Gas Chromatography를 이용한 멸치젓의 DHA 분석

육현균,하정욱,이승철 慶南大學校 附設 工業技術硏究所 1998 硏究論文集 Vol.16 No.-

멸치젓은 한국의 고유 수산발효식품으로 널리 이용되고 있는 기호식품이다. 멸치젓의 기능성을 살펴보기 위한 기초연구로 기능성 소재인 docosahexaenoic acid (DHA) 함량을 gas chromatorgraphy를 이용하여 분석 하였다. 먼저 산분해법에 의해 고형분의 경우 평균 4,520 ppm 검출되었으며, 액젓의 경우 농축을 하지 않고 산분해법으로 처리한 것과 농축을 한 후 산분해법으로 처리하여 측정한결과 전자는 평균 108 ppm, 후자는 82 ppm으로 검출되었다. 또한 시간이 경과함에 따라 멸치 액젓이 DHA 함량이 감소되어 정확한 검출을 위해서는 항산화제의 첨가가 필요하다. The anchovy-jeot (salt-fermented anchovy) has being widely used as a traditional fish fermented food in Korea. For examining the functional characteristic of the anchovy-jeot, docosahexaenoic acid (DHA) was analyzed by gas chromatography. DHA contents of anchovy solid and anchovy sauce by acidolysis method was 4,520 ppm and 108 ppm, respectively, while that of anchovy sauce by acidolysis method after concentration was 82 ppm. That means that the condition of previous treatment for anchovy sauce would affect the determination of DHA. Furthermore, addition of antioxidant would be needed because DHA of anchovy-jeot was decreased with days by oxidation.

배박에서 펙틴의 추출을 위한 Exo-polygalacturonase의 반응조건 검토

육현균(Hyun-Gyun Yuk),최진호(Jin-Ho Choi),조용진(Yong-Jin Cho),하정욱(Jung-Uk Ha),황용일(Yong-Il Hwang),이승철(Seung-Cheol Lee) 한국식품과학회 1999 한국식품과학회지 Vol.31 No.4

Antioxidant and Tyrosinase Inhibitory Activities of Different Parts of Oriental Cherry (Prunus serrulata var. spontanea)

박지원,Hyun Gyun Yuk,이승철 한국식품과학회 2012 Food Science and Biotechnology Vol.21 No.2

Six different parts (branch, flesh, flower, fruit,leaf, and seed) of oriental cherry (Prunus serrulata var. spontanea) were extracted with ethanol or water, then total phenol content (TPC), antioxidant activity, and tyrosinase inhibitory activity of the extracts were evaluated. The ethanol extracts showed higher TPC and antioxidant activity than the water extracts regardless of parts. The ethanol extracts of leaf as well as branch possessed superior TPC and antioxidant activity. The highest tyrosinase inhibitory activity was found in ethanol extract of leaf. There was no dramatic difference of tyrosinase inhibitory activities according to parts of cherry. The results suggest that leaf and branch of oriental cherry could be a candidate for antioxidant and anti-whitening materials in food or cosmetic industries.

Antioxidant, Tyrosinase Inhibitory, and Acetylcholinesterase Inhibitory Activities of Green Tea (Camellia sinensis L.) Seed and Its Pericarp

조영홍,Hyun-Gyun Yuk,이종화,김종철,김루미,이승철 한국식품과학회 2012 Food Science and Biotechnology Vol.21 No.3

The present study evaluates antioxidant, tyrosinase inhibitory, and acetylcholinesterase (AChE) inhibitory activities of seed and its pericarp of tea plant (Camellia sinensis L.). Water and methanol extracts of tea seed and pericarp were prepared in a shaking incubator overnight at room temperature. The highest total phenolic contents,DPPH and ABTS radical scavenging activities, reducing power, β-carotene bleaching inhibition activity, highest tyrosinase inhibitory activity, and AChE inhibitiory activity were found in the methanol extracts of pericarp. Caffeine,gallic acid, several phenolic compounds, hydroxymethyl furfural, and fatty acid derived compounds were detected in the extract of tea seed and pericarp. The results indicate that seed and pericarp could be utilized as the potential resources for antioxidant ingredients in food industry. In addition, these compounds may protect Alzheimer’s disease as they had inhibitory activity of acetylcholine esterase.

