• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.757-761
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• 1995

The relationship between the molecular structure of rice starch and the texture of cooked rice was investigated using hot-water soluble rice starch. The structure of hot-water soluble starch bound amylose which was composed of small molecular weight and amylopectin which was composed of chain length of $\overline{DP}\;10{\sim}20$, and the average composition of amylose : amylopectin was 7 : 3. The molecular weight of amylose was the smaller and super long chain of amylopectin was the fewer, the extractable ratio of hot-water soluble rice starch was the higher. And hot-water solubility of rice starch be responsible for molecular structure of starch. On the texture of cooked rice, the extractable ratio of hot-water soluble rice starch was the higher, the hardness was the lower and the adhesiveness was the higher. The results suggest that the molecular structure of rice starch could be responsible for the texture of cooked rice.

• Food Science and Preservation
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• v.14 no.3
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• pp.332-335
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• 2007

Hot water and 95%(v/v) ethanol extracts were prepared from dried Lespedeza cuneata seeds and antioxidant compounds were isolated by solvent fractionation, silica gel adslorption chromatography, Sephadex LH-20 column chromatography, and preparative HPLC. Antioxidant activity was measured using DPPH radical scavenging activity. The 80%(v/v)ethanol and ethylacetate fraction of Lespedeza cuneata seed extracts had stronger antioxidant effects than did the n-hexane fraction. The active antioxidant compounds obtained from hot water and 95%(v/v) ethanol extracts may be identical, based on analysis by Sephadex LH-20 column chromatography and preparative HPLC.

• Korean Journal of Food Science and Technology
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• v.35 no.2
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• pp.188-194
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• 2003

천마식품가공시 기초자료로 활용될 수 있는 천마 추출농축액의 리올로지 특성을 조사하였다. 천마의 열수 및 50% 에탄올 추출물운 각각 5, 10, 15, 및 20 Brix와 10, 20, 30, 40 및 50 Brix로 농축하여 제조하였다. 열수 및 50% 에탄올 농축액의 정상유동특성과 동적점탄성을 조사하였다. Power law model로 구한 n에 의하면 모든 열수 농축액들은 전형적인 의가소성$(n=0.484{\sim}0.802)$유체의 흐름특성을 보였고, 50% 에탄올 농축액들은 뉴튼유체$(n=0.875{\sim}1.078)$에 가까운 흐름특성을 나타내었다. 열수 및 50% 에탄올 농축액의 ${\eta}_{app}$는 온도가 증가함에 따라 감소하는 경향을 나타내었다. Herschel-Bulkley model에 의한 열수 및 50% 에탄올 농축액의 C는 각각 $0.030{\sim}1.255$ Pa와 $0.007{\sim}0.065$ Pa이었다. ${\eta}_{app}$에 대한 온도 및 농도의 영향은 arrhenius식으로 해석하였다. 열수 및 50% 에탄올 농축액의 $E_a$는 농도가 증가함에 따라 각각 $3.340{\sim}4.620{\times}10^3\;J/mol{\cdot}kg$과 $1.6289{\sim}18.6699{\times}10^3\;J/mol{\cdot}kg$의 범위로 나타났다. 진동수(angular frequency, ${\omega}$)가 증가할수록 저장탄성률(storage modulus, G#)과 손실탄성률(loss modulus, G@)은 일반적으로 증가하는 경향을 나타냈다. 50% 에탄올 농축액의 경우 모든 진동수에서 G#이 G@보다 높게 나타나 전형적인 저분자용액의 흐름특성을 보였다. 그러나 열수농축액의 경우 G@이 G#보다 높았고 0.5 rad/sec에서 교차점을 형성하였으며 전형적인 고분자 용액의 흐름특성을 나타내었다.

