• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.3
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• pp.211-215
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• 1994

Lipoxygenase is involved in the formation of certain undesirable flavors of soybean products. Three isozymes(L-1, L-2 and L-3) of lipoxygenase have been identified in soybean seeds, and the three types of mutants lacking L-1, L-2 and L-3, respectively, were detected in the 1980's. In this paper, lipoxygenase activity was measured to investigate the response of lipoxygenase in organs and tissues during soybean development. There was no tendency according to genotypes between lipoxygenase lacking mutants and normal soybeans in lipoxygenase activity of leaf at $V_3$ and $V_5$ stage. Likewise, pod wall lipoxygenase was no difference among genotypes tested at R$_{6}$ stage. Seed coat lipoxygenase activity was similar among the lipoxygenase lacking mutants, while normal soybean was lower as compared with that of the lipoxygenase lacking mutants. Embryo and cotyledon lipoxygenase activity in the lipoxygenase lacking mutants was much lower than that of normal soybean, also there was large difference among lipoxygenase lacking mutants. Thus, the lipoxygenase null mutant showed very weak value although the lacking L-3 mutant had a large effect on developing embryo lipoxygenase activity. It was suggested that soybean lipoxygenase isozymes expressed in embryo may be different from those expressed in the pod wall and leaf tissues.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.2
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• pp.171-174
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• 1994

Lipoxygenase are responsible for offensive grassy and green bean flavors which limit the wide utilization of soy protein products. This study was carried out to investigate the processing characteristics of soybean genotypes lacking lipoxygenase. Soybean curd made from soybeans with and without seed lipoxygenase showed nearly similar yield, while those sensory evaluation was better in lipoxygenase lacking lines than noramal one. Chemical composition of soybean curd also was similar between different genotypes, but total sugar content was higher in lipoxygenase lacking lines. Significant different quality of soymilk was showed by sensory test. The flavor and taste of soymilk were better in soybeans without seed lipoxygenase, although soymilk was made by two different processing methods. Therefore, in soybean breeding pro-gramme for food processing, lipoxygenase-lacking soybean genotypes could be useful economically and nutritionally.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.3
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• pp.209-214
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• 2006

Three lipoxygenase isozymes in soybean seeds are thought to be a major contributor to lipid peroxidation and generation of free radicals which may result in seed deterioration. This study was conducted to get the basic information for changing lipoxygenase activity during seed germination in lipoxygenase-lacking soybeans. Fresh weight of soybean seedling of Jinpumkong 2 and Taekwangkong increased more rapidly than that of Jinpumkong. Hypocotyls of Jinpumkong and Jinpumkong 2 were longer and thicker than that of Taekwangkong. Type I lipoxygenase activity (pH 9.0) in cotyledon of Jinpumkong lacking lipoxygenase-2, 3 showed higher than that of Taekwangkong, and Type I lipoxygenase activity of two cultivars decreased continually. On the other hand, Type II lipoxygenase activity of Taekwangkong began to increase continually two days after germination, reached to the maximum between 4 days and 5 days, and began to decrease continually five days after germination. Type I and II lipoxygenase activity in hypocotyls was not detected in all soybean cultivars.

• 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 CROP SCIENCE
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• v.47 no.2
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• pp.123-126
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• 2002

Lipoxygenase might be associated with seed deterioration by catalyzing the incorporation of molecular oxygen into fatty acids and generating free radicals. This study was performed to determine whether seed lipoxygenase activity would alter soybean seed longevity. In this study, germination percentage of lipoxygenase-lacking cultivar Jinpumkong2 (lx1lx1lx2lx2lx3lx3) was lower than that of Taekwangkong (Lx1Lx1Lx2Lx2Lx3Lx3). Segregation ratio for the three lipoxygenase isozymes of the F2-derived from the cross between Taekwangkong and Jinpumkong2 was fitted to 9 (Lx1Lx2Lx3) : 3 (Lx1Lx2lx3) : 3 (lxllx2Lx3) : 1 (lx1lx2lx3), suggesting the tight linkage between the Lx1 and Lx2 loci. Germination percentages varied widely but not differed among lipoxygenase isozyme types of F$_3$ seeds before and after accelerated aging. Seed coat of Jinpumkong2 was damaged severely following accelerated aging, whereas that of Taekwangkong was not. Thus, seed of lipoxygenase-lacking soybean cultivar, Jinpumkong2 showed greater deterioration compared with that of the normal Taekwangkong. However, the presence or absence of lipoxygenase activity had no effect on soybean germination.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.603-606
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• 2009

