Optimization of Subcritical Water Extraction of Flavanols from Green Tea Leaves

Ko, Min-Jung,Cheigh, Chan-Ick,Chung, Myong-Soo American Chemical Society 2014 Journal of agricultural and food chemistry Vol.62 No.28

<P>The subcritical-water extraction (SWE) of six kinds of flavanols from green tea leaves and the effect of extraction conditions were investigated by varying the temperature and time. The maximum yield of total flavanols, 71.36 ± 4.23 mg/g green tea leaves (mean ± SD), was obtained under extraction temperature/time conditions of 150 °C/5 min. The efficiency of SWE for total flavanols was slightly higher than that of the conventional extraction solvents such as methanol and ethanol. The extraction of flavanols via SWE was specifically adequate for epimer structures such as catechin, catechin gallate, and gallocatechin gallate due to the epimerization of epicatechins. The extraction efficiency of epimers was increased at temperatures up to 170 °C, whereas that of epicatechins was decreased. Thus, most epicatechins were converted to epimers during SWE, leading to some flavanol destruction at high temperatures, except when a short extraction time of 5 min was used.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jafcau/2014/jafcau.2014.62.issue-28/jf5012006/production/images/medium/jf-2014-012006_0006.gif'></P>

Conversion of 6-gingerol to 6-shogaol in ginger (<i>Zingiber officinale</i>) pulp and peel during subcritical water extraction

Ko, Min-Jung,Nam, Hwa-Hyun,Chung, Myong-Soo Elsevier 2019 Food chemistry Vol.270 No.-

<P><B>Abstract</B></P> <P>Subcritical water extraction is an eco-friendly method for the extraction of less polar compounds without the use of organic solvents. This study determined the extraction conditions that maximize the contents of 6-gingerol and 6-shogaol obtained from ginger pulp and peel. The highest yields of 6-gingerol (0.68 ± 0.08 mg/g), and 6-shogaol (0.39 ± 0.03 mg/g) were obtained from ginger pulp at the extraction conditions of 130 °C/25 min, and 190 °C/15 min. 6-Shogaol content increased with the increasing extraction temperature and extraction time due to the conversion of 6-gingerol to 6-shogaol by thermal cracking. The antioxidant activity of ginger extracts were increased depending on the increasing of 6-shogaol content.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Extraction of 6-gingerol and 6-shogaol from ginger was conducted by using subcritical water. </LI> <LI> The contents of 6-gingerol and 6-shogaol from the peel were smaller than pulp. </LI> <LI> 6-Gingerol can be converted to 6-shogaol via processes of subcritical water extraction. </LI> <LI> The antioxidant activity was increased depending on the 6-shogaol content. </LI> </UL> </P>

대추 아임계수 추출물의 폴리페놀 함량 및 산화방지 평가

고민정(Min-Jung Ko),권미리(Mi-Ri Kwon),정명수(Myong-Soo Chung) 한국식품과학회 2021 한국식품과학회지 Vol.53 No.3

