• Korean Journal of Food Science and Technology
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• v.48 no.4
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• pp.341-346
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• 2016

The AMY2B gene, encoding human pancreatic ${\alpha}$-amylase isozyme (HPA II), was expressed in Pichia pastoris, and the effects of chloride ions on HPA II activity toward starch substrates were investigated. As seen with chloride ion-dependent ${\alpha}$-amylases-including HPA I, the isozyme of HPA II-chloride ions increased enzyme activity and shifted the optimal pH to an alkaline pH. The activity enhancement by chloride was more significant at pH 8 than that at pH 6, suggesting that the protonation state of the general acid/base catalyst of HPA II was important for the hydrolysis of starches at an alkaline pH because of the increase in its $pK_a$ by chloride ions. The turnover values for cereal starches as the substrates markedly increased in the presence of chloride by up to 7.2-fold, whereas that for soluble starch increased by only 1.7-fold. Chloride inhibited substrate hydrolysis at high substrate concentrations, with $K_i$ values ranging from 6 to 15 mg/mL.

• The Korean Journal of Applied Statistics
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• v.33 no.3
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• pp.335-345
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• 2020

This paper deals with the problem of estimating the log-transformed linear regression model to fit actual battle data from the Ardennes Campaign of World War II into the Lanchester model. The problem of determining a global solution for parameters and multicollinearity problems are identified and modified by examining the results of previous studies on data. The least squares method requires attention because a local solution can be found rather than a global solution if considering a specific constraint or a limited candidate group. The method of exploring this multicollinearity problem can be confirmed by a statistic known as a variance inflation factor. Therefore, the Lanchester model is simplified to avoid these problems, and the combat power attrition rate model was proposed which is statistically significant and easy to explain. When fitting the model, the dependence problem between the data has occurred due to autocorrelation. Matters that might be underestimated or overestimated were resolved by the Cochrane-Orcutt method as well as guaranteeing independence and normality.

• Applied Biological Chemistry
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• v.44 no.4
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• pp.219-223
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• 2001

Effects of hemoglobin (Hgb) concentration and degree of hydrolysis (DH) of Hgb on the separation of heme-iron were examined to produce highly enriched heme-iron from Hgb hydrolysate. Separation efficiency of Hgb hydrolysate with different DH was studied at wide pH range (pH $1.0{\sim}11.0$). Separation efficiency expressed as heme-iron/peptide ratio increased with decreasing Hgb concentration. When 5% Hgb (pH 10.0) was hydrolyzed using commercially available Esperase for 5 h at $50^{\circ}C$, DH was 25%. The precipitation of heme-iron-enriched peptides were remarkably high at pH range $3{\sim}6$. Optimal pH range for heme-iron with high heme-iron/peptide ratio shifted to acidic pH with increasing DHs of Hgb. The enriched heme-iron fraction in the precipitates showed a single band through urea-SDS-PAGE, with a molecular mass of 1 kDa. In the dry heme-iron product produced in a pilot bioreactor, content of heme-iron and heme-iron/peptide ratio were 27.1 and 38.7%, respectively, and production yield was 9.3%.

• The Korean Journal of Mycology
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• v.24 no.1 s.76
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• pp.8-16
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• 1996

The ${\alpha}-amylase$ of Alternaria alternata was purified through ammonium sulfate precipitation, dialysis and Sephadex G-100 column chromatography. One single band was obtained in SDS-polyacrylamide gel electrophoresis. The optimum pH for enzyme activity was 5.0 and the enzyme activity was maintained at $3.6{\sim}7.0$pH range. The optimum temperature for ${\alpha}-amylase$ activity was $40^{\circ}C$ and 71% of the activity was still maintained until 30 min after heating at $80^{\circ}C$. The ${\alpha}-amylase$ was slightly activated by $Mn^{2+},\;Zn^{2+}\;and\;Sn^{2+}$, but inhibited by $Ba^{2+},\;Pb^{2+},\;Co^{2+}\;and\;Ag^{1+}$. The $Hg^{2+}\;and\;Ag^{2+}$ slightly inhibited the activity of the enzyme at concentrations of $10^{-3}\;and\;10^{-4}M$. The Michaelis constant $(K_m)$ to soluble starch was $6.50{\times}10^{-2}M$ and inhibition constant $(K_i)$ by the 1mM EDTA was $8.0{\times}10^{-2}M$. The inhibition of this enzyme by EDTA was competitive one.

