• Journal of Life Science
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• v.23 no.3
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• pp.426-431
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• 2013

With the objective of developing a functional food source, we established optimal processing conditions for the larvae of Allomyrina dichotoma, which have been used in traditional medicine to treat hepatic disorders in Korea. Without suitable processing, the larvae are difficult to consume as a food because of their disgusting taste and smell; moreover, in this form they might be a potential microbial hazard. In this study, we investigated the effect of feeding material, sterilization, and powdering after freeze-drying on the food quality of the larvae of A. dichotoma and on cytotoxicity against Raw 264.7 cells. Three to five days feeding with the sawdust from discarded oak-trees is sufficient for the breeding process. The sawdust was sterilized by vapor for five minutes. Sterilization of the larvae at a high temperature ($115^{\circ}C$ for 5 min, 0.9 $kgf/cm^2$) is necessary to eliminate pathogenic bacteria and fungi. The results of the cytotoxicity assay showed no toxicity in the prepared extract from larvae of A. dichotoma. In addition, to prepare the larvae for human consumption, various feeds were used and the smell, color, and taste were evaluated. Our results suggested that larvae of A. dichotoma could be developed as food source when a suitable processing method is established.

• The Korean Journal of Pesticide Science
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• v.7 no.2
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• pp.139-148
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• 2003

The purpose of this study was to investigate damages of garlics occurred under cold storage and farmhouse storage condition, influence of cultural and environmental factors on storage spoilage of garlics, and to establish control strategies to reduce damages occurred under storage of garlics. Decays of garlics were highly related with cultural condition (paddy field or upland soil), ventilation, storage temperature and relative humidity, continuous cropping years, and harvesting stage. Early-harvested garlics were more decayed than late-harvested garlics. Garlics cultivated on paddy field were less decayed than ones cultivated on upland soil under farmhouse storage condition. The densities of Penicillium spp. and Fusarium spp. were higher on plot with long term continuous cropping cultivation history than on plot with short term continuous cropping cultivation history. However there is no relation between continuous cropping years and percent of decay of garlics. As a result of investigating influence of environmental factors on decay of garlics, P. hirsutum caused severe spoilage under high relative humidity condition, while F. oxysporum and Stemphyllium botryosum were not related with relative humidity. The three postharvest pathogens grew well above woe. In addition when P. hirsutum and S. botryosum were cultured for two months, they grew even at $-1^{\circ}C$. Except for environmental factors, wounds occurred through farming works. had an effect on storage spoilage of garlics. Garlics only hurt with a toothpick without inoculation of pathogens were decayed more severe than those inoculated with pathogens without wounds. Seven agro-chemicals showed highly suppressive effect were selected by measuring mycelial growth of three major pathogens of garlics on potato dextrose agar amended with 0.1% (v/v) of each fungicide. When they were foliar-sprayed on garlics 30 days before harvesting, it was confirmed that they suppressed storage spoilage of garlics. Also when garlics were sprayed with and drenched into the suspension of Benoram WP very after harvesting garlics, garlic damages by postharvest pathogens were reduced remarkably.

• Microbiology and Biotechnology Letters
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• v.26 no.3
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• pp.250-256
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• 1998

D-Tagatose production from D-galactose was investigated using 35 type strains of American Culture Type Collection (ATCC) and Korean Collection for Type Cultures (KCTC) which have potential to produce D-tagatose. Enterobacter agglomerans ATCC 27987 was selected as a D-tagatose producing strain due to its short fermentation time and high production of D-tagatose. Optimization of the culture conditions for D-tagatose production by E. agglomerans ATCC 27987 was performed. Among various carbon sources, D-galactose was the most effective carbon source for D-tagatose production. As the D-galactose concentration was increased, cell growth and D-tagatose production increased. Effect of nitrogen sources on D-tagatose production was studied. Of inorganic nitrogen sources, ammonium sulfate was effective one for D-tagatose production and yeast extract was the most suitable organic nitrogen nutrient. The concentrations of inorganic compounds such as KH$_2$PO$_4$, K$_2$HPO$_4$, and MgSO$_4$$.$7H$_2$O were also optimized for D-tagatose production. The optimal medium was determined to contain D-galactose of 20 g/l, yeast extract of 5.0 g/l, (NH$_4$)$_2$SO$_4$ of 2.0 g/l, KH$_2$PO$_4$ of 5.0 g/l, K$_2$HPO of 5.0 g/l, and MgSO$_4$$.$7H$_2$O of 5 mg/l. The optimal environmental conditions in a 250-$m\ell$ flask were found to be pH of 6.0, temperature of 30$^{\circ}C$, and agitation speed of 150 rpm. D-tagatose of 0.41 g/l could be obtained in 24 h from 20 g/l D-galactose at the optimal culture condition without induction and cell concentration.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.5
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• pp.549-557
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• 2006

