• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.3
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• pp.412-417
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• 2015

This study was carried out to investigate the effect of steam-drying method on physicochemical properties and antioxidant activities of Alliun hookeri root (AHR). Moisture, crude protein, crude fat, and crude ash contents of raw and steam-dried AHRs were 10.91~14.15%, 11.14~13.49%, 0.83~3.02%, and 7.55~8.98%, respectively. Sulfur contents of steam-dried AHRs were 2.0 and 2.2 times lower than that of raw AHR (0.51%), respectively. pH and total sugar contents of AHRs were reduced by steam-drying, whereas titrate acidity and browning intensity were increased. The L and b values of AHRs in Hunter's value were also reduced, but a value was increased by steam-drying. Among hot water extracts from raw and steam-dried AHRs, four times steam-drying showed the lowest $EC_{50}$ values (0.44, 9.01, and 0.48 mg/mL, respectively) in DPPH radical assay, ABTS radical assay, and reducing power, whereas four times steam-drying had the highest total phenolic content ($34.47{\mu}g/mg$) and browning intensity (2.05 and 0.20 at 280 and 420 nm, respectively). The antioxidant activities of hot water extracts from raw and steam-dried AHRs were closely correlated with their total phenolic contents and browning intensity, showing coefficient of determination ($R^2$) values higher than 0.87. From the results, we suggest that steam-drying method could be used as an effective process for increasing the antioxidant activity of AHR.

• Korean Journal of Environmental Biology
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• v.30 no.2
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• pp.136-142
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• 2012

Acute toxicity test of heavy metal (Cd, Cu, Zn) were examined using the hatching rates of fertilized eggs in the oliver flounder, Paralichthys olivaceus. Eggs were exposed to Cd, Cu, Zn (0, 10, 100, 500, 1000, 2500, 5000 ppb) and then normal hatching rates were investigated after 48 h. The normal hatching rates in the control condition (not including Cd, Cu and Zn) were greater than 80%, but suddenly decreased with increasing of heavy metal concentrations. Cd, Cu and Zn reduced the normal hatching rates in concentration-dependent way and a significant reduction occurred at concentration grater than 1000, 100, 100 ppb, respectively. The ranking of heavy metal toxicity was Zn>Cu>Cd, with $EC_{50}$ values of 584, 1015 and 1282 ppb, respectively. The no-observed-effect-concentration (NOEC) and the lowest-observed-effect-concentration (LOEC) showed each 100 and 500 ppb of normal hatching rates in exposed to Cu and Zn. The NOEC and LOEC of normal hatching rates in Cd were 500 ppb and 1000 ppb, respectively. From these results, the normal hatching rates of P. olivaceus have toxic effect at greater than the 100 ppb concentrations in Cu, Zn and the 500 ppb concentrations in Cd in natural ecosystems. These results suggest that biological assay using the normal hatching rates of P. olivaceus are very useful test method for the acute toxicity assessment of a toxic substance as heavy metal in marine ecosystems.

• Journal of Applied Biological Chemistry
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• v.54 no.4
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• pp.296-302
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• 2011

Insect-resistant transgenic rice was developed by inserting the mCry1Ac1 a modified gene from the soil bacterium Bacillus thuringiensis (Bt). For biosafety assessment, we studied the effects on survival of cantor Daphnia magna, a commonly used as a model organism in ecotoxicological studies. D. magna fed on Bt rice and its near non-genetically modified (GM) counterparts (Nakdong) grown in the same environment (100% ground rice suspension). The Bt rice was comfirmed to have the insertion of T-DNA and protein expression by the polymerase chain reaction and ELISA analysis. Feeding study showed similar cumulative immobility and abnormal response of D. magna between Bt rice and non-GM counterparts. 48 h-$EC_{50}$ values of Bt rice and non-GM rice showed 4,429 and 2,889 mg/L respectively. The rice no observed effect concentration (NOEC) values for D. magna was suggested 1,000 mg/L. We conclude that the tested Bt-rice and Nakdong similar cumulative immobility for D. magna the widely used model organism. We found out that there is strong possibility that the growth of Bt rice didn't affect to non-target insects.

