• Journal of Food Hygiene and Safety
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• v.33 no.1
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• pp.44-49
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• 2018

As generic health functional food items have been expanded, this research project has been conducted to prepare a scientific and systematic standardized analytical method of relevant food item and examine the suitability of the method for health/functional foods on sale. Total polyphenol was necessary for development and verification of standardized analytical method. The method exhibited high linearity in the tannic acid calibration curve ($r^2$ > 0.999) over concentrations of $5-50{\mu}g/mL$. The limits of detection and quantitation for tannic acid were $5{\mu}g/mL$ and $15{\mu}g/mL$, respectively, while tannic acid recovery was 102.3-112.4% with standard deviations of 0.8-3.2%. To verify the accuracy of the analytical method, the labeled amounts of purchased health functional foods were monitored. The recovery for tannic acid was 105.6% of the labeled amounts. Thus, the new method was suitable for all cases.

• Journal of the Korean Applied Science and Technology
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• v.35 no.1
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• pp.254-262
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• 2018

It was intended to check a possibility of activity of Psidium guajava leaf extract as anti-oxidant and anti-inflammatory material. Total polyphenol and total flavonoid content of Psidium guajava leaf extract was checked. Cream having inhibitory effect on inflammation through toxicity and NO production inhibition in RAW 264.7 cell was manufactured, and skin safety was evaluated. It was confirmen that total polyphenol and flavonoid content of Psidium guajava leaf extract was 126.4 mg/g and 223.17 mg/g respectively, which was high content. According to the results of checking toxicity through cell viability in RAW 264.7 cell, cytotoxicity was not shown. And NO production indicating inflammatory disease was inhibited concentration-dependently. According to the results of carrying out single patch test after manufacturing the cream containing the Psidium guajava leaf extract, skin irritation did not occur for 24 h to put patch on skin or for 24 h after removing the patch. Putting these results together, it was verified that there was possibility of application as raw materials for cosmetics, which would have anti-oxidant activity owing to the high polyphenol and flavonoid content of Psidium guajava leaf extract and anti-inflammatory material through NO production inhibition.

• Korean Journal of Food Science and Technology
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• v.45 no.6
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• pp.667-674
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• 2013

This study was aimed to investigate the effect of microwave-assisted extraction on Schizandra fruit extract dried by two different treatments: freeze-drying and hot air-drying. Two extraction parameters were measured in particular: total polyphenol content and antioxidant activity. Both values were found to increase as the microwave power increased, for both drying processes. However, the extract from the freeze-dried sample exhibited higher antioxidant activity than that from the hot air-dried samples. Additionally, the total polyphenol content and antioxidant activity of the extract from the freeze-dried samples increased with the extraction time, whereas they decreased with the extraction time in the case of the hot air-dried sample. Solvent concentration was also found to have a significant effect on total polyphenol content and antioxidant activity; the highest values for both properties were achieved at 50 and 70% ethanol concentrations, respectively. In summary, a higher total polyphenol content and antioxidant activity were observed for Schizandra fruit extracted by freeze-drying than that by hot air-drying.

• Korean Journal of Food Science and Technology
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• v.34 no.5
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• pp.775-779
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• 2002

Barley brans, divided into fractions I $(pearlers\;1{\sim}4)$, II $(pearlers\;5{\sim}20)$, and III $(pearlers \;21{\sim}24)$, germ, and broken kernels were collected as pearling by-products produced by an industrial process consisting of 24 consecutive barley pearlers. The pearling by-products were extracted with 75% ethanol, and polyphenol extracts were separated using Sepabeads SP-850 resin. Total polyphenol content was the highest (43.68%) in the polyphenol extract separated from fraction I. Polyphenol compounds analyzed by HPLC were tentatively identified as proanthocyanins and prodelphinidin polymers, which were known to have antioxidative and antimutagenic activities. Antioxidative abilities were estimated to be in the following order: fraction I>germ>fraction II>fraction III. At 0.01% polyphenol extract, angiotensin I-converting enzyme inhibitory activity was the highest in the germ fraction (40.04%). Nitrite-scavenging activity was over 70% in all fractions. Superoxide dismutase-like activity was in the range of $64{\sim}78%$ in fractions I and II.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.8
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• pp.1143-1150
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• 2005

Antioxidative activities of 5 common edible seaweeds in Korea, three brown algae (seaweed fusiforme, sea mustard, sea tangle), one green algae (sea lettuce) and one red algae (laver), were examined. The antioxidative activities of ethanol extracts from these seaweeds were examined by measuring of inhibition rates against iron-induced linoleate peroxidation, DPPH (1,1-diphenyl -2-picrylhydrazyl) radical generation and MDA-BSA (malondialdehyde-bovine serum albumin) conjugation. Sea lettuce ethanol extract showed the strongest anti-oxidative activity among them, especially in inhibition against conjugation of lipid peroxide and protein. Second to sea lettuce, laver and sea tangle ethanol extracts showed high DPPH radical scavenging activity and inhibition against MDA-BSA conjugation. However, seaweed fusiforme and sea mustard ethanol extracts did not show antioxidative activities. Sea mustard contained the highest total flavonoids (11.33 mg/g dry wt) and sea lettuce contained the highest total polyphenol (8.97 mg/g dry wt) among these seaweeds. In addition, there was strong positive correlation between the antioxidative activity and total polyphenol content in these seaweeds, suggesting polyphenol compounds may contribute to antioxidative effect of seaweeds. From these data, it is suggested to consume much of seaweeds such as sea lettuce, laver and sea tangle to prevent age-related chronic diseases, and also develope neutraceutical products using polyphenol rich fraction from sea lettuce.

