• Food Science of Animal Resources
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• v.40 no.2
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• pp.209-220
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• 2020

Milk fat globule membrane (MFGM) is a lipid carrier in mammals including humans that consists mainly of polar lipids, like phospholipids and glycolipids. In this study, a process to enrich polar lipids in commercial butter and whey powder, including polar lipids of MFGM, was developed. WPC (whey protein concentrate) 60 was selected as the most suitable raw material based on the yield, phospholipid, protein, and lactose content of the polar lipid fraction obtained by ethanol extraction of two WPC (WPC60 and WPC70) and two buttermilk (A and B). After fractionation under optimum conditions, the polar-lipid enriched fraction from WPC60 contained 38.56% phospholipids. The content of glycolipids, cerebroside, lactosylceramide, ganglioside GM3, ganglioside GD3, was 0.97%, 0.55%, 0.09%, and 0.14%, respectively. Rancimat results showed that the oxidation stability of fish oil increased with an increase in the polar-lipid fraction by more than 30 times. In addition, the secretion of IL-6 and TNF-α decreased in a concentration-dependent manner after treatment of RAW 264.7 cells with 0.1 to 100 ppm of the polar lipid fraction. In this study, polar lipid concentrates with antioxidant and anti-inflammatory activity, were prepared from milk processing by-products. The MFGM polar lipid concentrates made from by-products are not only additives for infants, but are also likely to be used as antioxidants in cooking oils and as active ingredients for functional foods.

• Journal of Nutrition and Health
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• v.30 no.1
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• pp.3-11
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• 1997

This study was conducted to investigate the effects of protein levels and casein/whey ratios on organ growth and protein metabolism in early weaned rats. Premature rats weaned by the 17th day were fed six semipurified synthetic, isocaloric and gel diets that contained three levels (low, medium and high) and two different combinations(casein/whey ; 80 : 20 or 20 : 80) of milk protein for 8 days. On the 25th day postpartum, frest weigth and DNA, RNA and milk protein contents in brain, liver, kidney and muscle were determined to ascertain organ and cellular growth. Futher, with a view to ascertain protein metabolism and renal functions, serum total protein, $\alpha$-amino N, urea N, and creatinine and creatinine and urinary urea N, creatinine and hydroxproline were determined. Total DNA contents of brain, liver and kidney, which may represent as an index of cell numbers in those organs were significantly decreased in the rats fed diets containing low level protein regardless of casein/whey ratio. However, as fat as the rats fed high protein diets were concerned, their fresh weight, protein contents and GFR of kidney were significantly increased. Furthermore, nitrogen components, $\alpha$-amino N, urea N and creatinie in serum and urine were also increassed. Another observation was that high casein/whey ratio significantly facilitated accumulation of porteins in muscle and kidney and urinary hydorxyproline excretion, not affecting the DNA content of those organs. This study showed that low(8%) or high(32%) contents of protein had less desirable effects either on protein metabolism or on organ cellular growth in prematurely weaned rats, whereas there were no effects on general growth and bone strength.

• 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.

• Food Science and Biotechnology
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• v.18 no.3
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• pp.610-617
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• 2009

The stability of corn oil-in-water emulsions coated by milk proteins, sodium caseinate (CAS), or whey protein concentrate (WPC), was compared under the environmental stress of pH change. Emulsions were prepared at 0.1 of protein:oil because the majority of droplets were relatively small ($d_{32}=0.34$ and $0.35\;{\mu}m$, $d_{43}=0.65$ and $0.37\;{\mu}m$ for CAS- and WPC-emulsions, respectively) and there was no evidence of depletion flocculation. As the pH of the emulsions was gradually dropped from 7 to 3, there was no significant difference in the electrical charges of the emulsion droplets between the 2 types of emulsions. However, laser diffraction measurements, microscopy measurements, and creaming stability test indicated that WPC-emulsions were more stable to droplet aggregation than CAS-emulsions under the same circumstance of pH change. It implies that factors other than electrostatic repulsion should contribute to the different magnitude of response to pH change.

• Journal of the East Asian Society of Dietary Life
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• v.14 no.5
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• pp.449-456
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• 2004

Different types of coagulant and characteristics of its concentration added in the process of making milk curd were compared in this study. The pH of whey decreased when the amount of coagulant increased. The turbidity of whey was decreased when 5% of acetic acid and lemon juice were put into as coagulants. The texture of milk curd made with cow's milk and skim milk was measured the highest when acetic acid and lemon juice were added at 3, 5% of their concentration. The fracturability of milk curd made only with cow's milk decreased as the concentration of each coagulant increased. The cohesiveness was decreased as concentration of coagulant increased. The springiness was slightly changed depending on its coagulant but didn't show much of difference. The gummminess of milk curd made with cow's milk was increased when 3, 5% of coagulant was added. The result of sensory evaluation of milk curd showed that preference of milk curd wasn't depending on types of milk nor its coagulant. Also, flavor preference showed better when lemon juice was added. Preference in texture of milk curd was the highest made with cow's milk and skim milk. Preference in taste was high when 10% of lemon juice was added to skim milk and preference in its appearance showed higher when the alum was added as a coagulant to both cow's milk and skim milk than other coagulants.

