• Korean Journal of Food Science and Technology
• /
• v.23 no.4
• /
• pp.442-446
• /
• 1991

Three peroxidase fractions (peak I, II, III) were isolated from Fuji apples using CM-cellulose chromatography. The homogeneity of the isolated peroxidase isozymes was established by isoelectric focusing and electrophoresis. Isoelectric points of the isozymes were 3.80, 3.82, and 3.85, respectively. The optimum pH of peroxidase isozymes were pH 5.0(peak I) or 5.5(peak II, III), and optimum temperature was $40^{\circ}C$ when assayed by using guaiacol and $H_{2}O_{2}$ as substrates. Inactivation rate of three peroxidase isozymes were different at temperature of $70^{\circ}C$ and at pH of 5.5. The isozyme of peak II was found to be more heat stable than those of peak I and III. D values at $70^{\circ}C$ of peroxidase isozymes (peak I, II, III) were estimated to be 660 sec, 1,320 sec, and 600 sec, respectively. The thermal stability of Fuji apple peroxidase was not influenced in the presence of 0.032 M sucrose or lactose. However, the thermal stability of the enzyme was decreased by fructose and glucose.

• Korean Journal of Environmental Agriculture
• /
• v.3 no.2
• /
• pp.37-42
• /
• 1984

The effect on the activities of peroxidase and lipoxygenase by chemicals was determined. Peroxidase activities of horseradish and apple were inhibited strongly by maneb and comparativelyby mancozeb, zineb. The inhibitory rate of enzyme activity was ranged in $12.5{\sim}34.5%$ by maneb, $11.0{\sim}30.5%$ by mancozeb, and $9.7{\sim}27.5%$ by zineb in the level of $10{\sim}30\;ppm$ at the final concentration. No signification was in the peroxidase activity of apple during ripening between control and plot, treated with 500 ppm mancozeb. On the activity of purified soybean lipoygenase, zineb inhibited it more strongly than carbofuran or phosphamidon, but maneb did not have inhibitory effect on that. The inhibition ranges of $14.0{\sim}40.0%$ by zineb, $6.5{\sim}20.0%$ by carbofuran and $4.5{\sim}13.0%$ by phosphamidon were shown in the final pesticide concentration of $10{\sim}30$ ppm. But in $100{\sim}200$ ppm, lipoxygenase activity was almost inhibited by carbofuran and phosphamidon.

• Korean Journal of Agricultural Science
• /
• v.16 no.1
• /
• pp.26-35
• /
• 1989

Studies were carried out to compare from the viewpoint of peroxidase isoenzyme patterns by ages, locations and organs. In addition, the relationships among six cultivars peroxidase isoenzyme patterns were compared and the relationships between cultivars and their hybrids were examined. The results are summarized as follows. 1. The zymogram was not affected by the ages of 'Fuji' cultivar. 2. There was no locational difference in zymogram among Suwon, Taejon and Yesan in 'Fuji' and 'Tsugaru' cultivars. 3. Significant difference in isozyme patterns was found between stems and leaves in 'Fuji' and 'Tsugaru' cultivars. 4. There were some differences in zymogram among 'Ralls Genet', 'Fuji', 'Jonathan', 'Starking', 'Golden Delicous' and 'Tsugaru' cultivars. 5. Classification was made by the peroxidase isozyme development between cultivars and their hybrids. 1) The type showed both parent's isozyme pattern. 2) The type showed a loss of a part of parent's isozyme bands. 3) The type developed new isozymes which were not detected in parent plants.

• Journal of Food Hygiene and Safety
• /
• v.27 no.4
• /
• pp.401-405
• /
• 2012

The dual effectiveness of Opuntia ficus indica extracts for browning inhibition and microbial inactivation on fresh-cut apples was investigated. Prepared apple slices were treated with 25, 50, 100, 200 mg/mL Opuntia ficus indica extracts, packaged in polyethylene bags, and stored for 10 days at 4, $21^{\circ}C$. Results indicate that Opuntia ficus indica extracts significantly (P < 0.05) inhibited the browning reaction of fresh-cut apples. This treatment also reduced peroxidase activities. The populations of Staphylococcus aureus significantly decreased with increasing extract concentration (p < 0.05). In particular, S. aureus was reduced to non-detectable levels after 2 days in 100 mg/mL treatment at $4^{\circ}C$ and $21^{\circ}C$. Opuntia ficus indica extracts therefore have antibacterial and antibrowning effects. The results suggest that Opuntia ficus indica extracts could be useful as a natural food preservative.

• Korean Journal of Environmental Agriculture
• /
• v.11 no.1
• /
• pp.59-66
• /
• 1992

An enzyme immunoassay(EIA) was developed for the analysis of insecticide endosulfan and its degradation products. The sensitivity and specificity of the antibody produced were examined. Optimal conditions in the ELISA system for residue analysis were also discussed. A mixed suspension of endosulfan-hemocyanin conjugate(ES-KLH) 1.1 mg/ml and Freund's adjuvant was injected subcutaneously to white rabbits and then collected antisera were tested for titers by indirect ELISA(1/24,000). Because of difficulties in the synthesis of endosulfan peroxidase conjugate, amine derivative of endosulfan-diol was synthesized and it showed 40% of conjugate yields(2mg/ml of conjugate). the highest sensitivity obtained enzyme-conjugate was a concentration of 200ng/ml. The detection limit of endosulfan in ELISA system was 5 ppb on the standard curve. In application of ELISA for residue analysis, the recoveries were really 100% both in the spiked soil and apple sample regardless of endosulfan concentration treated. On the other hand, chlorinated hydrocarbons of similar structure with endosulfan showed low cross-reactivity$(2.2%{\sim}29.2%).$