• 유기물자원화
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• 제17권1호
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• pp.39-48
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• 2009

바이오디젤은 온실가스 배출의 큰 비중을 차지하는 수송용 차량의 대체연료로서 가장 우수한 재생에너지원으로 평가되고 있다. 그러므로 바이오디젤의 폭넓은 확대와 신뢰성 향상을 위해서는 바이오디젤의 품질 개선에 대한 연구가 필요하다. 본 연구에서는 폐식용유를 원료로 에스테르화 반응을 통해 바이오디젤 (BD100, BD20)을 제조한 후 품질기준 24개 항목의 적합성 여부를 분석하였다. 폐식용유와 바이오디젤은 Oleic acid, Linoleic acid, Linolenic acid과 같은 불포화 지방산의 함량이 높아서 바이오디젤의 원료로 사용해도 이상 없는 것으로 확인되었다. 바이오디젤 품질기준 항목 분석 결과 BD100의 산화안정도는 2시간, BD20의 지방산메틸에스테르 18.6w%, 필터막힘점 $-5^{\circ}C$로서 기준범위에 미달하였으나 나머지 항목들은 품질기준에 적합한 것으로 나타났다. 일부 항목에 대한 품질개선 기술에 대한 연구가 뒷받침되면 폐자원을 이용한 대체에너지로서의 활용도 향상에 기여 할 것으로 사료된다.

• 공업화학
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• 제20권3호
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• pp.285-289
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• 2009

최근 지구온난화 및 식량문제에 대한 관심이 증대되면서 그 해결책으로 미세조류에 대한 많은 연구가 이루어지고 있다. 특히 광합성 미세조류 Spirulina platensis는 이산화탄소를 고정할 수 있으며, 영양적 가치가 우수하여 많은 관심을 받고 있다. 본 연구에서는 Spirulina platensis NIES 39의 대량 배양을 위한, 배양온도, 초기 pH, 조도, 탄소와 질소원의 농도 등의 요인에 대한 최적 조건을 확립하고자 하였다. 배양 온도 $35^{\circ}C$에서 초기 pH 9.5, 조도 4500 lux에서 건조균체중량 2.10 g/L, 클로로필 함량 29.53 mg/L로 가장 우수한 결과를 나타내었으며, 이때의 탄소원과 질소원의 농도는 각각 16.8 g/L $NaHCO_3$, 2.5 g/L $NaNO_3$이었다.

• Food Science and Biotechnology
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• 제17권3호
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• pp.573-577
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• 2008

$^1H$-Nuclear magnetic resonance (NMR) spectrometry was applied to the quantitative analysis of coumarins in the roots of Angelica gigas without any chromatographic purification. The experiment was performed by the analysis of each singlet germinal methyl, which was well separated in the range of 1.0-2.0 ppm in the $^1H$-NMR spectrum. The quantity of the compounds was calculated by the ratio of the intensity of each compound to the known amount of internal standard (dimethyl terephthalate). These results were compared with the conventional gas chromatography (GC) method. The contents of decursin and decursinol angelate in A. gigas were determined $1.98{\pm}0.07$, $1.13{\pm}0.08%$ in quantitative $^1H$-NMR method and $2.06{\pm}0.24$, $1.17{\pm}0.24%$ in GC method, respectively. The advantages of quantitative $^1H$-NMR analysis are that can be analyzed to identify and quantify, and no reference compounds required for calibration curves. Besides, it allows rapid and simple quantification for coumarins with an analysis time for only 10 min without any preprocessing.

• Asian-Australasian Journal of Animal Sciences
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• 제13권1호
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• pp.60-67
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• 2000

A survey involving 71 cattle and buffalo farming households under coconut plantations was carried out in three districts (Pannala, Bingiriya and Kuliyapitiya) with the aim of assessing the status of livestock farming. Also, 24 households (eight from each district) were visited monthly for period of one year to collect information on feeding practices. Apart from milk, animals were reared for selling, draught, bio-gas and for manure. Due to difference in system of management of cattle and buffaloes, manure from buffaloes (46%) was more frequently used for coconuts than that from cattle (10%). Majority of cattle were improved breeds (temperate origin) or their crosses, as compared to buffaloes (mainly indigenous). The most predominant management system was tethered grazing during the day, and stall feeding during the night. Coconut land (own or others) and paddy fields were the major grazing areas for the animals. The grass from coconut land was lower in crude protein (8.2%) and digestibility (48%) compared to those from paddy fields (12.1 and 57%, respectively). Of the 288 rations analysed, grass was included in 280 of the daily rations for cattle as compared to 251 for buffaloes. Straw was more commonly included in mixed rations for buffaloes (137 out of 288) than for cattle (53 out of 288). The frequency of use of straw for buffaloes was high in Pannala (75 out of 137 cases). There was wide variation among the improved breeds of cattle and buffaloes in milk production (2 to 9 litres/day), lactation length (6 to 10 months) and calving interval (13-21 months).

