• Korean Journal of Food Science and Technology
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• v.21 no.5
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• pp.676-685
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• 1989

Optimal operating conditions of on-farm red pepper dryer were searched by using the simulation-optimization algorithm combining the drying and quality deterioration models of red pepper with Box's complex method. Determination of control variables such as air temperature, air recycle ratio and air flow rate was based on a criterion of minimizing energy consumption under the constrainst conditions that satisfied the specified color retention of carotenoids. As quality constraint was stricter, energy consumption increased and total drying time decreased with lower recycle ratio and higher air flow rate Product mixing during drying was found to be able to improve the energy efficiency and product quality. Currently used air flow rate was assessed to be increased for the optimal operation. Two stage drying at the fixed optimal air flow rate was proven to be useful means for further saying of energy consumption. In the optimal bistaged drying, the second stage began at about one third of the total drying time and low air temperature in the first stage Increased to a high value and air recycle ratio increased slightly in the second stage. Optimal control variable scheme could be explained by the dryer performance and the carotenoids destruction kinetics in red pepper drying.

• Korean Journal of Food Science and Technology
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• v.8 no.3
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• pp.161-171
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• 1976

The meat samples of carp (Cyprinus carpio, Linne) and rainbow trout (Salmo gairdnerii) packaged in aluminum pouches with polyethylene adjuvant were exposed to gamma radiation of doses up to 1.5 Mrad for the purpose of determining optimum dose range required to bring about a significant storage-life extension at refrigerated temperatures. The maximum permissible dose for carp was determined to be 1.5 Mrad and that for rainbow trout 0.2 Mrad, while the optimum dose was 0.25 Mard and 0.05 Mrad, respectively. By irradiating them at each optimum dose, the practical storage-life of carp could be extended from one week to five at both $0^{\circ}\;and\;5^{\circ}C$ and that of rainbow trout from one week to 3-4 weeks at $0^{\circ}C$ and from 3 days to 14 days at $5^{\circ}C$. The carp meat suffered from extensive drip loss during the post-irradiation storage and it could be reduced effectively by dipping the samples into 10% polyphosphate solution prior to the radurization treatment. The rainbow trout was highly radiosensitive, while carp appeard to one of promising species to be radurization treated for the purpose of extending storage-life at refrigerated temperatures.

• Korean Journal of Food Science and Technology
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• v.7 no.4
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• pp.243-249
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• 1975

This experiment were carried out to investigate the conditions of amylase produced by Candida muscorum in wheat bran cultures and the properties of its amylase (crude enzyme). The results obtained were as follows. 1. The optimum conditions for amylase production in wheat bran cultures were; water content 75 percent, temperature $25^{\circ}C$ and incubation time 4-7 days. 2. The production of amylase was increased about 20 percent in the medium added 0.5 percent of ammonium sulfate or ammonium chloride to wheat bran, but the production of those was decreased in the case of addition of nitrates. 3. No significant effect was found in the case of the addition of carbon source on the production of amylase. 4. The properties of liquefying amylase of the selected strain were; the optimum pH 4.2, the optimum temperature $60-65^{\circ}C$, the stable pH 3.2-6.8 and the stable heating (for 15 minutes heating) below $65^{\circ}C$. 5. The properties of saccharifying amylase of the selected strain were; the optimum pH 4.5, the optimum temperature $55^{\circ}C$, the stable pH 3.8-6.2 and the stable heating (for 15 minutes heating) below $45^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.8 no.3
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• pp.147-160
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• 1976

Pacific oyster, hard clam and mussel were irradiated at doses up to 0.5 Mrad, the optimum dose rather than the maximum permissible was sought for in each species and post-irradiation storage characteristics studied at $0^{\circ}\;and\;5^{\circ}C$. No shellfish meat irradited at doses as high as 0.5 Mrad produced any adverse odor. However the organoleptic quality of each sample irradiated at lower doses was superior to those irradiated at the higher during the early storage period. The optimum dose was determined to be 0.2 Mrad for Pacific oyster and mussel and 0.1 Mrad for hard clam. By irradiating at the optimum dose, the storage life of Pacific oyster cculd be extend from less than 14 days to 35 days at $0^{\circ}C$ and from only 3 days to 21 days at $5^{\circ}C$. A similar storage extension was observed with mussel. The storage life of hard clam was extended from 7 days to 14 days at $0^{\circ}C$ and from 3 days to 12 days at $5^{\circ}C$. The hard clam meats were particularly susceptible to tissue softening by irradiation; an earlier onset and more extensive softening were observed with increasing dose.

