• Korean Journal of Food Science and Technology
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• v.13 no.1
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• pp.53-56
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• 1981

Several tests were conducted to study lipoxygenase activity and off-flavor developement in frozen sweet corn. Fresh corn contained about 60% of total lipoxygenase activity in the germ section. When non-blanched frozen sweet corn was stored at $-10^{\circ}F$, it developed off-flavor and most significant changes in the flavor profile of off-flavored sweet corn was $4{\sim}5$ times higher hexanal peaks. The high hexanal peaks observed in the sterilized sweet corn with added lipoxygenase, alone and in combination with other enzymes, suggested the fact that high hexanal peaks in off-flavored sweet corn could be due to an oxidative reaction of lionleic acid (and other unsaturated fatty acids) catalyzed by lipoxygenase. Based on lipoxygenase activity and linoleic acid content in sweet corn, this reaction occur most heavily in the germ section of sweet corn. There was a significant relationship between flavor score of frozen stored corn-on-the-cob and hexanal peak in the germ section of corn-on-the-cob. This result indicated that hexanal peak could be used as an objective index of off-flavor development in frozen sweet corn.

• Korean Journal of Food Science and Technology
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• v.27 no.3
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• pp.290-293
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• 1995

This study was designed to investigate the effect of potato lipoxygenase on the change of dough chemical composition including lipid distribution, fatty acid composition, carotenoids content and color value in wheat flour dough. For the study, the potato lipoxygenase was added to wheat flour at a level of $6.5{\times}10\;unit/g$ flour. The addition of potato lipoxygenase to wheat flour dough was found to cause an increase in free lipid content, an effect apparently related to the decrease in linoleic acid content and increase in peroxide value. This phenomena might be due to the enzymatic oxidation of polyunsaturated fatty acid. Also, the bleaching effect of lipoxygenase was observed as the decrease in carotenoids content of wheat flour dough. In comparison of color value, it was shown that redness, yellowness and total color difference$({\delta}E)$ were lower by addition of lipoxygenase.

• Environmental Analysis Health and Toxicology
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• v.8 no.3_4
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• pp.1-5
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• 1993

Using mixed incubation of cultured endothelial cells, cultured fibroblasts, neutrophils activated with PMA and paraquat, the production of superoxide anion, $H_2O$$_2$and lipoxygenase metabolites (5-HETE and 12-HETE) of arachidonate was estimated. The results was as follows: 1. Neutrophils activated with PMA was produced superoxide anion,$H_2O_2$and lipoxygenase metabolites (5-HETE and 12-HETE) of arachidonate. 2. Fibroblasts did not alter the production of superoxide anion and $H_2O_2$ by neutrophils, it was markedly reduced by mixed incubation with endothelial cells. 3. Mixed incubation with endothelial cells significantly augmented the production of 5 or 12-HETEs, but fibroblasts did not. 4. Using mixed incubation of endothelial cells, fibroblasts, neutrophils and paraquat (50ug/m1 and 100ug/m1), the production of superoxide anion, $H_2O_2$and HETEs was significantly increased on both cells at low concentration (50ug/m1), but markedly reduced at high concentration (1001g/m1). 5. Paraquat showed concentration dependent effects on arachidonate lipoxygenase metabolism.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.6
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• pp.959-963
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• 1994

To detect bioactive compounds present in unused marine resources, the screening for the 5-lipoxygenase inhitors in Asterina pectinifera, Halocynthia roretzi skin, Nototodarus sloani ink, Anthocidaris crassispina skin, SArgassum horneri, Agarum cribrosum, Odonthalia corymbifera and Desmarestia ligulata was carried out. THe ether and acetone extracts of Sargassum horneri had the strongest antioxygnic activityon lipid oxidation by potato lipoxygenase-1 (one of 5-lipoygenase) among the tested marine samples and their $IC_{50}$ were 0.3 and 1.1g/ml, respectively. The ether and acetone extracts of Asterina pectinifera, the acetone extracts of Halocynthia roretizi, and the acetone extracts of Nototodarus sloani ink had strong inhibitory activity and their $IC_{50}$ were 72.5, 65, 13.3 and $13.3\mu\textrm{g}/ml$, respectively. In addition, the $IC_{50}$ of the acetone extracts of Agarum cribrosum and Desmarestia ligulata, and the ether extracts of Desmarestia ligulata were 15.5, 35 and $30.5\mu\textrm{g}/ml$, respectively. The nonpolar solvent (ether, acetone) extracts of tested marine organism had more antioxigenic effect against 5-lipoxygenase than the polar solvent(water) extracts.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.5
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• pp.808-812
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• 1998

Melania snail(Semisulcopira bensoni) is used as ingredient in Korean traditional soup and nutritional foods. Generally, lipoxygenase in several food products may produce off-flavors during their processing and storage. Therefore, the inactivation of lipoxygenase is required to make the better extracts from Melania sanil. Also, the quality on freshness of Melania snail may be evaluated by lipoxygenase activity. The lipoxygenae activity was the highest at 40~60% saturation among several concentrations in salting-ouot saturated solution of ammonium sulfate. The partial purification of lipoxygenase was successfully obtained by Sephacryl S-200 gel chromatography. The first peak among three peaks for protein determination showed the highest activity of lipoxygenase in 13~16 fractions among 100 fractions. The highest peak of lipoxygenase activity by ion exchange chromatography was shown at 0.1M NaCl. In the purification step, the specific activity was 20.8U/mg and activity yield was 19.8%. The optimum pH and temperature were pH6.0~8.0 and 3$0^{\circ}C$, respectively. Molecular weight of the lipoxygenase was estimated about 35kDa by SDS-PAGE.