아임계수 추출 기술을 이용하여 대추 추출물을 얻고 총 페놀 함량, DPPH 라디칼 소거능과 ABTS 라디칼 소거능을 이용하여 추출조건에 따른 페놀 성분 함량 변화 및 산화 방지효과를 확인하였다. 아임계수 추출물은 총 페놀 함량, DPPH라디칼 소거능, ABTS 라디칼 소거능의 결과 값이 모두 메탄올 및 에탄올을 이용하여 추출한 결과 보다 우수하게 나타났다. 아임계수 추출법은 메탄올 및 에탄올을 이용하여 추출하는 방법 보다 추출 시간도 20분 이내로 짧았고, 유기용매를 사용하지 않고 친환경적으로 추출할 수 있었다. 아임계수 추출물의 총 페놀 함량과 산화방지 효과의 결과는 높은 상관관계를 보였는데, 항산화 효과가 있는 페놀류가 많이 추출될수록 산화방지 효과도 우수하게 나타났다. 본 연구를 통해, 아임계수 추출 방법은 오직 물을 사용하여 유효성분을 추출하는 친환경적이고 안전한 신가공기술이며 잠재성과 우수성을 확인하였다. 아임계수 추출기술은 앞으로도 다양한 유효성분추출 및 소재 가공으로 식품 산업에 응용하여 사용될 수 있을 것이다. Subcritical water extraction (SWE) is an eco-friendly extraction method that uses only purified water as a solvent under high temperature and high pressure conditions. In this study, total phenolics, and antioxidant activity were evaluated in Ziziphus jujuba Mill extracts from subcritical water obtained by varying the extraction temperature (110-190℃) and extraction time (1-20 min). Total phenolics was maximized with extraction at 190℃ for 15 min (67.79±3.45 mg gallic acid equivalent/g jujube). The 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity (48.84±4.74%) and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) free radical scavenging activity (84.75±1.15%) were maximal at extraction conditions of 190℃, for 20 min. All jujube extracts prepared using SWE had higher total phenolics and antioxidant activities than extracts prepared using organic solvent extraction (60℃, 120 min), including methanol and ethanol. SWE could be an excellent alternative to organic solvents for extracting phenolics and antioxidant compounds.

자몽껍질 유래 플라바논의 최적 추출 및 기능성 소재 캡슐화

고민정(Min-Jung Ko),권혜림(Hye-Lim Kwon),정명수(Myong-Soo Chung) 한국식품과학회 2014 한국식품과학회지 Vol.46 No.4

버려지는 자몽 껍질에 다량 함유되어있는 플라바논을 추출하여 기능성 성분을 재이용하였다. 친환경용매인 아임계수 추출기술을 이용하여 170℃, 10 min의 최적 조건에서 추출함으로써 무독성 용매로 빠르고 경제적으로 추출할 수 있었다. 자몽껍질 추출물을 β-cyclodextrin을 이용하여 처리함으로써 플라바논과 같은 비극성 물질을 캡슐화하여 소재의 가용화를 용이하게 하였다. 이것은 항산화 기능이 향상된 대체 소재의 개발 및 건강지향식품에 이용할 수 있으며, 이를 통하여 세계 기능성 식품 시장으로의 진출을 위한 발판으로도 삼을 수 있을 것으로 기대된다. The extraction of flavanones such as naringin, narirutin, naringenin, hesperidin, and hesperetin from grapefruit peels was performed using subcritical water extraction (SWE), hot water extraction, and conventional methods such as methanol and ethanol extraction. We analyzed the total flavanone content using high-performance liquid chromatography (HPLC) for each extracting method. Among the three methods, SWE was the optimal method with optimal operating conditions of 170℃ temperature and 10 min operating time. The maximum total flavanone extracted was 86.539±3.52 mg/g grapefruit peels. Moreover, we treated the extracts with 60% β-cyclodextrin and then analyzed the surface structure of the encapsulated compounds by field emission-scanning electron microscopy (FE-SEM). The results indicated that the encapsulation in β-cyclodextrin improved solubilization, and the inclusion complex could serve as food supplements.

추출방법에 따른 감귤 과피 유래 Flavonoid의 추출효율 및 항산화 효과에 대한 비교

최찬익 ( Chan Ick Cheigh ),정원근 ( Won Guen Jung ),정은영 ( Eun Young Chung ),고민정 ( Min Jung Ko ),조상우 ( Sang Woo Cho ),이재환 ( Jae Hwan Lee ),장판식 ( Pahn Shick Chang ),박영서 ( Young Seo Park ),백현동 ( Hyun Dong Paik 한국산업식품공학회 2010 산업 식품공학 Vol.14 No.2

