• 한국식품과학회지
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• 제19권2호
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• pp.140-145
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• 1987

폴리에틸렌 글라이콜-덱스트란 흔합수용액이 형성하는 수용액 2상계에서 표면 소수성의 크기를 알고 있는 표준 단백질들의 분획계수를 관찰하였다. 또한 폴리에틸렌 글라이콜(PEG)에 palmitate를 부착시킨PEG-P를 첨가함으로써 상층부의 소수성을 증가 시켰을때 단백질들의 분획계수 변화를 조사하였다. PEG/dextran 2상계에서 단백질의 분획계수는 딘백질의 유효 소수성에 관계없이 2상계의 용적비가 동일한 조건에서 PEG와 dextran의 농도가 함께 증가함에 따라 분획계도 증가하였다. 그러나 PEG에 78%친환도를 가지는 PEG-P를 소량 첨가하여 만든 2상계에서는 유효 소수법이 큰 bovine serum albumin과 $\beta-lactoglobulin$의 분획계수가 10배 이상 증가하였고. 유효 소수성이작은 ovalbumin은 큰 변화를 보이지 않았다. 이러한 분획계수의 급격한 중가는 PEG-P의 첨가량이 아주 낮은 2% 수준일 때 나타났으며 그 이상 침가시에는 모든 단백질이 공히 10% 첨가될때까지 완만히 증가하는 경향을 나타내었다.

• 한국축산식품학회지
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• 제26권1호
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• pp.121-126
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• 2006

Major milk proteins have considerable variane which comes from substitution and deletions in their amino arid sequences. Variants in genes that code for milk proteins, such as ${\beta}$-lactoglobulin (${\beta}-LG$) have been established as genetic markers for milk production and milk protein composition in dairy cattle. The effect of ${\beta}-LG$ variant on milk production traits, such as milk yield. fat yield, protein yield, fat percentage and protein percentage, was estimated for 482 Holstein cows in the first lactation. The ${\beta}-LG$ variants were determined by PCR-RFLP technique at the DNA level. Single trait linear model was used for the statistical analysis of the data. Results of this study indicated that ${\beta}-LG$ variants affected significantly protein yield (p<0.05) and fat percentage (p<0.05). Animals with the AA variant produced 31kg of milk protein more than animals with the BB variant. On the contrary, cows with the BB variant had fat percentage higher by 0.35 and 0.32% compared with cows with the AA and AB variants, respectively. No associations between the ${\beta}-LG$ variants and milk yield, protein percentage and fat yield were found Therefore, milk production traits could be improved through ${\beta}-LG$ typing by increasing the frequency of A variant for protein yield or the frequency of B variant for fat content in Holstein dairy cattle population.

• Preventive Nutrition and Food Science
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• 제3권2호
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• pp.143-151
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• 1998

Protein -surfactant interactions have been investigate by measuring ζ-potential of $\beta$-lactoglobulin-coated emulsion droplets and $\beta$-lactoglobulin in solution in the rpesenceof surfactant, with particular emphasis on the effect of protein heat treatment(7$0^{\circ}C$, 30min). When ionic surfactant (SDS or DATEM) is added to the protein solution, the ζ-potential of the mixture is found to increase with increasing surfactant concentration, indicating surfactant binding to the protein molecules. For heat-denatured protein,it has been observed that the ζ-potential tends to be lower than that of the native protein. The effect of surfactant on emulsions is rather complicated .With SDS, small amounts of surfactant addition induce a sharp increase in zeta potential arising from the specific interaction of surfactant with protein. With further surfacant addition, there is a gradual reductio in the ζ-potential, presumably caused by the displacement of adsorped protein (and protein-surfactant complex) from the emulsion droplet surfac by the excess of SDS molecules. At even higher surfactant concentrations, the measured zeta potential appears to increase slightly, possibly due to the formation of a surfactant measured zeta potential appears to increase slightly, possibly due to the formation of surfactant micellar structure at the oil droplet surface. This behaviour contrastswith the results of the corresponding systems containing the anionic emulsifier DATEM, in which the ζ-potential of the system is found to increase continuously with R, particularly at very low surfactant concentration. Overall, such behaviour is consisten with a combination of complexation and competitive displacement between surfactant and protein occurring at the oil-water interface. In addition, it has also been found that above the CMC, there is a time-dependent increase in the negative ζ-potential of emulsion droplets in solutions of SDS, possibly due to the solublization of oil droplets into surfactant micelles in the aqueous bulk phase.

• Animal Bioscience
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• 제34권8호
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• pp.1283-1289
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• 2021

Objective: The progestogen-associated endometrial protein (PAEP) gene encodes the main whey protein in milk, β-lactoglobulin. The aim of the study was to investigate polymorphism in the PAEP gene and its association with milk yield, composition, and quality. Methods: Test-day records for 782 dairy cows were analysed. A total of 10 single nucleotide polymorphisms (SNP) within the PAEP gene were investigated. The following parameters were recorded: milk yield (MY, kg/d), percent milk fat (%), protein (PP, %), dry matter (DMP, %) and lactose (LP, %), urea content (UC, mg/L) as well as natural logarithm for somatic cell count (LnSCC, ln). Effect on genomic estimated breeding values accuracy was evaluated with pedigree and single step model. Results: Results show that only three SNPs were polymorphic, creating 5 composite genotypes: P1 to P5. Differences in MY between composite genotypes were noted in the two tested herds. Cows with P5 composite genotypes were characterised by the highest PP and LnSCC and the lowest LP and UC (p<0.05). P4 was linked to an increased DMP and UC, while P3 to an increase in LP and decrease in PP and LnSCC. Both factors are important markers in herd management and have high influences on the herds economics. For 5 out of 7 traits the accuracy of prediction was improved by including the haplotype as a fixed effect. Conclusion: Presented results may suggest a new way to optimise breeding programmes and demonstrate the impact of using genomic data during that process.

