. The dose constant was increased by 1.6 fold and over 15.6 fold at pH 2 and 13, respectively, when compared with that at pH 7 When irradiation dose of 200 kGy was applied, the removal efficiencies of TOC were 91, 46 and 53% at pH 2, 7 and 13, respectively. Ammonia and nitrate were detected as the main nitrogen byproducts of TNT and glyoxalic acid and oxalic acid were detected as organic byproducts. The results showed that a gamma irradiation was an attractive method for the decomposition of TNT in an aqueous solution. However, regarding the application of high energy radiation for the TNT decomposition and mineralization, an application of an acidic pH below 3 to the solution before irradiation should be considered.

• The Korean Journal of Applied Statistics
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• v.26 no.5
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• pp.747-758
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• 2013

The covariance matrix is important in multivariate statistical analysis and a sample covariance matrix is used as an estimator of the covariance matrix. High dimensional data has a larger dimension than the sample size; therefore, the sample covariance matrix may not be suitable since it is known to perform poorly and event not invertible. A number of covariance matrix estimators have been recently proposed with three different approaches of shrinkage, thresholding, and modified Cholesky decomposition. We compare the performance of these newly proposed estimators in various situations.