• The Korean Journal of Pesticide Science
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• v.12 no.3
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• pp.215-221
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• 2008

To assess the impact of molinate on freshwater aquatic organisms, acute and chronic toxicity studies for waterfleas were conducted. In acute toxicity studies for Daphnia magna, and Moina macrocopa, the 48-h $EC_{50}$ values were 11.4 and 8.3 mg/L respectively. And in reproduction toxicity studies for the same species, the NOEC's were 2.5 and 2.0 mg/L respectively. These results suggest that waterfleas have simillar sensitivity to molinate. On the other hand, the NOEC for 3-generation toxicity of moina macrocopa 0.16 mg/L, was much lower than those of acute values. This studies concludes that molinate has minimal risk to waterfleas in river.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.6
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• pp.695-702
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• 2017

This study was carried out to investigate the effects of seed vinegar on antioxidant activity and antimicrobial activities of concentrated blueberry vinegar (CBV). Of the nine strains of yeast and six strains of acetic acid bacteria provided by the Microbial Institute for Fermentation Industry, each strain of yeast (Saccharomyces cerevisiae SRCM 100610, showing the highest ethanol content) and acetic acid bacteria (Acetobacter pasteurianus SRCM 101342, showing the highest total acidity) was selected for production of CBVs. Sugar content, pH, total acidity, total phenolic content (TPC), and browning intensity (280 nm and 420 nm) in CBVs using concentrated blueberry juice were $11.05{\sim}12.70^{\circ}Brix$, 2.63~2.98, 1.65~5.72%, 3.03~4.24 mg/mL, 0.95~1.50, and 0.11~0.20, respectively. Sugar content and total acidity of CBVs increased upon addition of seed vinegar, whereas pH, TPC, and browning intensity decreased. Of all CBVs with various additions of seed vinegar, the control showed the lowest $EC_{50}$ values in DPPH radical scavenging assay, ABTS radical scavenging assay, and reducing power (23.80, 19.48, and 79.21 dilution factor, respectively), whereas the 40% seed vinegar group showed the highest clear zone diameter values for Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, and Bacillus cereus (4.31, 4.59, 5.81, and 3.97, respectively). Antioxidant activities of CBVs were closely correlated with their TPC, browning intensity at 280 nm, pH, and total acidity values, showing correlation determination coefficient ($R^2$) values higher 0.82. However, antimicrobial activities of CBVs were closely correlated with their pH and total acidity values, showing higher $R^2$ values more than 0.92. These results suggest that CBVs using concentrated blueberry juice, S. cerevisiae SRCM 100610, and A. pasteurianus SRCM 101342 may be useful as potentially functional foods for enhancing health.

• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.4
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• pp.77-86
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• 2006

This study was performed to investigate the stream water quality characteristics in the Dowoncheon basin of Dongjin River during the 12 months from January to December in 2005. Also, pollutant loads were calculated on the basis of the water quality and runoff results. The measured pH and EC of the stream water were ranged 6.48-7.32, $18.06{\sim}38.60{\mu}S/cm$, respectively. The concentration of DO, BOD, COD, SS, T-N and T-P were observed as 4.90-11.50 mg/L, 0.5-6.0 mg/L, 1.22-18.46 mg/L, 1.0-2,124.0 mg/L, 1.35-5.67 mg/L, 0.02-0.43 mg/L respectively. T-N showed low correlativity with other water quality parameters. However, T-P had very high correlativity with COD and SS. In the meantime, the runoff pollutant loads of T-N, T-P were estimated as 72,114 kg/yr, 5,027 kg/yr. In the case of the correlativity between runoff pollutant loads and concentrations, T-N did not show significant relationships, while T-P had significant relationships.

• Journal of Life Science
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• v.12 no.6
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• pp.752-758
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• 2002

This study was investigated on properties and thermostability of gelatin-degrading proteinases in the fruit of Actinidia chinensis (kiwifruit) for the industrial application. Three gelatin-degrading proteinases (PI, PII and PIII) were detected from the pulp of fruits. The molecular weights of these proteinases, PI, PII and PIII, were approximately 220 kD, 51 kD, and 26 kD respectively, on the basis of gelatin-containing SDS-PACE. The optimum pH of these proteinases ranged from 2.0 to 5.0 with a maximal activity at pH 4.0. These proteinases had a high sensitivity to E-64 and iodoacetate which are cysteine protease inhibitors, and required DTT, cysteine, and $\beta$-mercaptoethanol for their activities which are stimulators for cysteine proteases. These results indicate that these proteinases are cysteine proteinases and the proteinase PIII is actinidin (EC 3.4.22.14), based on the molecular weight and/or susceptibility against proteinase inhibitors. These proteinases were strongly activated by $Ca^{2+}$, $Mg^{2+}$ and $Mn^{2+}$, whereas strongly inhibited by Zn$^{2＋}$ and Hg$^{2＋}$. However, these proteinases have slightly different susceptibility against other cations ($Ca^{2+}$, $Cu^{2+}$, $Al^{3+}$, $Ca^{3+}$. The temperature stability of proteinase PIII was more stable than proteinases PI and PII. Moreover, proteinase PIII remained stable below $50^{\circ}C$ for 48hr, showing the residual activity above 75% of the enzyme activity.