• Korean Journal of Food Science and Technology
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• v.29 no.4
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• pp.710-715
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• 1997

Inactivation of lipoxygenase activity in Chinese cabbage was shown after salting and heat treatments. Crude lipoxygenase was obtained from treatment of $(NH_{4})_{2}SO_{4}$. Lipoxygenase activity in Chinese cabbage was about 50% after 20 hrs of salting in 13% (w/v) concentration. After heating at $90^{\circ}C$ for 15 min, residual activity of lipoxygenase was about 50%. Inactivation of lipoxygenase was highly accelerated by increasing temperature and heating time. Decimal reduction time (D-value) were 42, 20 and 14 min at 70, 80 and $90^{\circ}C$, respectively. When cabbage was soaked in 0.05 M $CaCl_{2}$ and heated at $55^{\circ}C$ for 1.5 hr, higher activity of crude lipoxygenase was found compared with the heat treatment without $CaCl_{2}$.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.157-163
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• 2002

An investigation was carried out to study the characteristics of lipoxygenase in dioctyl sulfosuccinate (aerosol-OT, AOT)/isooctane revered micelles of microaqueous system containing infinitesimal water. ${\alpha}-Linoleic$ acid as a substrate could be analyzed by the colorimetric methodology using 5%(w/v) cupric acetate-pyridine solution and the activity of lipoxygenase was able to be assayed by the degree of ${\alpha}-linoleic$ acid consumption per minute. Optimal pH, temperature, and R-value ([water]/[AOT]) were determined as the value of 5.0, $25^{\circ}C$, and 10.0, respectively. Kinetic analysis of the enzyme reaction under the optimal conditions showed that the values of $K_m$ and $V_{max}$ were 0.31 mM of ${\alpha}-linoleic$ acid and $384.16{\mu}mol$ of ${\alpha}-linoleic$ acid decomposed/min, respectively. The results indicate the reaction to be lipoxygenase-catalyzed oxidation of ${\alpha}-linoleic$ acid in AOT/isooctane reversed micellar system. The inhibitory effect of natural antioxidants on lipoxygenase showed little inhibitory effect of L-ascrobic acid while ${\alpha}-tocopherol$ showed 72% of inhibitory effect.

• Korean journal of food and cookery science
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• v.4 no.2
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• pp.57-64
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• 1988

The present study was conducted to characterize lipoxygenase isoenzymes isolated from germinating soybean seeds to obstain pH profiles, carbonyl Production, carotene bleaching abilities, and stability to heat. The roles of these lipoxygenase isoenzymes in the generation of volatile carbonyl compounds were investigated to associate with off-flavor and odor of soybean sprouts cooked to different temperatures. Lipoxygenase isoenzymes were isolated from soybean sprouts using ammonium sulfate fractionation, gel filtration and ionexchange chromatography. Two main lipoxygenases exhibited maximum activity at pH 6.5 (lipoxygenase 2) and at pH 9.5 (lipoxygenase 1), respectively. Both lipoxygenase 1 and 2 produced 280 nm absorbing carbonlys and bleached carotene. The abilities of hydroperoxide formation, 280 nm absorbing carbonyl production and carotene bleaching of lipoxygenase isoenzymes were decreased significantly as the cooking temperature raised. Sensory evaluation data presented that raw and $50^{\circ}C$ cooked soybean sprouts showed significantly higher grassy odor than $80^{\circ}C$and $100^{\circ}C$ cooked soybean sprouts. On the other hand beany odor was significantly higher in $50^{\circ}C$ and $80^{\circ}C$ cooked soybean sprouts than in raw and $100^{\circ}C$ cooked soybean sprouts. These results indicate that lipoxygenase plays a role in the development of off-odor and flavors in soybean sprouts under the condition of chewing and inadequate heating.

• Korean Journal of Pharmacognosy
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• v.28 no.4
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• pp.247-251
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• 1997

The effects of the extract of the root of Cynanchum wilfordi (Asclepiadaceae), the alkaloid fraction, and the isolated main constituent (gagaminine) on 5-lipoxygenase(5-LOEC 1.13.11.34) in bovine PMNL have been studied. The effect of the crude extracts of wildand cultivated plant was also compared each other. Furthermore, the inhibitory effect of gagaminine on 5-Lo was compared with those of the standard drugs. Gagaminine inhibited 5-Lo activity with an $IC_{50}$ value of $26\;{\mu}M$, this result indicates that gagaminine may be useful for in vivo experiments as 5-LO inhibitor.

• Korean Journal of Breeding Science
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• v.40 no.1
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• pp.26-30
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• 2008

Normal soybean seed contains three lipoxygenase isozymes called L-1, L-2, and L-3, respectively, which are responsible for the generation of undesirable grassy-beany flavors. Simple and effective methods for the detection of lipoxygenase isozymes were developed in soybean seeds. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) has been tried in separating these isozymes. It was done effectively on 7.5% separating gel and 4.5% stacking gel. However, no reliable method has been developed specifically for separating L-3, L-13 and L-23. Visual judging methods were based on the bleaching activities of lipoxygenase in contact with methylene blue and ${\beta}$-carotene. Sodium linoleate bleaching method was adopted to determine L-1 and L-2. Carotene bleaching and spectrophotometric methods were used to determine L-3. These systems were very rapid within one minute, furthermore only required a small piece of cotyledon (below 10 mg) and the other part could be used for generation advance after analysis. It was demonstrated that 200 seed samples could be analyzed per day by one laboratory assistant. The combination of visual judging methods and electrophoresis is suitable for breeding programs. It took 6.5 hours for analysis of 100 seed samples by one person.