• Korean Journal of Food Science and Technology
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• v.15 no.2
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• pp.101-107
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• 1983

The four varieties of Korean soybeans were allowed to undergo natural fermentation for seven days at ambient temperature. The average pH of the product was 3.93 and titratable acidity was 1.94%. For all varieties of soybeans the content of riboflavin increased from 98 to $309.4{\mu}g/100g$ dry-matter, relative nutritive value from 78.66 to 94.59% and available lysine from 6.56 to 7.38 mg/gN, respectively. During fermentation, the activities of protease and lipase increased, while lipoxygenase and trypsin inhibitor activity decreased markedly. The capacity of water sorption of fermented soybean flour was increased with progress of proteolysis during fermentation. The cookie and noodle prepared with 20:80 mixture of fermented soybean flour and wheat flour were in the 'like' category, but it was desirable to neutralize the sour taste produced by fermentation. Among five kinds of products prepared from the fermented soybean flour pan cake was liked most by rural consumers.

• Clean Technology
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• v.12 no.2
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• pp.53-61
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• 2006

A PGSS (Particles from Gas Saturated Solutions) process designed to generate nano-particles using supercritical fluids has been conducted for the fabrication of Poly(lactide-co-glycolide) (PLGA) microparticles that encapsulate a protein drug. It is demonstrated that the polymer and the dry powder of a protein can be mixed under supercritical carbon dioxide conditions and that the protein component retains its biological activity. In this experiment, the mixture of polymer which is plasticized and dry powder protein was sprayed to form solid polymer that encapsulate the protein. It is found that supercritical fluid process give fine tuning of particle size and particle size distribution by simple manipulations of the process parameters. Porous particles were formed with irregular shape. Protein encapsulated in the polymer was found to have enzymatic activity without significant loss of its initial value.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.10
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• pp.1447-1452
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• 2011

Polyphenol oxidase (PPO) isoforms were partially purified from oyster mushroom (Pleurotus ostreatus) using various chromatography techniques, and their characteristics of heat stability, substrate affinity, optimum pH, and optimum temperature were investigated. Three PPO isoforms named PO-I, PO-II-1, and PO-II-2 were partially purified from oyster mushroom. The molecular weight of PO-II-1 was 70 kDa and PO-I and PO-II-2 were less than 6 kDa each. Characterization was carried out using a PPO isoform partially purified by hydrophobic interaction chromatography. Optimum temperature was $55^{\circ}C$ and optimum pH 5.0. However, the PPO was inactivated at neutral pH or by heating at $80^{\circ}C$ for 30 min, while the 40% PPO still remained active after heating at $60^{\circ}C$ for 45 min. The PPO isoform showed the highest substrate affinity to chlorogenic acid and pyrogallol, in which KM values were 1.01 and 2.06 mM, respectively. Therefore, these results suggested that the mushrooms should be stored at a pH higher than 7.0 and at a low temperature to prevent enzymatic browning.

• Microbiology and Biotechnology Letters
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• v.33 no.4
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• pp.281-287
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• 2005

The endoinulinase gene (inu, 2.733 kb, EC 3.2.1.7) from Paenibacillus polymyxa was subcloned into an Escherichia coli-yeast shuttle vector with GALl promoter for the expression in Saccharomyces cerevisiae. The constructed plasmid, pYGENIU27 (8.6 kb) was introduced into S. cerevisiae SEY2102 cell and then the yeast transformant was selected on the synthetic defined media lacking uracil and on the inulin-containing media. The recombinant endoinulinase was predominantly localized in the periplasmic space of the yeast cell. The total activity of the endoinulinase reached 1.81 unit/ml by cultivation of yeast transformant on YPDG medium. The optimized conditions determined for the inulooligosaccharides (IOSs) production from inulin were as follows; pH, 8.0; reaction temperature, $45^{\circ}C$; inulin source, Jerusalem artichoke. Enzyme activity was stably maintained up to the pH of 10.0. Under the optimized condition and with endoinulinase of 36 unit/g-inulin, IOSs started to be produced after 10 min of enzymatic reaction. By the reaction with inulin, IOSs consisting of inulobiose (F2), inulotriose (F3), and inulotetraose (F4) were produced and F3 was the major product. Consequently, these data would be used as a fundamental parameters for the production of functional sweetener IOSs from inulin by recombinant yeast endoinulinase.

