• Journal of the Korean Home Economics Association
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• v.20 no.1
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• pp.57-64
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• 1982

This study was designed to observe the effect of two levels of dietary protein intake on the development and growth of rats from fetus to adult. The pregnant rats were fed either 20% casein diet or 7% casein diet. After weaning or two weeks postweaning, some of the pups from malnourished mothers were rehabilitated by feeding 20% casein diet. The results were. 1. On the 14th day of gestation, no differences were found in weight and total body fat or protein between fetuses from dams fed 7% casein diet and those from those from 20% casein diet. 2. The birth weight of the pups from 7% casein diet group were significantly lower than those from 20% casein diet group. 3. After rehabilitation, the total body fat and protein of low protein group were not different from those of control group when they were compared at the same body weights regardless the age of rats or the duration on the low protein diet. 4. The nitrogen retention of low protein group, after rehabilitation, was higher than that of control group when they were compared at the same body weight.

• Journal of Nutrition and Health
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• v.27 no.10
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• pp.979-987
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• 1994

We have examined the antigen specificity in orally tolerant mice fed with the casein(CN) diet. In contrast to previous reported results of studies on oral tolerance, these mice responded poorly to ovalbumin(OVA) and ovomucoid(OM), as well as $\alpha$sl-enriched fraction of these cells suppressed anti $\alpha$sl-CN antibody production of naive mice, but could not significantly suppressed antibody response of previously immunized recipient mice. These results indicate that oral tolerance was not medicate through suppressor T cell activities.

• Korean Journal of Agricultural Science
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• v.29 no.2
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• pp.43-52
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• 2002

This study was performed to provide the basic data for preservation and improvement of genetic resources according to finding genetic construction obtained from analysis of genetic characteristics of $\beta$-casein gene in Korean Native goat and Saanen using the PCR-RFLP. This study confirmed the amplified products of 481bp fragments obtained from the amplification of $\beta$-casein loci by PCR. The $\beta$-casein AB genotype showed 481, 284 and 197bp, and $\beta$-casein BB genotype showed 284 and 197bp fragments in Korean Native goat and Saanen. The frequencies of $\beta$-casein genotype in Korean Native goat were 6.25 and 93.75% for AA and AB and the frequencies of $\beta$-casein genotype in Saanen were 57.14 and 42.86% for AA and AB types. The frequencies of $\beta$-casein A and B alleles were 0.031 and 0.969 in Korean Native goat and the frequencies of $\beta$-casein A and B alleles are 0.286 and 0.714 in Saanen, respectively. The nucleotide sequence of $\beta$-casein gene of Korean Native goat was 97.71% higher homology with 11 nucleotide sequences difference of that of goat reported in GeneBank (M90556). Therefore, this study of molecular genetic characteristics by the analysis of genetic polymorphism and sequencing for $\beta$-casein gene should be used as basic and applying data for preservation and improvement of genetic resources in Korean Native goat breeding.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.2
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• pp.263-270
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• 2002

In the recent studies, many researchers are interested in foods as functional components rather than nutrient sources. Cow's milk is considered as an excellent food sources because of its many nutrients. Casein is a major milk protein and has been reported to have hyperlipidemic and hypercholesterolemic effects. But several reporters have suggested that peptide fractions and hydrolysate of casein have hypolipidemic effects differing from intact protein, casein. Therefore, the objective of the study was to investigate how the casein peptide fractions affect lipid metabolism in rats fed normal or high fat diets. The peptide fractions and hydrolysate of casein were obtained by casein hydrolysis with trypsin. The male rats (Sprague-Dawley), weighing approximately 150 g, were fed each experimental diet containing casein (CAS), casein hydrolysate (CH), casein hydrolysate precipitate (Cpt) and two kinds of peptide fractions (CL & CB) for three weeks, respectively. In the exit I, the male rats were fed normal fat diets (7% soybean oil & cholesterol-free; Expt. I), and in the expt II, fed high fat diets (18% beef tallow & 1% cholesterol; Expt. II). Crude protein contents were calculated from nitrogen contents. Amino acid composition of each fraction was also analyzed. The concentration of total lipid, total cholesterol and triglyceride in serum, liver and feces were measured. As the results of study, tole rats fed peptide fractions with normal fat diets (Expt. I) had no effects on total lipid, total cholesterol and triglyceride concentration in serum and liver and fecal excretion. However, in the rats fed hydrophobic casein peptide fractions (CB) with high fat diet, fecal lipids excretion were significantly increased and the lipids concentration of serum and those of liver tended to decrease, numerically.

