• Korean Journal of Food Science and Technology
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• v.35 no.4
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• pp.556-560
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• 2003

It was determined whether the sandwich ELISA using specific anti-CP4 EPSPS polyclonal and monoclonal antibodies, developed in the previous study, could be applied to detect GM soybean or not. The soybeans (47 imported and 20 domestic soybeans) were analyzed by a sandwich ELISA. The results of imported soybeans were divided into two groups which were high contents $(39.1{\pm}13.5\;{\mu}g/g,\;n=33)$ and low contents of CP4 EPSPS $(2.6{\pm}1.2\;{\mu}g/g,\;n=14)$. The ratio of GM in imported soybeans was about 70.2%. One the other hand, the contents of CP4 EPSPS in domestic soybeans was very low $(0.9{\pm}0.5\;{\mu}g/g,\;n=20)$ which determined to be non-GM soybeans. In case of soybean sprouts, the contents of CP4 EPSPS in soybean sprouts were different between GM and non-GM soybean sprout. The CP4 EPSPS in cotyledon of GM soybeans sprout was higher than that in root hair. The contents of CP4 EPSPS in soybeans sprout of domestic soybeans were very low. Thus, it was possible to determine that the soybeans sprout was made of GM or non-GM soybeans. Also, PCR experiment showed that the sandwich ELISA was accurate to distinguish the soybeans to be GM or non-GM. These results showed the sandwich ELISA could determine the soybeans were GM or non-GM, rapidly and simply.

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 2002.05a
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• pp.166-169
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• 2002

유전자재조합(GM)식품에 대해 듣거나 읽어서 알고 있는 사람이 67%정도 되었고,GM식품을 자발적으로 먹겠다는 사람은 18%를 약간 상회하였고 기다려보고 결정하겠다는 사람들이 약 50%정도였다. 농약 등의 화학물질 오염이나 취급부주의 및 기업인의 윤리의식에 대한 불신에 비해 GM식품에 대한 우려는 매우 적게 나타났으나 GM방법에 의해 개발한 제초제 내성 콩을 먹겠다는 사람은 적은 데 비해 같은 방법으로 개발한 비타민이 많은 콩을 먹겠다는 사람은 많은 것으로 보아 소비자들은 GMO이기 때문에 제초제 내성 콩을 거부하는 것이 아니라, 제초제 내성 콩에 대한 내용의 이해부족으로 인한 거부감을, 그리고 비타민 콩은 비타민이 인체에 중요한 영양소라는 것 때문에 호감을 가지는 것으로 해석되었다. 전체적으로 소비자들이 GMO에 관한 정보를 많이 접하기는 하지만 보통 식품에도 유전자가 있다는 사실을 아는 소비자들이 조사 대상자의 40%정도인 것으로 보아 노출된 만큼 내용을 잘 알지 못하는 것으로 나타났다. GM식품에 대하여는 90%이상이 표시하기를 바라고 있는 것과 같이 2001년 7월부터 가공식품에 GM원료 함유여부 표시제도가 시행되고 있는 데, 이 제도의 시행 사실을 알고 있는 소비자는 22%에 지나지 않았다. 효과적인 표시제도의 시행을 위해서는 일반시민이 제도의 시행에 대해 잘 숙지하고 있어야 할 것이다.

• Applied Biological Chemistry
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• v.48 no.1
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• pp.77-81
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• 2005

To monitor GM soybean in soybean processed foods, tofu and biji, we prepared tofu and biji containing 0%, 1%, 3%, 5% and 100% GM soybean, respectively. We examined epsps gene inserted in soybean by PCR and EPSPS protein expressed in soybean using western blotting and lateral flow strip test to compare the sensitivity of these methods. A PCR product of 123 bp inserted in GM soybean was detected in all tofu and biji containing 1%, 3%, 5% and 100% GM soybean with the exception of 0% samples; however, the size of 600 bp inserted in GM soybean was only detected in tofu containing 100% soybean and in biji containing 5% and 100% soybean. In the protein level, GM soybean product was only detected in tofu and biji containing 100% GM soybean by western blotting. In addition, only biji containing 100% GM soybean was detected by lateral flow strip test. We concluded that in order to detect GM soybean efficiently in processed food, the PCR method is more sensitive than immunological methods. With the PCR method, small size product with approximately 100 bp in PCR product is sensitive to detect GM soybean in processed foods.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.9
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• pp.1310-1314
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• 2012

