• Korean Journal of Food Science and Technology
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• v.44 no.6
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• pp.763-771
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• 2012

In this study, total antioxidant properties of extracts from different parts of Lespedeza bicolor were determined using techniques of measuring 1,1-diphenyl-2-picryl hydrazyl/2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)-radical scavenging activity and total phenolic contents. The total antioxidant activities of leaf, stem and root extracts from various solvents (water, 50, 70, 100% ethanol, and hot-water) indicated that 50 and 70% ethanol extracts have high radical scavenging activities and phenolic contents. A systematic approach was used to determine the total antioxidant activity of different solvent fractions of the Lespedeza bicolor extracts, partitioning with chloroform, ethyl acetate, n-butanol, and water, and the ethyl acetate fraction was found to have the strongest antioxidant activity. Antioxidant assay-guided isolation was carried out to isolate potential antioxidant compounds. The ethyl acetate fraction of the leaf extract was subjected to silica gel, LH-20 and RP-18 column chromatography successively, and afforded compound 1, which was identified as eriodictyol by NMR and MS analysis, after which its antioxidant activity was determined.

• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.147-152
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• 1999

HPLC was used for determining polyphenols which are known as the functional compounds in the unripe apples Fuji and Aori. The changes in their contents caused by heat treatments were monitored. The carbohydrate contents in Fuji and Aori were 14.1% and 13.5% respectively. Both apple juices showed pH 3.2 and $8.0\;brix^{\circ}$, which were relatively low levels. The major polyphenols were composed of (+)-catechin, chlorogenic acid, (-)-epicatechin, and tannic acid. Total polyphenol contents in Fuji and Aori were 0.11, 0.12% by Folin-Denis method. HPLC analysis of polyphenols showed that four major components were contained by 0.06% in Fuji and 0.07% in Aori. Chlorogenic acid was three times higher in Fuji than in Aori. After water blanching, the area percent of polyphenols resulted in an increase by 3.54% in Fuji but a decrease by 2.93% in Aori. Pasteurization of juices led to decrease by 1.39% and 3.31% respectively. Blanching and pasteurization of unripe apple juices induced negligible changes in polyphenol contents during storage. During concentration, polyphenol contents increased in proportion to the concentration of unripe apple juices.

• Korean Journal of Food Science and Technology
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• v.49 no.6
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• pp.714-716
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• 2017

Rose flower is widely used in the preparation of tea and contains a large variety of phytochemicals, including phenolics such as catechin, quercetin, and rutin. The effects of aging on rose (Rosa hybrida L.) flower extracts (RFE) were examined under conditions of varying temperature and relative humidity. The total phenolic content, antioxidative activity, and catechin levels were measured to evaluate the effects of temperature and relative humidity on the aging process. Performing the aging process at $30^{\circ}C$ under 60% or 90% relative humidity for 24 h significantly increased the total phenolic content and the antioxidant activities of RFE (p<0.05). Additionally, an aging process performed at $30^{\circ}C$ and 60% relative humidity for 24 h maximized the extraction rate of phenolics such as catechin and consequently led to increased antioxidative activity of RFE. In summary, this study indicates that the extraction rate of physiologically active phenolic compounds in rose flower can be increased by performing an aging process under optimized temperature and relative humidity conditions.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.2
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• pp.274-279
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• 2000

Effect of potato polyphenolic compound on the concentrations of serum and liver lipids, serum glucose, and urine protein was investigated in Sprague Dawley rats by feeding a diet containing 0.5% of cholesterol for 2 weeks. Polyphenolic compound extracted from potato (Solanum tuberosum variety Dejima) was supplemented at a 0.5% level in the basal diet or the cholesterol diet. The supplementation of potato polyphenolic compounds decreased slightly the concentrations of total cholesterol and VLDL+LDL-cholesterol in serum, and atherosclerotic index in rats fed the cholesterol diet, while those measurements were not altered by the supplementation of potato polyphenolic compounds in rats fed the basal diet. In the rats fed the basal diet or the cholesterol diet containing potato polyphenolic compounds, urine protein increased by 12% and 27% at 1st week, respectively, but this change was not seen at 2nd week. The concentration of serum glucose, however, was not significantly different in the dietary groups.

• Journal of Ginseng Research
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• v.24 no.2
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• pp.64-67
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• 2000

This study was carried out to investigate the possible determination of total phenolic compounds by Folin-Denis method from Panax ginseng C.A. Meyer and their extraction conditions. It was possible to apply the method for determination of total phenolic compounds from Korean red ginseng. But 3 kinds of amino acids such as tyrosine, cystein and tryptophan, and 3 kinds of vitamins such as ascorbic acid, pyridoxin HCI and thiamine HCI affected strongly the colorization by the method. Effective alcoholic solvent for the extraction was 60% ethanol, appropriate extraction temperature, time and times were 40-80。C, 1-2 hours and 3 times, respectively.

