• Korean Journal of Breeding Science
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• v.42 no.2
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• pp.129-138
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• 2010

Total phenolic content, total anthocyanin content and antioxidant activity were analyzed from rice samples collected in Korea, Japan and China. The results showed that the total phenolic content and free-radical scavenging activity differed significantly in these rice lines. The correlation between content and activity was subsequently investigated. The results showed that in black rice, anthocyanin was the major phenolic component and that both phenolic content and anthocyanin content were closely correlated with free-radical scavenging activity. Reverse Phase High Performance Liquid Chromatography (RP-HPLC) data showed that cyanidin-3-O-glucoside and peonidin-3-O-glucoside composed about 90% of the total anthocyanin content in black rice and in red rice. In the red rice extract, the total phenolic content produced a high correlation coefficient with antioxidant activity but correlated very poorly with the total anthocyanin content. The $OD_{458}$ and the $OD_{500}$ values which represent the proanthocyanidin content of the rice extract, produced high correlation coefficients with antioxidant activity and total phenolic content. These results suggest that the $OD_{458}$ and the $OD_{500}$ values can be used to evaluate the quality of red rice. In addition, based on the data obtained, a competitive accumulation model of anthocyanin and proanthocyanidin in black and red rice was proposed.

• Food Engineering Progress
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• v.14 no.4
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• pp.342-345
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• 2010

The purpose of current study was to examine bioaccessibility of antioxidant activity and total phenolic content in each part of water spinach (Ipomoea aquatic Forsk.). In vitro biomimicking system simulated human digestive fluid was employed in order to measure bioavailable anti-oxidative effect and phenolic content. Antioxidant activity and total phenolic content was measured by using the DPPH method and the Folin-Ciocalteu assay, respectively. Stem of water spinach had a higher DPPH free radical scavenging effect (5.43 mg/mL for $IC_{50}$) than leaf (5.95 mg/mL for $IC_{50}$), while leaf had a greater level of total phenolic content (287.45 ${\mu}g$ GAE/mL) than stem (216.45 ${\mu}g$ GAE/mL). Bioaccessible antioxidant capacity and digestive stability of total phenolic content showed a similar pattern to what found in raw materials. Our result also indicated that total phenolic content was not found to be a major marker for prediction of antioxidant activity. It is plausible that other constituents such as vitamin E and C in water spinach could be contributors for antioxidant activities.

• Natural Product Sciences
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• v.28 no.2
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• pp.75-79
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• 2022

As a result of comparing the phenolic components of cinnamon medicines, the total phenolic component content of Cinnamomi Cortex in China was about 2.65 times higher than that of Cinnamomi Cortex in Vietnam. In addition, the total phenolic component content of Vietnamese Cinnamomi Cortex Spissus was about 1.80 times higher than that of Chinese Cinnamomi Cortex Spissus. Meanwhile, Vietnamese Cinnamomi Ramulus showed a content about 3.29 times higher than that of Chinese Cinnamomi Ramulus. Cinnamaldehyde, the main component of cinnamon medicines, showed the same tendency as the total phenolic component content. In terms of the average content of the total phenolic components, Cinnamomi Cortex showed the highest content at 23964 ㎍/g, followed by Cinnamomi Cortex Spissus at 17489 ㎍/g and Cinnamomi Ramulus at 5435.8 ㎍/g. These results showed that Cinnamomi Cortex and Cinnamomi Cortex Spissus with stem bark as usage sites had about 3.22 to 4.41 times higher content of phenolic components than Cinnamomi Ramulus with young branches as usage sites.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.3
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• pp.383-389
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• 1997

Doenjang(fermented soybean paste) was prepared by the series of processes including soaking, cooking, first fermentation(3 days at 30$\pm$2$^{\circ}C$) for the preparation of meju(soybean koji) after inoclulation of Aspergillus oryzae, and further fermentation (60 days at 30$\pm$2$^{\circ}C$) for the ripening after addition of salt 13% to meju. the crude phenolics extracted from defatted soybean and doenjang were fractionated onto the neutral phenolics(isofavonoids) and acidic phenolics(phenolic acids), respectively. Composition and antioxidative characteristics of phenolic fractions were determined. The neutral phenolic fractions contained genistin, genistein and daidzein; on the other hand, acidic phenolic fractions had syringic acid and seven other components. The content of genistin in doenjang dramatically decreased at the early stage of fermentation, whereas the content of genistein rather increased. In addition, the content of syringic acid of acidic phenolic fractions were increased during fermentation. These changes in individual phenolic components affected the antioxidative activity of neutral phenolics or acidic phenolics. antioxidative activity of phenolic compounds were evaluated during soybean fermentation. The antioxidative and free radical scavenging activity of neutral phenolic fractions and acidic phenolic fractions on linoleic acid autoxidation were also investigated.