• Journal of Life Science
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• v.22 no.3
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• pp.354-359
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• 2012

In our study, we investigated the antioxidant effect of methanol extract from the leaves of Picrasma quassioides (PQ) and Chamaecyparis obtuse (S. et Z.) ENDL (CO). Total polyphenol contents of methanol extracts from PQ and CO varied from 138.3 to $367.52{\mu}g/mg$ and total flavonoid contents varied from 8.12 to $46.41{\mu}g/mg$. Contents of polyphenol and flavonoid in PQ were found to be extremely high. In addition, the methanol extract of PQ had a higher antioxidant activity in both DPPH ($4.79{\mu}g/ml$) and ABTS ($7.21{\mu}g/ml$) compared to other plants (CO). Based on the results of the FRAP assay, PQ showed a value of $8.52{\mu}mol/{\mu}g$ and CO exhibited a value of $1.77{\mu}mol/{\mu}g$. The methanol extracts from the leaves of PQ showed the highest radical-scavenging activity in various antioxidant systems.

• Journal of Plant Biotechnology
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• v.48 no.3
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• pp.193-200
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• 2021

Barley (Hordeum vulgare cv. Hangmaeg) sprouts are important microgreens that contain high levels of polyphenols and flavonoids, as well as minerals, vitamin and chlorophyll. Barley sprouts were grown for 9 days and growth was checked every 3 days. In this study, the cultivation efficiency according to the nutrient solution treatment was evaluated by analyzing the length of barley sprouts, fresh weight, chlorophyll, and the yield by growth period. In addition, we tried to increase the industrial applicability of germinated barley through analysis of inorganic component, total polyphenol and total flavonoid content of the extract, and functional substance analysis using HPLC. As a result, the growth rate of the nutrient solution treatment group was faster than that of the control group. When harvested on the 9th day of sowing, the nutrient solution treatment group showed a significant increase in yield compared to the control group. And the barley sprout extract of the nutrient solution treatment group had higher total flavonoid content and luteolin content. Also, the efficiency of water was higher than that of ethanol when extracting phenolics from barley sprouts. Therefore, this study suggests that nutrient input is effective for increasing polyphenol content and increasing production in barley sprout hydroponics.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.10
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• pp.1356-1362
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• 2012

UV-VIS spectrophotometric and high-performance liquid chromatographic (HPLC-DAD) methods were applied in order to identify and quantify the composition of polyphenols in commercial cocoa-containing products. Total polyphenolic contents of cocoa mix, choco-syrup, milk chocolate, and dark chocolate were evaluated using Folin-Ciocalteu's phenol reagent according to a UV-VIS spectrometric method. Antioxidant capacities of cocoa extracts by methanol were evaluated by 2,2'-azino-bis(3-ethyl benzothiazoline-6-sulfonic acid) (ABTS) assay and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The obtained results show that the polyphenolic contents and antioxidant capacities of cocoa products and chocolates depend on solid cocoa content. Among the tested cocoa products and chocolates, the most abundant phenolic compound was epicatechin.

• Korean Journal of Food Science and Technology
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• v.44 no.5
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• pp.540-544
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• 2012

The aim of this study was to evaluate the antioxidant activity, total phenolics, flavonoids, and vitamin C contents in peels of 11 commercial fruits commonly consumed in the Republic of Korea. The antioxidant activities were evaluated by ABTS, DPPH radical scavenging methods and reducing power. The peels of plum (Prunus spp.) and golden kiwifruit (Actinidia chinensis) exhibited the highest values of antioxidant activity and total phenolics, while the highest level of ascorbic acid was recorded in the peel of citrus fruit (p<0.05). There were positive correlations between the antioxidant activity assessed by both reducing power and ABTS methods and total polyphenol content ($R^2$=0.6356), suggesting that phenolic compounds are the major contributors to these activities. The results indicate that plum and golden kiwifruit peels can be used as natural antioxidant ingredients and in production of functional foods in the Korean diet.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.5
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• pp.769-775
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• 2010

The genus Lespedeza belonging to Leguminosae is an annual or perennial herb, which has been used as a Chinese herbal medicine. Antioxidant activity on DPPH ((1,1)-diphenyl-2-picrylhydrazyl) and ABTS (2,2'-azino-bis(3-ethylenebenzothiazoline-6-sulfonic acid) radicals and the contents of total polyphenol and flavonoid were analyzed with 12 methanol extracts from six Lespedeza genus plants with different plant parts. The highest content of total polyphenol was detected in the leaves of Lespedeza$\times$robusta (194.6 mg GAE/g), while the highest content of total flavonoid existed in the aerial part of Lespedeza thunbergii var. intermedia (47.9 mg QE/g). Generally, the amounts of polyphenol and flavonoid compounds were higher in the leaves than in the stems. The $SC_{50}$ value of DPPH radical scavenging activity ranged from 10.16 to 90.94 ppm, of which the strongest activity was determined in the leaves of L. robusta. Most ABTS radical scavenging activities from the investigated methanol extracts were higher than that of L-ascorbic acid, implying the excellent antioxidant activity. The radical scavenging activity in this study showed high correlation with the amount of total polyphenol rather than that of total flavonoid. These data suggest that the methanol extracts from these Lespedeza spp. could be potential candidates for natural antioxidants.