• Applied Biological Chemistry
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• v.30 no.4
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• pp.364-370
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• 1987

The $O_2^-$ level of the extract from young rice leaves, which was cold treated for 2 days and then placed at room temperature for a period of time significantly higher than that from tissues untreated. $O_2^-$ level in leaves was practically unchanged during cold treatment for 48 hours. But it started to increase to arrive at maximum in 8 hours, once the plants were placed under room temperature. The abnormal production of $O_2^-$ in mitochondria during postchilling process was interpreted as a biochemical consequence of accumulation of glycolysis product(s) in cytosol and/or NADH in mitochondrial matrix due to disruption of catabolic balance at low temperature. Mitochondria isolated from the chilling injured tissue was found to have lost considerably their respiratory activity. This fact may imply the involvement of intramitochondrial accumulation of $O_2^-$ in the inactivation of electron transport chain system. The observation that mitochondria in the presence of the $O_2^--producing$ enzymatic system (Xanthine/Xanthine oxidase) lost their respiratory activity supports this inference. It was also found in this work that Superoxide dismutase (SOD) is a substrate inducible enzyme, and that SOD is a possible protective agent in plant cell against chilling injury.

• Applied Biological Chemistry
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• v.51 no.3
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• pp.159-163
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• 2008

Xylogone sphaerospora ${\beta}$-mannanase was purified by Sephadex G-100 column chromatography. The specific activity of the purified enzyme was 8.44 units/ml protein, representing an 56.27-folds purification of the original crude extract. The final preparation thus obtained showed a single band on SDS-polyacrylamide gel electrophoresis. The molecular weight was determined to be 42kDa. Konjac glucomannan was hydrolyzed by the purified ${\beta}$-mannanase, and then the hydrolysates was separated by activated carbon column chromatography. The main hydrolysates were composed of D.P. (Degree of Polymerization) 3 and 4 glucomannooligosaccharides. For elucidate the structure of D.P 3 and 4 glucomannooligosaccharides, sequential enzymatic action was performed. D.P 3 and 4 were identified as M-G-M and M-M-G-M (G- and M- represent glucosidic and mannosidic link-ages). To investigate the effects of konjac glucomannooligosaccharides on in vitro growth of Bifido-bacterium longum, B. bifidum, B. infantis, B. adolescentis, B. animalis, B. auglutum and B. breve. Bifidobacterium spp. were cultivated individually on the modified-MRS medium containing carbon source such as D.P. 3 and D.P. 4 glucomannooligosaccharides, respectively. B. longum and B. bifidum grew up 3.9-fold and 2.8-fold more effectively by the treatment of D.P. 4 glucomannooligosaccharides, compared to those of standard MRS medium. Especially, D.P. 4 was more effective than D.P. 3 glucomannooligosaccharide on the growth of Bifidobacterium spp.

• The Korean Journal of Pesticide Science
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• v.5 no.4
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• pp.57-61
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• 2001

Tank mixing application of pesticides has been used to reduce labor and to control wide spectrum of pests, but it may cause significant pesticide poisoning on human and animals due to carelessness. The toxic response of pesticides for the tank mixtures and mixtures was investigated to determine acute toxicity and enzymatic change using experimental animals. Acute oral toxicity and acute dermal toxicity were tested by RDA test guideline. The $LD_{50}$ was calculated by probit analysis method and cholinesterase was measured with automatic analyzer. The toxicities were generally higher than estimated toxicities in tank mixing and mixture. Serum cholinesterase activity was inhibited more than expected at the dose levels of 1/5, 1/10 and 1/20 of $LD_{50}$. Therefore, the results of this study showed that acute toxicity caused by the pesticide mixtures should be considered before the tank mixing method is applied.