• Korean Journal of Food Science and Technology
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• v.52 no.3
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• pp.226-236
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• 2020

This study was designed to evaluate the biological activities and main constituents of different parts (fruit, leaf, and stem) of aronia (Aronia melanocarpa). The total phenolic and flavonoidcontents, DPPH and ABTS⁺ radical-scavenging activity, reducing power, and ferric reducing/antioxidant power were observed to follow the order of: leaves > stems > fruits, regardless of extraction solvents. The inhibitory activity against lipopolysaccharide-induced NO production in Raw 264.7 cells was significantly higher in the aronialeaf extract-treated group than in the groups treated with stem and fruit extracts. The ultra-performance liquid chromatography (UPLC) analysis was mainly composed of routine. In addition, the highest content level was measured in the case of the catechinmemberepigallocatechin witha higher value than that found in green tea. Theresults of this studyprovide useful information for understanding the chemical constituents and biological activities of aroniafruits and byproducts.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.12
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• pp.1725-1730
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• 2010

To obtain basic information on the potential use of propolis as a raw material in functional food, proximate composition, total phenolics content and antioxidant activities of different propolis extracts in Korea were investigated. Propolis had the highest level of crude fat and the lowest level of crude fiber. The total phenolics content of ethanol and water extract of propolis from Geochang (GEE and GWE), ethanol and water extract of propolis from Jeju (JEE and JWE) were 184.17, 316.19, 204.33 and 47.83 mg gallic acid equivalent/g, respectively. GWE contained relatively higher levels of total phenolics than the other extracts. The antioxidant potential of the extracts was assessed by different in vitro assays such as DPPH, ABTS, reducing power, ferric reducing/antioxidant power (FRAP) and peroxidation inhibiting activities through linoleic acid emulsion system. DPPH and ABTS radical scavenging activities of all the extracts were dose dependent. The GWE exhibited the best performance in reducing power, FRAP, and lipid peroxidation using ferric thiocyanate (FTC) assay. These results demonstrated that GWE has excellent antioxidant activities and thus it has great potential as a raw material for functional food.

• Korean Journal of Medicinal Crop Science
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• v.14 no.1
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• pp.8-13
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• 2006

This study was carried out to investigate drying methods for keeping freshness and active components of aerial part of Saururus chinensis. Chopped samples were prepared using hot air drying, hot air drying + roasting, presteamed + hot air drying, freeze drying, and sun drying. Drying time was shorter $88{\sim}93%$ in hot air drying and freeze drying than in sun drying. Percentage of dry matter was higher in the order of freeze drying > sun drying > hot air drying, and moisture content in the order of sun drying > hot air drying > freeze drying. The contents of total phenolics and quercetin related substances were greater in the order of freeze drying > hot air drying > sun drying, while were decreased due to treatments before or after hot air drying. Electron donating ability (EDA) was highest in freeze drying, and showed a little difference between hot air drying and sun drying, but was increased because of treatments before or after hot air drying. In color values, the a value was lower in the order of freeze drying < hot air drying < sun drying. The contents of active components of plant parts of hot air dried were higher in the order of flower >leaf > chopped sample > stem. EDA showed similar tendency with those. The a value was lower in the order of leaf < chopped sample < flower < stem. As a result, freeze drying of chopped samples or hot air drying of leaf and flower were effective to maintain qualities of aerial part of Saururus chinensis.

• Korean Journal of Food Science and Technology
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• v.46 no.3
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• pp.390-393
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• 2014

The effects of roasting temperature and time on the antioxidant activities of tartary buckwheat were investigated. Compared to raw seeds (2.05 mg TAE/g), seeds roasted at $175^{\circ}C$ for 5 min showed significantly higher total polyphenol content (p<0.05), while those roasted at $250^{\circ}C$ for 10 min showed significantly lower total polyphenol content (2.77 and 2.56 mg TAE/g, respectively). The electron-donating abilities of tartary buckwheat seeds increased with an increase in the roasting time at lower temperatures (p<0.05). However, seeds roasted at a higher temperatures ($250^{\circ}C$) for 10 min showed significantly lower electron-donating abilities (p<0.05). Seeds roasted at $175^{\circ}C$ showed adequate L values, regardless of the roasting time. In contrast, seeds roasted for 10 min at $250^{\circ}C$, showed markedly lower L values. Our results suggest that the roasting temperature and time must be controlled to produce high-quality tartary buckwheat products.

• Food Science and Preservation
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• v.17 no.2
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• pp.202-207
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• 2010

The effects of ultrasound treatment, in combination with ascorbic acid, on the quality of fresh-cut 'Jonathan' apples was investigated. Prepared apple slices were ultrasonicated in distilled water (US) or in 1%(w/v) ascorbic acid solution (UA) and the other samples were just dipped in 1%(w/v) ascorbic acid solution (AA). All samples were stored at$10^{\circ}C$ for 12 days. UA-treated samples showed high $L^{*}$ and hue values and low $a^{*}$, $b^{*}$, chroma, and ${\Delta}E$ value. Both control and US-treated samples showed considerable browning. A significant inhibition of polyphenol oxidase activity was observed after UA treatment. The level of total phenolics in UA-treated samples was higher on the day of treatment compared with other samples. Total soluble solids, pH, titratable acidity, and gas concentrations were similar in all samples. This study demonstrated that the simultaneous treatment of ultrasound and ascorbic acid was effective in preventing enzymatic browning of fresh-cut 'Jonathan' apples and maintaining total phenolics contents.