• Korean Journal of Agricultural Science
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• v.46 no.1
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• pp.85-92
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• 2019

This study was intended to provide basic data for a health functional food study by exploring antioxidant activity of reflux extract according to the concentration of ethanol and the extract of ultrasonic waves extracted and reflux extracted under the same solvent conditions. In the same solvent condition, the reflux extract ($75.10{\pm}1.99mg$) showed a higher total phenol content than the ultrasonic wave extract ($51.74{\pm}2.28mg$). Flavonoids also had a higher reflux extract ($25.05{\pm}1.53mg$) than did ultrasonic extracts ($16.23{\pm}1.95mg$). Reflux extract according to ethanol concentration was found to have a higher phenol content than the 70% ethanol extract ($40.60{\pm}1.49mg$) in 60% ethanol extract. Flavonoid content was also similar to phenol content in reflux extract as determined by ethanol concentration from 60% ethanol ($25.05{\pm}1.53mg$) to 70% ethanol extract ($6.60{\pm}0.46mg$). In addition, the antioxidant activity (DPPH, TEAC, FRAP, ORAC) of the reflux extract in the same solvent conditions tended to be higher than that of ultrasonic extracts. Also, 60% ethanol extract had better antioxidant activity than 70% ethanol extract. However, an analysis of phenolic acid content through HPLC showed that the ultrasonic extract had a higher content in the same solvent condition than did the reflux extract. Not only the presence of phenolic acid, but also those of other compounds are believed to be attributed to the activity of antioxidants. Therefore, further studies are needed to clarify this phenomenon.

• Food Science and Biotechnology
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• v.17 no.2
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• pp.251-256
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• 2008

Changes in antioxidant activity of Rubus coreanus fruit of 3 clones (S13, S114, and S16), which were selected from different sites, were studied at different ripening stages. Antioxidant activities (tree radical scavenging activity and reducing power) were determined and their relationships to total phenolic contents and ascorbic acid were analyzed. The highest tree radical scavenging activities of 3 clones (S13, S14, and S16) were 79.39, 75.80, and 81.16% at $125\;{\mu}g/mL$, respectively. In general, the antioxidant activity and the related parameters, including total phenolic content and vitamin C content decreased during fruit ripening. Total phenolic contents of the R. coreanus fruits (S13, S14, and S16) were correlated with tree radical scavenging activity ($R^2=0.8114$, 0.9186, and 0.9714). These results improve knowledge of the effect of ripening on the antioxidant activity and related compounds contents that could help to establish the optimum R. coreanus fruit harvest data for various usages.

• Preventive Nutrition and Food Science
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• v.22 no.3
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• pp.216-222
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• 2017

Antioxidant rich green leafy vegetables including garden spinach leaf, water spinach leaf, Indian spinach leaf, and green leaved amaranth were selected to evaluate the effects of water boiling and oil frying on their total phenolic content (TPC), total flavonoid content (TFC), reducing power (RP), and antioxidant capacity. The results revealed that there was a significant increase in TPC, TFC, and RP in all the selected vegetables indicating the effectiveness of the cooking process on the antioxidant potential of leafy vegetables. Both cooking processes enhanced significantly (P<0.05) the radical scavenging ability, especially the oil fried samples showed the highest values. There is a significant reduction in the vitamin C content in all the vegetables due to boiling and frying except in the Indian spinach leaf. However, the present findings suggest that boiling and frying can be used to enhance the antioxidant ability, by increasing the bioaccessibility of health-promoting constituents from the four vegetables investigated in this study.

• Food Science and Biotechnology
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• v.16 no.2
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• pp.187-192
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• 2007

The objectives of this study were to examine changes in the color and antioxidant compounds of paprika powder under various conditions, as well as to establish the suitable conditions for drying and storage. Paprika was dried using the following methods: freeze-drying, vacuum drying, far infrared-ray drying, and hot-air drying. Measurements of the moisture content, color pigments, and antioxidant compounds (total carotenoids, capsanthin, ascorbic acid, and total polyphenols) were completed during 120 days of storage at 4 and $30^{\circ}C$. We found that drying methods, storage temperatures, and packaging materials affected the American Spice Trade Association (ASTA) and Hunter color values, as well as the antioxidant content of paprika powder. There was a high correlation (r=0.87, p<0.01) between the ASTA color and the $a^*/b^*$ value. The loss of red color was closely related to the reduction of moisture content (r=0.81, p<0.01) during storage. Drying paprika with a low temperature in the absence of air resulted in better retention of the carotenoids and ascorbic acid. Also, as the retention of the carotenoids and ascorbic acid increased, the stability of the red pigment increased. Freeze-drying was found to be the most suitable drying method for the stability of the antioxidant compounds and red pigment.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1387-1390
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• 2008

This study evaluated the effects of heat treatment on antioxidant activity of Rehmannia radix Libosch (RRL). RRL was heated at various temperatures ($110-150^{\circ}C$) for various times (1-5 hr), and the total polyphenol, flavonoid content, and antioxidant activity were investigated. With increased heating temperature and exposure time, total content of polyphenol, flavonoid, as well as antioxidant activity increased. The highest total polyphenol and flavonoid contents were 21.65 and 3.56 mg/g, respectively, these values were occurred after heating for 3 hr at $150^{\circ}C$ (RRL was 5.09 and 0.83 mg/g, respectively). The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity was highest value of 83.46% after heating for 3hr at $150^{\circ}C$. The 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) cation radical scavenging activity was highest value of 20.43mg ascorbic acid (AA) eq/g after heating for 2 hr at $150^{\circ}C$. There were highly significant differences in the total polyphenol, flavonoid content, and antioxidant activity among heating temperatures and times (p<0.001), with heating temperature having the greater effect.