• Food Science of Animal Resources
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• v.37 no.6
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• pp.940-947
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• 2017

Goat milk has a protein composition similar to that of breast milk and contains abundant nutrients, but its use in functional foods is rather limited in comparison to milk from other sources. The aim of this study was to prepare a goat A2 ${\beta}$-casein fraction with improved digestibility and hypoallergenic properties. We investigated the optimal conditions for the separation of A2 ${\beta}$-casein fraction from goat milk by pH adjustment to pH 4.4 and treating the casein suspension with calcium chloride (0.05 M for 1 h at $25^{\circ}C$). Selective reduction of ${\beta}$- lactoglobulin and ${\alpha}_s$-casein was confirmed using sodium dodecyl sulphate-polyacrylamide gel electrophoresis and reverse-phase high-performance liquid chromatography. The hypoallergenic property of A2 ${\beta}$-casein fraction was examined by measuring the release of histamine and tumor necrosis factor alpha from HMC-1 human mast cells exposed to different proteins, including A2 ${\beta}$-casein fraction. There was no significant difference in levels of both indicators between A2 ${\beta}$-casein treatment and the control (no protein treatment). The A2 ${\beta}$-casein fraction is abundant in essential amino acids, especially, branched-chain amino acids (leucine, valine, and isoleucine). The physicochemical properties of A2 ${\beta}$-casein fraction, including protein solubility and viscosity, are similar to those of bovine whole casein which is widely used as a protein source in various foods. Therefore, the goat A2 ${\beta}$-casein fraction may be useful as a food material with good digestibility and hypoallergenic properties for infants, the elderly, and people with metabolic disorders.

• Journal of Dairy Science and Biotechnology
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• v.21 no.2
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• pp.97-104
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• 2003

It is extremely important to destroy the antigenicity of milk proteins for dietetic treatment of infants with milk allergy. Enzymatic digestion of milk protein is not only effective for destroying antigenicity, but it also is less liable to alter the nutritive value. Bovine casein was hydrolyzed with eight different commercial proteases derived from bacterias or fungi, either individually or in combination to eliminate protein allergenicity. The average molecular weight of casein hyrdolysates determined by size exclusion chromatography is about 550${\sim}$2,300 dalton range. Antigenicity of the casein hyrdolysates was not detected by heterologous passive cutaneous anaphylaxis in guinea pig-rabbit antiserum system. The inhibition test on the enzyme-linked immunosorbent assay(ELISA) showed that the antigenicity of casein hydrolysates is lowed up to 1/8,000 than that of intact bovine casein. As the enzyme reaction was carried out by the combination of bacterial and fungal protease, casein hydrolysates showed much lower bitterness and antigenicity. It suggests that these hydrolysates will be applied to many kinds of foods including the development of hypo-allergenic infant formula.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.6
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• pp.1117-1124
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• 1998

Chymosin was purified from commercial rennet with DEAE Sepharose CL 6B and immobilized on CeliteTM using glutaraldehyde. Whole casein from fresh raw milk was hydrolyzed by immobilized chymosin and total CMP was isolated by trichloroacetic acid(TCA) and ultrafiltration, and characterized. The amount of chymosin purified from 15g commercial rennet by DEAE Sepharose CL 6B was 0.16g and 18mg of chymosin was immobilized on 1g of CeliteTM by 5% glutaraldehyde. Immobilized chy mosin hydrolyzed most of casein on whole casein within 2 hours to leave para casein and casei nomacropeptide(CMP). The total CMP isolated from 10g of whole casein hydrolyzate by TCA and ultrafiltration was 0.4g and 0.1g, respectively. Results of electrophoresis, amount of sialic acid, com position of amino acid and ratio of A280 to A214 showed that total CMP by TCA was purer and had more CMP without carbohydrate than one by ultrafiltration. CMP isolated from total CMP by 12% TCA precipitation was 50% of total CMP and most of caseinoglycopeptide(CGP) was removed from total CMP, indicating less amount of sialic acid in CMP than in total CMP.