• Journal of Korean Medicine for Obesity Research
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• v.23 no.1
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• pp.10-17
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• 2023

Objectives: The aim of this study was to compare the total phenolic content of Korean Acanthopanax senticosus stems harvested in different seasons and provide basic data for developing functional reinforcement products based on the optimal harvesting time. Methods: Each sample harvested in different seasons was extracted and concentrated twice for 2 hours using 70% ethyl alcohol. Phenolic compounds were analyzed using high-performance liquid chromatography for simultaneous multi-component analysis of 14 compounds, including syringaresinol and so on. Results: The results showed that the stem of Korean Acanthopanax senticosus harvested in winter (November 29th) (EAS-5) had the highest phenolic content of 1.038%. The stem of Korean Acanthopanax senticosus harvested in autumn (October 1st) (EAS-4) showed the second-highest phenolic content of 0.764%, followed by the stem of Korean Acanthopanax senticosus harvested in spring (February 2nd) (EAS-1) with a content of 0.390%. On the other hand, the stem of Korean Acanthopanax senticosus harvested in the summer (June 2nd) (EAS-3) showed the lowest content at 0.342%. In conclusion, the stem of Korean Acanthopanax senticosus harvested in winter (EAS-5) showed the highest phenolic compound content. Conclusions: Considering the extraction yield and the total phenolic content, as well as the concentrations of key functional components such as eleutheroside B, chlorogenic acid, and syringaresinol in the 70% ethyl alcohol extract of Korean Acanthopanax senticosus, it is suggested that the stems of Korean Acanthopanax senticosus harvested during the winter season are suitable for the development of novel materials with enhanced anti-obesity functionality.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.164-169
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• 2002

Five kinds of red wine from three different grape varieties, such as Gerbong (G), Campbell (C), Moru (M), Gerbong+Moru (70:30, GM), and Gerbong+Campbell(70:30, GC) were prepared in the year of 2000. The total phenolic content and color changes were monitored using hunter colorimeter and spectrophotometry methods during wine processing. The total phenolic content of Gerbong (G), Campbell (C), Moru (M), Gerbong+Moru(70:30, GM), and Gerbong+Campbell(70:30, GC) were 712.6 mg/L, 3472.9 mg/L, 2209.4 mg/L, 2019.4 mg/L, and 1184.5 mg/L, respectively. Between total phenolic content and hunter colorimeter value (L, a, and b) of red wine showed no significant difference, but that of spectrophotometry color value (hue and intensity) were significantly different (p<0.001). The total phenolic content, hue, and intensity values represented significantly different between grape varieties (p<0.01, p<0.001). the hue showed a negative correlation relationship $(r^2=0.8660,\;p<0.0001)$, and that of intensity was a positive $(r^2=0.8304,\;p<0.0001)$ between total phenolic contents. The total phenolic content of red wine could be estimated simply using these equations, $Y_{Total\;phenolic\;content\;(mg/L)}=3319.3-X_{Hue}/2208.36,\;and\;Y_{Total\;phenolic\;content\;(mg/L)}=1230.97-X_{intensity}/98.93$

• Journal of Ecology and Environment
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• v.36 no.1
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• pp.57-63
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• 2013

This study compared the antimicrobial activity and total phenolic content of three Pinus plants (Pinus densiflora, P. thunbergii, P. rigida) for the first time. The antimicrobial activity of the water fraction of methanol extract of fresh leaves was stronger than that of fallen leaves at any concentrations. The water fraction of crude methanol extract from fresh leaves of P. thunbergii showed a higher growth inhibitory activity against gram-positive and gram-negative bacteria than that of P. densiflora and P. rigida. The results from the disc diffusion method followed by measurements of minimal inhibition concentration (MIC) indicate that Bacillus subtilis was the most sensitive microorganism with the lowest MIC value. The highest total phenolic content was found in fresh leaves of P. rigida and P. thunbergii. The assay showed that the fresh leaves of the three Pinus plants contained higher total phenolic content than fallen leaves of the three plants. The antimicrobial activity was related with the total phenolic content.