• Microbiology and Biotechnology Letters
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• v.18 no.6
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• pp.578-584
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• 1990

A microorganism capable of producing high level of extracelluar cyclomaltodextrin glucanotransferase(EC 2.4.1.19; CGTase) was isolated ’rom soil. The isolated strain No. 239 was identified as Bacillusstearothermophilus. The maximal CGTase production (about 7.0 unitslml) was observed in medium containing2% soluble starch, 0.5% defatted soybean meal, 0.1% NaH_2PO_4.2H_2O$ and 0.015% $ CaC_l2 $ with initial pH 7.0. The strain was cultured at $55^{\circ}C$ for 48 hr with reciprocal shaking. At 0.83% substrated concentration potato starch was the optimum substrate with 50.1% conversion to cyciodextrin (CD)after the reaction at $65^{\circ}C$ for 24 hr (CGTase 10 unitlg starch). Using soluble starch as substrate (5% substrate concentration, CGTase 10 unitlg starch), the maximum conversion of 40% was obtained at11 hr reaction, and the ratio of $\alpha-, \beta-$ and $\gamma$-CD production at this time were 1.0:1.3:0.4, respectively., respectively.

• Journal of Plant Biology
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• v.38 no.4
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• pp.349-357
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• 1995

The alkaline invertase ($\beta$-D-fructofuranoside fructohydrolase, EC 3.2.1.26) was isolated and characterized from the hypocotyls of mung bean (Phaseolus radiatus L.). The enzyme was purified by consecutive step using diethylaminoethyl (DEAE)-cellulose anion exchange, 1st Sephadex G-200, DEAE-Sephadex A50 and 2nd Sephadex G-200 chromatography. The overall purification was about 77-fold with a yield of about 6%. The finally purified enzyme exhibited a specific activity of about 48 $\mu$mol of glucose produced mg-1 protein min-1 at pH 7.0 and appeared to be a single protein by nondenaturing polyacrylamide gel electrophoresis (PAGE). The enzyme had the native molecular weight of 450 kD and subunits molecular weight of 63 kD and 38 kD as estimated by Sephadex G-200 chromatography and SDS-PAGE, respectively, suggesting that the enzyme is a heteromultimeric protein composed of two types of subunits. On the other hand, the enzyme appeared to be not a glycoprotein according to the results of Con A chromatography and glycoprotein staining. The enzyme had a Km for sucrose of 19.7 mM at pH 7.0 and maximum activity around pH 7.5. The enzyme was most active with sucrose as substrate, compared to raffinose, cellobiose, maltose and lactose. These results indicate the alkaline invertase is a $\beta$-fructofuranosidase.

• The Korean Journal of Food And Nutrition
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• v.25 no.3
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• pp.529-537
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• 2012

This study examined the manufacturing characteristics of sweet potato doenjang in order to gain a more efficient use of the sweet potato. Sweet potato(Sinwhangmi, Sinjami) koji(mixed sweet potato paste and soybean powder in a ratio of 1:1) was cultured with Aspergillus oryzae KCCM 11372 at $35^{\circ}C$ for 48 h. Sweet potato doenjang was fermented for 60 days using a sweet potato koji(20%, 45%) and steamed soybean(70%, 45%), with salt accounting for 10%. The glutamic acid content was determined to be much higher in sweet potato doenjang using Sinwhangmi koji(45%) and steamed soybean (45%), than that of general doenjang. The DPPH radical scavenging activity has the largest $EC_{50}$(0.9 mg) in sweet potato doenjang using Sinjami potatoes 45%. Sensory evaluation indicated a good preference for sweet potato doenjang using Sinwhangmi(45%) and steamed soybean(45%).