• Journal of Animal Science and Technology
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• v.48 no.5
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• pp.719-726
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• 2006

Bovine whey protein are rich in cysteine, which is the rate limiting amino acid for synthesis of antioxidant glutathione(GSH). Some strains of Lactobacillus caseihas been reported to contain high level of GSH in cell extracts. The objective ofthis study was to determine whether enzymatically hydrolyzed whey protein isolate(WPI) and cell extract of Lb. casei HY2782 could increase intracellular GSH concentrations and protect against oxidant induced cell death in human prostate epithelial cell line (designated as RWPE1, and PC3MMM2 cells). Treatment of RWPE1 cellsandPC3MMM2 cells with hydrolyzed WPI (500g/ml) significantly increased GSH by28.2% and38.4% respectively. Compared with control cells receiving no hydrolyzed WPI(P<0.05). hydrolyzed WPI and Lb casei HY2782 cell extracts significantly protected RWPE1 and PC3MMM2 cellsfrom oxidant induced cell death compared with controls receiving no WPI. DNA damage associated with oxidant treatment was demonstrated by single cell gel (SCG) electrophoresis.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.947-954
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• 1997

Selected physical properties of cornmeal extrudates fortified with dairy products and extrusion process by $CO_2$ gas injection were analysed. Dairy products including whole milk powder, whey protein concentrate non-fat dry milk, and sodium caseinate were tested at the addition of 10% and 20%, based on cornmeal weight. $CO_2$ gas was injected to the barrel at the pressure of 0.7 and 1.4 MPa. Specific mechanical energy (SME) input was decreased by the addition of dairy products. Sodium caseinate had a little effect on decreasing the SME input, however whole milk powder tremendously reduced SME input when the concentration increased. An increase in milk product content resulted in increasing the piece density at the injection pressure of 0.7 MPa. At both 10% and 20% milk product content, the piece density was lowest at the injection pressure of 0.7 MPa. The sectional expansion index was highest at the injection pressure of 0.7 MPa. However, the specific length was constantly increased with the increase in $CO_2$ injection pressure. Water absorption index was decreased and water solubility index was increased by the addition of milk products. The injection pressure of $CO_2$ was optimum at 0.7 MPa. The addition of whole milk powder limited to puff the melt, but the other milk products tested resulted in puffing with $CO_2$ injection to 1.4 MPa.

• Journal of Aquaculture
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• v.11 no.1
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• pp.1-10
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• 1998

A feeding trial was conducted to investigate optimum dietary protein and lipid levels in diets for parrot fish (Oplegnathus fasciatus). Three groups of 25 fish averaging 7.0g were fed each of the experimental diets containing 30, 40, 50 or 60% crude protein (CP) with 8 or 16% crude lipid level ($4{\times}2$factorial desing) for 8 weeks. Weight gain and feed efficiency increased significantly (P<0.05) with dietary protein level up to 50% CP when diets contained 16% lipid level, and increased with dietary protein level up 60% CP when diets contained 8% lipid level (P<0.05). The broken-like model showed that an optimum dietary protein level was 46% when the diet contained 16% dietary lipid. Fish fed diets containing 16% lipid level showed significantly (P<0.05) higher weight gain, feed efficiency and protein efficiency ratio than did fish fed diets containing 8% lipid level when diets contained 40 or 50% dietary protein (P<0.05).

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.4
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• pp.587-594
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• 2010

To develop commercially available food protein hydrolysates, the effects of different types of enzymes and substrates on bitterness and solubility of partially hydrolyzed food proteins were investigated. Four types of proteins (casein, isolated soy protein (ISP), wheat gluten, and gelatin) and five types of proteolytic enzymes (a microbial alkaline protease (alcalase), a microbial neutral protease (neutrase), papain, bromelain, trypsin) were used. To profile the pattern of hydrolysis, the degree of hydrolysis (DH) were monitored during 180 min of reaction time by pH-stat method. Casein showed the highest susceptibility to hydrolysis for all five proteases compared to those of ISP, gluten, and gelatin. In addition, the bitter intensity and solubility (nitrogen soluble index, NSI) of each protein hydrolysate were compared at DH 10%. Bitterness and solubility of protein hydrolysates were highly affected by DH and the types of enzymes and substrates. At DH=10%, casein hydrolysate by trypsin, ISP and gluten hydrolysates by either bromelain or neutrase, and gelatin hydrolysates by the five proteases tested in this study were highly soluble and less bitter.