Antioxidant and Tyrosinase Inhibitory Activities of Different Parts of Guava (Psidium guajava L.)

유동현,박지원,Hyun-Gyun Yuk,이승철 한국식품과학회 2011 Food Science and Biotechnology Vol.20 No.4

The antioxidant and the tyrosinase inhibitory activities of 4 different solvents (acetone, ethanol, methanol,and water) for preparation of extracts from guava (branch,fruit, leaf, and seed) were evaluated by measuring total phenolic contents (TPC), DPPH radical scavenging activity, ABTS radical scavenging activity, reducing power (RP), and tyrosinase inhibitory activity. The extracts of branch and leaf showed relatively higher antioxidant properties than those of fruit and seed. The highest TPC (141.28 mg/g gallic acid equivalents), DPPH radical scavenging activity (IC50=34.01 μg/mL), ABTS radical scavenging activity (IC_50=3.23 μg/mL), and RP (IC_50=75.63 μg/mL) were found in acetone extract of leaf, while water extract of seed had the lowest antioxidant activity. The tyrosinase inhibitory activity of ethanol extract from guava leaf was 69.56%, which was the highest activity among the extracts. These results indicate that useful bioactive substances exist in the guava branch as well as leaf extracts.

Stabilization of Retinol through Incorporation into Liposomes

(Seung Cheol Lee),(Hyun Gyun Yuk),(Dong Hoon Lee),(Kyung Eun Lee),(Yong Ll Hwang),(Richard D. Ludescher) 생화학분자생물학회 2002 BMB Reports Vol.35 No.4

Chemical and photochemical processes during storage and preparation rapidly degrade retinol, the most active form of vitamin A. Therefore, the efficacy of incorporation into liposomes in order to modulate the kinetics of retinol degradation was investigated. Retinol was readily incorporated into multilamellar liposomes that were prepared from soybean phosphatidylcholine; the extent of the incorporation was 98.14±0.93% at pH 9.0 at a ratio of 0.01 : 1 (wt : wt) retinol : phospholipid. It was only marginally lower at higher retinol concentrations. The pH of the hydration buffer had a small effect. The incorporation efficiency ranged from 99.25±0.47% at pH 3 to 97.45±1.13 % at pH 11. The time course of the retinol degradation in the aqueous solution in liposomes was compared to that of free retinol and free retinol with atocopherol under a variety of conditions of pH (3, 7, and 11), temperature (4, 25, 37, and 50℃), and light exposure (dark, visible, and UV). The retinol that was incorporated into the liposomes degraded significantly slower than the free retinol or retinol with α-tocopherol at pH 7 and 11. At pH 3, where the free retinol degrades rapidly, the degradation kinetics were similar in liposomes and the presence of α-tocopherol. At pH 7.0 and 4℃ in the light, for example, free aqueous retinol was completely degraded within 2 days, while only 20% of the retinol in the liposomes were degraded after 8 days. In general, the protective effect of the liposome incorporation was greater at low temperatures, at neutral and high pH, and in the dark. The results suggest that protection is greater in the solid, gel phase than in the fluid liquid crystalline phase lipids. These results indicate that the incorporation into liposomes can extend the shelf-life of retinol under a variety of conditions of temperature, pH, and ambient light conditions.

Antibacterial mechanism of combination of light emitting diode (405 nm and 460 nm) treatment and chitosan for pathogenic bacteria observed by TEM and flow cytometry

Su-Jin Kim,Hyun-Gyun Yuk,Woo-Suk Bang 한국식품영양과학회 2021 한국식품영양과학회 학술대회발표집 Vol.2021 No.10

This study was to evaluate the bactericidal effects and antibacterial mechanism on Escherichia coli O157:H7, Salmonella Typhimurium, Listeria monocytogenes serovar 1/2a, and Staphylococcus aureus by combining blue light LED (405, 460 nm) and chitosan at low temperature. The D-values of E. coli O157:H7, S. Typhimurium, L. monocytogenes, and S. aureus irradiated with 405 nm LED at 4℃ were 5.7, 3.2, 1.0, and 2.1 h, respectively. Also, the D-values of combination treatment by 405 nm LED and 1% chitosan was significantly reduced to 2.1, 2.3, 0.4, and 1.4 h, respectively. Loss of efflux pump activity, damage to the glucose uptake system, and changes in membrane depolarization and permeability were observed by flow cytometry in all strains irradiated. Additionally, cell morphology of E. coli O157:H7 and L. monocytogenes were observed by transmission electron microscope (TEM). In the treated cells, the normal cellular structure was destroyed and the intracellular components were released. These results showed that the combination of 405 nm LED with chitosan (1%) caused severe damage to the cell membrane and cytoplasmic regions of bacterial cells, leading to cell death.

