• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.5
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• pp.792-799
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• 2013

This study was designed to develop natural browning inhibitors. The anti-browning effects of distilled water (SBD) and 80% ethanol extracts (SBE) of Scutellaria baicalensis Georgi in apple slices were investigated by L and ${\Delta}E$ values. Both SBD and SBE were effective in reducing the browning of apple slices and were successively fractionated into chloroform ($CHCl_3$), ethyl acetate (EtOAc), and water ($H_2O$) fractions. These extracts were measured for total phenolic content, flavonoid content, anti-oxidative activity (through free radical scavenging activity and the FRAP assay), ferrous ion chelation, and the inhibition of PPO (polyphenol oxidase) activity. Overall, fractions of SBE were better than fractions of SBD in all measurements. The highest total phenolic and flavonoid content were measured in the EtOAc and $CHCl_3$ fractions of SBE. EtOAc and $CHCl_3$ fractions also exhibited the highest anti-oxidative activities (in DPPH and ABTS free radical scavenging and the FRAP assay). Unusually, the highest ferrous ion chelating capacity was found in the $H_2O$ fraction of SBD, but the other fractions showed more than triple the ascorbic acid already in use. Also, $CHCl_3$ fractions showed a stronger inhibition of PPO activity than ascorbic acid. All of these results suggest that EtOAc and $CHCl_3$ fractions from Scutellaria baicalensis can be used as natural anti-browning agents.

• Korean journal of food and cookery science
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• v.8 no.3
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• pp.241-246
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• 1992

In this study. we measured the degree of browning of 3 potato culitivars harvested in Korea and compositions such as total phenols, tyrosine and polyphenol oxidase (PPO) activity. And we compared the extent of browning and composition factors to investigated which was related to the differences among 3 cultivars in browning. The results are as follows. 1. Among 3 culitivars, Sumi browned most after grinding and showed that browning in Sumi was preceded by significant1y shorter lag time. Namjak and Sumi were rapid to brown compared to Daejima. 2. Among 3 culitivars, Sumi contained significant1y more total phenols than did Namjak and Daejima. On the other hand, tyrosine contents by automatic analyzer of Sumi and Namjak were similar and mat of Daejima was the lowest. PPO activities were higher when catechol was used as substrate and Sumi contained more PPO than did the other culitivars. 3. When we compared me browning behavior and composition of 3 culitivars, significant correlation was obtained between browning extent and total phenols, tyrosine and PPO. For me individual cultivar, Sumi which browned much extensively showed higher correlation between browning and PPO. On the other hand, the other cultivars showed higher correlation with total phenols and tyrosine, respectively.

• Horticultural Science & Technology
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• v.33 no.1
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• pp.55-60
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• 2015

Skin blackening is a serious postharvest disorder occurring in 'Fuyu' persimmon fruits (Diospyros kaki, 'Fuyu'). Phenolic content, polyphenol oxidase (PPO) and peroxidase (POD) activity, and lipid saturation were investigated in skin tissue of 'Fuyu' fruits. The phenolic compounds were accumulated unevenly on fruit skin depending on sunlight exposure, i.e., the most accumulation on sunny side and the least on the opposite, shaded side. The fruits harvested from shaded branches inside the canopy showed relatively even distribution of phenolic compounds in the skin. The activity distribution of PPO and POD were also uneven but only in fruits suffering f rom skin b lackening disorder, w ith the h ighest and the lowest a ctivity of PPO and P OD, respectively, in the blackened area of the fruit. When the sunny, southern sides of fruits were marked at harvesting time and fruits were stored at low temperature, a round black spot, as a symptom of skin blackening disorder, developed during storage exactly on the marked region. In addition, the sunny side of fruit showed higher lipid saturation, thus indicating adaptation to high temperature caused by the sunlight. These results suggest that the skin blackening disorder of 'Fuyu' fruits can be considered as a kind of chilling injury symptom that develops on the high-temperature-acclimated skin tissue of sunlight-exposed fruits when they are later exposed to low temperature.