• Economic and Environmental Geology
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• v.55 no.2
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• pp.183-195
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• 2022

Hydrothermal gold deposits are evidence of intensive fluid flow through fault zones, and the resultant vein structures and textures reflect the fluid redistribution mechanism. This review introduces the suction pump and fault valve models as fluid circulation mechanisms causing hydrothermal gold deposits in the frameworks of the concepts of fault mechanics. The suction pump and fault valve models describe faulting-driven heterogeneous fluid flow and related vein formation mechanisms, accompanied by the cycles of (1) stress accumulation and fluid pressure build-up and (2) seismic rupture and stress/fluid pressure release. The models are available under different geological environments (stress conditions), and the vein structures and textures representing the mechanisms have similarities and differences. The suction pump and fault valve models must help better to interpret the origins of hydrothermal gold deposits in Korea and improve the efficiency of further exploration.

• Journal of Mushroom
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• v.18 no.1
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• pp.20-28
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• 2020

This study was conducted to determine the antioxidant, nitrite scavenging, melanin tyrosinase inhibitory, and melanogenesis inhibitory activities of fermented Coix lacryma-jobi L. var. mayuen Stapf. by Hericium erinaceum (Bull.: Fr.) mycelial hot water extract (FCLHE). Additionally, we analyzed β-glucan and ergosterol contents in FCLHE and C. lacryma-jobi hot water extract (CLHE). The ergosterol and β-glucan contents in FCLHE were 740.2 mg% and 245.3 mg%, respectively, whereas these components were not detected in CLHE. FCLHE showed higher cell viability than CLHE. When B16F10 cells were treated with 500 ㎍/mL each of CLHE and FCLHE, the FCLHE treated cells produced 8.9 uM nitric oxide (NO), which was lower than that produced by CLHE treated cells (10.6 uM). The FCLHE treated cells showed significantly greater tyrosinase inhibition and melanin production at all tested concentrations than when compared to the CLHE treated group. Antioxidant parameters such as DPPH and ABTS radical scavenging activities were higher in FCLHE than in CLHE. These results suggest that FCLHE can be used as a raw material for functional foods, for food additives, and in the cosmetic industry.

• Journal of Life Science
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• v.21 no.8
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• pp.1190-1198
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• 2011

Extraction methods of medicinal plants were evaluated for growth enhancing effects of human neuroblastoma SK-N-SH cells. Hot-water extraction (reflux for 5 hr), hot-water extraction post treatment (100$^{\circ}C$ or 120$^{\circ}C$, 90 min) and ethanol extraction (reflux for 5 hr) methods were applied to Angelica gigas, Rhemania glutinosa, Paeonia lactiflora and Cnidium officinale samples to extract their constituents. Cells were treated for 2 hr with various concentrations of extracts (0, 0.5, 1, 2, 4 ${\mu}g/{\mu}l}$ media) prior to $H_2O_2$ (250 ${\mu}M$) treatment for 2 hr to provide oxidative stress. Cell viability, caspase-3 expression and apoptosis were measured for cells treated with sample extracts. Hot-water extract exhibited a stronger growth enhancing and apoptosis protecting ability than other extracts. These activities were shown at less than 1 ${\mu}g/{\mu}l}$ concentration, and not greater than 2 ${\mu}g/{\mu}l}$ concentration. Hot-water extract contained more polyphenolic compounds than other extracts coming along with stronger antioxidant activity. The efficacy of antioxidant activity was stronger in the hot-water extract of Angelica gigas than other hot-water extracts of medicinal plants. These results suggest that hot-water extraction is an appropriate method to extract materials for growth enhancing and apoptosis protection of SK-N-SH cells, and hot-water extracts of Angelica gigas might be useful materials for protection from aging brain cells.

• Journal of Life Science
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• v.21 no.6
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• pp.811-818
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• 2011

Physiological activities of hot water (MHW) and 80% ethanol (MEH) extracts from Maesaengi (Capsosiphon fulvescens) were investigated in this study. For the evaluation of antioxidant activities for MHW and MEH, 2,2-diphenyl-1-pic-rylhydrazyl (DPPH) radical scavenging activity and superoxide dismutase (SOD)-like activity were measured. DPPH radical scavenging activity and SOD-like activity of MHW, and MEH were increased weekly in a dose-dependent manner, and were about 10.8, 13.8, 62.4, and 27.1% at 10 mg/ml, respectively. The angiotensin converting enzyme (ACE) inhibitory activities of MHW and MEH were about 5.9% and 49.7% at 1 mg/ml, respectively. The ${\alpha}$-glucosidase inhibitory effect of MHW and MEH were about 1.4% and 67.3% at 1 mg/ml, respectively. To determine the influence of MHW and MEH on alcohol metabolizing activity, the generating activities of reduced-nicotinamide adenine dinucleotide (NADH) by alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH) were measured. Facilitating rates of ADH activity by MHW and MEH were increased weekly in a dose-dependent manner and ALDH activities were not detected. Elastase inhibitory activities of MHW and MEH were 75.9% and 51.2% at 10 mg/ml, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.5
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• pp.542-549
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• 1999