• The Korean Journal of Community Living Science
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• v.15 no.3
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• pp.113-120
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• 2004

This study is to investigate the effect of dietary L-carnitine supplementation on lipid metabolism in rats fed with isolated soy protein and casein for their source of protein. Four experimental groups were organized and each group had eight Sprague-Dawley male rats with the initial weight of around 180g. The four groups were CO (casein only supplemented group); CC (casein and 3% L-carnitine supplemented group); ISO (isolated soy protein only supplemented group); ISC (isolated soy protein and 3% L-carnitine supplemented group). All groups were supplemented with the experimental diet for four weeks and carnitine comprised 3% of. their diet. The results were as follows; 1. There was no significant difference in food intake among the groups. 2. Final weight gain was significantly lower in the groups supplemented with isolated soy protein than in the groups supplemented with casein (P<0.05). The groups with supplemented casein and carnitine showed the effect of weight reduction (p<0.05). 3. Food efficiency ratio was lower in the groups supplemented with isolated soy protein than in the groups supplemented with casein (p<0.01). The groups supplemented with casein and carnitine showed low food efficiency ratio. 4. The serum total lipid was higher in the groups supplemented with casein than in the groups supplemented with isolated soy protein (p<0.05). 5. Serum total cholesterol was higher in the groups supplemented with casein than in the groups supplemented with isolated soy protein. 6. There was no significant difference in triglyceride, HDL-cholesterol, and LDL-cholesterol in serum among the groups. 7. Out of the groups supplemented with isolated soy protein the total cholesterol level in liver was low in the groups to which carnitine was supplemented (p< 0.05). However, there was no significant difference of liver total lipid and triglyceride among the groups. 8. There was no difference in TBARS levels and GSH-Px activities in liver among the groups.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.3
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• pp.311-317
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• 1998

A total of 1033 Brown Swiss and 610 Canadienne cows were phenotyped for the genetic variants ${\alpha}_{s1}$-casein, ${\beta}$-casein, ${\kappa}$-casein, ${\beta}$-lactoglobulin and ${\alpha}$-lactalbumin. In Brown Swiss, frequency distributions were: 97.3% B and 2.7% C variant of ${\alpha}_{s1}$-casein; 31.6% $A^1$, 51.8% $A^2$, 0.5% $A^3$ and 16.1% B variant of ${\beta}$-casein; 70.4% A, 29.3% B, and 0.3% C variant of ${\kappa}$-casein; 41.7% A and 58.3% B variant of ${\beta}$-lactoglobulin; and 100% B variant of ${\alpha}$-lactalbumin. Corresponding frequencies in Canadienne for those five milk proteins were: 98.6 and 1.4%;58.5, 33.5, 0.08 and 7.9%; 78.8, 21.1 and 0.1%, 42.4 and 57.6%; and 100%. Analysis of variance by least squares showed possible association between milk protein phenotypes and some lactational production traits. There were no significant association of phenotypes of ${\alpha}_{s1}$-casein, ${\beta}$-casein and ${\beta}$-lactoglobulin with milk yield, fat yield, protein yield, fat percentage and protein percentage in both breeds during the three lactations. In the Brown Swiss, ${\kappa}$-casein phenotype was associated with 305-day fat yield and protein yield during the first lactation. ${\kappa}$-Casein AB was associated with higher milk, fat and protein yield during the second lactation. During the third lactation, ${\beta}$-lactoglobulin AA in Canadienne cows was associated with higher protein content in the milk (3.70%) when compared to phenotypes AB (3.54%) and BB (3.64%).

• Food Science and Biotechnology
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• v.16 no.4
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• pp.565-571
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• 2007

This study was carried out to investigate an optimum condition for the high angiotensin-l converting enzyme (ACE) inhibitory activity and the yield on enzyme concentration, casein concentration, and hydrolysis time. The optimum condition was performed by response surface methodology for acquirement of casein hydrolysate of milk which shows high ACE inhibitory activity, Among 8 tested enzymes, Protamex showed the highest activation degree with 77.03 unit/g from casein. Their hydrolysis degrees of flovourzyme 500MG, protamex, mixture from 1% casein were 85.5, 88.5, and 93.5%, respectively. The ranges of enzyme concentration (0.25-1.25%), casein concentration (2.5-12.5%), and hydrolysis time (20-100 min) as 3 independent variables through preliminary experiments of the yield of casein hydrolysate and ACE inhibitory activity, and it shows optimum response surface at a saddle point. It shows enzyme concentration (0.64%), casein concentration (8.38%), and hydrolysis time (55.81 min) in the yield aspect and showed the highest activity at enzyme concentration (0.86%), casein concentration (5.97%), and hydrolysis time (63.86 min) in ACE inhibitory aspect. The $R^2$ value of a fitted optimum formula on the hydrolysis yield was 0.9751 as the significant level of 1%. The $R^2$ value of a fitted optimum formula on ACE inhibitory activity is 0.8398, and the significance is recognized in the range of 5%.