• Korean Journal of Plant Resources
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• v.27 no.6
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• pp.610-621
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• 2014

Phenolic compounds such as isoflavones contribute to the antioxidant properties of soybean. This study investigated differences in the phenolic content and antioxidant activity of ten soybean cultivars grown in two different locations in Korea. We observed a wide range of variation in total isoflavone and phenolic content by location and cultivar. The total isoflavone content of cultivars grown at Pyeongchang (sub-highland) was significantly higher than that in cultivars grown at Gangneung (lowland). In contrast, the total phenolic content of cultivars grown at Gangneung was greater than that of cultivars grown at Pyeongchang. The radical scavenging activity of DPPH was similar to that of the total phenolic content rather than that of the total isoflavone content. These results suggest that antioxidant activity of soybean was associated with phenolic compounds rather than isoflavones. To identify the individual antioxidant components, we used an on-line HPLC-$ABTS^+$-based assay system, ESI/MS, and NMR. The results showed that the strongest antioxidant activity was linked to epicatechin.

• Journal of the Korean Society of Food Culture
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• v.23 no.4
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• pp.489-498
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• 2008

The objectives of this study were to provide fundamental information on how individual phenolic compounds form on the inside of apple slices during cold storage, the changes in the content of four types of phenols, ingredient variation of individual phenolic compounds and the influence of phenolic compounds on enzymatic browning. This study measured the changes in the content of soluble solids, pH and vitamin C in order to investigate the correlations between these variables. HD and FA were the main phenolic compounds found in the apple slices, and HD was the most prevalent phenol. Furthermore, comparison of the CG and EP content revealed that there were more CGs than EPs. The phenol content tended to decrease considerably in the fresh apple slices and water-dipped apple slices but only slightly in the CP from sucrose-dipped apple slices and 0.5% ascorbic acid solution-dipped apple slices. The degree of browning increased in the following order: fresh apple slices, water-dipped apple slices, 0.5% ascorbic acid solution-dipped apple slices and CP from sucrose-dipped apple slices. The vitamin C content tended to decrease in the fresh apple slices, water-dipped apple slices, 0.5% ascorbic acid solution-dipped apple slices and CP from sucrose-dipped apple slices. The pH tended to increase in all sample groups, but the pH of the water-dipped apple slices was lower than that of the comparison group. The CP from sucrose-dipped apple slices had the lowest value of pH. The change in soluble solids tended to increase in all treatment groups, but this increase was less in the CP from sucrose-dipped apple slice. Correlation analysis revealed a high degree of correlation between browning and chlorogenic acid content. The results of the present study show that, when stored in the fridge, the change in phenol ingredient content in apple slices influences the browning of the slices. The results also showed that HD and FA were the main phenolic compounds, while CG was shown to have the greatest influence on browning.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.5
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• pp.792-798
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• 1994

In order to investigate the antioxidant activity of phenolic compounds contained in domestic Meju and Doenjang , the methanolic extract from defatted Meju and Doenjang was fractionated into the phenolic acid and the isoflavone fractions by alumina column and polyamide-6 column chromatography, respectively. Both phenolic acid and isoflavone fractions exhibited an identical antioxidative effect against the oxidation of linoleic acid. GC analysis revealed that the phenolic acid fractio contained vanillic , chlorogenic ,p-coumalic , ferulic, and caffeine acid. The content of caffic acid was greater than 70% in the phenolic acid fraction and the content of vanillic and chlorogenic acids were disappeared during fermentation, and thus, the facts are thought to be reasons for the low antioxidant activity of the phenolic aicd fraction from Doenjang. Similarly, the isoflavone fraction cotained daidzin, glycitin-65-0 glucosider and genistin and their aglycons such as daidzein, glyciten and genistein. The content of daidzin and genistin in Meju dramatically decreased at the early stage of fermentation ,whereas the content of daidzein an dgenistein rather increased ; however, these change in isoflavone contents did not affect the antioxidant activity of isoflavone fractions.