Gastrointestinal digestibility of new proteins inserted in the food supply is a significant parameter for assessing the safety of GM foods based on the assumption that digestive stability is undesirable. In this study, we performed in vitro digestion of CP4EPSPS, a new protein, expressed in genetically modified (GM) soybean in order to evaluate its digestibility in three different ratios of simulated gastric fluid with preheating. Ratios of GM soybean to simulated gastric fluid were 2:2, 2.5:1.5, and 1.5:2 and preheating was conducted at $100^{\circ}C$ for 5 min. Electrophoresis and Western blotting were used to confirm changes in soybean protein patterns and CP4EPSPS gene expression after in vitro digestion. At ratios in which the amount of gastric fluid was equal to (2:2) or relatively higher than that of soybean (1.5:2), no CP4EPSPS (47.4 kDa) protein was detected after 15 seconds of simulated gastric fluid incubation, the earliest time interval evaluated. However, when the ratio of GM soybean to gastric fluid was 2.5:1.5, CP4EPSPS was detected in 5 min and gradually decreased according to time. After preheating, no CP4EPSPS protein was detected after 15 seconds under all conditions. From these results, we concluded that the digestibility of CP4EPSPS in simulated gastric fluid increased upon preheating. Accordingly, we suggest that it is important to account for the ratio of gastric fluid to GM food in in vitro digestibility assessment models of GM food.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.3
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• pp.227-231
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• 2004

A total of 219 polymerase chain reaction tests of genetically modified (GM) DNA sequences in soybean seeds and soybean sprouts were conducted during 2000-2001. No CM gene was found in 96 tests of soybean seeds. However, either a functional CP4EPSPS gene or the 355 promoter gene was found three times in 2000 and eight times in 2001, in between 0.01 and 0.17％ of soybean spout products, in 123 tests. Since the amount of GM genes was much less than the threshold limit of 3％, none of the 11 positive soybean-sprout samples needed to be libeled GM crops. Of these, seven sprout samples were from domestic seeds and four were from seeds imported from China. To find the contamination route, the raw materials, seed surface, floor of the storage room, area around the selection machine, surface of the packaging film and corn powder used in the package were tested. The 35S promoter gene was detected in only two samples of the corn powder (0.1％). Although we could not find the cause of the GM contamination, the sprout package film is one possibility. In total,8.9％ of the soybean sprout tests were GM positive, but the amounts were much less than the threshold of 3％. This means that there are frequent false-positives and these would threaten the sprout industry if GMO were decided qualitatively. Food companies should make their safety data available to the public and make an effort to address people's concerns about GM food more openly. In addition, there is a need to establish a quantitative test for GM genes in sampled water and a sampling method for raw materials.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.10
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• pp.1629-1637
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• 2013

The properties of non-GM soybeans with lipoxygenase (LOX) free genotypes, such as Gaechuck#1 (black, LOX2,3-free), Gaechuck#2 (yellow, LOX2,3-free) and Jinyangkong (yellow, LOX1,2,3-free), were compared to Taekwangkong (yellow, LOX1,2,3-present) as control. Length and weight of soybeans were significantly longer in Gaechuck#1, but LOX free genotypes of yellow beans was smaller than Taekwangkong, in terms the size and weight. After soaking for 12 hr, increased ratios of soybean weight were 217.07~226.55%, and they were significantly higher in Gaechuck#2. The total color difference (${\Delta}E$) to Taekwangkong was the highest in Gaechuck#1, but another yellow soybean were similar. Crude lipids content was significantly higher in Taekwangkong (17.30%), and these LOX free genotypes (13.71~14.66%) did not show significant difference. Crude protein contents were significantly higher in Gaechuck#1 (34.79%) compared to the other soybeans (32.93~33.47%). Contents of glutamic acid among the detected composition amino acid were highest, and its total contents were highest in Gaechuck#1 (32.42 g/100 g), and the total content of Gaechuck#2 was similar to Taekwangkong. Contents of total isoflavone were higher in LOX free genotypes than Taekwangkong, especially significantly higher in Gaechuck#1 (1672.54 ${\mu}g/g$). Contents of total phenol were highest in Gaechuck#1 (276.91 mg/100 g), and flavonoids content of Gaechuck#1 (26.93 mg/100 g) was 2.6~2.8 times higher than the other samples. DPPH, ABTS radical scavenging activities and reducing power were significantly higher in Gaechuck#1. The yield of soybean curd from tested samples was the highest in Gaechuck#2. Gaechuck#2 as LOX free genotypes was similar to Taekwangkong with regard to physicochemical properties and antioxidant activities. Therefore, we propose that Gaechuck#2 is a more suitable genotype for soybean curd products.