본 연구에서는 감귤 과피 가공부산물로부터 기능성 polyphenol 및 flavonoid가 새로운 추출방법인 아임계 추출법을 통해 추출되었고, 열수(80oC), 에탄올, 설탕용액을 이용한 기존 추출법과의 추출효율이 비교 분석되었다. 건조된 감귤 과피로부터 총 polyphenol(27.25±1.33mg QE/g DCP) 및 flavonoid(7.31±0.41mg QE/g DCP)에 대한 최대수율이 아임계 추출법(190°C, 1300 psi, 10 min)을 통해 획득되었으며, 이것은 기존 추출법 가운데 가장 높은 수율을 보인 에탄올 추출법을 통한 총 polyphenol(3.79±0.73mg QE/g DCP) 및 flavonoid(0.86±0.27mg QE/g DCP) 수율 대비 7.2배와 8.5배 이상 더 높은 것이었다. 추출방법에 따른 감귤 과피 추출물의 항산화 활성은 큰 차이를 나타내지 않았으나, 이러한 결과는 건조 감귤 과피 1g 당 아임계 추출법(190oC, 1300 psi, 10 min)에 의한 항산화 성분의 상대 수율(relative yield, %)이 다른 추출방법을 통해 획득된 것보다 대략 9.5배 이상 더 높다는 것을 설명하는 결과로, 아임계 추출법이 기존의 전통적 추출법에 비하여 감귤 과피의 기능성 polyphenol 및 flavonoid를 추출하는데 매우 적합한 방법임을 제시하고 있다. The extraction of polyphenol and flavonoid from citrus peel was performed by the ethanol, sugar, hot water (80oC), and subcritical water extraction methods. The maximum yields of total polyphenolic compounds (27.25±1.33mg QE/g DCP, QE and DCP indicate quercetin equivalent and dried citrus peel, respectively) and flavonoids (7.31±0.41mg QE/g DCP) were obtained by subcritical water extraction (SWE) with operating conditions of 190oC, 1300 psi, and 10 min. The yields by SWE were over 7.2-, and 8.5-fold higher than those of total polyphenols (3.79±0.73mg QE/g DCP) and flavonoids (0.86±0.27mg QE/g DCP) obtained using the ethanol extraction, which showed the highest extraction efficiency among tested conventional methods, respectively. Antioxidant activities of extracts obtained by different methods showed no significant differences. However, the relative antioxidant yield per 1 g dried citrus peel by SWE (190oC, 10 min) was over 9.5-fold higher than that by the ethanol extraction.

아임계수 추출에 의한 홍삼 추출물의 진세노사이드 조성 및 이화학적 특성

이주미(Joo-Mi Lee),고민정(Min-Jung Ko),정명수(Myong-Soo Chung) 한국식품과학회 2015 한국식품과학회지 Vol.47 No.6