• Korean Journal of Food Science and Technology
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• v.12 no.2
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• pp.109-114
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• 1980

Protein efficiency ratio (PER), net protein utilization (NPU), nitrogen digestibility (ND), organ weights, and amino acid composition were investigated for rapeseed protein isolates (RPI) prepared by alkaline countercurrent extraction and isoelectric precipitation of defatted rapeseed meal (DRM). The PER values for 3 kinds of RPI obtained at pI of 6.7, 5.6 and 5.0 were 2.8, 3.1 and 2.9, and for DRM 2.5 while the NPU values for these RPI appeared to be 68, 73 and 71 %, and for DRM 56 %, respectively. Mean ND (85%), food intake (87), and weight gain (37.6) for RPI were significantly different from those of DRM (71 %, 77, and 28, respectively). There was no signicant difference in the PER among three RPI and casein (3.0), nor in the NPU among those proteins and casein (74%). These data attributed to the favorable amino acid patterns of proteins isolated which contained balanced essential amino acids in proportions which meet the requirements of human adult(FAO/WHO, 1973).

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 1999.06a
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• pp.97-117
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• 1999

This study was performed to investigate the effect of pork on the cadmium detoxification in rats. Ninety male Sprague-Dawley rats weighing $125.3{\pm}1.4g$ were divided into five groups based on cadmium treatment(0, 25, 50, 100, 250ppm) and five levels of Cd in AIN-76 purified diet had been fed for 8 weeks. Cadmium was supplemented with a form of $CdCl_2$.. During following 8 weeks of intoxication, casein was replaced by pork and the effect of pork on cadmium- detoxification was compared with casein. After 8 weeks of Cd intake had resulted in apparent cadmium intoxication; reduced growth rate, enlarged kidney and testis, decreased hematocrit value and hemoglobin content in response to the supplemented Cd levels in the diets. Discontinuing cadmium feeding, the body weights were relieved. Pork-fed groups seemed to have higher body weight than casein-fed groups. Hemoglobin content and hematocrit value became normal range at detoxification stage. The weights of liver, kidney, and testis were decreased along with cadmium intake. However, organ weight ratio was not affected by cadmium. Cadmium accumulation in liver and kidney showed a tendency to increase in the cadmium-exposed groups. The levels of metallothionein were also significantly elevated in the tissues of liver in response to the levels of Cd supplemented(p<0.05). Cadmium concentration in kidney was two times higher than that in liver. Cadmium removal rate of liver was higher than that of kidney. Cadmium accumulation of the pork-fed group was lower than that of casein. Especially, the factors which affected the cadmium contents in kidney were $Cd^{***}$ and $Cd{\times}pork^{***}$. Metallothionein(MT) was increased with cadmium, and MT was not likely to be affected by pork. Based on the findings from gross lesion, rats fed 250ppm of Cd were externally emaciated, had exposed penis and observed atrophies of kidney and testis. Histopathological observation seemed that the liver of groups feeding Cd supplemented diets showed cellular degeneration and accumulation of eosinophilic materials in the capillaries. In kidney, rats fed Cd diets had shown tubular epithelium degeneration and lesions of basophilic materials, while testis were weakened in numbers of spermatid and sporadically enlarged of giant cells. But the rats administered cadmium-detoxified diet supplemented pork for 7 weeks were shown individually decreased lesions compared with the rats supplied with casein diet.

• Korean Journal of Food Science and Technology
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• v.42 no.5
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• pp.554-558
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• 2010

In the study, the protease activity of kiwifruit (Actinidia deliciosa Planch) cultivated in Korea was estimated, with specific examination of proteolytic effects on myofibrilar protein. The crude protease extract of kiwifruit was prepared in two ways; one in which the kiwifruit was homogenized with buffer followed by centrifugation, and the other were the supernatant was precipitated by saturated ammonium sulfate followed by dialysis. The former had 21.23 mM/mL of protease activity, which corresponded to 112.28 mM/g kiwifruit utilized, and the latter had 11.58 mM/mL and 45.80 mM/g of kiwifruit. The crude protease extract of the kiwifruit showed high specificity for casein substrate followed by bovine serum albumin, egg white, collagen, and elastin, in order. The enzyme lost proteolytic activity in acidic conditions such as pH 2-3, and at high temperatures over $60^{\circ}C$. It showed optimal activity in both pH 3.0 and pH 7.5 as well as at $40^{\circ}C$ for casein substrate and at $50^{\circ}C$ for myofibrilar protein substrate. The proteolytic activity toward casein was high with up to 0.5M salt, followed by a sharp decrease beyond this concentration. On the other hand the proteolytic activity for myofibrilar protein decreased steadily with increasing of salt concentration. Kiwifruit has been used as a for meat tenderizer for in home cooking and these results support the its tenderizing effectiveness of kiwifruit especially for Korean style marinating of meat for cooking.

