• Korean Journal of Animal Reproduction
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• v.4 no.1
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• pp.28-34
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• 1980

This experiment was carried out to study effects fo dosage and insemination interval on fertility and hatchability of whole semen and diluted semen with yolk skim milk and skim milk dilutors. The results obtained are as follows: 1. Whole semen showed higher fertility than diluted semen with yolk skim milk and skim milk dilutors. In case of diluted semen, the fertility was higher in 0.04$m\ell$ dosage than 0.02$m\ell$ and in skim milk than yolk skim milk dilutor. 2. The average fertility in inseminational intervals of 6, 5, 4 and 3 days was 52.4, 35.5, 48.7 and 44.2% in whole semen and 40.6, 17.2, 13.9 and 20.5% in 0.04$m\ell$ diluted semen with yolk skim milk dilutor. The fertility was not improved by shortening of insemination interval. 3. There was no considerable difference in hatchability of fertilized egg among the dosage of 0.02$m\ell$ of whole semen, 0.02$m\ell$ and 0.04$m\ell$ of diluted semen with yolk skim milk, and among the insemination intervals of 6, 5, 4 and 3 days. 4. Some differences in fertility among the passed days after insemination were decreased in the whole semen by shortening insemination interval from 6 and 5 days to 4 and 3days and also decreased in the diluted semen by shortening it to 3 days and by increasing dosage from 0.02$m\ell$ to 0.04$m\ell$. 5. Hatchability of fertilized egg showed no difference among the passed days during 6 days insemination interval both in the whole semen and the diluted semen. 6. The whole semen and the diluted semen with skim milk had not considerable difference in fertility among the passed days during 3 and 4 days insemination intervals, but the diluted semen with yolk skim milk had. 7. Hatchability of fertilized egg from the whole semen diluted semen with yolk skim milk and skim milk dilutors showed no difference among the passed days during 3 and 4 days insemination intervals.

• Microbiology and Biotechnology Letters
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• v.43 no.4
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• pp.385-390
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• 2015

In order to develop an eco-friendly biofertilizer, a plant growth promoting rhizobacterium (PGPR), Bacillus sp., SH1RP8 was investigated. SH1RP8 was lyophilized via freeze-drying along with other protective agents that protect cells from lysis. The freezedried powder of Bacillus sp. SH1RP8, containing 5% skim milk (w/v), exhibited the highest survival rate of 30.6% among all the protective agents (skim milk, glucose, and peptone). The lyoprotective effect of the skim milk, mixture including 5% skim milk, and substrates on the survival of the test strain was examined. Control group was added only skim milk and test groups were added skim milk and other substrates. As a result, the group supplemented with both glycerol and 5% skim milk showed the protective effect much higher by 214.29% than the control group. Freeze-dried Bacillus sp. SH1RP8 could be a good candidate as a potential biofertilizer due to its effective PGPR activity.

• Journal of Nutrition and Health
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• v.26 no.8
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• pp.998-1005
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• 1993

This study was attempted to investigate the effects of enzymatic modification of milk protein with Meju protease on its acid clotting and digestibility. The proteases used in this study were isolated from Meju(fermented soybeans) and had specific acticity of 250 units/mg protein at pH 7.0. These proteases were found to be at least 3 different isoenzymes of different pH optima(pH 4.0, 6.0, 10.0). The optimum temperature was 5$0^{\circ}C$. Hydrolyzed skim milk showed 30.5% degree of hydrolysis for 1 hr. and 36.4% degree of hydrolysis for 3.5 hrs. of protease treatment at pH 7.0. Upon acidification to pH 4.0, skim milk produced large and dense coagulum, but the coagulum was getting smaller by protease treatment. Generally, digestability of skim milk at pH 4.0 was lower than pH 2.0. At pH 4.0, native skim milk and control group had problem with hydrolysis of skim milk protein. Among protease treated groups, 1 hour treated skim milk was most effectively hyrolyzed at pH 4.0.