• Korean Journal of Food Science and Technology
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• v.21 no.1
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• pp.136-144
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• 1989

The purification of myrosinase from radish roots was performed using Concannavalin A-Sepharose affinity chromatography and gel permeation HPLC, which gave a 22-fold-purification(S.P.A.=39,000 units/mg) with 50% recovery, SDS-polyacrylamide gel electrophoresis showed a single major band, suggestive of a relatively pure myrosinase, and the M.W. of the enzyme determined on gel permeation HPLC was ca. 124K. The enzyme showed on optimum pH of 6.5 and was stable at pH 6 to 7 at room temperature, but unstable below pH 4. The enzyme possessed an optimum temperature of $37^{\circ}C$, and gave a Vmax value of $40\;{\mu}moles/mg{\cdot}min$ and a Km value of 0.12mM for sinigrin. The purified myrosinase was activated maximally by 0.6mM of ascorbic acid, but somewhat inhibited by more than 2 mM ascorbic acid. The activities of myrosinase present in the peelings and the peeled radish amounted to approximately 1,333 units/g and 140 units/g weight, respectively and the peelings contained much more myrosinase activity than the peeled radish.

• Food Science and Preservation
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• v.20 no.3
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• pp.379-385
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• 2013

To establish the optimal manufacturing conditions of soybean koji, soybean Koji prepared with Aspergillus oryzae 6-M-1 and Bacillus subtilis 3-B-1 isolated from traditional Korean meju. During 7 days of making Koji, the amount of amino-type nitrogen was getting more increase. The amount of amino-type nitrogen of Koji prepared with A. oryzae 6-M-1 was 686.16 mg% (w/w), that of Koji with B. subtilis 3-B-1 was 643.46 mg% (w/w) at seventh day of making Koji. The ${\alpha}$-amylase activity of Koji prepared with A. oryzae 6-M-1 was 1472.54 unit/g, that of Koji with B. subtilis 3-B-1 was 791.00 units/g on the seventh day of the making. The acidic protease activity of Koji prepared with A. oryzae 6-M-1 was 309.00 unit/g, that of Koji with B. subtilis 3-B-1 was 135.88 unit/g at 7th day of making. The amount of amino-type nitrogen and enzyme activities of soybean Koji prepared with A. oryzae 6-M-1 and B. subtilis 3-B-1 were produced more than those of wheat flour Koji made in factory. Sensory evaluation on a commercial doenjang and doenjangs prepared with A. oryzae 6-M-1 and B. subtilis 3-B-1 was not significantly different at p<0.05.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.7
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• pp.697-703
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• 2005

Iron-coated sand(ICS) was prepared with variation of particle size of Joomoonjin sand, primary and secondary coating temperature, coating time, and dosage of initial Fe(III). An optimum condition of the preparation ICS was selected from the coating efficiency, stability of coated Fe(III), and removal efficiency of As(V). Coated amount of Fe(III) increased as primary coating temperature increased with smaller particle size of sand. Coating efficiency was quite similar over the investigated secondary coating temperature and time, while adsorption efficiency of As(V) onto ICS was severely reduced with ICS prepared at higher secondary coating temperature. By considering these results, an optimum secondary coating temperature and time for the preparation of ICS was selected as $150^{\circ}C$ and 1-hr, respectively. Coating efficiency increased us the dosage of initial Fe(III) up to 0.8 Fe(III) mol/kg sand and then no distinct increase was noted. Maximum As(V) adsorption was observed at 0.8 Fe(III) mol/kg sand. Secondary coating temperature and time were important parameters affecting stability of ICS, showing decreased dissolution of Fe(III) from ICS prepared at higher coating temperature and at longer coating time. From anionic type adsorption of As(V) onto ICS, it is possible to suggest the application of ICS for the removal of As(V) contaminated in acidic water system.

