• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.1
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• pp.6-13
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• 2001

The study was conducted to investigate the effect of the browning inhibitors such as PVPP(polyvinylpoly-pyrrolidone), A.A.(ascorbic acid) on nonezymatic browning factors [free sugar, total amino acid, organic acid, A.A., HMF (hydroxymethylfurfural)] and enzymatic browning factors [PRO (polyphenoloxidase) activity, polyphenol compounds] in concentrated apple juice during 90 days storage. Considering color value (L value, $\Delta$E), absorbance at 420 nm, concentrated apple juice during 90 days storage. Considering color the effect of browning inhibition. According to the storage period, the changes of nonenzymatic factors in concentrated apple juice added with browning inhibitors were similar to those in control (concentrated apple juice without browning inhibitors), which were the decreased of sucrose(0.24~0.35% at 90 days), the slight increase of glucose and fructose, the decrease of total amino acid (530.4~573.1 mg/10g at 90 days), same value of A.A. at 90 days (38.5~78.6 mg/100g), and the increase of HMF (27.8~30.6 mg/100g at 90 days). On the contrary, enzymatic browning factors were significantly inhibited in concentrated apple juice added with PVPP, judging from the slow increase of PRO activity and the significant decrease of initial value in polyphenol compounds (especially chlorogenic acid). These results suggest that PVPP plays an important role as enzymatic browning inhibitor, that is, a scavenger of polyphenol compounds by adsorption in concentrated apple juice.

• Food Science and Biotechnology
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• v.18 no.6
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• pp.1358-1364
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• 2009

Electric polarity of working electrode and counter electrode was periodically switched at the intervals of 30 sec. Electric current generated by anodic and cathodic reaction of working electrode was reached to +30 and -12 mA in low intensity pulsed electric field (LIPEF). The yeast growth, ethanol production, and malate consumption in the initial cultivation time were more activated in the LIPEF than the conventional condition (CC). Polyphenol, total phenolic contents (TPC), and total flavonols (TF) were gradually decreased in all cultivation conditions during incubation for 2 weeks but antioxidation activity was not. TF was significantly lower in 3 and 4 V of LIPEF than CC and 2 V of LIPEF; however, the polyphenol, TPC, and antioxidation activity were a little influenced by the LIPEF. After ripening of the winemaking culture for 15 days, polyphenol, TPC, and TF were a little increased but the antioxidation activity was not.

• The Korean Journal of Food And Nutrition
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• v.25 no.2
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• pp.357-361
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• 2012

To evaluate the antioxidant and potential of Humulus japonicus, total polyphenol and flavonoid content, radical scavenging activities, and antitumor activities were measured. The total polyphenol and flavonoid contents of the methanol extracts from Humulus japonicus were $30.13{\pm}1.13$ and $13.61{\pm}0.49$ mg gallic acid equivalent/g extract, respectively. DPPH radical and hydroxyl radical scavenging activities of methanol extracts of Humulus japonicus were 60% and 35%, respectively. The Humulus japonicus higher activities of anticancer activities on liver cancer cell lines compared to other cancer cell lines.

• Preventive Nutrition and Food Science
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• v.17 no.2
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• pp.136-140
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• 2012

Trifoliate orange seed extracts (TSEs) were made using either distilled water (TW), ethanol (TE), or n-hexane (TH), to measure total polyphenol contents, DPPH and ABTS radical scavenging activities, and anti-complementary activity. The results showed that the total polyphenol content showed higher value at TE (235.24 ${\mu}g/mL$, p<0.05) than those of TW (132.65 ${\mu}g/mL$) and TH (165.44 ${\mu}g/mL$) at 10 mg/mL and TE exerted the highest DPPH radical scavenging activity (61.77%, p<0.05), which occurred in the following order: TE TW (56.87%)>TH (39.78%). The results of ABTS radical scavenging activity showed that TW (34.26%) and TE (31.81%) showed similar activities, which were higher than TH (12.74%, p<0.05). Anti-complementary activity of TE (61% at 500 ${\mu}g/mL$) showed a higher activity when compared with the positive control (60% at 1,000 ${\mu}g/mL$) polysaccharide-K (PSK), a known immuno-active polysaccharide from Coriolus versicolor. Consequently, among TSEs, TE is a byproduct from trifoliate orange and could be an important source of dietary polyphenolic antioxidant compounds and immunopotentiating activity, including complement activation.

• Korean Journal of Food Science and Technology
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• v.3 no.1
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• pp.29-36
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• 1971

When a low-temperature treatment was given to a small sweet pepper variety Zairaisisi, the seed browning effect appeared soon. This change attracted the studies to determine and discuss the browning metabolites, polyphenolic compounds, and changes in their between-step components. (1) Chlorogenic acids were found as a polyphenolic compound in seed, whereas no flavanol-type polyphenol was observed. (2) There was sharp increase in total polyphenol content and chlorogenic acid with a low-temperature treatment. The contents of these substrates dropped below that of room-temperature treatment after the browning effect took place. (3) A marked increase in between-step metabolites phenylalanine, tyrosine, shikimic acid contents, and thus assumed activated shikimate pathway in this process. (4) It was suggested by determining the effect of specific metabolic inhibition and respiratory inhibitor administrations on enzymes that active biosynthesis of polyphenolic compounds takes place in shikimate pathway with combination of phosphoenolpyruvate and erythrose-4-phosphate connected to TCA cycle jaming after an active EMP pathway was gone through with sugars in pepper seeds at a low-temperature. (5) It was also suggested from the observation of increased K ion flow-out in pepper seeds with a low-temperature treatment that there is an abnormality in the plasma membrance.

