• Journal of the Korean Wood Science and Technology
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• v.45 no.3
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• pp.278-287
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• 2017

In this study, lignin was efficiently degraded via two-step catalytic cracking process and lignin-oil, char, and gas was produced as lignin degraded products. Three kinds of catalysts (MgO, CaO, and Pt/C) were used in first catalytic cracking step and the highest lignin-oil yield (76.2 wt%) was obtained in Pt/C catalyst with the smallest char formation (4.1 wt%). GC-MS/FID analysis revealed that 18 kinds of monomeric phenols existed in lignin-oil and sum of them was the highest in Pt/C condition (97.8 mg/g lignin). Meanwhile, relatively lower yield of monomeric phenols was produced in MgO and CaO condition because of their absorption on catalysts. Lignin-oil produced over Pt/C was introduced to second catalytic cracking process with porous Pd/activated carbon aerogel catalyst. From this process, four kinds of monomeric phenols such as 4-ethylguaiacol, 4-propylguaiacol, 4-ethylsyringol, 4-propylsyringol were selectively produced at 0.89 - 1.82 wt% level.

• Korean Journal of Food Science and Technology
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• v.50 no.5
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• pp.464-473
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• 2018

The objective of the current study was to evaluate the effects of roasting methods on volatile flavor compounds of boricha using solvent-assisted flavor evaporation-gas chromatography (GC)-mass spectrometry and GC-olfactometry. The barley roasting methods tested were air roasting (AR), drum roasting (DR), and air/drum roasting (ADR). Twenty, twenty-one, and eighteen aroma-active compounds were detected in the products of AR, DR, and ADR, respectively. Guaiacol (smoky), 2-acetylpyrazine (almond-like), and furfuryl alcohol (burnt sugar-like) were detected as high intensity aroma-active compounds. Intensities of most aroma-active compounds produced by the DR method were higher. On the other hand, aroma intensities of phenols produced by the AR method, such as guaiacol and 2-methoxy-4-vinylphenol (curry-like), tended to be stronger. Aroma characteristics of phenols are not considered to be desirable for boricha. Although roasting time for DR was longer than that for AR, DR may be an effective barley roasting method for enhancing desirable aroma characteristics of boricha.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.3
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• pp.338-345
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• 2003

Response surface methodology was used for monitoring changes in phenolic compounds properties of Rubi Fructus extract depening on extraction conditons. The three independent variables (extraction conditions) were ratio of solvent to sample content (5, 10, 15 mL/g), ethanol concentration (20, 40, 60%) and extraction time (2, 4, 6 hr). It was anticipated that each of the five dependent Y variables (responses) would be affected by the three independent variables. The dependent responses were total yield, total phenolics content, electron donating ability, antioxidant ability and nitrite-scavenging ability (pH 1.2, 3.0, 4.2, 6.0). Total yield, total phenolics content, electron donating ability and antioxidant ability were affected by ratio of solvent to sample content. Nitrite- scavenging ability at pH 1.2 and pH 6.0 was affected by ethanol concentration, while it was affected by extraction time at pH 3.0 and pH 4.2. The optimum extraction conditions for total yield were 14.16 mL/g ratio of solvent to sample content,39.08% ethanol concentration and 2.99 hr extraction time. The maximum total phenolics content of extracts were shown at 14.06 mL/g ratio of solvent to sample content, 35.51% ethanol concentration and 3.15 hr extraction time.

• Journal of Bio-Environment Control
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• v.32 no.4
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• pp.342-352
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• 2023

Ultra-violet (UV) light is one of abiotic stress factors and causes oxidative stress in plants, but a suitable level of UV radiation can be used to enhance the phytochemical content of plants. The accumulation of antioxidant phenolic compounds in UV-exposed plants may vary depending on the conditions of plant (species, cultivar, age, etc.) and UV (wavelength, energy, irradiation period, etc.). To date, however, little research has been conducted on how leaf thickness affects the pattern of phytochemical accumulation. In this study, we conducted an experiment to find out how the antioxidant phenolic content of kale (Brassica oleracea var. acephala) leaves with different thicknesses react to UV-A light. Kale seedlings were grown in a controlled growth chamber for four weeks under the following conditions: 20℃ temperature, 60% relative humidity, 12-hour photoperiod, light source (fluorescent lamp), and photosynthetic photon flux density of 121±10 µmol m^-2 s^-1. The kale plants were then transferred to two chambers with different CO₂ concentrations (382±3.2 and 1,027±11.7 µmol mol^-1), and grown for 10 days. After then, each group of kale plants were subjected to UV-A LED (275+285 nm at peak wavelength) light of 25.4 W m^-2 for 5 days. As a result, when kale plants with thickened leaves from treatment with high CO₂ were exposed to UV-A, they had lower UV sensitivity than thinner leaves. The Fv/Fm (maximum quantum yield on photosystem II) in the leaves of kale exposed to UV-A in a low-concentration CO₂ environment decreased abruptly and significantly immediately after UV treatment, but not in kale leaves exposed to UV-A in a high-concentration CO₂ environment. The accumulation pattern of total phenolic content, antioxidant capacity and individual phenolic compounds varied according to leaf thickness. In conclusion, this experiment suggests that the UV intensity should vary based on the leaf thickness (age etc.) during UV treatment for phytochemical enhancement.