• Food Science and Preservation
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• v.9 no.2
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• pp.240-247
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• 2002

This study, to enhance the sterilization, browning inhibition and precooling effect of electrolyzed oxidizing water(EOW) as cleaning water on food industry, was carried out to investigate the efficacy of electrolyzed oxidizing water(EOW) with 0.85% NaCl, 0.5% ethanol, polysorbate 80 of 1 ppm, 0.5% lemon juice and 0.5% citron juice. Escherichia coli KCTC 1039 with initial count of 5.63$\times$10$\^$8/ CFU/mL were reduced to <10$^1$CFU/mL after 15∼30 sec when it was treated by electrolyzed oxidizing water added with various food additives. Bacillus cereus KCTC 1012 were reduced to <10$^1$ CFU/mL after 2 minutes treatment with electrolyzed oxidizing water containing polysorbate 80 and ethanol. Iactobacillus plantarum KCTC 3108 were reduced to <10$^1$CFU/mL after 30 sec treatment with electrolyzed oxidizing water containing polysorbate 80, citron juice and lemon juice, respectively. Erwinia carotovora subsp. carotovora KCTC 2776 were reduced to <10$^1$CFU/mL after 30 sec treatment with electrolyzed oxidizing water containing polysorbate 80 and lemon juice. Browning inhibition effect was determined by comparison of polyphenol oxidase activity. Inhibition ratio of polyphenol oxidase was approximately 62∼84% in most treatments with the exception of 57% and 25% inhibition by 0.5% ascorbic acid and polysorbate 80, respectively. Sliced potato dipped in electrolyzed oxidizing water containing NaCl and citron juice for 30 minutes showed significantly low PPO activity, 64 units in treatment with NaCl and 91 units in treatment with citron juice. At the same time, changes in color value(△E) of sliced potato was below 3 in most treatments.

• Horticultural Science & Technology
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• v.30 no.1
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• pp.42-49
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• 2012

This experiment was conducted to find out the effects of nitrous oxide ($N_2O$) on the postharvest quality of 'Janghowon hwangdo' peach fruits. Fruits were harvested at commercial maturity for marketing in late September, and treated with 70% $N_2O$ + 20% $O_2$ + 10% air, 80% $N_2O$ + 20% $O_2$, and 90% $N_2O$ + 10% $O_2$ for 48 h, and then stored at $15^{\circ}C$. No significant treatments for soluble sugar and titratable acidity contents were detected. However, good appearance and taste in peach fruit were maintained better in 80% $N_2O$ treatment than in air treatment. The treatment with 90% $N_2O$ had negative effects on weight loss and taste because of rotting by anaerobic fermentation. 80% $N_2O$ treated fruit had significantly higher fungus (Botrytis cinerea) growth inhibition of saprogenic approximately than air treatment until 12 days of storage. The browning and rotting at surface of peach were also retarded when peaches were treated with 80% $N_2O$ before they were artificially wounded. The activity of polyphenol oxidase (PPO) was inhibited about 80% in peach of 80% $N_2O$ treatment compared with in air treatment. The result showed that 80% $N_2O$ treatment was able to extend the shelf life of peach fruits through maintaining taste and inhibition of softening and browning by rotting and wounding during storage.

• Food Science and Biotechnology
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• v.18 no.3
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• pp.661-666
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• 2009

The heat tolerance and the inactivation kinetics of peroxidase (POD) and polyphenol oxidase (PPO) in pineapples (Ananas comosus) were studied in the temperature range $45-95^{\circ}C$. The kinetic parameters, such as deactivation rate constant (k), activation energy ($E_a$), and decimal reduction rate (D) of the thermal inactivation process, were determined. POD in pineapples showed biphasic inactivation behavior at temperatures range $45-75^{\circ}C$ but was monophasic at $85-95^{\circ}C$. This indicate that POD has 2 isozymes, namely heat labile and heat resistant, with $E_a$ of 68.79 and 93.23 kJ/mol, respectively. On the other hand, the heat denaturation of pineapple PPO could be described as simple monophasic first-order behavior with $E_a$ of 80.15 kJ/mol. Thus, the results of this study is useful in blanching technology where it shows a shortened time with higher temperature can be applied. The determination of the heat tolerance and inactivation POD and PPO, at different temperature range as done in the present work, was very important to improve the blanching process. This also will help to optimize the pineapple canning process which is one of the most important food industries in many tropical regions.

