• Korean Journal of Food Science and Technology
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• v.32 no.5
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• pp.991-996
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• 2000

Enzyme-linked immunosorbent assay was developed for the analysis of soy protein in foods. Competitive indirect ELISA (ciELISA) was established by using specific antibodies against the heat-stable acidic subunits (AS) of glycinin. Soy proteins in each sample used in this study were solublized in the presence of urea and DTT and boiled at $100^{\circ}C$ for 1hr and then were renatured with a cystine-containing solution. After these treatments, each isolated soy protein (ISP) heated at 60, 70, 80, $90^{\circ}C$ for 10 minutes showed almost the same curve as unheated one in the ciELISA. The detection limit of ISP was 0.3 ${\mu}g/mL$. Anti-AS antibodies have very low reactivities less than 0.1% toward non-meat proteins such as skim milk and casein and did not show any reactivities toward egg white powder and ovalbumin. When laboratory-made sausages containing ISP of $0.5{\sim}3%$ were assayed by ciELISA, the mean recovery was about 83% (C.V., 19%). In addition, the average content of soy protein in commercial sausages was 1.27%.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.4
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• pp.429-437
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• 2007

This study aims to develop a sulfur-using denitrification process which is possible a renovation to advanced treatment plant submerging a simple module in activated sludge aeration tank. At first, the impact factor of sulfur-using denitrification was appreciated by the batch test. Secondly, reflecting a dissolved oxygen effect of sulfur-using denitrification that was confirmed by the batch test, in a continuous nitrification/sulfur-using denitrification, high-rate nitrogen removal reaction was induced at optimum condition controlling DO concentration according to phases. Also, inside and outside of sulfur-using denitrification module was covered with microfilter and the module was considered as an alternative of clarifier. Result of batch test for sulfur-using denitrification, $NO_2{^-}N$ was lower for consumption of alkalinity and sulfur than that of $NO_3{^-}-N$. These results revealed the accordance of theoretical prediction. In continuous nitrification/sulfur-using denitrification experiment, actual wastewater was used as a influent, and influent nitrogen loading rates were increased 0.04, 0.07, 0.11, $0.14kg\;N/m^3-day$ by changing hydraulic retention times. At this time, nitrogen loading rates of packed sulfur were increased 0.23, 0.46, 0.69, $0.93kg\;N/m^3-day$. As a result, nitrification efficiency was about 100% and denitrification efficiency was 93, 81, 79, 72%. Accordingly, nitrogen removal was a high-rate. Also the module of sulfur-using denitrification covered with microfilter did not make a fouling phenomena according to increased flux. And the module was achieved effluent suspended solids of below 10 mg/L without a clarifier. In conclusion, it is possible a renovation to advanced treatment plant submerging a simple module packed sulfur in activated sludge aeration tank of traditional facilities. And the plant used the module packed sulfur is expected as a effective facilities of high-rate and the smallest.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.635-639
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• 1995

The effective extraction of antioxidative substances from soybean was investigated by using various solvents, such as water, ethanol, methanol, acetone, chloroform, benzene, ethyl acetate, ether, dichloromethane, and hexane. Extraction was performed by cold method at $30^{\circ}C$ and by reflux method at $85^{\circ}C$. The antioxidative effect of the extracts was determined by peroxide value during the oxidation of soybean oil containing the extracts at $105^{\circ}C$ for 10 hours, and also by TBARS(thiobarbituric acid reactive substances) formed during the peroxidation of egg lecithin liposomes. The antioxidant activity of the extracts from raw soybean was higher than that from defatted soybean. The antioxidant activity of the extracts by reflux method was higher than that by cold method. The methanol extract from defatted and roasted soybean(DRS) showed the highest antioxidative effect against oxidation of soybean oil, while the water extract from DRS in egg lecithin liposomes. In the peroxidation of egg lecithin liposomes, the antioxidative effect of polar solvents extracts were higher than those by nonpolar solvents extracts.