The hydrothermal extracts were produced from fish head and their functional properties were investigated. The extracts exhibited an antioxidative effect and synergistic effect with $\alpha$-tocopherol by measuring peroxide values. The $5\%$ solution showed more antioxidative effect than $1\%$ solution. The extracts showed cryopropective effect, but the effect was less than sucrose. The solubility of the extracts was over $70\%$ in the all range of pH, and its lowest solubility was shown in pH 3.0. The extracts exhibited an emulsifying activity less than sugar ester (EAI=34.72) and little higher than or similiar to egg white (EAI= 14.69). The extracts showed a relatively high foam activity. The osmolality of the hydrothermal extracts at $1.0\%$ concentration were 23$\~$31 mOsmole which were much lower than 317 mOsmole at $1\%$ NaCl.

• Food Science and Preservation
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• v.19 no.6
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• pp.901-908
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• 2012

This study was conducted to analyze the antioxidant activities of fermented black jujube and to compare these with those of dried jujube, for the development of functional materials. The antioxidative activities of dried jujube and fermented black jujube extracts were analyzed by electron-donating ability (EDA) using 1,1-diphenyl-2-picryl hydrazyl (DPPH), superoxide-dismutase-(SOD)-like activity by pyrogallol, nitrite-scavenging ability, and xanthin oxidase. The yield of the fermented black jujube extracts was higher than that of the dried jujube extracts, and that of the ethanol extracts was higher than that of the hot-water extracts. The total phenol contents of the hot-water extracts from fermented black jujube were higher. The EDA values of the hot-water and ethanol extracts from fermented black jujube and dried jujube increased with an increase in extract concentration, and were about 85% in a $1000{\mu}g/mL$ extract concentration. The SOD-like activity increased with an increase in extract concentration. The SOD-like activity of the hot-water extract from fermented black jujube was higher than that of the other extracts. The nitrite-scavenging ability at pH 1.2 of the hot-water extracts from dried jujube was higher than that of the other extracts. The xanthine oxidase inhibitory activities of the hot-water and ethanol extracts from fermented black jujube were higher than those of the other extracts, and increased along with the concentrations of the extracts.

• Journal of Life Science
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• v.29 no.1
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• pp.52-59
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• 2019

The leave of Polygonum tinctorium (LPT) have been used for centuries as a traditional medicine and as a food ingredient and natural dye. The aim of the current study was to develop high-value added products using LPT. Hot water extract (HWE) and ethanol extract (EE) of LPT were prepared, respectively, and their bioactivity was evaluated. The extraction ratio for the HWE was 27.6%, which was two-fold higher than that of the EE. The contents of total polyphenol in the HWE and total sugar in the EE were 51.2 mg/g and 297.8 mg/g, respectively. The total flavonoid and reducing sugar contents were similar in the extracts, irrespective of the extraction solvent. The HWE did not show antimicrobial activity in a disc-diffusion assay, but the EE showed strong growth inhibition against gram-positive bacteria. The EE exhibited stronger DPPH and ABTS radical scavenging activities and reducing power than those of the HWE. The HWE was particularly effective as a scavenger of nitrite ($RC_{50}$ of $6.0{\mu}g/ml$). In an antithrombosis activity assay, the EE showed significant anticoagulation activity as determined by an extended blood coagulation time (thrombin time, prothrombin time, and activated partial thromboplastin time), in addition to platelet aggregation activity. The HWE also showed platelet aggregation inhibitory activity. This report provides the first evidence of antithrombosis activities of LPT. Our results suggest that LPT has potential as a new antioxidant and antithrombosis agent.