• Current Research on Agriculture and Life Sciences
• /
• v.4
• /
• pp.55-64
• /
• 1986

Polyphenol oxidase in japanese pear (Pyrus communis var. mansamkil) was isolated, partially purified and its some properties were investigated. Polyacrylamide disc gel electrophoresis indicated two bands with polyphenol oxidase activity in the extract from acetone dry powder of par flesh. These two polyphenol oxidases (PPO A and PPO B) were purified through acetone precipitation and diethylaminoethyl cellulose column chromatography. PPO A and B were purified 7.8 fold and 8.7 fold by the present procedure, respectively. The Rm values of partially purified PPO A and B were estimated to be 0.58 and 0.68, respectively. The optimum temp, and pH of PPO A activity were $33^{\circ}C$ and pH 7.0, while those of PPO B were $30^{\circ}C$ and pH 4.2, respectively. Two PPO were unstable over the temperature of $60^{\circ}C$. The substrate specificity of pear PPO showed high affinity toward o-diphenolic compounds, especially catechol in PPO A and chlorogenic acid in PPO B, but inactive toward m-diphenol, p-diphenol and monophenols. PPO A showed affinity toward the trihydroxyphenolic compound. $Zn^{{+}{+}}$ activated the PPO A activity but $Fe^{{+}{+}}$ inhibited PPO B activity, while $Fe^{{+}{+}}$ and $Zn^{{+}{+}}$ activated the PPO B activity, while $Fe^{{+}{+}}$ and $Zn^{{+}{+}}$ activated the PPO B activity but $K^+$, $Mg^{{+}{+}}$, $Ca^{{+}{+}}$ and $Hg^{{+}{+}}$ inhibited at 10mM concentration. $Cu^{{+}{+}}$ activated the enzyme action at low concentrations but inhibited at high concentration. Inhibition studies indicated that L-ascorbic acid, L-cysteine and thiourea were most potent. The Km values of PPO A and PPO B for catechol were 20mM and 14.3mM, respectively.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.37 no.9
• /
• pp.1101-1108
• /
• 2008

This study was carried out to compare the physiological activities of the extracts from Korean and Chinese Viola mandshurica W. Baker. The water extract from leaves of Chinese V. mandshurica exhibited the highest extraction yields of 30.45 g/100 g and the highest content of total flavonoids as 102.30 mg/g. Also, its ethanol extract showed the best content of polyphenol compounds as 136.16 mg/g. The leaf extract of Korean V. mandshurica produced higher electron donating abilities (EDA) of 92.69% (KLW) and 93.61% (KLE) than the other fractions. The strongest SOD-like activity was shown in the ethanol extract from Korean leaves of 17.28% at the concentration of 1.0 mg/mL. The nitrite scavenging abilities (NSA) of the leaf extracts of V. mandshurica from China were intense over 50% at pH 1.2 and 3.0. In the results of inhibitory rates of xanthine oxidase (XO), both ethanol extracts from Korean and Chinese leaves were higher than the other fractions as 98.67% and 93.80% respectively. Effect of tyrosinase inhibition was the highest in the water extract (45.04%) of Chinese leaves, followed by its ethanol extract (31.36%). The results of EDA, SOD-like activity and XO inhibition of the leaf extracts from Korean V. mandshurica were higher than those of Chinese, on the other hand, determinations on total polyphenol contents, NSA and tyrosinase inhibition were higher in those of Chinese.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.37 no.2
• /
• pp.129-135
• /
• 2008

The objectives of this study were to determine antioxidant activity of the methanolic extracts from some specialty rices and to investigate relationships between antioxidant activities and antioxidant contents in the extracts. ABTS (2,2-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid)) radical cation scavenging activity, inhibitory effect on lipid peroxidation, chelating activity, reducing power and inhibitory effect on xanthine oxidase have been used to investigate the relative antioxidant activity of the extracts from specialty rices. The concentrations of total polyphenolics, phytic acid, and anthocyanin in the extracts were measured by spectrophotometric methods and vitamin E analysis was carried out by HPLC. The methanolic extracts prepared from black and red rices showed higher antioxidant activities and contained higher antioxidant compounds compared with other rices, apparently due to their intense red-purple color. The correlation coefficient between total polyphenolic content of methanolic extracts and ABTS radical cation scavenging activity, reducing power, and inhibitory effect of xanthine oxidase were 0.9921, 0.9856, and 0.8032, respectively.

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

• Korean journal of food and cookery science
• /
• v.13 no.4
• /
• pp.390-395
• /
• 1997

The inhibitory effects of cereal extracts and concentrates from barley, waxy rice flours and malt on enzymatic browning were measured using apple polyphenol oxidase (PPO). Malt concentrate showed the largest inhibitory effect on PPO among all. The relationship between the properties of malt concentrate such as browning intensity and reducing power and their inhibitory effect on PPO was also studied. As the heating time increased, the browning intensity and the reducing power of malt concentrates were increased, while PPO activities were decreased. Inhibitory effect of malt concentrates on PPO increased with heating time and their concentration. L-value and compression force of the apple slices dipped in malt concentrate decreased by 6.9% and 14.3%, respectively, showing the smallest changes compared with raw and water-dipped apple slices during cold storage for 9 days. These results suggest that malt concentrate can be a potential source for the control of enzymatic browning.