• Journal of Applied Biological Chemistry
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• v.64 no.1
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• pp.97-102
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• 2021

In this study, enzymes were screened for hydrolysis of defatted perilla seed residue (DPSR) and optimal conditions for enzymatic treatment were determined to produce the hydrolysate of DPSR. Also its antioxidant activity and utilization as a culture medium were examined. The combined treatment of Alcalase and Ceremix is most effective for solubilization of protein and carbohydrate in DPSR. The optimal dosage, pH, and reaction time for enzymatic treatment were found to be 2.0% (w/w), 7.0, and 2 h, respectively. Treatment with optimal conditions of enzymes dramatically increased reducing sugar, soluble protein, and total phenolic content. The hydrolysate of DPSR possessed better scavenging activity against cation and free radicals than enzyme-untreated extract. When Leuconostoc mesenteroides 310-12 was cultured in the hydrolysate of DPSR, cell population rapidly increased compared to enzyme-untreated extract, and titratable acidity increased in proportion to the bacterial growth. In conclusion, these results imply that the hydrolysate of DPSR could be utilized as a bacteria culture medium as well as a physiologically active material with antioxidant activity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.5
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• pp.493-501
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• 1986

The present work aims to estimate the effect of heat treatment on the in vitro protein digestibility and formation of trypsin inhibitor or trypsin indigestible substrate(TIS) of raw and defatted flounder. It was also carried out to assess the formation of lipid-protein complexes under the conditions of different ratio of lipid addition. The in vitro protein digestibility increased when steamed for 5 min showing $88.09\%$ in raw and $90.56\%$ in defatted samples, respectively. After 40 min steaming, the digestibility decreased by $2{\sim}4\%$. As for microwaving, heating for 1 min resulted in slight increase of digestibility, however, heating for 7 min did decrease of digestibility by $3{\sim}4\%$ for both raw and defatted materials. There was no difference in fatty acid composition found with heat treatment. The major fatty acids of flounder meat were $C_{16:0},\;C_{16:1},\;C_{18:1},\;C_{20:5},\;C_{22:6}$ and the ratio of the unsaturated to saturated was 67.3:32.6. Fat oxidation and nonenzymatic browning were enhanced by heat treatment and protein solubility decreased necessarily as the brown pigment formation increased. On the other hand, the effects on the digestibility and TIS of the complexes formed from interaction of lipid and myofibrillar or meat protein of flounder were examined. The interaction of protein with lipid was considered to mostly contribute to the drop of digestibility of fish products. The digestibility of myofibrillar protein was $93.72\%$ for flounder, and it generally decreased as the amount of lipid added to protein and reaction time increased. Also mixed and heated samples were more active in digestibility decline than those mixed after heating. The result probably indicated that lipid-protein interaction was involved in the drop of digestibility which coincided with protein denaturation.

• Korean Journal of Microbiology
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• v.32 no.4
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• pp.291-296
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• 1994

A bacterial strain NO. AM-28, showing proteolytic activity against defatted soybean was isolated from domestic soil. The isolated strain was identified as Aeromonas hydrophila by both the biochemical tests using API kit and the analysis of cellular fatty acid profile with MIDI system. The protease production from A. hydrophila AM-28 was highly enhanced when it was cultivated in the medium containing glycerol as a carbon source, tryptone or $(NH_4)_2HPO_4$ as a nitrogen source, and $CaCl_2$ as a mineral source. The optimal pH and temperature for the enzyme was 8.0 and $65^{\circ}C$, respectively. The enzyme was stable up to $55^{\circ}C$ and at pH values ranging from 7.0 to 13.0. The enzyme activity was inhibited by phenylmethylsulfonyl fluoride and EDTA, indicating that serine residue and metal ions be involved in enzyme activity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.5
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• pp.273-288
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• 1991

To elucidate the physiological and biochemical differences between chondrichthyes and osteichthyes, the properties of the specific digestive enzymes in cat-shark, Cephaloscyllium umbratile, and mackerel, Scomber japonicus, were studied. Homogenous trypsin proved through the disc-electrophoresis, SDS-PAG electrophoresis and gel filtration was obtained from the pancreas of cat-shark by $50-70\%$ saturated ammonium sulphate fractionation, DEAE-Sephadex A-50 column chromatography, benzamidine-Sepharose 6B affinity chromatography and Sephadex G-75-120 gel filtration. Two types of trypsins were also obtained from the pyloric caeca of mackerel by $30-70\%$ saturated ammonium sulphate fractionation and the slightly modified procedure from the method adopted in the purification of cat-shark trypsin. The two trypsins, designated trypsin A and B, were proved their homogeneity by disc- and SDS-PAG electrophoresis and gel filtration. The molecular weights of the trypsins were estimated to be 31,700 for cat-shark trypsin, 30,000 for mackerel trypsin A and 29,000 for mackerel trypsin B by SDS-PAG electrophoresis, but those were estimated to be 21,500 for cat-shark trypsin, 23,700 for mackerel trypsin A and 21,500 for mackerel trypsin B by gel filtration. The trypsins exhibited their optimum conditions at pH 9.0 and on temperature ranged from $45^{\circ}C\;to\;50^{\circ}C$ for cat-shark, and at pH 8.0 and a temperature of $50^{\circ}C$ for mackerel trypsin A and B, respectively. The cat-shark trypsin was stable at pH 10.0 and the temperature below $10^{\circ}C$, whereas the mackerel trypsin A and B, were stable in the range over pH 7.0 to pH 9.0 below $10^{\circ}C$ and at pH 8.0 below $35^{\circ}C$, respectively. The mackerel trypsins were severely inhibited by some heavy metal ions such as $Ag^{2+},\;Cu^{2+}\;and\;Hg^{2+}$ compared to cat-shark trypsin. All of the enzymes were also inhibited by antipain, leupeptin, TLCK(tosyllysine chloromethyl ketone) and SBTI(soybean trypsin inhibitor) remarkably. The inhibitory effects of PMSF(phenylmethane sulphonylfluoride), DFP(diisopropyl fluorophosphate) and benzamidine were indicated that these enzymes belong to serine-proteases.