• Applied Biological Chemistry
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• v.46 no.4
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• pp.344-347
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• 2003

A method using PCR was developed for the monitoring of genetically modified soybean (GMS) and GMS derived foods utilized in the market. We designed 3 pairs of specific oligonucleotide primers based on epsps and pat inserted in GMS and ferritin gene as internal standards. Template DNAs isolated from soybean and processed foods were used for multiplex PCR with 3 primer sets. PCR, used with specific primer sets for GMS detection, showed the amplified DNA fragments with GMS template DNA. In this study, GMS containing epsps was detected from soy processed foods manufactured before GM food labeling system, however, GMS containing epsps or pat was not detected from soy processed foods manufactured after GM food labeling system.

• Applied Biological Chemistry
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• v.45 no.4
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• pp.185-189
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• 2002

Along with the worldwide rapid increase of the cultivation area and commercial production of genetically modified (GM) crops, the amount of GM grains imported to Korea has also been increasing. Roundup-Ready soybean (RRS) was introduced with 5-enolpyruvyl shikimate-3-photphate synthase (EPSPS) gene derived from Agrobacterium CP4 to confer the resistance to herbicide, glyphosate. In this study, we tried to develop PCR-based analytical method to detection the presence of RRS among non-GM soybeans. In order to detect RRS specifically, oligonucleotide primers were specifically designed based on the nucleotide sequence of EPSPS transgene. Qualitative PCR method was established and its specificity and accuracy were confirmed by analysing the nucleotide sequence of PCR DNA fragments. Bioassay was also conducted by spraying glyphosate at seedling stage. Survived individuals showed obvious resistance to Roundup Ready, however all of non-GM seedlings died in two weeks after spray. Conclusively, the highly selective detection systems for RRS were successfully established by both PCR using specific primers to EPSPS transgene and bioassay using the herbicide resistance of RRS. In addition to, the imported soybean showed to be mixed to several varieties regarding to 100-seed weight and hilum color.

• Korean Journal of Food Science and Technology
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• v.36 no.4
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• pp.677-682
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• 2004

Debates on safety of genetically modified (GM) crops have led to mandatory-labeling legislation of GM foods in many countries including Korea. Effects of heat, pressure, and acid treatments on degradation of DNAs or proteins in GM soybean at levels below detection limits of qualitative PCR and lateral flow strip test (LFST) methods were examined. Results showed that genomic DNAs and proteins were degraded into fragment sizes no longer possible for detection of inserted gene depending on thermal, or thermal and pressure treatment period. Detectaability of LFST for toasted meal increased in weakly treated soybean. DNA and protein detection methods were barely effective for detection of GM ingredient after $121^{\circ}C$ and 1.5 atmospheric treatment for 20 min. These results will be useful in determining GM labeling requirements of processed foods.

• Korean Journal of Environmental Agriculture
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• v.25 no.4
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• pp.346-351
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• 2006

The study was performed to investigate the effect of incorporation of green manures (GM) into a sandy loam soil for organic vegetable production in the condition of plastic film house, relating to growth and yield of tomato crop. Three species of GM as perennial ryegrass, sudangrass and soybean are cultivated during the rest time of summer season and incorporated into soil just after the harvest. Thereafter tomato crop was transplanted as the following crop to soil incorporated GM. Among GM, soybean was proper as GM crop for organic farming, due to the effect of yield increase by continuous supply of nitrogen on following the tomato crop. Yield of tomato crop after soybean incorporation into soil was $4.2Mg\;ha^{-1}$ similar to $4.4Mg\;ha^{-1}$ of N-P-K standard fertilization (conventional) treatment. But perennial ryegrass and sudangrass were improper, because the biomass yield of perennial ryegrass was very low due to growth retardation by high temperature during summer season and soil incorporation of sudangrass as GM results in yield decrease of following the tomato crop caused by high C/N ratio of sudangrass itself. In conclusioa soybean incorporation into soil had advantage of producing conventional level on following the tomato yield and therefore it could recommend as GM for organic vegetable production.