The characteristics of supercritical water oxidation have been studied to decompose the waste anionic exchange resins which were produced from a power plant. The waste resins from a power plant were mixture of anionic and cationic exchange resins. The waste anionic exchange resins had been separated from the waste resins using a solid-liquid fluidized bed. It was confirmed that the cationic exchange resins were not included in the separated anionic exchange resins by the elemental and thermogravimetric analysis. A slurry of anionic exchange resins which could be fed continuously to a supercritical water oxidation apparatus by a high pressure pump was prepared using a wet ball mill. Although the COD of liquid effluent had been reduced more than 99.9% at 25.0 MPa and $500^{\circ}C$ within 2 min, the total nitrogen content was reduced only 41%. The addition of nitric acid to the slurry could reduce the total nitrogen content in treated water. The central composite design as a statistical desist of experiments had been applied to optimize the conditions of decomposing anionic resin slurry by means of the COD and total nitrogen contents in treated waters as the key process output variables. The COD values of treated waters had been reduced sufficiently to $99.9{\sim}100%$ af the reaction conditions of $500{\sim}540^{\circ}C$, 25.0 MPa within 2 min. The effects of temperature and nitric acid concentration on COD were not significant. However, the effect of nitric acid concentration on the total nitrogen was found to be significant. The regression equation for the total nitrogen had been obtained with nitric acid concentration and the coefficient of determination($r^2$) was 95.8%.

• Microbiology and Biotechnology Letters
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• v.45 no.1
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• pp.63-70
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• 2017

A functional screen of 60,672 fosmid metagenomic clones amplified from marine sediment obtained from the Dokdo islets in Korea identified the gene EstES1, whose product, EstES1, displayed lipolytic properties on tributyrin-supplemented media. EstES1 is a 576 amino acid protein with a predicted molecular weight of 59.4 kDa including 37 N-terminal leader amino acids. EstES1 exhibited the highest sequence similarity (44%) to a carboxylesterase found in Haliangium ochraceum DSM14365. Phylogenetic analysis indicated that EstES1 belongs to a currently uncharacterized family of lipases. Within the conserved domain, EstES1 retains the catalytic triad that consists of the consensus penta-peptide motif, GESAG. EstES1 demonstrated a broad substrate specificity toward the long acyl group of ethyl esters (C2-C12), and its optimal activity was recorded toward p-Nitrophenyl butyrate (C4) at pH 9.0 and $40^{\circ}C$ (specific activity of 255.4 U/mg). The enzyme remained stable in the ranges of $60-65^{\circ}C$ and pH 9.0-10.5 and in the presence of methanol, ethanol, isopropanol, and dimethyl sulfoxide. Therefore, EstES1 has potential for use in industrial applications involving high temperature, organic solvents, and/or alkaline conditions.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.5
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• pp.253-261
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• 2015

In this study, Chlorophyll-a (chl-a) prediction model and multiple parameters affecting algae occurrence in Mulgeum site were evaluated by statistical analysis using water quality, hydraulic and climate data at Mulgeum site (1998~2008). Before the analysis, control chart method and effect period of typhoon were adopted for improving reliability of the data. After data preprocessing step two methods were used in this study. In method 1, chl-a prediction model was developed using preprocessed data. Another model was developed by Method 2 using significant parameters affecting chl-a after data preprocessing step. As a result of correlation analysis, water temperature, pH, DO, BOD, COD, T-N, $NO_3-N$, $PO_4-P$, flow rate, flow velocity and water depth were revealed as significant multiple parameters affecting chl-a concentration. Chl-a prediction model from Method 1 and 2 showed high $R^2$ value with 0.799 and 0.790 respectively. Validation for each prediction model was conducted with the data from 2009 to 2010. Training period and validation period of Method 1 showed 20.912 and 24.423 respectively. And Method 2 showed 21.422 and 26.277 in each period. Especially BOD, DO and $PO_4-P$ played important role in both model. So it is considered that analysis of algae occurrence at Mulgeum site need to focus on BOD, DO and $PO_4-P$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.2
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• pp.166-172
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• 2002

The top shell, Omphalius pfeifferi capenteri meat vacuum-packed in can (diameter$\times$height, 74.1mm$\times$50.7mm) were heated at 115$^{\circ}C$ up to $F_0$ values of 5 min, 10 min, 15 min and 20 min, and the changes in food components were studied. After 14 days storage at 37$^{\circ}C$ and 55$^{\circ}C$, no growth of microorganism and panelling were recognized from the canned meats which were sterlized at 115$^{\circ}C$ with $F_0$ value of S min and over. In the case of proximate composition of the canned meats, the moisture content decreased with the increase of $F_0$ value, while crude protein increased. The increase of volatile basic nitrogen content, pH and degree of browning and the decrease of mineral, total amino acid, free amino acid, trimethylamine oxide, total creatinine contents and yields were observed during thermal processing, In sensory evaluation on color, texture and taste in the canned meats, no significant difference was observed among a boiled sample and the canned meats heated at re value of 10 min and below. But, in the canned meats heated at $F_0$ value of over 15 min, its sensory scores decreased with the increase of $F_0$ value. From these results, the reasonable $F_0$ value for preparation of the heat-treated top shell meats was in the range of 5$\~$10 min.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.5
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• pp.423-435
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• 1984