• Journal of the Korean GEO-environmental Society
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• v.24 no.9
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• pp.5-13
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• 2023

Cement-based reinforcement materials, which are representative slope reinforcement materials, can cause contamination of ground and groundwater when ground injection or surface application is applied. Accordingly, slope reinforcement materials using eco-friendly biopolymers are attracting attention as a means of replacing existing materials, but the biopolymers currently used are easily dissolved when exposed to groundwater or rainfall environments, reducing strength. In order to solve this problem, the cross-linking of protein between sodium casein and Transglutaminase (TGase, C₂₀H₁₆N₄O₂S₂) was used to increase the water resistance of biopolymers, and a rainfall slope test was conducted to evaluate their usability and applicability as a slope reinforcing material. In the case of reinforcement with only sodium casein, the precipitation dissolved sodium casein, and the slope was completely destroyed in 1 hour. On the other hand, it was observed that the slope reinforced by adding a small amount of TGase (0.5%) do not collapse even after 80 hours of rainfall duration due to increased water resistance. Strength and water resistance increases due to the addition of a small amount of TGase, and its applicability as an eco-friendly reinforcement is confirmed.

• Journal of Life Science
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• v.25 no.2
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• pp.214-222
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• 2015

Aeromonas hydrophila is the most common water fish pathogen and cause diseases such as hemorrhagic septicemia, dropsy, ulceration and asymptomatic septicemia. A. hydrophila secretes many extracellular products (ECPs) which contribute to effective infection, wide distribution and great adaptability to environmental changes. Crude ECPs of A. hydrophila CK257, a strain used in this study, exhibits a toxic activity to the animals including mouse, rabbit and fish. Toxic symptoms were indicated by tissue damage and skin injuries in animal. When ECPs were subcutaneously injected to animals, skin damages were observed, appearing like necrosis. Preliminary research demonstrated that the active factors are protein component. The crude ECPs were collected after ammonium sulfate precipitation of cell-free culture supernatant. ECPs were fractionated with the use gel filtration chromatography. Five ECP fractions were obtained, of which one fraction was found to be toxic to goldfish. MALDI-TOF analyses provided two interesting proteases called M35 and M28. Both M35 and M28 are known as metalloprotease. Accordingly, proteins in an active fraction exhibited caseinolytic activity. These proteins were difference of caseinolytic activity under different metallic ions. Also active fraction has elastolytic activity. These results suggested that peptidase M28 and M35 may be a candidate factor for tissue necrosis activity about infection with A. hydrophila.

• Journal of Aquaculture
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• v.11 no.2
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• pp.133-140
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• 1998

A 20-week growth trial was conducted in flow-through aquarum system to investigate the practical dietary carbohydrate sources for juvenile abalone (Haliotis discus hannai). Four replicate grops of the abalone averaging 0.125g were fed one of eight diets containing 24.2% wheat flour (WF), 20% dextrin (DEX), 20% sucorse (SUC), 10% $^{\alpha}$-potato starch+10% $^{\beta}$-potato starch (ab-S), 15% $^{\alpha}$-potato starch (a-S15), 20% $^{\alpha}$-potato starch (a-S20), 25% $^{\alpha}$-potato starch (a-S25), or mixture (MIX) with practical ingredients such as soybean meal, corn gluten meal, cotton seed meal and heat flour. In addition, these formulated diets were compare with macroalgae such as dried sea mustard Undaria (D-SM) or dried sea tangle Laminaria(D-ST). Survival rate, weight gain, shell growth and soft body weight of abalone were not significantly affected by the different dietary carbohydrate sources (P>0.05), whereas those fed a-S15 diet were slightly low. These values of abalone fed D-ST were lowest (P<0.05), followed by those fed D-SM. Lipid contents of soft body from abalones fed a-S25, D-ST or D-SM were significantly lower than those of abalone fed other diets (P<0.05). These data indicate that abalone can equally utilize any carbohydrate sources used in this study.