• Korean Journal of Food Science and Technology
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• v.5 no.1
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• pp.33-35
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• 1973

If soybeans are presoaked, two minutes heating at $100^{\circ}C$ is sufficient to inhibit production of objectionable green beany flavors, with dry beans, three minutes heating at $100^{\circ}C$ accomplishes the same inhibition, These brief heat treatments are not sufficient to inactivate growth inhibition factors as determined by chick feeding trials. The inhibition of off flavor coincides with loss of lipoxygenase activity, and the inhibition is thought to be due to lipoxygenase inactivation.

• Journal of Applied Biological Chemistry
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• v.42 no.3
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• pp.130-133
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• 1999

Lipoxygenase activities of three cultivars of black rice (Chindo, Suwon-415, Yongkeum-1) were determined using an oxygen polargraphic method to measure oxygen uptake. Studies at different pH levels revealed that the optimum pH was about pH 7.0 for Suwon-415 and pH 7.5 for Chindo and Yongkeum-1. The specific activities of Chindo, Suwon-415 and Yongkeum-1 at optimal pH were 41.0, 27.3, and 29.6 unit/mg-protein, respectively. In all the cultivars, there was an increase in the activity with increase in reaction temperature. Enzyme activity was tested at different concentrations of the substrate. The resulting $K_m$ and $V_{max}$ values of Chindo, Suwon-415, and Youngkeum-1 were 0.059, 0.050, and 0.066 mM and 2020, 2283, and 1616 unit/g-grain, respectively. Enzyme activity decreased at all storage temperatures(25, 4, and $-40^{\circ}C$).

• Journal of the Korean Chemical Society
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• v.39 no.9
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• pp.741-748
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• 1995

Various catechol derivatives inhibiting 5-lipoxygenase were studied with theoretical calculations and QSAR study. It was hypothesized that receptor site model could accept the active site of the catechol derivatives. The molecular length, molecular surface area, C5 net charge, HOMO/LUMO energy, van der Waals surface area and volume were used as variables to find the relationships between activity and physicochemical parameters.

• BMB Reports
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• v.29 no.6
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• pp.564-568
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• 1996

Bursts of ethylene production occurred in twice at an early exponential (EEP) and prestationary (PSP) phases, respectively, during growth of callus tissue isolated from the root of soybean seedlings. The second burst of ethylene production at PSP was smaller in magnitude than the earlier one at EEP, but was followed by increases in both guaiacol peroxidase (GuPOX) and ascorbate peroxidase (AsPOX). The increase in AsPOX activity was also preceded by an increase in lipoxygenase (LOX) activity. Treatment of the tissue with the ethylene antagonist 2,5-norbonadiene (NBD) resulted in substantial reduction in LOX and AsPOX activities during this period. GuPOX activity was reduced only slightly, if any, by NBD. Role of ethylene in the sequential induction of LOX and AsPOX in senescing callus tissue is discussed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.2
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• pp.202-207
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• 1995

The effects of lipoxygenase, linoleic acid, tocopherol and pH on the co-oxidation of $\beta$-carotene in the aqueous system were studied. It showed that the co-oxidation of $\beta$-carotene was noticeable at both pH 7.4 and 9.0. As the concentraitons of linoleic acid and $\beta$-carotene increased, the rate of oxidation of $\beta$-carotene tended to be increased. However, $\alpha$- and $\delta$-tocopherol retarded the co-oxidation of $\beta$-carotene. As the concentrations of tocopherols increased, $\beta$-carotene was more stabilized, generally. But low concentration of $\alpha$-tocopherol(10-4M) acted more effective antioxidant than high concentration of it(10-3M) at pH 7.4. The antioxidant effect of tocopherol greatly depended on pH ; it was outstanding at pH 7.4.