• Food Science of Animal Resources
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• v.21 no.1
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• pp.32-37
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• 2001

The study investigated the effects of protein concentration, EGTA and strength of hydrostatic pressure on pH, viscosity and turbidity for ultra filtrated skim milk retentates. The results showed that hydrostatic pressure treatments up to 600 MPa did not affect the viscosity of skim milk, while the turbidity of skim milk increased at higher than 200 MPa. Addition of EGTA caused reduction in turbidity of skim milk, two times (2SR) and three times (3SR) concentrated skim milk retentates. Viscosity for 2SR and 3SR increased proportionally to the amount of EGTA, but viscosity of skim milk was not influenced by EGTA. High pressure treatment also did not cause any difference in viscosity and turbidity of skim milk. However, this treatment decreased viscosity and turbidity for 2SR and 3SR. In particular, 200 MPa treatment showed to induce a higher decrease in turbidity compared with 400 MPa.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.7
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• pp.1019-1025
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• 2004

The experiment was conducted to investigate the feasibility of using vegetable oil and non-fat dry milk (powdered milk) with skim milk for the preparation of dahi. In this experiment, six different types of dahi were prepared from whole milk, skim milk and admixture of non-fat dry milk with different levels of vegetable oil. The prepared dahi samples were subjected to physical, chemical and microbiological analysis to evaluate their quality. It was observed that the addition of non-fat dry milk and vegetable oil with skim milk improve the physical qualities (smell and taste, body and consistency, color and texture) of prepared dahi samples. Addition of non-fat dry milk and vegetable oil also improve the total solids, fat and protein content of dahi samples. It is concluded that the addition of vegetable oil at a rate of 4 to 6% together with 5% non-fat dry milk gave the best result.

• Journal of Food Hygiene and Safety
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• v.9 no.3
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• pp.169-174
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• 1994

This stydy was performed to investigate the inhibitory effect of bovine milk on the atherosclerotic rats. Eighty male rats of 5-weeks of age were divided into 4 groups, control, active treatment control fed the atherogenic feed, and skim milk and whole milk groups fed powdered skim or whole milk mixed with the atherogenic feed and observed for 13 weeks. Growth, clinical and pathological changes of the rats were examined. Rats of the 4 groups did not show significant difference of feed intake and weight gain. The level of serum cholesterol, high density lipoprotein cholesterol (HDL-cholesterol) fraction, and inorganics between skim milk and whole milk groups were not significantly different though significant difference was shown between active treatment control and milk groups. Milder calcification and nearosis in aorta, heart and kidney and fat degeneration in liver were seen in the milk groups than were in active treatment control. Marked difference, however, was not found between the skim milk and whole milk groups. Both powdered skim and whole milks could have a helpful effect of vitamin D2-and -cholesterol-induced atherosclerosis in rats.

• Korean journal of food and cookery science
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• v.9 no.4
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• pp.278-283
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• 1993

This study was attempted to investigate the effects of enzymatic modification of milk protein with protease on functional properties. The selected functional properties were solubility, emulsifying activity (EA), emulsion stability(ES), foam expansion(FE), and foam stability(FS). These properties were measu-red from pH 3.0 to pH 8.0. The proteases used in this study were iaolated from Meju(fermemted soybean) and had specific activity of 250 units/㎎ protein at pH 7.0, 1600 units of pretense was used for 1gr. of skim milk protein. Skim milk showed 30.5％ degree of hydrolysis for 1 hr. and 36.4% degree of hydrolysis for 3.5 hrs. of protease treatment at pH 7.0. Solubility of native skim milk, control, 1 hr. and 3.5 hrs. groups were 3.37, 3.64, 10.21, 14.34％o at pH 4.0 respcetively. The emulsifying activity of native skim milk, control, 1 hr. and 3.5 hrs. groups were 38.8,42.0,43.0,46.7ft at pH 4.0, respectively. Enzymatic modification resulted in the increase of solubility and emulsifying activity at pH 4.0. However at pH 5.0 emulsifying activity of 1 hr. and 3.5 hr. group were lower than native skim milk and control groups. 1 hr. protease treatment was found to be most effective way of increasing foam expansion at pH 4.0 to 6.0. It was supported that, protease treated skim milk can be used to improve solubility, emulsifying activity, foam expansion at acid pH. meju protease. skim milk, solubility, emulsion, foam.