Lipoxygenase and Kunitz trypsin inhibitor protein of mature soybean [Glycine max (L.) Merr.] seed are main anti-nutritional factors in soybean seed. A new soybean cultivar, "Gaechuck#1" with the traits of black seed coat, green cotyledon, lipoxygenase2,3 and Kunitz trypsin inhibitor protein free was developed. It was selected from the population derived the cross of "Gyeongsang#1" and C242. Plants of "Gaechuck#1" have a determinate growth habit with purple flowers, brown pubescence, black seed coat, black hilum, oval leaflet shape and brown pods at maturity. Seed protein and oil content on dry weight basis have averaged 39.1% and 16.2%, respectively. It has shown resistant reaction to soybean necrosis, soybean mosaic virus, Cercospora leaf spot and blight, black root rot, pod and stem blight, and soybean pod borer. "Gaechuck#1" matured on 5-10 October with a plant height of 50 cm. The 100-seed weight of "Gaechuck#1" was 23.2g. Yield of "Gaechuck#1" was averaged 2.2 ton/ha from 2005 to 2007.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.612-615
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• 2009

Lipoxygenase and Kunitz trypsin inhibitor protein are the main antinutritional factor in mature soybean seed. A new soybean cultivar, "Gaechuck#2" with yellow seed coat, lipoxygenase2,3-free and Kunitz trypsin inhibitor protein-free was developed. It was selected from the population derived from the cross between "Jinpumkong2ho" and C242. Plants of "Gaechuck#2" have determinate growth habit with purple flowers, tawny pubescence, yellow seed coat, yellow hilum, oval leaflet shape and brown pods at maturity. Seed protein and oil content on a dry weight basis were 40.7% and 18.7%, respectively. It has shown a resistant reaction to soybean necrosis, soybean mosaic virus, Cercospora leaf spot and blight, black root rot, pod and stem blight, and soybean pod borer. Gaechuck#2 matured in 4 October with plant height of 54cm and a 100-seed weight of 24.4g. Average Yield of Gaechuck#2 was 230 - 250 kg/10a in 2005 - 2007.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.6
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• pp.528-533
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• 1992

Soybean seeds contain lipoxygenase, which is responsible for the objectionable beany flavors in soybean seeds. The isozymes of lipoxygenase (1$\times$1, 1$\times$2, 1$\times$3) were discovered in United States of America, Japan, and Korea, and the mode of inheritance of the mutant genes was determined. This investigation was conducted to screen lipoxygenase-1, 2, and 3 lacking soybean lines from the Korean soybean land race population. Two lipoxygenase-1lacking lines, KAS 610-8 and KAS 621-8 were found in this investigation. In general, lipoxygenase acking varieties were small in seed size and low in oil content. A severe pod borer damage was observed in the two selected lipoxygenase-1 lacking lines. Lipoxygenase lacking line was not found in Korean wild soybean population used in this study and the lipoxygenase lacking lines were found only in Kyung-Nam province and the results imply that lipoxygenase lacking mutants were induced recently in cultivars.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.2
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• pp.180-186
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• 1994

Lipoxygenase activity of soybean seeds of approximately 507 genotypes as well as its inheritance and selection efficiency in early breeding generation was measured in the Department of Agronomy, Seoul National University to facilitate breeding for low lipoxygenase activity of soybean. Average seed lipoxygenase activity of 507 cultivars and strains was 350 unit (unit: $\Delta$0.01 /min. /mg at 234nm) and ranged from 50 to 670 unit. There was no difference in mean lipoxygenase activity according to apparent seed characters such as seed coat and embryo color. But early mature soybean genotypes had fairly low lipoxygenase activity. Lipoxygenase activity was inherited quantitatively, in which additive effect was greater than dominant one and proportion of gene with positive effects was similar to that with negative ones. Estimated narrow- and broad-sense heritabilities were 0.78 and 0.86 for lipoxygenase activity, respectively. Heritability measured from selection in early breeding lines for high or low lipoxygenase activity was 64~76% or 54~62%, respectively. And selection for high lipoxygenase activity increased by 29.7~44.7%, whereas that for low ones decreased by 21.8~27.3%, respectively, when compared to random population. Clear effect in selecting of lipoxygenase activity was present in early generation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.17 no.3
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• pp.185-190
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• 1988

Soybean lipoxyeenase isozymes were isolated from acetone-defatted soybean seeds(Glycine max [L.] Merr. variety AmSoy) by ammonium sulfate fractionation, eel filtration, and ion exchange chromatoeraphy. The final preparation of lipoxygenase-1 and -2 obtained was 19- and 32-fold purified, respectively, to the crude extract. But a considerable loss of total enzyme activity occurred during purification. On 7% polyacrylamide gel electrophosis at pH 9.0, employing lipoxigenase specific staining technique, lipoxyeenase-1, -2, and -3 showed distinctive Rf values of 0.38, 0.29, and 0.33, respectively.