홍삼의 신규 추출 방법으로 아임계수 추출(subcritical water extraction, SWE)을 적용하여 홍삼 추출물의 이화화적 특성 및 진세노사이드 추출 특성을 조사함으로써 최적 아임계수 추출 조건을 결정하고 기존 추출 방법과 비교함으로써 산업적 이용 효율을 평가하였다. 아임계수 추출에 의한 홍삼 추출물의 당도, 고형분 함량, 색차 및 탁도는 추출 온도가 높아지고 추출 시간이 길어질수록 증가하였고 pH는 낮아졌으며, 조 사포닌은 120℃, 20분에서 최대였다. TLC 및 HPLC 분석 결과, 총 및 극성 진세노사이드 농도는 120℃, 20분에서 최대였고 홍삼 특유의 저극성 진세노사이드 Rg3, Rh1 등은 150℃, 15분에서 최대 농도였다. 또한 최적 아임계수 추출과 열수, 에탄올 및 메탄올을 용매로 환류 냉각 추출하여 비교한 결과, 저극성 진세노사이드의 추출 이행률은 150℃, 15분의 아임계수 추출에서 가장 높았고 특히 Rg3는 3.5-5배, Rh1은 2-2.5배의 높은 농도로 나타났다. 홍삼의 특이 사포닌으로 극미량 존재하는 Rg3 및 Rh1은 강력한 항암 효과 등이 보고되면서 최근 화학적, 물리적, 생물학적 방법에 의한 전환 연구가 활발히 진행되고 있으나 낮은 선택성과 생산성의 저하, 부 반응으로 인한 환경 공해 및 대량 생산의 한계 등으로 산업적 적용에 제약이 존재하여 왔다. 본 연구에서는 아임계 상태에서의 물의 특성 변화를 이용한 아임계수 추출을 적용하여 홍삼으로부터 특히 저극성 진세노사이드의 선택적 추출 및 전환에 효과적인 대체 기술로서 가능성을 확인하였다. Red ginseng was treated by subcritical water extraction (SWE) whose two parameters were the extraction temperature (105-150℃) and time (5-20 min) under a high pressure. The oBrix value, solid content, color difference, and turbidity of the red ginseng extract increased with increasing extraction time and temperature, while the pH decreased. The total concentration of ginsenosides in the red ginseng extract was maximal at 120℃ and 20 min. The concentrations of ginsenosides Rg3 and Rh1 were maximal at 150oC and 15 min. The concentrations of Rg3 and Rh1 were respectively 3.5- 5 times and 2-2.5 times higher than those treated by conventional extraction methods with hot water, ethanol, and methanol. SWE is a particularly effective method for the selective extraction of less-polar ginsenosides such as Rg3 which is well known to exert strong anticancer effects.

Improving the subcritical water extraction of flavonoids narirutin and hesperidin from Citrus unshiu peel by pulsed electric fields

Hui-Ju Kim,Mi-Ri Kwon,Hye-Ji Kang,Na-Yeon Kim,Hee-Jeong Hwang,Min-Jung Ko,Myong-Soo Chung 한국산업식품공학회 2017 학술대회 및 심포지엄 Vol.2017 No.11

Citrus fruit is important source of flavonoids, mainly flavanones which are narirutin and hesperidin. Those citrus flavonoids have been found to have health-related properties including antioxidant, anticancer, and anti-inflammatory. The main purpose of this study was to verify that the extraction of narirutin and hesperidin from Citrus peel can be more effective by combining pulsed electric field (PEF) pre-treatment and subcritical water extraction (SWE). Citrus unshiu peels were treated with PEF under conditions of electric field strength (3 kV/cm) and times (1 and 2 min). Subsequent SWE was conducted by using a Dionex Accelerated Solvent Extractor (ASE, Model 350) at extraction temperature 170°C for 10 min. The total flavonoids content was measured by using the aluminum chloride colorimetric method and the antioxidant capacity was analyzed by the Ferric reducing antioxidant power (FRAP) assay using spectrophotometer. The concentrations of narirutin and hesperidin were increased as PEF pre-treatment time increased. The highest concentrations of narirutin and hesperidin were 13.41 mg narirutin/g dry citrus peel and 141.16 mg hesperidin/g dry citrus peel at PEF pre-treatment condition of 3 kV/cm and 2 min. The total flavonoids contents of the extracts increased 105.2% and 123.1% for citrus peel PEF treated at 1 and 2 min, respectively. In addition, compared to the untreated sample, PEF pre-treatments of 1 and 2 min increased the antioxidant capacity of the extracts 109.2% and 160.8%, respectively. Therefore, the results demonstrate the potential of PEF pre-treatment to improve the SWE of flavonoids from citrus unshiu peel.

