• Asian-Australasian Journal of Animal Sciences
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• v.26 no.6
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• pp.896-904
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• 2013

Cattle breeds have a striking effect on milk, including milk composition and technological characteristics. This study aims to compare milk composition, acidification activity, viscosity, milk dispersion system stability and casein molecular weight among three buffalo breeds in China. The technological characteristics of milk produced by three cattle breeds of river buffalo (Murrah), crossbreed 1st generation ($F_1$), crossbreed multiple generation ($F_H$, $H{\geq}3$) buffaloes were investigated. Cattle breeds showed evident effect on milk protein, fat and total solids content, but little effect on most of buffalo casein molecular weight. Milk fat, protein content and the viscosity of buffalo milk from river buffalo were lower than those of $F_1$ and $F_H$, so was the buffer capacity. The viscosity was negatively correlated to temperature and concentration. Results of stability coefficient showed that milk dispersion system had the best dynamic stability characteristics under pH 6.6 and 6 times dilution, while zeta potential of Murrah milk was slightly higher than that of hybrid offspring ($F_1$, $F_H$). SDS-PAGE results showed that buffalo ${\alpha}_s$-casein had a slightly faster mobility than standard ${\alpha}_s$-casein; while buffalo ${\beta}$-casein showed a slightly slower mobility than standard ${\beta}$-casein. There is no clear differences in molecular weight of ${\alpha}_s$-, ${\beta}$-, and ${\kappa}$-casein among Murrah, $F_1$ and $F_H$.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.4
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• pp.559-567
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• 2015

Ex vivo digestion of proteins and fat in Red Chittagong Cattle milk from Bangladesh was carried out using human gastrointestinal enzymes. This was done to investigate the protein digestion in this bovine breed's milk with an especial focus on the degradation of the allergenic milk proteins; ${\alpha}_{s1}$-casein and ${\beta}$-lactoglobulin and also to record the generation of peptides. Lipolysis of the milk fat and release of fatty acids were also under consideration. After 40 min of gastric digestion, all the ${\alpha}_s$-caseins were digested completely while ${\beta}$-lactoglobulin remained intact. During 120 min of duodenal digestion ${\beta}$-lactoglobulin was reduced, however, still some intact ${\beta}$-lactoglobulin was observed. The highest number of peptides was identified from ${\beta}$-casein and almost all the peptides from ${\kappa}$-casein and ${\beta}$-lactoglobulin were identified from the gastric and duodenal samples, respectively. No lipolysis was observed in the gastric phase of digestion. After 120 min of duodenal digestion, milk fat showed 48% lipolysis. Medium (C10:0 to C16:0) and long (${\geq}C17:0$) chain fatty acids showed 6% to 19% less lipolysis than the short (C6:0 to C8:0) chain fatty acids. Among the unsaturated fatty acids $C18:1{\sum}others$ showed highest lipolysis (81%) which was more than three times of $C18:2{\sum}all$ and all other unsaturated fatty acids showed lipolysis ranging from 32% to 38%. The overall digestion of Bangladeshi Red Cattle milk was more or less similar to the digestion of Nordic bovine milk (Norwegian Red Cattle).

• Korean Journal of Food Science and Technology
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• v.25 no.3
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• pp.277-281
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• 1993

To elucidate the conformational stability of proteins in colloidal food system, molecular properties of various proteins such as chemically modified ${\beta}-lactoglobulin$, bovine serum albumin (BSA) structural intermediates, and ${\beta}-casein$ under chaotropic conditions, were examined using circular dichroism, SS bond content, and hydrodynamic radius determination. As refolding time increases, BSA intermediates approach the conformation of native BSA. And succinylation made ${\beta}-lactoglobulin$ have more aperiodic structure by increasing net negative charge. Also, under chaotropic conditions, the conformation of P-casein was affected by hydrophobic interactions. This study clearly indicates that hydrophobic interactions and electrostatic interactions are major contributing factors in conformational stability of proteins.

• Korean Journal of Food Science and Technology
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• v.22 no.3
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• pp.337-342
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• 1990

The changes in cheese casein components and the resultant palatability of the cheese were studied. Camember cheese was made with P. caseicolum and mixed lactic cultures and ripened for 45days. The pH value increased rapidly during ripening Water soluble, pH 4.6-soluble and non protein nitrogenous compounds were all increased during ripening. The electrophoretic patterns of pH 4.6-insoluble casein showed that the caseins were seperated into 4 bands after 10 days,12 bands after 45 days of ripening, ${\alpha}_{s1}-casein$ was completely degraded after 17 days of ripening and a targe percentage of ${\beta}-casein$ was broken down after 45 days of ripening. On gel filtration, pH 4.6-soluble casein fragments ripened for 10 days,24 days and 31 days were fractionated into 3,4 and 5 fractions respectively The sensory evaluation of Camembert cheese showed that cheese ripened for 31 days had the best palatability.

• Journal of Dairy Science and Biotechnology
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• v.25 no.2
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• pp.11-16
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• 2007

The nomenclature of genetic variants of casein which is major protein in milk have had a lot of confusion, but now have established. Genetic variants of ${\alpha}_{s1}-CN,\;{\alpha}_{s2}-CN,\;{\beta}-CN,\;{\kappa}-CN$ have reported 8 variants(A, B, C, D, E, F, G, H), 4 variants(A, B, C, D), 13 variants ($A_1,\;A_2,\;A_3,\;A_4$, B, C, D, E, F, G, $H_1,\;H_2$, I), 11 variants(A, B, C, E, $F_1,\;F_2,\;G_1,\;G_2$, H, I, J), respectively. Their data detailed have introduced in several web sites including www.uniprot.org. The studies on genetic variants of casein from Korean native cattle have been reported only ${\beta}-casein\;A_4$ but still not established the protein sequence. The classification and distinct nomenclature of genetic variants of bovine casein were required because the development of milk science and technology have been focused in the region that have to studied biochemically such as functional foods, EMC and GMO et al.