• Culinary science and hospitality research
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• v.21 no.3
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• pp.259-269
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• 2015

This study was performed to investigate the phenolic compounds content and antioxidative activity of methanol extract from Chinese soybean. The content of total phenolics and total flavonoids of Chinese soybean Heinong 48) extract were $9.91{\pm}0.57GAE\;mg/g$ and $4.15{\pm}0.39QE\;mg/g$, respectively. The antioxidative activities of Chinese soybean extract were significantly increased in a dose dependent manner on 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical scavenging and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS) radical scavenging($IC_{50}$ values were $2.04{\pm}0.16$ and $3.31{\pm}0.31mg/mL$, respectively). These results suggest that Chinese soybean may have great potential as a natural antioxidant source with health benefits.

• Journal of the Korean Applied Science and Technology
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• v.30 no.4
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• pp.761-769
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• 2013

This study used HPLC to analyze the contents of catechins, alkaloids, theanine, total phenolic compounds and antioxidant activities of commercial Hadong green tea leaves(Uzen, Sezak, Jungzak, Daezak). The content of catechins, alkaloids, theanine, total phenolic compounds were lower by water extracts than by 80% ethanol-water extracts. Total catechin and alkaloid contents in Uzen(172.33 mg/g, 30.80 mg/g) by 80% ethanol extract were the highest. Theanine contents of 80% ethanol-water extracts ranged form 55.36 to 37.48 mg/g of tea leaves. Total phenloic compounds contents of green tea were higher than Uzen. Antioxidative of green tea by DPPH, FTC, TBA method were higher than that Uzen.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.107-107
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• 2018

양파는 백합과에 속하는 여러해살이풀로 서남아시아의 페르시아가 원산인데 세계 각국의 온대지방에서 많이 재배하고 있다. 양파의 생약명은 옥총(玉憁)으로 피 속의 콜레스테롤을 떨어뜨리고 심장혈관의 혈류량을 증가시켜 성인병 예방에 좋다. 철원지역은 내륙지방이면서도 고도가 높아 기온차가 큰 대륙성 기후의 성격이 강하기 때문에 이 지역에서 재배한 양파는 남부지방에서 재배된 양파보다 당도가 높고 맛도 좋다고 알려져 있다. 인산질 성분은 특히 근의 발육을 촉진시키는 중요한 성분이다. 하지만 토양부의 인산성분이 수확 시까지 다량 지속되면 양분의 경합으로 뿌리부의 부패를 초래하기 쉽다. 따라서 수확기에 환원형 인산질을 중심으로 엽면시비 방법으로 영양균형을 유도하여 양파의 품질과 저장성을 향상시키는 것이 중요하다. 본 연구는 아인산(H3PO3)과 수산화칼륨(KOH)을 희석하여 산도조절 후, 아인산염으로 철원양파에 엽면 처리한 후 성분을 비교분석하였다. 본 연구에서 아인산염의 농도를 500, 1000, 1500배 희석하여 철원양파에 2018년 5월에 분무기를 이용하여 3회 엽면살포 한 후 6월 말경 수확한 후 HPLC를 이용하여 페놀화합물을 분석하였다. 그 결과 양파에서 중요한 물질 중의 하나인 큐에르세틴(quercetin)함량은 대조구(96.39 ug/g)에 비해 500배(179.70 ug/g), 1000배(150.27 ug/g), 1500배(105.95 ug/g) 처리구에서 높은 함량을 보였다. 또한 caffeic acid, p-coumaric acid, ferulic acid, rutin, kaempferol, 당도 함량은 처리구에서 대조구보다 높은 함량을 보였다. 따라서 아인산염 처리는 철원양파에서 페놀화합물의 함량을 높이는데 중요한 역할을 한다는 것을 알 수 있었다. 본 연구를 통하여 아인산염과 같은 환원형 엽면시비법을 이용하여 재배한다면 고품질의 기능성 양파를 생산할 수 있을 것이라 생각한다.

• Polymer(Korea)
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• v.36 no.4
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• pp.470-477
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• 2012

A tyrosinase-immobilized biosensor was developed based on various amine-modified multi-walled carbon nanotube (MWNT) supports for the detection of phenolic compounds. MWNTs with various amine groups were prepared by radiation-induced graft polymerization of glycidyl methacrylate (GMA) onto MWNT supports and the subsequent amination of poly(GMA) graft chains. The physical and chemical properties of the poly(GMA)-grafted MWNT supports and the aminated MWNT supports were investigated by SEM, XPS, and TGA. Furthermore, the electrochemical properties of the prepared tyrosinase-modified biosensor based on MWNT supports with amine groups were also investigated. The response of the enzymatic biosensor was in the range of 0.1-0.9 mM for the concentration of phenol in a phosphate buffer solution. Various parameters influencing biosensor performance have been optimized: binder effects, pH, temperature, and the response to various phenolic compounds. The biosensor was tested on phenolic compounds contained in two different commercial red wines.

• Proceedings of the Korean Nutrition Society Conference
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• 2001.11a
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• pp.45-45
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• 2001

• Bulletin of Food Technology
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• v.18 no.1
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• pp.99-109
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• 2005