• Journal of Life Science
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• v.13 no.6
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• pp.805-813
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• 2003

cDNA encoding somatolactin (SL) was obtained by RT-PCR from pituitary glands of rock bream (Oplegnathus fasciatus). The full length cDNA of rock bream somatolactin (rbSL) is 1636 bp long. It contains a 696 bp open reading frame encoding a signal peptide of 24 amino acids (an) and a mature protein of 207 aa. rbSL has seven cysteine residues$(Cys^{5},\; Cys^{15},\; Cys^{42},\; Cys^{65},\; Cys^{181},\; Cys^{198}\; $and $Cys^{206})$ and two potential N-glycosylation sites at positions $Asn^{121}$and $Asn^{153}$. The rbSL shares 61.1∼92.6% amino acid sequence similarities and 63∼92.6% nucleotide sequence identities with other teleost SLs, except for goldfish and channel catfish SL. Amino acid sequence alignment revealed that rbSL has four conserved domains $(A_{SL},\; B_{SL},\; C_{SL}and\; D_{SL})$ common to all SLs. Out of these domains, $(A_{SL},\; B_{SL},\; C_{SL}and\; D_{SL})$, are also conserved in all teleost growth hormones and prolactins. The cDNA of rbSL has been cloned into pET expression vector in order to produce recombinant rbSL in E. coli BL2l(DE3) cells. The recombinant protein showed a molecular weight of 27 kDa in SDS-PAGE.

• Journal of Life Science
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• v.26 no.8
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• pp.943-947
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• 2016

The objective of this study was to see if fairly simple magnetic nano-particle treatment enhances boar semen qualities. Boar semen samples were prepared from the swine AI center and samples were divided by 4 different motility groups (1, >90%; 2. 80~90%; 3. 70~80%; 4. <70%) using computer assisted sperm analysis (CASA) evaluation. Boar semen was extended using BTS extender and same number of magnetic nano-particles as total number of spermatozoa in each sample was treated for 20 min and collected for 5 min at room temperature. Sperm qualities such as motility and viability were evaluated by the CASA before and after treatment. Sperm abnormality and degree of agglutination were also evaluated under the microscopic examination before and after treatment. There were significant changes (p<0.05) on sperm motility from all 4 different groups in the average of 7.11% after treatment. The enhancement of sperm motility changes was more clear in the groups of lower sperm motile groups (<70% and 70~80%; 19.12±1.08% and 5.67±0.71%, p<0.05). The sperm motility character in terms of curvilinear velocity (VCL), straight line velocity (VSL), average path velocity (VAP) and linearity (LIN, %) showed also similar pattern but motility enhancement wear more clear in below 70% motile group. Average sperm viability was increased to 4% by magnetic nano-particles (p<0.05). The percentage of sperm abnormality was also reduced significantly (p<0.05) to the range of 3.7~4.5% before after treatment. The degree of sperm agglutination was also reduced in lower motility groups by the magnetic nano-particle purification.

• Journal of Life Science
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• v.21 no.9
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• pp.1329-1335
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• 2011

Korean native goats, which are characterized by black coat color, have existed on the Korean peninsula for a long time. Until now, there has been no comprehensive investigation concerning their genetic diversity, phylogenetic analysis or origin. In this study, we investigated the genetic diversity and verified phylogenetic status of the Korean native goat using the 453-bp fragment of the hypervariable fragment I (HVI) of mitochondrial DNA (mtDNA) D-loop region from 60 individuals among 5 populations. The Korean native goat showed less haplotype diversity when compared with goats from other countries. In addition, 6 haplotypes that had not been previously reported were verified in this study. In phylogenetic analyses with other country's goats, 10 haplotypes from Korean native goats were classified into mtDNA lineage A. Moreover, in a phylogenetic tree for goats which contained mtDNA lineage A, 8 of 10 haplotypes could be included in a subgroup with goats from Vietnam and an area of China. However, none of the remaining haplotypes belonged to a major group of Korean native goats and were located on different independent positions. These results suggest that almost Korean native goats aligned more closely to China and Vietnam breeds in mtDNA lineage A and there was no gene flow from other mtDNA lineages. Our results will contribute to conservation strategies and genetic breeding of Korean native goats.