• Korean journal of food and cookery science
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• v.23 no.1 s.97
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• pp.41-49
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• 2007

The substitution effects of whey protein isolate(WPI) for egg in the preparation of sponge cake were determined by objective and subjective tests. Milk whey is drained from milk curd as a by-product of cheese manufacture. Whey protein is known as a good nutritional source and a functional material for many processed foods, especially baked goods. WPI contains above 90% whey protein. The specific gravity and viscosity of sponge cakes tend to be affected by WPI substitution. The cooking loss of sponge cakes with WPI substituted for egg(abbreviated as WPI cake) during oven baking was smaller than that made with egg(abbreviated as egg cake) and the specific loaf volume of WPI cake was larger than that of egg cake. The number of pores was highly increased and the size of pores was more uniformly and finely distributed in the cross section of WPI cake than those of egg cake, as observed by scanning electron microscopy(SEM). The hardness, gumminess and chewiness of WPI cake made with 10-20% WPI substitution were the lowest among all the tested cakes, including egg cake, thereby confirming the considerable improvement in their cake qualities. By the results of sensory evaluation, appearance, pore uniformity, softness, chewiness, moistness, flavor, mouth feeling, and overall acceptability of 10-20% WPI substitute cakes were evaluated as being significantly superior to those of all other cakes(p<0.05). These results support the better physicochemical characteristics and sensory evaluations of sponge cake prepared with 10-20% of WPI substitution for egg.

• Journal of Animal Science and Technology
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• v.47 no.1
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• pp.83-90
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• 2005

ACE-inhibitory peptides derived from goat's whey hydrolyzed by various proteolytic enzymes were separated and purified for antihypertension materials. The highest ACE-inhibitory activity of goat's whey hydrolysates was 85.5 % by pepsin for 72 hrs. Also the highest ACE-inhibitory activity of goat's whey hydrolysates was F-4 by pepsin for 72 hrs by Sephadex G-25 gel chromatograms. F-4e and F-4ed from F-4 by RP-HPLC to first and second purification were the highest in ACE-inhibitory activity, respectively. The most abundant amino acid was leucine(I 8.54 %) in F-4ed of ACE-inhibitory peptides after second purification. Amino acid sequence of F-4ed of ACE-inhibitory peptides showed Leu-Lys-Asp-Tyr-Gly-GlyVal- Ser-Leu and Leu-Gly-Asp-Gly-Ala-Gly- Asp-Val-Ala-Phe. $IC_{50}$ calibrated in peptic hydrolysates(72 hrs), F-4, F-4e and F-4ed from goat's whey hydrolysates by pepsin for 72 hrs were 33.93, 28.75, 11.74 and 1.09 mg/ml, respectively. From the results of this experiment, goat's whey hydrolysate by pepsin was shown to have ACE-inhibitory activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.2
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• pp.161-164
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• 1993

To find out the effective indicators for identification and classification of different heat treatment, the contents of nitrogen fractions and the degrees of whey protein denaturation in market milks were investigated by Kjeldahl method. The contents of nitrogen fractions per 100ml raw milk were total nitrogen (431.3mg), casein nitrogen (341.0mg) and non-casein nitrogen(90.3mg), in which non-protein nitrogen (31.6mg) and denatured whey protein nitrogen (58.8mg), while those of LTLT, HTST, UHT pasteurized and UHT sterilized showed different values. The degrees of whey protein denaturation were 26.7%(LTLT), 32.9%(HTST), 60.7%(UHT pasteurized) and 38.4%(UHT sterilized), respectively. As the higher temperature was applied for the treatment of milk, the degree of the whey protein denaturation was higher. Remarkable differences in the degree of whey protein denaturation according to the heating methods were observed.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.9
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• pp.1184-1189
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• 2010

This work was conducted to examine the variation of immunoglobulins (Igs) in serum, immune milk, normal milk and colostrum upon implantation of a new Antigen Releasing Device (ARD). The core of each ARD housed an immunostimulating complex (ISCOM) that was made of adjuvant Quil A and type XIII lipase from a Pseudomonas sp. Each ARD was coated with polylactic acid, known as polylactide, that controls antigen release. Twenty lactating Chinese Holstein cows were divided into 2 groups (n = 10): test group and control group. All cows in the test group were implanted with a single injection in the right iliac lymph node with 3 types of ARDs, which were designed to release the antigens at d 0, 14 and 28 post-implantation. Blood and milk samples were collected from both groups, and colostrum samples were also collected from other post-partum cows in the same farm. Concentrations of $IgG_1$, IgA and IgM in whey and serum were measured by sandwich ELISA. The results showed that the $IgG_1$, IgA and IgM concentrations in serum and whey from the test group were higher than from the control group. Among the three Igs measured, the $IgG_1$ concentration in serum was significantly higher at d 40 after ARD implantation, and the $IgG_1$ concentration in whey peaked at d 9, 17 and 30, which corresponded with release of the antigen. Based on Pearson's correlation between Ig concentration and production parameters, IgA concentration in normal milk was positively correlated with lactation period, which reflected IgA changes during the lactation period in immune milk. In colostrum, $IgG_1$, IgA and IgM decreased abruptly from d 0 to 3, and then decreased slightly. In conclusion, serum $IgG_1$ concentration can be affected by controlled release of the ARD, while whey IgA levels are primarily affected by lactation period. These results may be useful in future studies designed to regulate concentrations of Igs in immune milk.

• Journal of Dairy Science and Biotechnology
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• v.28 no.1
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• pp.35-41
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• 2010

Food allergy is defined as adverse reactions toward food mediated by aberrant immune mechanisms. Therefore, an allergic response to a food antigen can be thought of as an aberrant mucosal immune response. Food allergy most often begins in the first 1~2 years of life with the process of sensitization by which the immune system responds to specific food proteins, most often with the development of allergen-specific immunoglobulin E (IgE). Over time, most food allergeies are lost, although allergy to some foods is often long lived. The most important allergen sources involved in early food allergy are milk, eggs, peanut, soybean, meat, fish and cereals. Milk allergy seem to be associated with casein and whey protein. Important features of proteins as allergenicity are size, abundance and stability. Strategies for the prevention of milk allergy is breast-feeding, partially hydrolysised infant formula, using of probiotics, immune components in milk, preparation of low allergenicity milk protein and allergy therapy (immune therapy).