• Applied Biological Chemistry
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• v.17 no.4
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• pp.247-256
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• 1974

The Merit variety of soybean (Glycine max L.), harvested in 1971 was germinated in the dark at $21{\sim}25^{\circ}C$ for 10 days. The soybean sprout were divided into cotyledons and seedling axis and subjected to the determination of lipoxygenase activity and fatty acid composition of triglycerides, free fatty acids, phosholipids and crude fat fractions at two-day intervals during the germination periods. The results are summarized as follows 1) The lipoxygenase activity in cotyledons declined sharply after second day, but the activity in seedling axis inclined slightly after second day. However, the decrease of lipoxygenase activity in cotyledons coincided with decrease of linoleic and linolenic acids in cotyledons and increase of lipoxygenase activity in seedling axis coincided with increase of those acids in seedling axis. 2) The iodine value of neutral fat in cotyledons decreased continuously, but the iodine value of the neutral fat in seedling axis remained almost constant. iodine value in cotyeldons was greater than in seedling axis. 3) In the fatty acid composition of triglycerides in cotyledons, palmitic acid did not changes significantly, stearic acid increased continuously, oleic acid changed irregularly, linoleic and linolenic acids continuously decreased significantly. But in the fatty acid composition of triglycerides in seedling axis, palmitic acid remained unchanged, linoleic and linolenic acids slightly increased continuously, stearic and oleic acids changed irregularly. 4) Composition of free fatty acids in cotyledons and seedling axis changed irregularly, suggesting that all fatty acids produced by hydrolysis of triglycerides by lipase are used(or either biosynthetic Purpose or energy Production at random. 5) Fatty acids with odd-numbered carbon chain were not detected in the triglycerides and free fatty acid fractions during the germination periods, suggesting that all fatty acids are utilized as $C_2$-unit in degradation and biosynthesis. 6) The changes of fatty acids composition of Phospholipid in cotyledons and seedling axis during the germination were similar to these of triglyceride fraction.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.8
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• pp.979-984
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• 2008

The stems of P etasites japonicus were extracted with ethanol and then partitioned with hexane, chloroform, ethyl acetate, n-butanol and water, successively. The antioxidant potency of five crude fractions were determined using (1) 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, (2) thiobarbituric acid reactive substances (TBARS) assay in the linoleic acid model system, and (3) lipoxygenase inhibition assay. Among the crude fractions, the ethyl acetate fraction exhibited the most potent antioxidant effect. By activity-guided fractionation, compound PJ-4 was isolated from the ethyl acetate fraction through the repeated silica gel open column chromatography. The chemical structure of the isolated compound was determined as kaempferol by $^1H-$ and $^{13}C$-NMR analysis and its antioxidative capacity was further investigated. DPPH radical scavenging activity of the compound was 65.76% at the concentration of $100 \;{\mu}g/mL$. The inhibitory activity of the compound against lipid peroxidation and lipoxygenase exhibited 43.47% and 58.60%, respectively at the concentration of $100\;{\mu}g/mL$. The result suggests that the compound may serve as a useful natural antioxidant and furthermore indicates the possibility of developing the stems of Petasites japonicus as a natural antioxidant source.

• Korean Journal of Food Science and Technology
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• v.30 no.5
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• pp.1012-1017
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• 1998

This study was performed to investigate the change of lipoxygenases and urease activities, trypsin inhibitor, tannin and phytic acid contents during heat treatment of Jinpum soybean. The lipoxygenase-1 and urease possessed their activities after heating at $60^{\circ}C$ for 100 min, but their activities disappeared rapidly at $80^{\circ}C$ and $100^{\circ}C$ for 20 and 10 min. There were no lipoxygenase-2 and -3 activities in Jinpum soybean with and without heating. Trypsin inhibitor was lost 91.9%, 78,1% and 58.6% of the activity after heat treatment at $100^{\circ}C$ for 50 min, at $80^{\circ}C$ for 100 min and at $60^{\circ}C$ for 100 min, respectively. The tannin content was increased by heat treatment. The content of and phytic acid was increase after heating at $60^{\circ}C$ for 100 min, unchanged at $80^{\circ}C$ for 100 min and decreased at $100^{\circ}C$ for 100 min.

• BMB Reports
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• v.34 no.3
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• pp.259-261
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• 2001

• Bulletin of the Korean Chemical Society
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• v.32 no.10
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• pp.3752-3755
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• 2011