• Conservation Science in Museum
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• v.4
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• pp.71-78
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• 2003

The wooden striker on the Divine Bell of King Seongdeok was examined to identify the species of the wood and the outdoor wood weathering caused by solar light, moisture, temperature and air. The species of the wooden striker was identified to Zelkova serrata. When observed the striker with naked eyes, the results were surface discoloration (graying), cracking and roughness. In order to examine the morphological changes according to deterioration type, the specimen were separated to three part(I, II,III-spot). The I-spot was discolored to gray and at the same time entirely covered with dust. So the observation was impossible. The II-spot was also discolored but its texture could be observed. On it could observe numerous fungal hypae and dirts like dust flown into the cell lumens. The cell wall has been so weakened by weathering that it lost the physical intensity. This have made microchecks and splits on the cell wall. Although fungal hypae covered the cell, they did not result in wood decay. The III-spot, located just 0.5 mm below the surface, was maintaining the natural red-brown color of the wood. Its cell wall was similar to that of sound wood. These changes are different from wood decay, and limited only to the surface of the striker-less than or equal to 0.5 mm below.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.10
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• pp.1433-1438
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• 2010

This study was carried out to investigate the antioxidative and antimicrobial activities of internal organs of Aplysia kurodai (AK). The internal organs of AK were extracted with methanol (AKM), which was then further fractionated into four subfractions by using solvent partition method, affording hexane (AKMH), methanol (AKMM), butanol (AKMB), and aqueous (AKMA) soluble fractions. The antioxidative activity of fractions from AK was investigated by measuring the scavenging activities of AK against DPPH radical, peroxynitrite ($ONOO^-$) and reactive oxygen species (ROS). Among the various solvent fractions, AKMB showed a marked scavenging effect against DPPH radical, peroxynitrite ($ONOO^-$) and reactive oxygen species (ROS). The antimicrobial activity was increased in proportion to its concentration by the paper disk method. Among the various solvent fractions, AKMM fractions of AK showed the strongest antimicrobial activities. The methanol extracts exhibited antimicrobial activity against all organisms tested, while the hexane extracts showed antimicrobial activity only against Proteus vulgaris. The results suggest that the AK may be suitable for development as a food preservative and alternative antioxidant.

• Journal of Korean Society of Forest Science
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• v.103 no.1
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• pp.51-58
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• 2014

Genetic diversity and genetic structures were estimated in seven natural populations of Phellodendron amurense Rupr in South Korea using ISSR markers. The average of polymorphic loci per primer and the proportion of polymorphic loci per population were 4.5 and 78.8% respectively with total 27 polymorphic loci from 6 ISSR primers. The Shannon's diversity index(I) was 0.421 and the expected heterozygosity($H_e$) was 0.285, which was similar to the heterozygosity (hs =0.287) inferred by Bayesian method. In AMOVA, 7.6% of total genetic variation in the populations was resulted from the genetic difference among populations and the other 92.4% was resulted from the difference among individuals within populations. Genetic differentiation(${\theta}^{II}$) and inbreeding coefficient(f) for total population were estimated to be 0.066 and 0.479 by Bayesian method respectively. In Bayesian clustering analysis, seven populations were assigned into three groups. This result was similar to the results of genetic relationships by UPGMA and PCA. The first group included Hwachoen, Gapyeong, Bongpyeong and Yongpyeong population, and the second included two populations in Sancheong region. Muju population was discretely assigned into the third group in spite of the geographically short distance from the Sancheong region. There was no significant correlation between genetic relationship and geographic distribution among populations in Mantel's test. For conservation of the phellodendron trees, it would be effective to consider the findings resulted from this study with ecological traits and life histories of this species.