• Korean Journal of Food Science and Technology
• /
• v.27 no.6
• /
• pp.991-996
• /
• 1995

Effects of high hydrostatic pressure on microorganisms and browning enzymes in Angelica keiskei juice were investigated using response surface methodology. The optimum process condition for maximum reduction of total aerobes was $5700\;kg_f/cm^2$ (558.6 MPa) pressure and 7.16 min process time, and 3.44 log cycle reduction of total aerobes was predicted at the optimum condition. E. coli, initially $8.8{\times}10^3\;CFU/ml$, was completely inactivated by high hydrostatic pressure at all process conditions ($3800{\sim}6700\;kg_f/cm^2\;pressure;\;3{\sim}17\;min\;process\;time$). Polyphenol oxidase and peroxidase were partly inactivated by the high hydrostatic pressure. It was also indicated that inactivation of microorganisms and browning enzymes by hydrostatic pressure is dependent on pressure rather than process time.

• The Journal of Internal Korean Medicine
• /
• v.30 no.1
• /
• pp.94-106
• /
• 2009

Objectives : This study aimed to evaluate the effect of Wongisaengmaek-san (extracted with water or 50% ethanol) on antioxidative activity and recovery of fatigue induced by weight-loaded forced swimming exercise. Methods : Antioxidant activity of Wongisaengmaek-san was evaluated in terms of total amount of polyphenol, 1.1-diphenyl-2-picrylhvdroxyl (DPPH) radical scavenging activity and xanthine oxidase inhibition. The anti-fatigue effect of Wongisaengmaek-san was investigated using an acute weight-loaded forced swimming test by monitoring swimming test times and blood biochemical parameters creatinine. BUN, lactic acid dehydrogenase (LDH), free fatty acid (FFA) and lactic acid (LA). Results : 1. 50% EE (ethanol extract) had 2.3 times higher amount of total polyphenol compared to water extract. 2. It was identified that 50% ethanol extract showed enhancement of xanthine oxidase inhibition and DPPH scavenging effect in vitro. 3. According to anti-fatigue effect in the scale of 5% weight loaded mouse swimming test, both water and 50% ethanol extract showed significant improvement of swimming time elongation respectively, and 50% ethanol extract induced a more positive result. 4. After swimming for 1% weight-loaded mouse. water extract and 50% ethanol showed significant anti-fatigue effect with manifestation of blood sampling among both of the intervention: 50% ethanol extract showed a greater result. Conclusions : 50% ethanol extract of Wongisaengmaek-san has more effective antioxidant activity and anti-fatigue than water extract.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.34 no.1
• /
• pp.15-20
• /
• 2014

To investigate lignification process and its physiological significance under water-deficit condition, the responses of peroxidases, polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL) in relation to leaf water status to the short term of water deficit treatment in the leaves with different maturities in forage rape were measured. The significant decrease in relative water content (RWC) and leaf osmotic potential (${\Psi}{\pi}$) were apparent after 5 d of water-deficit treatment. The activity of guaiacol peroxidase (GPOD), ascorbate peroxidase (APOD), coniferyl alcohol peroxidase (CPOD), and syringaldazine peroxidase (SPOD) was depressed especially in middle and old leaves when compared with that of control leaves. On the other hand, in young leaves, a significant increase in CPOD (+34%) and SPOD (+24%) activity as affected by water-deficit treatment was apparent. The activation of PAL and PPO was observed in middle and old leaves for PAL and in young and middle leaves for PPO. These results suggest that peroxidases in middle and old leaves did not involve in lignification under mild water-deficit stress, whereas CPOD and SPOD in young leaves participate in lignification by a coordination with PAL and PPO to incorporate phenol and lignin into the cell walls.

• The Korean Journal of Food And Nutrition
• /
• v.34 no.4
• /
• pp.390-397
• /
• 2021

The purpose of this study was to investigate at how the quality of citron changed during storage as a result of the browning inhibitor treatment. In the browning inhibitor treatment, Vit.C, Vit.C+NaCl, Vit.C+NaCl+CD substances were used. As a result of investigating the browning degree, Vit.C+NaCl+CD showed the lowest value of 0.76 when stored for 12 weeks. The 𝚫E of the chromaticity value indicated that significant color change occurred when the value was high. As the Vit.C+NaCl+CD mixture showed the lowest value of 46.01 at 25℃, it was found that browning did not occur much compared to other treatments. The change in polyphenol oxidase (PPO) activity of citron increased as browning progressed. Among the browning inhibitor solutions, Vit.C+NaCl+CD solution showed the lowest value 118.8 u/g at 25℃ after 12 weeks. Based on these findings, it seems that CD mixing solution can be used as a citron browning inhibitor.

• The Plant Pathology Journal
• /
• v.39 no.2
• /
• pp.159-170
• /
• 2023

Spot blotch disease of wheat caused by Bipolaris sorokiniana (Sacc.) Shoem is considered as an economically important disease which affects all the growing stages of wheat crop. Therefore, it is important to search some effective management strategies against the spot blotch pathogen. Some synthetic elicitor compounds (salicylic acid, isonicotinic acid, and chitosan) and nano-particles (silver and aluminum) were tested against the pathogen to observe the change in biochemical activity and defense action of wheat plant against spot blotch disease. All the tested elicitor compounds and nano-particles showed a significant increase in activity of peroxidase, polyphenol oxidase (PPO), and total phenol over control. The highest increase in activity of peroxidase was recorded at 72 h from chitosan at 2 mM and 96 h from silver nano-particle at 100 ppm. Maximum PPO and total phenol activity were recorded from chitosan at 2 mM and silver nano-particle at 100 ppm as compared to pathogen-treated and healthy control. The lowest percent disease index, lowest no. of spots/leaf, and no. of infected leaves/plant were found in silver nano-particle at 100 ppm and chitosan at 2 mM, respectively. The use of defense inducer compounds results in significantly up-regulated enzymatic activity and reduced spot blotch disease. Therefore, chitosan and silver nano-particle could be used as alternative methods for the management of spot blotch disease.