• Korean Journal of Food Science and Technology
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• v.27 no.6
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• pp.978-984
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• 1995

This study was conducted to investigate the physiological functionality of the hot water and 70% acetone extracts obtained from the pine needle and mugwort. Flavanol tannin content was above 60% of the total polyphenol in pine needle extracts. 70% Acetone extract from pine needle exhibited inhibition percentage of about 82.2% on the mutagenicity of Trp-P-1. Angiotensin I converting enzyme(ACE) inhibition activity was 61% and 50% in the hot water extract and in the 70% acetone extract respectively. Electron donating ability(EDA) of the hot water and 70% acetone extracts obtained from the pine needle was significantly good above 80%. 70% Acetone extract from pine needle showed inhibitary effect against the polyphenol oxidase(PPO) of water dropwort. The nitrite scavenging ability was appeared in all the extracts examined and it showed $80{\sim}90%$ at pH 3.0. The oxidative stability was determined by POV. Results showed that ethyl acetate fraction is better antioxidants than chloroform and butanol fractions in the soybean oil. Then, in the mugwort extracts, antimutagenicity of 70% acetone extract was similar to that of pine needle. Ratio of ACE inhibition activity was higher than that of pine needle extracts. EDA of hot water and 70% acetone extracts was 45%. Extracts from the mugwort were lower in nitrite scavenging ability about $20{\sim}30%$ than extracts from pine needle.

• Applied Biological Chemistry
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• v.40 no.2
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• pp.123-127
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• 1997

To improve the quality and prolongation of chopped ginger, they were treated with NaCl, citric acid, ascorbic acid alone or combination of them at $5^{\circ}C$. The browning and stink of chopped ginger were prevented by adding 10% NaCl, $0.5{\sim}2.0%$ citric acid, but the control became severely browned and deteriorated after 1 month storage. The application of 0.5% citric acid maintained citrine color and decreased the activity of polyphenol oxidase(PPO) more significantly compared to 5.0% NaCl or 0.5% ascorbic acid. Ascorbic acid treatment become browned at $1.0{\sim}2.0%$ and easily deteriorated compared to citric acid. Citric acid(0.5%) or ascorbic acid (0.5%) treatment was largely variation of pH compared to NaCl(5.0%)+citric acid(0.5%) or NaCl(5.0%)+ascorbic acid(0.5%) treatment during 8 month storage. The activity of PPO in NaCl(5.0%)+ascorbic acid(0.5%) treatment was elevated after 4 month storage. In chopped ginger, NaCl(5.0%)+citric acid(0.5%)+ascorbic acid(0.25%) treatment was more effective than 5.0%+0.1%+0.1%, 5.0%+0.5%+0.1% during 12 month storage.

• Horticulture, Environment, and Biotechnology : HEB
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• v.59 no.6
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• pp.835-845
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• 2018

We studied the role of ethylene control in regulating energy metabolism, antioxidant enzyme activity, and vase life of cut rose Rosa hybrida 'Carola'. Rose flowers at stage II were sprayed with one of the following solutions: water (control), $10{\mu}L\;L^{-1}$ 1-methylcyclopropene (1-MCP), or $0.5g\;L^{-1}$ 2-chloroethanephosphonic acid (ethephon). After harvest, ethylene production rate, respiration intensity, energy charge (EC), activities of energy metabolism-related and antioxidant enzymes, and malondialdehyde (MDA) content were measured. Results showed that 1-MCP enhanced the activities of superoxide dismutase, $H^+$-adenosine triphosphatase, $Ca^{2+}$-adenosine triphosphatase, succinic dehydrogenase, and cytochrome c oxidase, increased adenosine triphosphate (ATP) content, maintained high EC levels, inhibited respiration intensity, reduced peroxidase (POD) and polyphenol oxidase (PPO) activity and MDA accumulation, and prolonged vase life. Ethephon promoted ethylene production and respiration intensity, increased POD and PPO activity, reduced ATP content and EC levels, and accelerated senescence. Our results support a novel role for ethylene control in regulating senescence of 'Carola'.

• YAKHAK HOEJI
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• v.46 no.4
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• pp.237-241
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• 2002

Polyphenoloxidase activity (PPO) in the leaves of Erechitites hieracifolia was estimated by Warburg's manometric method. The emzyme was most reactive toward chlorogenic acid followed by caffeic acid. Diethyldithiocarbamate and potassium cyanide were shown powerful inhibition rate to the polyphenoloxidase from the leaves of Erechitites hieracifolia. We confirmed antioxidant activity of the leaves of Erechitites hieracifolia by DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging method. Electrophorectic isoenzyme banding patterns of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were observed by native PAGE. The correlation of PPO and antioxidant enzymes is not investigated yet. That is need to further study.