• Korean Journal of Food Science and Technology
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• v.20 no.6
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• pp.820-826
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• 1988

The freezing point$(t_f)$, latent heat of freezing$({\triangle}\;H_f)$ and kinetic constant of fleering$(k_f)$ were determined from DSC thermogram at cooling rate $-2.5^{\circ}C/min{\sim}-10.0^{\circ}C/min$. The freezing point of various starches was decreased with an increase in cooling rate, and that of whole starches were lower than defatted starches. Changes of the latent heat of freezing was not observed at above cooling rate $-2.5^{\circ}C/min$. The latent heat of freezing$({\triangle}\;H_f)$ could be deduced as a function of water content(W) as follows: ${\triangle}\;H_f=0.700W-13.048$, (Kcal/kg) $(35%{\leqq}W{\leqq}70%)\;{\triangle}\;H_f=1.569W-73.861,\;(Kcal/kg)\;(W{\geqq}70%$) In the water content range $35{\sim}90$(wt %), the activation energy of various starches in freezing process was determined $126{\sim}270$ Kcal/mol.

• The Korean Journal of Food And Nutrition
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• v.26 no.4
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• pp.831-840
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• 2013

In this study, an attempt is being made to extract surface-active substances from defatted rapeseed cakes by supercritical carbon dioxide fluid. Independent variables for the extraction process, being formulated by D-optimal design, are pressure (150~350 bar), temperature ($33{\sim}65^{\circ}C$ and co-solvent (ethanol, 50~250 g). The dependent variables of the extraction yield, the content of neutral lipids, phospholipids and glycolipids in the extracts were analyzed upon the results through the response surface methodology. As for the extraction yield, it was found to increase with increasing independent variables, among which the co-solvent proved to be a major influencing parameter. Similar trends were found for the content of surface-active substances (i.e, phospholipids and glycolipids) in the extracts, except for the content of neutral lipids. Regression equations were suggested to coincide well with the results from the experiments. Extraction conditions are being optimized to maximize the extraction yields, the content of phospholipids, and glycolipids were 350 bar (pressure), $65^{\circ}C$ (temperature) and 228.55 g (co-solvent), respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.15 no.4
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• pp.32-39
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• 1986

A strain of Aspergillus niger CAD 1 which produces considerable amount of beta-galactosidase was selected from extracellular beta-galctaosidase producing fungi isolated from soil. Optimal conditions for the enzyme from Aspergillus niger CAD 1 were the growth in wheat bran supplemented with 0.5% skim milk powder at $30^{\circ}C$ for 72 hrs. The crude enzyme was purified 1,387 fold through DEAE-cellulosc and Sephadex G-100 chromatographr and its recovery was 6.2%, The optimal pH and temperature for the purified enzyme were pH 4.5 ana $45^{\circ}C$, respectively. The Km and Vmax on ONPG were $3.57{\times}10^3M$ and 33.0 unit/mg protein, whereas those on lacose were $83.3{\times}10^3M$and 15.33 unit/mg protein, respectively, The activation energy for the enzyme was 9,900 cal/mol and the enzyme had no metal ion requirement for its activity and stability. The hydrolysis of lactose in skim milk, 4.8% lactose solution and acidic whey were 65%, 70% and 78% after 10 hrs incubation at $45^{\circ}C$, when 182 units of the enzyme were used 50ml of the substrate solutions.