• KSBB Journal
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• v.4 no.3
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• pp.229-234
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• 1989

NAD+ analogs, 8-( 6-aminohexyl) aminonicotinamide adenine dinucleotide and N6-[(6- aminohewl)-carbamoylmethyl]- NAD+, were imobilized on bovine caseins by the action of hansglutaminase. It appears that NAD+ analogs bind with $\alpha$S1-and $\beta$-caseins through formation of the r-glutamylamine bond between the amino groups attached to the hexyl chains in NAD+ analogs and the glutaminyl residues in caseins. The NAD+ analogs immobilized on the caseins were enzymatically reducible by alcohol dehydrogenase. $\beta$-Casein was more useful carrier than the $\alpha$S1-casein and 8-substituted NAD+ analog was more effective than N6-substituted one in immobilization. Michaelis constant of 8-substituted NAD+ analog immobilized on $\beta$-casein in alcohol dehydrogenase reaction was similar to that of free from of NAD+ and that of NAD+ analog. Immobilized NAD+ was much more stable at alkaline pH than free NAD+ and its analog while maximum velocity was reduced to 31% of the free NAD+ analog. The coenzyme casein conjugated was recovered almost completely in casein precipitated by calcium.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.7
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• pp.1022-1028
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• 2016

Milk composition is an imperative aspect which influences the quality of dairy products. The objective of study was to compare the chemical composition, nitrogen fractions and amino acids profile of milk from buffalo, cow, sheep, goat, and camel. Sheep milk was found to be highest in fat ($6.82%{\pm}0.04%$), solid-not-fat ($11.24%{\pm}0.02%$), total solids ($18.05%{\pm}0.05%$), protein ($5.15%{\pm}0.06%$) and casein ($3.87%{\pm}0.04%$) contents followed by buffalo milk. Maximum whey proteins were observed in camel milk ($0.80%{\pm}0.03%$), buffalo ($0.68%{\pm}0.02%$) and sheep ($0.66%{\pm}0.02%$) milk. The non-protein-nitrogen contents varied from 0.33% to 0.62% among different milk species. The highest r-values were recorded for correlations between crude protein and casein in buffalo (r = 0.82), cow (r = 0.88), sheep (r = 0.86) and goat milk (r = 0.98). The caseins and whey proteins were also positively correlated with true proteins in all milk species. A favorable balance of branched-chain amino acids; leucine, isoleucine, and valine were found both in casein and whey proteins. Leucine content was highest in cow ($108{\pm}2.3mg/g$), camel ($96{\pm}2.2mg/g$) and buffalo ($90{\pm}2.4mg/g$) milk caseins. Maximum concentrations of isoleucine, phenylalanine, and histidine were noticed in goat milk caseins. Glutamic acid and proline were dominant among non-essential amino acids. Conclusively, current exploration is important for milk processors to design nutritious and consistent quality end products.

• KSBB Journal
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• v.5 no.3
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• pp.241-246
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• 1990

ATP analogs were immobilized or bovine caseins by the action of transglutaminase. The ATP analogs immobilized on the caseins were enzymatically active and interconverten by kinases. The immobilized ATP was dephosphorylated to the corresponding ADP by hexokinase and rephosphorylated to the ATP in solid form by acetate kinase. Under the conditions chosen, about 55% of the immobilized ATP was dephosphorylated and about 80% of the resulted ADP was rephosphorylated. Bovine $\beta$-casein was more useful than $\alpha$sf-casein as a carrier and C8-substituted ATP analognwas more effective than N6-substituted one in immobilization. Michaelis constant of C8-substituted ATP analog immobilized on $\beta$-casein was similar to that of free form of ATP and that of ATP analog. The immobilized ATP was much more stable than free ATP and its analog, while maximum velocity was reduced to 37% of the free ATP analog. The immobilized ATP was recovered almost completely by calcium precipitation.

• 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.

• Korean Journal of Animal Reproduction
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• v.16 no.2
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• pp.87-102
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• 1992

A rapid, sensitive, and specific enzyme-linked immuno-sorbent assay (ELISA) for bovine casein was developed. Biotinylated casein and peroxidase-conjugated avidin were used in the assay with antibody separated from yolks of immunized hens. Caseins were biotinylated with sulfo-N-hydroxy succinimido biotin and peroxi-dase-conjugated avidin bound the biotinylated casein which became bound to immobilized anti-body on a microplate. The antibodies were specific for bovine $\alpha$- and $\beta$-caseins, and their cross-reactivities with whey proteins, IgG, and serum albumin from bovine were not detectable by ELISA and Western blot. Various sensitivities ranging from 2ng/ml to 20${\mu}\textrm{g}$/ml of casein were achieved, and were controlled by adding vanous concentrations of the biotinylated casein. Parallelism was observed between standard and sample curves. The coefficients of variation of intra-assays and inter-assays from the most sensitive assay were 5.5 and 5.7%, respectively, at the 50% displacement. Casein contents of peripaturient milk samples showed that casein secretion rapidly increased 3d prepartum.