Antioxidant and Tyrosinase Inhibitory Activities of Different Parts of Oriental Cherry (Prunus serrulata var. spontanea)

Park, Ji-Won,Yuk, Hyun-Gyun,Lee, Seung-Cheol 한국식품과학회 2012 Food Science and Biotechnology Vol.21 No.2

Six different parts (branch, flesh, flower, fruit, leaf, and seed) of oriental cherry (Prunus serrulata var. spontanea) were extracted with ethanol or water, then total phenol content (TPC), antioxidant activity, and tyrosinase inhibitory activity of the extracts were evaluated. The ethanol extracts showed higher TPC and antioxidant activity than the water extracts regardless of parts. The ethanol extracts of leaf as well as branch possessed superior TPC and antioxidant activity. The highest tyrosinase inhibitory activity was found in ethanol extract of leaf. There was no dramatic difference of tyrosinase inhibitory activities according to parts of cherry. The results suggest that leaf and branch of oriental cherry could be a candidate for antioxidant and anti-whitening materials in food or cosmetic industries.

Bacillus subtilis IFO 12113 유래 Protopectinase 를 이용산 사과박의 펙틴 추출

이승철,조용진,육현균,황용일,최정선 한국농화학회 1999 Applied Biological Chemistry (Appl Biol Chem) Vol.42 No.1

Protopectinase는 불용성의 프로토펙틴을 수용화시켜 펙틴을 생산하는 효소로서, 사과박으로부터 펙틴추출을 위한 최적 pH, 반응시간, 반응온도를 조사하였다. 효소 작용 최적조건은 pH 7.8, 60℃에서 48시간의 반응시간이었으며, 펙틴 추출률은 34.3%이었다. 최적조건에서 protopectinase에 의해 추출된 펙틴의 순도는 52.9%이었으며, methoxyl 함량은 2.75%로서 저 methoxyl 함량의 펙틴이었다. 효소 반응 온도와 시간은 펙틴의 추출률과 methoxyl 함량에 크게 영향을 미치지 않았지만 반응 pH는 사과박의 펙틴 추출률과 methoxyl함량에 크게 영향을 미쳤다. 최적조건에서 추출된 펙틴의 고유점도와 분자량은 각각 0.178 ml/g과 4,900이었다. (1998년 12월 2일 접수, 1999년 1월 10일 수리)

유기용매의 처리에 따른 Bacillus subtilis IFO 12113 유래 Protopectinase의 회수

이승철,육현균,황용일 ( Seung Cheol Lee,Hyun Gyun Yuk,Yong Il Hwang ) 한국응용생명화학회 1997 Applied Biological Chemistry (Appl Biol Chem) Vol.40 No.2

To recover protopectinase (PPase) secreted from Bacillus subtilis IFO 12113, culture filtrate of the microorganism was treated with acetone, methanol, and ethanol, respectively. In the case of treatment with acetone at a ratio of 1 : 1 (culture filtrate : acetone, v/v), PPase was purified 1.7-fold with 59.2% recovery. The recovery of PPase was increased by increasing the acetone concentration. PPase was purified 4-fold with 100% recovery when the culture filtrate was precipitated with methanol at a ratio of 1 : 2 (culture filtrate : methanol, v/v). However, recovery of PPase was decreased by increasing the methanol concentration. PPase was purified 13.5-fold resulting in 68% recovery by the addition of ethanol with the final ratio 1 : 1(culture filtrate : ethanol, v/v) to the supernatant, which was obtained after precipitation of the culture filtrate with ethanol at a ratio of 1 : 0.5. These results show that methanol treatment is better than other organic solvent treatments for the simple recovery of PPase, whereas fractionated treatment of ethanol can recover PPase with higher purification fold.