• Journal of Food Hygiene and Safety
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• v.31 no.2
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• pp.132-139
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• 2016

The purpose of this study was to investigate the contents of antioxidant compounds and antioxidant activities in teas. A total of 99 teas were tested for their antioxidant activities based on their ability to scavenge DPPH (1,1-diphenyl-2-picrylhydrazyl) free radical. Antioxidant activity was expressed as mg of ascorbic acid equivalents per 100 g tea sample (L-ascorbic acid equivalent antioxidant capacity, AEAC) and was expressed as mg per 1 serving size (free radical scavenging activity, $FSC_{50}$). The total polyphenol contents of the extracts was quantified using the Folin-Ciocalteu method and the total flavonoid contents of the extracts was determined using a modied method of Davis. Vitamin C was analyzed by HPLC method. According to the AEAC value, mate tea, green tea, black tea, oriental raisin tea, chamomile tea and burdock tea showed relatively high antioxidant activities. Polyphenolic compounds were the major naturally occurring antioxidant compounds found in teas and the high concentrations of total polyphenol compounds were observed in black tea, green tea and mate tea. The high concentrations of total flavonoid compounds were observed in mate tea, black tea and yam tea and the amount of vitamin C contents were found to be high in citron tea and green tea. As a result, steeping tea was much higher in antioxidant activity than either powdered tea or liquefied tea. According to the study, a high correlation was demonstrated between the total polyphenol contents and antioxidant activities in teas (r = 0.846) and correlations between the total flavonoid contents and antioxidant activities was statistically significant in teas (r = 0.625). It was found that also the proportional relationship established among the total polyphenol content and antioxidant activities. That is, antioxidant activity of teas has been confirmed to have been caused by the total polyphenol.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.10
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• pp.1414-1421
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• 2009

Pine needle powder has medical and functional uses. In this study, cookies were prepared using different 0.5%, 1%, 3%, 5% of pine needle powder. The total phenolic content was measured by the Folin-Ciocalteu method, and antioxidant activity was evaluated by DPPH assay. The antioxidant activity was highly correlated with the total phenolic composition of pine needle cookies (r=0.989). In addition, the quality characteristics of the pine needle cookies were estimated based on the bulk density and pH of the dough, spread factor, loss rate, leavening rate, color, texture profile analysis, and sensory evaluations. The bulk density of the dough and the hardness, total polyphenol contents and DPPH free radical scavenging activity of cookies significantly increased with increasing pine needle powder, while the pH of the dough, spread factor and L values of the cookies decreased with increasing pine needle powder content (p<0.05). Additionally, the consumer acceptability scores for the 3% pine needle cookie groups ranked significantly (p<0.05) higher than those of the other groups in appearance, taste, flavor, texture and overall preference. Taken together, the results of this study suggest that pine needle powder is a good ingredient for increasing the consumer acceptability and the functionality of cookies.

• Korean Journal of Food Science and Technology
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• v.3 no.1
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• pp.37-43
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• 1971

(1) Relatively active polyphenol oxidase influence was seen at $0{\circ}C$, and the optimal pH level for the enzyme from the seeds of a small type sweet pepper Zairaisisi is 6.5. (2) The starting stage of the brown coloration with low-temperature injuries showed a strong activity of polyphenol oxidase, and the activity drops to 0 as the entire seed became brownish. (3) The browning effect with enzyme solution of polyphenol extracts suggested that the brown coloration continues in vitro even if polyphenol oxidase activity is nil. (4) Although cytochrome oxidase activity dropped when an abnormality occurrs in electron pathways of respiration at the starting stage of the browning with low temperature injuries, there was no marked influence of it on the total respiration, indicating the fact that polyphenol oxidase can take place of terminal oxidase in the compensatory respiration process.

• Food Science and Biotechnology
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• v.18 no.1
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• pp.43-47
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• 2009

Rheum undulatum and Rheum palmatum have been widely used as food material as well as medicinal ingredients for their therapeutic effects in oriental countries. Many kinds of herbs are being used in the manufacture of functional foods. The objective of this study was to determine polyphenol content, superoxide dismutase (SOD)-like activity, tyrosinase activity, and electron donating ability of R. undulatum and R. palmatum. Total polyphenol content were most effective in 50 and 100% ethanol extracts from R. undulatum and R. palmatum. SOD-like activities of R. undulatum extracts were higher than those of R. palmatum extracts, and water extracts of samples were highest. EDAs of R. undulatum extracts were higher (26.76-44.46%) than those of R. palmatum extracts, while those of both extracts were lower than 1.0 and 0.1% L-ascorbate. And these suggest that the extracts of R. undulatum and R. palmatum can be used as a material in functional food.

• The Korean Journal of Food And Nutrition
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• v.30 no.4
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• pp.742-748
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• 2017

This research aimed to improve the healthy properties of puffer fish broth, which has been utilized in Korean and Japanese food. Various healthy foods such as garlic, onion, mushroom, and cauliflower were added as ingredients to pufffer fish stock, and the antioxidative activity of each stock was measured by assaying the DPPH and ABTS radical scavenging activities, reducing power and amount of polyphenol. Shiitake was the most effective in increasing the antioxidative activity of puffer fish stock. The high antioxidative activity of shiitake mushroom seems to be correlated with the amount of polyphenol content in puffer fish broth. The antioxidant activities of puffer fish stock increased proportionally with increasing amount of added shiitake, which in turn was due to the increased amount of total polyphenol in the stock.