뼈흡수유도호르몬이 ROS17/2.8세포로부터 Nitric Oxide 형성에 미치는 영향

고선일,김민성,한원정,김세원,김정근 대한구강악안면방사선학회 2005 Imaging Science in Dentistry Vol.35 No.3

Purpose : We performed the present study to investigate whether osteotropic hormomes play roles on the nitric oxide (NO) production in culture of ROS17/2.8 osteoblastic cells. Materials and Methods : The osteoblastic cell line ROS17/2.8 cells were cultured in F12 medium supplemented with 5% fetal bovine serum (FBS) at 37?C in a humidified atmosphere of 5% CO₂ in air. ROS17/2.8 cells were plated in 96-well plates at a density of 2-3×10³ cells/well and grown to confluence. Then the cells were pretreated with osteotropic hormones (parathyroid hormone (PTH) 20-500 ng/mL, 1,25 dihydroxycholecalciferol (1,25[OH]₂D₃) 1-100 nM; prostaglandin E₂ (PGE₂) 20-500 ng/mL) in the medium supplemented with 0.4% FBS for 72 hours and the cells were treated with cytokines (TNFα and IFNγ) in phenol red-free F12 medium for an additional 48 hours. NO synthesis was assessed by measuring the nitrite anion concentration, the reaction product of NO, in the cell culture medium using Griess reagent. Results : PTH and 1, 25[OH]₂D₃ pretreatment induced a significant increase in NO production in the presence of TNFα and IFNγ. PGE₂ slightly induced NO production compared to the control group. But, PGE2 pretreatment did not affect in NO production in the presence of TNFα and IFNγ. Conclusions : These results suggest that the actions of osteotropic hormones in bone metabolism may be partiallymediated by NO in the presence of cytokines.

H9c2 심근 세포주에서 외인성 nitric oxide가 허혈에 의한 세포 독성에 미치는 영향

정성구,장현용,김명천,고영관,정주호,배영미,박원서,김대중,유영민,김성수,임성빈 대한응급의학회 2001 대한응급의학회지 Vol.12 No.4

Background: Nitric oxide(NO) is known to have protective effects on an ischemic heart and to exert triggering effects on ischemic preconditioning. However, the effects of NO during the ischemic period have not been investigated. To investigate the role of exogenous nitric oxide in a model of ischemic heart cell death, we studied the effects of ischemic preconditioning and ischemia in a normal and an ischemic buffer. Methods: Rat cardiac myoblast cells(H9c2) were cultured in a normal and an ischemic buffered medium. For the ischemic culture of heart cells, the cells were cultured in a dessicator with GasPak for 5 hrs. In ischemic preconditioning, the cells were pretreated with ischemic buffer for 5 min and then perfused with normal medium for 30 min. For the measurement of the cytotoxicity, a MTT(3-4-Sdimethylthiazol-2-yl-2,5-diphenyl tetrazolium bromide) assay was performed. A DAPI(4',6-diamidino-2-phenylindole dihydrochloride) staining procedure and a flow cytometry analysis were performed to confirm apoptotic cell death by ischemia. Results: Cell viability, as determined by using a MTT assay, showed that the preconditioned group treated with NO showed more cell death than with the not-preconditioned groups in both normal and ischemic buffers. But, In normal medium and not-preconditioned groups, NO showed protective effect according to the concentrations(100,1000μM) . No treatment with NO produced the different results. In normal medium, the protective effect of ischemic preconditioning was demonstrated, but no protective effect of ischemic preconditioning could be seen in the case of the ischemic buffer. The DAPI staining and flow cytometry analysis of heart cells showed characteristic apoptotic features. Conclusion: NO added in the ischemic phase had deterious effects on heart cells. Ischemic preconditioning was more harmful than ischemia alone. The toxicity of the cells was characteristic apoptosis.