• Journal of Dairy Science and Biotechnology
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• v.14 no.2
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• pp.135-146
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• 1996

This experiment was carried out to investigate the changes of casein of cheese base treated with substitute enzyme during ripening. The cheese base without enzyme treatment(control, D)and cheese base treated with only calf rennet(A), cheese base treated with mixed enzyme(calf rennet :porcine pepsin 1:1, B), cheese base treated with only porcine pepsin(C) were manufactured. The changes of casein were analyzed by means of HPLC and electrophoresis as experimental parameters during ripening. Gel filtration(HPLC) of casein by Superose 12 column in Cheddar cheese showed 5 fractions immediately after manufacturing and 8 fractions after six months ripening. Though D showed no difference in number of fraction(4 fraction) during 8 weeks ripening, A, B, C have represented the change of fraction number 4 to 5, 4 to 7, 4 to 8, respectively. As the mixing ratio of porcine pepsin increased, higher degradability of casein appeared. After 8 weeks ripening, electrophoresis of casein in cheese base showed three bands as an ${\alpha}$$_{s1}$casein from A and five bands from B, C. In case of D one major band and two minor bands were appeared as an ${\alpha}$$_{s1}$-casein. As the additional level of porcine pepsin increased the concentration of ${\beta}$-casein band decreased. however, that of ${\gamma}_1$ ${\gamma}_2$-casein band increased and para-${\kappa}$-casein band appeared from A, B, C, except D.

• Bulletin of the Korean Chemical Society
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• v.25 no.7
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• pp.1031-1035
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• 2004

The adsorption kinetics of ${\beta}$-casein on a hydrophobic surface has been studied by means of the quartz crystal microbalance (QCM). The self assembled monolayer of 1-octadecanethiol on a gold coated quartz crystal was used as a hydrophobic surface for adsorption. The adsorption kinetics was monitored in different solution conditions. Formation of monolayer is observed in most cases. At high concentration of protein, micelle formation which is interrupted by high ionic strength of solution is observed. Casein binding cations such as $Ca^{2+},\;Ba^{2+}\;and\;Al^{3+}$ increase the hydrophobicity of the protein and the multiple layer adsorption occurs. The strong and weak points of the QCM method in the study of protein adsorption are discussed.

• Korean Journal of Animal Reproduction
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• v.17 no.4
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• pp.375-383
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• 1994

The human growth hormone (hGH) gene uder the control of the rat $\beta$-casein promoter gene was designed to produce transgenic mouse expressed hGH gene in only mammary gland. One hundred seventy two eggs microinjected were transferred to the oviducts of pseudopregnants and 43 offspring were delivered. By Southern blotting hybridization, 3 were transgenic with rat $\beta$-casein/hGH gene. The copy numbers of three transgenic founder were 1, 5, and 15, respectively. A radioimmunoassay was developed to quantitate the amount of expression of the hGH gene in mammary gland of transgenic mice. The amount of hGH was 13.3ng/ml in the lactating milk of one transgenic line, showing predominantly higher than 3.0ng/ml in milk of control mice. Therefore, our findings suggested that $\beta$-casein promoter may induce the tissue specific expression of structural gene.

• Korean Journal of Veterinary Service
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• v.41 no.3
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• pp.171-177
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• 2018

Purified bee venom was collected from colonies of honeybees (Apis mellifera L.) using a bee venom collector under sterile conditions and then purified under strict laboratory conditions. Purified bee venom contained $63.9{\pm}5.4%$ melittin, $10.9{\pm}1.6%$ phospholipase A2, and $2.3{\pm}0.3%$ apamin. Purified bee venom has various anti-bacterial, anti-inflammatory and immunostimulating effects. In this study, we evaluated purified bee venom which are mammary gland cells, MAC-T cells are used to increase the synthesis of milk protein. Purified bee venom promoted the proliferation of MAC-T cells at concentrations below $1{\mu}g/mL$, but cytotoxicity at $10{\mu}g/mL$ and above. As a result of the increase in the synthesis of ${\beta}-casein$, a milk protein after treatment with MAC-T cells at a concentration of the bee venom without cytotoxicity, the ${\beta}-casein$ content in the cell culture was increased when treated at a concentration of 1 ng/mL or more. In addition, it was confirmed that purified bee venom significantly increased the expression of bovine ${\beta}-casein$ (bCSNB) mRNA, a ${\beta}-casein$ synthesis gene, at a concentration of 1 ng/mL or more. These results suggest that purified bee venom can be used to increase the production of livestock by ultimately increasing the expression of milk protein.

• Food Science of Animal Resources
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• v.28 no.3
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• pp.306-311
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• 2008

The aim of this work was to examine the reduction in antigenicity of milk proteins in powdered milk by gamma irradiation which is increasingly used for food safety. Skim milk powder samples were exposed to irradiation doses of 1, 5, and 10 kGy. A greater reduction of ${\alpha}_{S1}$-casein and ${\beta}_{A1}$-casein was found than ${\alpha}_{S0}$-casein and ${\beta}_{A2}$-casein by capillary electrophoresis. Competitive indirect ELISA and passive cutaneous anaphylaxis tests using guinea pigs showed a reduction in antigenicity of powdered milk by 10kGy gamma irradiation. These results indicated that gamma irradiation reduce allergenicity of milk proteins by structural changes of ${\alpha}_{S1}$-casein and ${\beta}_{A1}$-casein, and can be useful for dairy products.