• Korean Journal of Food Science and Technology
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• v.36 no.1
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• pp.97-104
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• 2004

Effects of sub-materials such as, ethanol, mustard, and chitosan, on enzymatic, microbial and physicochemical characteristics of kochujang were investigated during fermentation. Activity of ${\alpha}$-amylase was low in chitosan-added kochujang, whereas those of ${\beta}$-amylase and pretense did not show any remarkable difference. Viable cells of yeast and bacteria decreased in sub-material-added kochujang during fermentation, with yeast counts decreasing more rapidly in ethanol- and mustard-added kochujang than that with chitosan. Consistency of kochujang decreased during fermentation, with the highest consistency observed in ethanol-added kochujang. Oxidation-reduction potential was low in chitosan-added kochujang. Water activity of all kochujang groups decreased during fermentation with the lowest in ethanol-added kochujang. Hunter L-, a-, and b-values of chitosan-added kochujang were higher than other groups, whereas increase in total color difference of low-salt without sub-material group was lowest pH of kochujang was the highest in ethanol-added kochujang, whereas titratable acidity increased remarkably in chitosan-added group. Total sugar and reducing sugar contents of kochujang were high in ethanol-and mustard-added groups, whereas ethanol production decreased remarkably in mustard-added kochujang. Amino nitrogen content was highest in low-salt without sub-material kochujang during late aging period. Ammonia nitrogen content was lower in mustard-added kochujang. After 12 weeks of fermentation, ethanol-added kochujang was more acceptable than mustard-and chitosan-added groups in taste, color, and overall acceptabilities.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.12
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• pp.1263-1269
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• 2005

Horseradish peroxidase, had the phenol degradation rate of 95% in aqueous phase, was covalently immobilized on the surface of reticulated vitreous carbon(RVC) and the degradation of phenol was performed with in situ generated $H_2O_2$-immobilized HRP complex in an electrochemical reactor. The incorporation of carboxylic group on the RVC surface was confirmed by FT/IR spectrometry and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride(EDC) was used for peptide bonds between the carboxylic groups on the RVC surface and amine groups from HRP. The optimal conditions of in situ $H_2O_2$ generation such as concentration($10{\sim}200$ mM) and pH($5.0{\sim}8.0$) of electrolyte, supply of $O_2(10{\sim}50$ mL/min) and applied voltage($-0.2{\sim}-0.8$ volt, vs. Ag/AgCl) from potentiostat/galvanostat were determined by concentration of hydrogen peroxide and current efficiency. It was observed that the RVC immobilized HRP was stable maintaining 89% of the initial activity during 4 weeks. The phenol degradation rate of 86% was attained under the optimal condition of in situ $H_2O_2$ generation.

• Microbiology and Biotechnology Letters
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• v.41 no.2
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• pp.153-159
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• 2013

A mannitol dehydrogenase (MDH; EC 1.1.1.67) gene was cloned from the Sinorhizobium meliloti 1021 (KCTC 2353) genome and expressed in Escherichia coli. It was seen to have an open reading frame consisting of 1,485 bp encoding 494 amino acids (about 54 kDa), which shares approximately 35-55% of amino acid sequence identity with some known long-chain dehydrogenase/ reductase family enzymes. The recombinant S. meliloti MDH (SmMDH) showed the highest activity at $40^{\circ}C$, and pH 7.0 (D-fructose reduction) and pH 9.0 (D-mannitol oxidation), respectively. SmMDH could catalyze the oxidative/reductive reactions between D-mannitol and D-fructose in the presence of $NAD^+/NADH$ as a coenzyme, but not with NADP+/NADPH. These results indicate that SmMDH is a typical $NAD^+/NADH$-dependent mannitol dehydrogenase.