애니메이션에 나타난 남성 중심적 시선의 전복 연구 : 조안나 퀸과 앨리슨 스노우덴의 작품을 중심으로

고민정,김재웅 영상예술학회 2010 영상예술연구 Vol.16 No.-

영국 애니메이션의 황금기라고 일컬어지는 1980년대 중반에서 1990년대 중반에 이르는 기간 동안 여성 감독들에게 우호적인 환경이 마련되었다. 조안나 퀸(Joanna Quinn)과 앨리슨 스노우덴(Alison Snowden)은 이 시기에 활동을 시작했는데, 세계적으로 명성이 높은 안시 국제 애니메이션 페스티벌에서 스노우덴의 <2급 우편>(Second Class Mail)이 1984년에, 퀸의 <걸즈 나잇 아웃>(Girls’ Night Out)이 1987년에 각각 수상했다. 이 두 작품은 남성 중심적 시선에 따른 여성 재현이라는 기존 관습을 전복하는데, 퀸과 스노우덴은 이후에도 90년대 중반까지 이와 비슷한 경향의 작품들을 제작했다. 존 버거와 로라 멀비의 지적처럼, 여성을 대상화하는 남성 중심적 시선은 가부장제와 자본주의 사회에서 구조화된 시각양식이며 이것은 회화, 사진, 주류영화 뿐 아니라 밥 고드프리(Bob Godfrey)와 텍스 에이버리(Tex Avery)와 같은 남성 감독의 애니메이션에서도 지속적으로 나타난다. 그러나 조안나 퀸과 앨리슨 스노우덴은 밥 고드프리와 텍스 에이버리의 섹스 코미디를 패러디하여 기존의 회화와 애니메이션에서 재생산되던 남성 주체와 여성 대상이라는 관습을 전복한다. 여성 캐릭터들은 더 이상 성적 대상으로 머무르지 않고 스스로 욕망하는 주체이자 욕망을 성취하기 위해 행동하는 존재로서 남성 캐릭터를 밀어내고 그의 행동을 그대로 재연한다. 반면 시선의 주체인 남성은 성적 대상으로 전락한다. 그러나 남녀의 역할 전도를 통한 남성 중심적 시선의 전복은 오히려 성적 이분법을 강화하기 때문에 진정한 의미에서 전복이라고 할 수 없다. 퀸과 스노우덴의 시도는 남성적 시선에 반대되는 여성적 시선을 제시한다기보다는 이미 익숙하게 몸에 배어 있어서 당연시하게 되는 기존 관습의 존재 자체를 깨닫게 만드는 역할을 한다. 애니메이션은 다른 ‘진지한’ 예술들과 달리 관습을 깨고 변형시키는데서 새로운 유머를 생산할 수 있기 때문에, 지배적 재현을 해체하는 것은 일종의 전략적 실천으로서 유머를 창조하는 수단으로 작용할 수 있었다. There was a supportive environment for female filmmakers from the mid- 1980s to the mid-1990s, the so-called “golden age of animated film in the U.K.” In those days, Joanna Quinn and Alison Snowden began to create their own works. Both Snowden’s Second-Class Mail (1984) and Quinn’s Girls’ Night Out (1987) won the best-animated-film award and three other awards at the Annecy International Animated-Film Festival. In their respective works, they subverted the traditional representation of women as merely objects of the male sexual desire. Quinn and Snowden came up with a series of animations with the same subject until the mid-1990s. According to John Berger and Laura Mulvey, the male gaze, which is brought about by patriarchy and capitalism, is reproduced in photos and in the mainstream and animated films of male filmmakers. The works of Quinn and Snowden, however, which spoof the sex comedies of Bob Godfrey and Tex Avery, subvert the tradition of the male subject and the female object. In their works, the female characters are not depicted as objects of the male sexual desire. They reenact the male character’s role to make desire a subject, and a male who becomes the target of a gaze even just once may be degraded into an object of sexual desire. There is no true subversion, however, of the changing roles between men and women in the works of the two female filmmakers because their works actually further reinforce the sexual dichotomy. Quinn and Snowden’s attempts do not make the female gaze contradictory to the male gaze but make people realize the traditional representation of women. Contrary to serious art, it is a strategic practice to break dominant representations and to create new humor in animated films.