• Food Science of Animal Resources
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• v.20 no.1
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• pp.8-14
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• 2000

In order to examine physicochemical gelation behavior of ultra high temperature(UHT) pasteurized milk during storage at 4$^{\circ}C$ and 25$^{\circ}C$, pH, electrophoresis, alcohol test, sialic acid contents and free amino groups contents were biweekly determined. The pH of UHT pasteurized milk decreased with increasing storage time. Gelation of the UHT milk occured faster at 25$^{\circ}C$ than at 4$^{\circ}C$ with larger decreasing rate of pH. The alcohol test showed positive results at lower pH than 6.5, which could indicate the casein instability and beginning of gelation. The electrophoretic patterns showed a decrease in the concentrations of all caseins. Degradation of k-casein was faster in all cases, while $\alpha$-casein and $\beta$-casein were also extensively degraded later. The sialic acid contents of the samples increased gradually during storage, and the increasing rate was higher before gel formation. The free amino groups of the samples increased gradually during storage. The increasing rate of free amino groups was faster at 25$^{\circ}C$ than at 4$^{\circ}C$. The samples stored at 25$^{\circ}C$ gelled earlier than those stored at 25$^{\circ}C$, with corresponding increase of free amino groups. The residual proteolytic enzymes, which survived during the UHT heat treatments and were reactivated during storage, could be responsible for UHT pasteurized milk gelation during storage. It is assumed that proteolytic degradation of caseins followed by aggregation would be attributable to complicated reaction mechanism.

• Applied Biological Chemistry
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• v.38 no.3
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• pp.254-258
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• 1995

Various artificial casein micelle systems were prepared from dephosphorylated whole casein, ${\beta}$- or ${\kappa}$-casein and their stabilities towards ethanol were assessed. Ethanol stability was lower in the micelle systems with dephesphorylated whole casein as compared to the artificial micelles prepared from native whole casein, and the stability decreased with the extent of dephosphorylation. The casein micelles with partially dephosphorylated ${\kappa}$-casein had a lower ethanol stability than those with native ${\kappa}$-casein. Ethanol stability of the micelle system with dephosphorylated ${\beta}$-casein decreased as the degree of dephosphorylation increased. Progressive dephosphorylation of caseins in skim milk system resulted in a decrease of the stability towards ethanol. The decrease was less than that in the system with dephosphorylated individual caseins. Increase in pH of the artificial casein micelle systems in the range of $6.3{\sim}7.2$ led to an increased ethanol stability manifesting that the presence of serine phosphates contributes significantly to the stability towards ethanol.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.9
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• pp.1127-1136
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• 2010

Yogurt gels are a type of soft solid, and these networks are relatively dynamic systems that are prone to structural rearrangements. The physical properties of yogurt gels can be qualitatively explained using a model for casein interactions that emphasizes a balance between attractive (e.g., hydrophobic attractions, casein cross-links contributed by calcium phosphate nanoclusters and covalent disulfide cross-links between caseins and denatured whey proteins) and repulsive (e.g., electrostatic or charge repulsions, mostly negative at the start of fermentation) forces. Various methods are discussed to investigate the physical and structural attributes of yogurts. Various processing variables are discussed which influence the textural properties of yogurts, such as total solids content, heat treatment, and incubation temperatures. A better understanding of factors contributing to the physical and structural attributes may allow manufacturers to improve the quality of yogurt.

• Journal of Dairy Science and Biotechnology
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• v.39 no.4
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• pp.166-171
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• 2021

Since 1903, the International Dairy Federation (IDF) has been providing information on policies, standards, and regulations of the dairy industries to reach a global consensus on how to help feed the world with safe and sustainable dairy products. The 2021 IDF Global Dairy Conference was held in Copenhagen, Denmark with the theme of 'A Changing Climate for Dairy' for three days from the 13^th to the 15^th of October. Over 350 worldwide participants came together were expected to come together with several hundred additional online participants. An interesting topic among those presented at the conference was artificial milk at the Processing & Technology session on October 14^th. Dr. Eisner presented "Milk by Fermentation", in which he presented the technique of culturing and manufacturing artificial milk, based on artificially producing the caseins and enzymes through precision fermentation, which is suitable for making artificial cheeses. During the conference, the IDF launched the latest edition of the publication on global dairy markets, titled the World Dairy Situation Report 2021. According to report, South Korea is ranked 3^rd in the world for cheese imports.

• Journal of Animal Science and Technology
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• v.58 no.3
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• pp.10.1-10.10
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• 2016

Background: Airag, alcoholic sour-tasting beverage, has been traditionally prepared by Mongolian nomads who naturally ferment fresh mares' milk. Biochemical and microbiological compositions of airag samples collected in Ulaanbaatar, Mongolia and physiological characteristics of isolated lactic acid bacteria were investigated. Methods: Protein composition and biochemical composition were determined using sodium dodecyl sulfate-gel electrophoresis and high performance liquid chromatography, respectively. Lactic acid bacteria were identified based on nucleotide sequence of 16S rRNA gene. Carbohydrate fermentation, acid survival, bile resistance and acid production in skim milk culture were determined. Results: Equine whey proteins were present in airag samples more than caseins. The airag samples contained 0.10-3.36 % lactose, 1.44-2.33 % ethyl alcohol, 1.08-1.62 % lactic acid and 0.12-0.22 % acetic acid. Lactobacillus (L.) helveticus were major lactic acid bacteria consisting of 9 isolates among total 18 isolates of lactic acid bacteria. L. helveticus survived strongly in PBS, pH 3.0 but did not grow in MRS broth containing 0.1 % oxgall. A couple of L. helveticus isolates lowered pH of skim milk culture to less than 4.0 and produced acid up to more than 1.0 %. Conclusion: Highly variable biochemical compositions of the airag samples indicated inconsistent quality due to natural fermentation. Airag with low lactose content should be favorable for nutrition, considering that mares' milk with high lactose content has strong laxative effect. The isolates of L. helveticus which produced acid actively in skim milk culture might have a major role in production of airag.