• Journal of Animal Science and Technology
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• v.63 no.5
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• pp.1182-1193
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• 2021

The aims of this study were to develop a milk protein-based probiotic delivery system using a modified rennet-induced gelation method and to determine how the skim milk powder concentration level and pH, which can affect the rennet-induced intra- and inter-molecular association of milk proteins, affect the physicochemical properties of the probiotic delivery systems, such as the particle size, size distribution, encapsulation efficiency, and viability of probiotics in simulated gastrointestinal tract. To prepare a milk protein-based delivery system, skim milk powder was used as a source of milk proteins with various concentration levels from 3 to 10% (w/w) and rennet was added to skim milk solutions followed by adjustment of pH from 5.4 or 6.2. Lactobacillus rhamnosus GG was used as a probiotic culture. In confocal laser scanning microscopic images, globular particles with a size ranging from 10 ㎛ to 20 ㎛ were observed, indicating that milk protein-based probiotic delivery systems were successfully created. When the skim milk powder concentration was increased from 3 to 10% (w/w), the size of the delivery system was significantly (p < 0.05) increased from 27.5 to 44.4 ㎛, while a significant (p < 0.05) increase in size from 26.3 to 34.5 ㎛ was observed as the pH was increased from 5.4 to 6.4. An increase in skim milk powder concentration level and a decrease in pH led to a significant (p < 0.05) increase in the encapsulation efficiency of probiotics. The viability of probiotics in a simulated stomach condition was increased when probiotics were encapsulated in milk protein-based delivery systems. An increase in the skim milk powder concentration and a decrease in pH resulted in an increase in the viability of probiotics in simulated stomach conditions. It was concluded that the protein content by modulating skim milk powder concentration level and pH were the key manufacturing variables affecting the physicochemical properties of milk protein-based probiotic delivery systems.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.3
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• pp.351-357
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• 2001

The rapid formation of a cream line cannot be observed in raw goat's milk standing at a low temperature. Although the poor creaming ability of goat's milk has been considered to be due to the small size of milk fat globules and the lack of euglobulin capable of being adsorbed on milk fat globules, there is much left to study. The present work attempted to elucidate a factor for poor creaming ability of goat's milk. The creaming ability of the experimental milks reconstituted from creams and skim milks separated from cow's milk or goat's milk was measured by the volume of the cream layer and the fat content of bottom layer. The polypeptides composition of the P1 the fraction (i.e., the high molecular weight fraction eluted near the void volume obtained by the gel filtration of whey) and milk fat globule membrane prepared from both milks were compared. It was found that the promotion of creaming originated from goat's skim milk was lower than that from cow's skim milk. The P1 fraction in goat's skim milk was less than that in cow's skim milk. The polypeptide (M.W. $4.3{\times}10^4$), found in the P1 fraction of cow's milk was not found in the P1 fraction of goat's milk. It is suggested that the poor creaming ability of goat milk is caused mainly by the difference from cow milk in the amount and the composition of the P1 fraction.

• Journal of Dairy Science and Biotechnology
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• v.41 no.3
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• pp.149-156
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• 2023

Milk protein is often fractionated/concentrated by using various techniques in dairy industries. Among these techniques, ultrafiltration (UF) is particularly efficient at concentrating the casein fraction of milk protein. The objectives of this study were to produce casein hydrolysates by concentrating the casein fraction in skim milk using the UF technique and to investigate the chemical composition of the casein hydrolysates. The skim milk was concentrated using a UF laboratory test unit equipped with 10 kDa and 30 kDa membranes. After UF, the protein content of the milk was concentrated up to ~7.2% and the Ca was concentrated up to ~196 mg/100 g of milk. Trypsin was then added to the concentrated skim milk to produce the casein hydrolysates. The results of sodium dodecyl sulphate-polyacrylamide gel electrophoresis showed that the casein fraction was not present after hydrolysis, indicating that casein in the milk had been hydrolyzed. The Ca content in the casein hydrolysates was much higher (p<0.05) compared to Ca content in commercial casein phosphopeptides (CPP) indicating that was acidified during the manufacture of commercial CPP. In conclusion, it seems that casein hydrolysates containing large concentrations of protein and Ca can also be made from concentrated UF milk without acidification or renneting.