• Applied Biological Chemistry
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• v.11
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• pp.123-130
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• 1969

Five varieties of sweetpotatoes recommended in Korea were investigated with respect to the storing capacity, resin content and the possibility of developing sweetpotato chips as a new processed food item. The results are summarized as follows: 1) Two varieties, Suwon No. 147 and Chun-Mi were more resistant to chilling injury and soft-rot decay than other varieties. 2) The contents of resinous and polyphenolic substances were quite different depending upon the variety. 3) Sweetpotato chips of different color were made from different varieties and rapeseed oil was found to be the best as frying oil. 4) Best conditions to prepare sweetpotato chips with fresh color and proper texture were to dip slices of 1-2 mm thickness in 0.25% sodium bisulfite solution at $40^{\circ}C$ for 30-40 minutes and to subject to deep frying in an oil bath at $150-160^{\circ}C$ for 2.5 to 3.5 minutes. 5) Polyethylene-cellophane film as packing material of sweetpotato chips was the film in the moisture proof and film-impact tests.

• Journal of the Korean Geosynthetics Society
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• v.20 no.3
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• pp.1-10
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• 2021

The purpose of this study is to present the possibility a utilization of the tertiary mudstone in Pohang as road subsoil material through pilot experiments on the road embankment structure. This mudstone is an unconsolidated rock that is distributed in the soft rock sedimentary layer, the tertiary layer of the Cenozoic, and causes physical problems such as slaking, swelling, and reduced shear strength and chemical problem like acid drainage. In order to solve various complex problems, an laboratory mixing test was conducted, and the optimal mixing conditions of the tertiary mudstone (90%), composite slag (steel making 70%, blast furnace 30%), and neutralization and coating agent treatment were derived. In order to prove its utilization, a real-scale road embankment structure was constructed and tests were conducted for each section. The pre-processing section is stable due to the design of optimal mixing conditions, while in post-processing section, natural weathering proceeded rapidly, and structural problems were concerned. Since the effect of neutralizing and coating agents was confirmed in temporary-staking section, the neutralizing and coating agents can be applied during the temporary storage period.

• The Korean Journal of Food And Nutrition
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• v.29 no.3
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• pp.438-447
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• 2016

This study was conducted in order to investigate the physiochemical properties and antioxidative activity of red ginseng manufactured using the high temperature high pressure (HTHP) process, which is faster and simpler than the conventional process. According to increasing the steaming temperature, pressure and time, the content of minor non-polar ginsenosides, such as Rg3, Rk3, Rh4, Rk1 and Rg5 gradually increased. Also, the contents of acidic polysaccharide, total phenolic compounds and maltol gradually increased. Based on the results of the physiochemical properties and appearance quality, the optimum conditions of HTHP process were estimated as $140^{\circ}C$, $3kg/cm^2$ in 20 min. The total phenolic compounds and maltol contents of the HTHP process red ginseng (1.0% and 2.49 mg%, respectively) were higher than those of conventional red ginseng (0.23% and 0.60 mg%, respectively). In addition, the antioxidative activity was investigated using DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-aziono-bis(3-ethylbenzthiazoline-6-sulfonic acid)) radical scavenging activity. DPPH and ABTS radical scavenging activities of HTHP process red ginseng increased by 3.4 and 3.6 folds, respectively, compared with conventional red ginseng. In addition, total phenolic compounds and maltol contents, as well as the antioxidant activity of the HTHP process red ginseng were similar to black ginseng. The present results suggest that the HTHP process is available for the development of value-added red ginseng products.