• 공업화학
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• 제21권6호
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• pp.659-663
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• 2010

미세조류는 전 세계 바다에 분포하고 있으며 일부 종들은 인간의 식품에 이용되어 왔다. 특히, 광합성 미세조류 Nannochloropsis oculata는 영양적 가치가 우수하여 관심을 받고 있다. 본 연구에서는 광합성 미세조류 Nannochloropsis oculata의 고농도배양을 위한 배양온도, 초기 pH, 배양액 선정, 인공해수 농도, 배지농도, $CO_2$영향 등 최적조건을 확립하고자 하였다. 그 결과, 3%의 인공해수, 초기 pH 8.5, 배양온도 $25^{\circ}C$가 최적 배양조건으로 판별되었다. 미세조류에 $CO_2$를 공급하지 않았을 때에는 건조 균체량이 0.76 g/L이었지만, 5% $CO_2$ 공급 이후 1.50 g/L로 높은 성장률을 보였다. 클로로필 생합성은 미세조류 성장과 깊은 연관이 있는 것으로 판명되었다.

• 한국발생생물학회지:발생과생식
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• 제17권4호
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• pp.421-426
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• 2013

In this study, oocyte steroidogenesis are investigated in relation to oocyte development in the starry flounder, Platichthys stellatus, a marine multiple spawner. Vitellogenic (0.52 and 0.55 mm oocyte diameter) and mature oocytes (0.63, 0.66 and 0.71 mm oocyte diameter) were incubated in vitro in the presence of $[^3H]17{\alpha}$-hydroxyprogesterone ($[^3H]17{\alpha}$-OHP) as a precursor. Steroid metabolites were extracted from the incubated media and oocytes, the extracts were separated and identified by thin-layer chromatography (TLC), high performance liquid chromatography (HPLC) and gas chromatographymass spectrometry (GC-MS). The major metabolites produced from $[^3H]17{\alpha}$-OHP were androgens [androstenedione ($A_4$) and testosterone (T)] and estrogens [$17{\beta}$-estradiol ($E_2$) and estrone ($E_1$)] and progestins [$17{\alpha},20{\alpha}$-dihydroxy-4-pregnen-3-one ($17{\alpha}20{\alpha}P$) and $17{\alpha},20{\beta}$-dihydroxy-4-pregnen-3-one ($17{\alpha}20{\beta}P$)] in vitellogenic and mature oocytes. The results from this study suggest the potential roles of $E_1$ in the oocytes with diameter 0.52-0.71 mm, $17{\alpha}20{\alpha}P$ and $17{\alpha}20{\beta}P$ at the oocytes of 0.63, 0.66 and 0.71 mm.

• Journal of Ginseng Research
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• 제44권3호
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• pp.413-423
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• 2020

Background: Ginseng berries (GBs) show temporal metabolic variations among different maturation stages, determining their organoleptic and functional properties. Methods: We analyzed metabolic variations concomitant to five different maturation stages of GBs including immature green (IG), mature green (MG), partially red (PR), fully red (FR), and overmature red (OR) using mass spectrometry (MS)-based metabolomic profiling and multivariate analyses. Results: The partial least squares discriminant analysis score plot based on gas chromatography-MS datasets highlighted metabolic disparity between preharvest (IG and MG) and harvest/postharvest (PR, FR, and OR) GB extracts along PLS1 (34.9%) with MG distinctly segregated across PLS2 (18.2%). Forty-three significantly discriminant primary metabolites were identified encompassing five developmental stages (variable importance in projection > 1.0, p < 0.05). Among them, most amino acids, organic acids, 5-C sugars, ethanolamines, purines, and palmitic acid were detected in preharvest GB extracts, whereas 6-C sugars, phenolic acid, and oleamide levels were distinctly higher during later maturation stages. Similarly, the partial least squares discriminant analysis based on liquid chromatography-MS datasets displayed preharvest and harvest/postharvest stages clustered across PLS1 (11.1 %); however, MG and PR were separated from IG, FR, and OR along PLS2 (5.6 %). Overall, 24 secondary metabolites were observed significantly discriminant (variable importance in projection > 1.0, p < 0.05), with most displaying higher relative abundance during preharvest stages excluding ginsenosides Rg1 and Re. Furthermore, we observed strong positive correlations between total flavonoid and phenolic metabolite contents in GB extracts and antioxidant activity. Conclusion: Comprehending the dynamic metabolic variations associated with GB maturation stages rationalize their optimal harvest time per se the related agroeconomic traits.