• Journal of the Korean Society of Food Culture
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• v.38 no.6
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• pp.425-433
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• 2023

We determined physicochemical characteristics and antioxidant activities of cookies prepared by replacing wheat flour with 0, 3, 6, and 9% freeze-dried burdock powder instead of wheat flour. The leavening and loss rates of the cookies decreased in proportion to the amount of burdock powder added to the dough. The moisture content of the cookies increased in proportion to the amount of burdock powder added and the crude protein and hardness were higher in the burdock-added group compared to the control. The lightness and yellowness of the cookies decreased, and the redness increased in proportion to the amount of burdock powder added. The total flavonoid and polyphenol compounds in the cookies increased in proportion to the amounts of burdock powder added. The antioxidant activities also tended to increase in proportion to the amount of burdock powder added. Based on the above results, adding burdock powder to cookies can increase antioxidant activity by increasing the content of antioxidant components, such as polyphenols and flavonoids. In addition, it is believed that adding burdock powder at levels of 3 to 9% of the weight of flour would result in cookies with spreadability, swelling power, and hardness similar to those of regular cookies.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1156-1159
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• 2008

The antioxidant activity of hot water extracts of various parts, the leaf, stem, and root of Synurus deltoides was evaluated by various antioxidant assays, including total phenolic content, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, hydroxyl radical (${\cdot}OH$) scavenging, superoxide dismutase (SOD), and xanthine oxidase (XOI) activities. The various antioxidant activities were compared with the standard antioxidants such as L-ascorbic acid, $\alpha$-tocopherol, and butylated hydroxyanisole (BHA). Among the different plant parts, stem has been found to possess the highest activity in all tested model systems, the activity decreased in the order stems>roots>leaves. These results indicate that stem extract could be used as potential source of natural antioxidant.

• Korean Journal of Plant Resources
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• v.33 no.3
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• pp.170-182
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• 2020

Wheat is an economically important cereal worldwide and is a staple food in many countries. Extensive researches have been performed on the nutritional value and antioxidant potentials of sprouts of legumes like soybean, however very limited studies have been carried out on the sprouts of Korean wheat cultivar. The objective of this study was to investigate the phytochemical and antioxidant potentials of Korean wheat sprouts. The sprouts were grown for 10 (WS-10), 20 (WS-20), and 30 (WS-30) days at room temperature. The pH, color, chlorophyll, free amino acid, 1,1-diphenly-2-picrylhydrazyl (DPPH), and total polyphenol content of the sprout samples were determined. The pH of sprouts was increased in the older sprouts. Color values were significantly influenced by the age of sprouts. The chlorophyll content was lowest but the total free amino acid content was highest in WS-30. On the other hand, the DPPH free radical scavenging potential and total polyphenol content were lower in WS-30. The results suggested that Korean wheat sprouts could be a potential source of nutrients and natural antioxidants.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.5
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• pp.696-702
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• 2007

The purpose of this paper is to describe the differences in mineral, ascorbic acid, and total polyphenol content, and also the relationship between polyphenol content and antioxidant activity(DPPH radical scavenging, FTC, and TBA methods) in three sizes of Cudrania tricuspidata leaves. For the mineral contents of the leaves, Ca was highest(17.26 mg/g.d.w.), followed by K(15.53 mg), P(2.61 mg), and Mg(1.99 mg). Ascorbic acid was found to be slightly higher(43.4 mg/100g.f.w.) in the basal parts of the medium size leaves and lowest in the whole parts(9.9 mg) of the small size leaves. Total polyphenol content was highest($1,384{\sim}1,258mg/100g.f.w.$) in the leaves, for all sizes, when extracted with 80% ethanol, followed by the stem bark(543 mg%), roots(369 mg%), stems(243 mg%), and thorns(223 g%). By determining DPPH activity, we found that antioxidant activity was higher in the ethanol extracts of the leaves than in the ethanol extracts of the thorns, stems, roots, and stem bark. While in the tea, no differences were found between the ethanol and water extracts.

• The Korean Journal of Food And Nutrition
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• v.34 no.4
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• pp.347-355
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• 2021

This study evaluated the quality and antioxidant activities of pork patties after adding Cirsium nipponicum powder in a ratio of 0%, 1%, 2%, 3%, and 4%, and the potential of Cirsium nipponicum as a functional food. The moisture content increased with an increase in the Cirsium nipponicum powder content while the pH, cooking loss rate, diameter loss rate decreased. The L and b values decreased with increase in the Cirsium nipponicum powder content while the a value increased; this trend was observed before and after heating the patties. The hardness, chewiness, and gumminess increased with increase in the Cirsium nipponicum powder content. Consumer acceptability test revealed that the 2% Cirsium nipponicum powder group had a higher score than the other groups in respect to color, flavor, taste, texture, and overall acceptance. Notably, as the Cirsium nipponicum powder content increased, there was an increase in the antioxidant activities; increased total pheonlic, flavonoid, DPPH radical scavenging activity and ABTS radical scavenging activity. Based on the present study results, adding 2% of Cirsium nipponicum powder into pork patties achieved the best functionality and sensory qualities.