The reproductive cycle of the small filefish, Rudarius ercodes was investigated based on the annual variations of gonadosomatic index(GSI) and hepatosomatic index(HSI) by electronic and photic microscophy. The specimens used were collected at the coastal area of Benden island, Sizuokagen, Japan, from September 1982 to August 1983. GSI began to increase from March, starting season of longer daylength and higher water temperature, and reached the maximum value between June and August. It began to decrease from September with the lowest value appearing between November and February without any evident variation. The annual variations of HSI were not distinct in male filefish and were negatively related to GSI in female : HSI decreased in the summer season when the ovary was getting mature and reached the maximum in the winter season when the ovary was getting retrogressive. The ovary consisted of a pair of saccular structure with numerous ovarian sacs branched toward the median cavity. Oogonia divided and proliferated along the germinal epithelium of the ovarian sac. Young oocytes with basophile cytoplasm showed several scattering nucleoli along the nuclear membrane. when the oocytes growing to about 300 ${\mu}m$, nuclear membrane to disappear with nucleus migrating toward the animal pole. The regions of protoplasm were extremely confined within the animal hemisphere in which most of cytoplasms were filled with yolk materials and oil drops. After ovulation, residual follicles and growing oocytes remaining in the ovarian sacs degenerated. But perinucleatic young oocytes without follicles formed were not degenerated, and growing continuously still in the next year. Mitochondria and endoplasmic reticula in the cytoplasm remarkably increased with oocytes maturing and yolk accumulating. Those were considered to be functionally related to the yolk accumulation. Five or six layers of possible vitellogenin, oval-shaped disc structures with high electron density, appeared in the apex of follicular processes stretching to the microvilli pits of mature oocytes. Testis consisting of a pair of lobular structures in the right and left were united in the posterior seminal vesicle, Cortex of testis was composed of several seminiferous tubules, and medulla consisting of many sperm ducts connected with tubules. Steroid hormone-secreting cells with numerous endoplasmic reticula and large mitochondria of well developed cristae were recognized in the interstitial cells of the growing testis. Axial filament of spermatozoon invaginated deeply in the central cavity of the nucleus and the head formed U-shape with acrosome severely lacking, mitochondria formed large globular paranuclei at the posterior head, and microtubular axoneme of the tail represented 9+9+2 type. The annual reproductive cycles could be divided into five successive stages : growth(March to July), maturation(May to September), Spawning(mid May to early October) and resting stages(October to February). The spawning peak occurred from June to August.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.345-351
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• 1996

Studies on extraction and color characteristics of purple sweet potato (PSP) pigment were performed to provide the basic information for the utilization of PSP as a new source of natural food colorant. PSP pigment was extracted well with the polar solvents such as distilled water, ethanol, and methanol. but hardly extracted with the non-polar solvents. Among the tested solvents, 20% ethanol solution containing 0.1% citric acid was found to be the most efficient for extraction of the pigment from PSP. PSP contained high amount of pigment not only in the epidermis but also in the flesh of the potato. The PSP pigment was heat stable even under pretreatments such as autoclaving and blanching of the potato before extraction. The optimum temperature of the extraction for the PSP Pigment was decided to be $30^{\circ}C$ by considering the stability and the rate of extraction. The pigment was markedly influenced by the change of pH. The color of the pigment solution was red at the pH range of $1.0{\sim}3.0$, became blue at $7.0{\sim}8.0$, then turned green at $9.0{\sim}10.0$. A characteristic batho-chromic shift of the pigment solution was observed as the pH of the solution increased.

• Journal of the Korean Society of Food Science and Nutrition
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• v.17 no.3
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• pp.198-204
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• 1988

This study was aimed at obtaining elementary data on enzymatic browning of potato and potato products and examining the inhibitory method of browning. Therefore, we extracted polyphenol oxidase from potatoes(Solanum tubersum L.), and investigates its general properties and inhibiting effects of its activity with the different concentrations of sulfites($Na_2S_2O_4,\;Na_2SO_3{\cdot}7H_2O,\;NaHSO_3$). The optimum pH and temperature of polyphenol oxidase were observed to be 6.5 and $37^{\circ}C$ respectively. The polyphenol oxidase at PH5 was very stable, and the activity of polyphenol oxidase between pH $5.0{\sim}9.0$ was estimated to be relatively high, showing $72{\sim}75%$ of its activity at pH5. The polyphenol oxidase was very stable when heated at $40^{\circ}C$ for one hour, and almost 50% of enzyme activity was decreased when heated at $70^{\circ}C$ for twelve minutes. At 0.1mM concentrating of sulfites the relative activity of polyphenol oxidase was 98% in all the three cases of sulfites. Thus sulfites at 0.1mM concentration was found to have little inhibiting effect on polyphenol oxidase activity. At 1mM concentration of sulfites $NaHSO_3$ showed the lowest 36% relative activity among the three. At 5mM concentration of sulfites, the relative activity of $Na_2SO_3{\cdot}7H_2O$ was the lowest 14%.