• 한국식품위생안전성학회지
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• 제23권2호
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• pp.91-97
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• 2008

Kimchi is a representative traditional food in Korea and a type of vegetable product that is the unique complex lactic acid fermentation in the world. It can be considered as a unique fermented food generated by various flavors, which are not included in raw materials, that can be generated by mixing and fermenting various spices and seasonings, such as red pepper powder, garlic, ginger, and salted fish, added to Chinese cabbages. Functionalities in Kimchi have been approved through several studies and the probiotic function that is mainly based on lactic acid bacteria including their physical functions in its contents has also verified. Studies on the verification of the safety of Kimchi including its physiological functions have been conducted. In particular, the function of lactic acid bacteria, which is a caused of the fermentation of Kimchi. Although the lactic acid bacteria contributed to the fermentation of Kimchi is generated from raw and sub-materials, the lactic acid bacteria attached on Chinese cabbages has a major role in the process in which the fermentation temperature and dominant bacteria are also related to the process. The salt used in a salt pickling process inhibits the growth of the putrefactive and food poisoning bacteria included in the fermentation process of Kimchi and of other bacteria except for such lactic acid bacteria due to the lactic acid and several antimicrobial substances generated in the fermentation process, such as bacteriocin and hydrogen peroxide. In addition, the carbon dioxide gas caused by heterolactic acid bacteria contributes to the inhibition of aerobic bacteria. Furthermore, special ingredients included in sub-materials, such as garlic, ginger, and red pepper powder, contribute to the inhibition of putrefactive and food poisoning bacteria. The induction of the change in the intestinal bacteria as taking Kimchi have already verified. In conclusion, Kimchi has been approved as a safety food due to the fact that the inhibition of food poisoning bacteria occurs in the fermentation process of Kimchi and the extinction of such bacteria.

• 한국자동차공학회논문집
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• 제22권5호
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• pp.59-65
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• 2014

Diesel engines have the superior combustion efficiency and fuel economy that they are widely used for industry, heavyduty vehicles, etc. However, its exhaust emissions have become the major concerns due to their environmental impacts. Moreover, the depletion of fossil fuels is the main issue. Therefore, it is important to look for alternative sources of energy. Bio-diesel is one of the ideal energy which has proved to be ecofriendly for more than fossil fuels. The experimental tests analysed the engine performance and emission characteristics of a diesel engine using diesel and biodiesel blended of BD25, BD45 and BD65, in order to study the use of clean fuel to meet the increasingly stringent emission regulations. The engine performance was examined by using engine dynamometer while an exhaust gas analyzer was used to examine the emission characteristics. The effect of biodiesel on engine performance were lower to diesel through comparing their HP and torque but fuel consumption was slightly increased because of biodiesel has lower heating value and higher density than diesel. However, due to the better lubricity, the brake thermal efficiency of biodiesel was higher than diesel. The emission characteristics were strongly affected by the blending ratio of diesel and biodiesel. The results showed that the smoke opacity, hydrocarbons (HC) and carbon monoxide (CO) emissions decreased while the nitrogen oxides (NOX) slightly increased.

• Environmental Analysis Health and Toxicology
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• 제29권
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• pp.18.1-18.9
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• 2014

Objectives The purpose of this study was to determine a separation method for each arsenic metabolite in urine by using a high performance liquid chromatography (HPLC)-inductively coupled plasma-mass spectrometer (ICP-MS). Methods Separation of the arsenic metabolites was conducted in urine by using a polymeric anion-exchange (Hamilton PRP X-100, $4.6mm{\times}150mm$, $5{\mu}m$) column on Agilent Technologies 1260 Infinity LC system coupled to Agilent Technologies 7700 series ICP/MS equipment using argon as the plasma gas. Results All five important arsenic metabolites in urine were separated within 16 minutes in the order of arsenobetaine, arsenite, dimethylarsinate, monomethylarsonate and arsenate with detection limits ranging from 0.15 to $0.27{\mu}g/L$ ($40{\mu}L$ injection). We used G-EQUAS No. 52, the German external quality assessment scheme and standard reference material 2669, National Institute of Standard and Technology, to validate our analyses. Conclusions The method for separation of arsenic metabolites in urine was established by using HPLC-ICP-MS. This method contributes to the evaluation of arsenic exposure, health effect assessment and other bio-monitoring studies for arsenic exposure in South Korea.