• 한국축산식품학회지
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• 제22권1호
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• pp.59-65
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• 2002

이 연구는 Whey배지에 Whey protein concentrate 80% (WPC-80)와 Whey protein isolate(WPI)를 첨가하여 B. bifidum Bb-11의 생장촉진효과를 알아보고자 실시하였다. 또 이 단백질들의 구성성분인 $\alpha$-Lactalbumin과 $\beta$-Lactogluburin을 trypsin으로 처리하여 얻어진 분해물을 분자량에 따라 분획하여 각 분획별로 그 효과를 구명하였으며, 그 결과를 요약하면 다음과 같다. WPC 첨가에 의한 효과는 대조구에 비하여 생장촉진효과가 있는 것으로 나타났으나, 첨가농도에 따른 차이는 근소하였다. WPI는 뚜렷한 생장촉진효과를 보여주지 못하였으며, 첨가량이 많을수록 생장이 억제되었다. 두 종류의 유청단백질을 4$0^{\circ}C$에서 6시간 동안 trypsin처리한 후 UF처리에 의하여 분획하고 각 분획들을 Centricon-30 으로 농축한 후, 얻어진 $\alpha$-lactalbumin 분해물 3분획에 대한 단백질농도는 각각 11.63mg, 7.79mg 및 5.21mg 이었고, $\beta$-Lactoglubulin 분해물 3분획은 각각 4.12mg, 5.30 mg 및 9.35mg 이었다. $\alpha$-Lactalbumin분해물 세 분획 모두 대조구에 비하여 높은 생장촉진효과를 나타내었으며, 그중에서 분자량 10,000~3,000Da(F-II)과 3,000Da 이하(F-III)의 두 분획이 모두 높게 나타난 것으로 보아, 분자량 10,000Da 이하의 peptide들이 bifidobacteria의 생장을 향상시키는 것으로 밝혀졌다. $\beta$-Lactoglubulin 분해물 세 분획들도 대조구에 비하여 생장이 좋게 나타났다. 분자량 10,000Da 이하의 peptide를 함유하는 두 분획은 생장이 우수하였으며 배양 24 시간후에는 분자량 3,000Da 이상의 두 분획(F-I, F-II)이 대조구에 비하여 빠르게 생장이 저하된 반면, 분자량 3,000 Da이하의 분획(F-III)에서는 계속적인 생장촉진효과를 보여주었다.

• 한국생활과학회지
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• 제5권1호
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• pp.75-80
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• 1996

The immunogenecity of low molecular weight ($MW{\le}30,000$) immunogens in laying hens was investigated. Immunogens were insulin derivatives and ${\beta}$-lactoglobulin(${\beta}-Lg$). Insulin derivatives were reduced- carboxymethylated(RCM) insulin, and RCM-A and RCM-B chain of insulin. The yolk antibodies against RCM-A chain of insulin appeared after the first immunization. The yolk antibodies against RCM-B chain of insulin were elicited 5 weeks after the third booster injection. Although the anti-RCM-B chain yolk antibodies recognized native insulin, the anti-RCM-A chain yolk antibodies didn't native insulin. The anti-RCM insulin yolk antibodies were induced after the second booster injection and showed cross-reactivities with native insulin. On the other hand, ${\beta}-Lg$ showed stronger immunogenecity than insulin derivatives. The $anti-{\beta}-Lg$ yolk antibodies were produced after the second booster injection and the peak titer was reached 3 weeks after the third booster injection.

• Food Science and Biotechnology
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• 제14권1호
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• pp.131-136
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• 2005

The selective extraction behavior of lactoferrin (Lf) from whey protein mixture was examined using reverse micelles formed by the cationic surfactant, cetyldimethylammonium bromide (CDAB). The major whey proteins, including ${\beta}$-lactoglobulin, ${\alpha}$-lactalbumin and bovine serum albumin, were solubilized from aqueous phase to organic phase while Lf was recovered in the aqueous phase. The solubilization behaviors of the proteins were manipulated by the process parameters such as the pH and salt concentration of the aqueous phase and the surfactant concentration in the organic phase. Efficient forward extraction was achieved with sodium borate buffer (50 mM, pH 9) containing 50 mM KCl and organic phase containing 100 mM CDAB. Based on SDS-PAGE and densitometry, about 96% of the initial Lf remained in the aqueous phase after forward extraction. The dialyzed Lf fully maintained its bacteriostatic activity against E. coli O157:H7.

• Preventive Nutrition and Food Science
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• 제3권2호
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• pp.133-142
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• 1998

Effects of protein heat treatment and surfactant additionoo the orthokindetic stability of $\beta$-lactoglobulin-stabilized emulsions have been investigated under turbulent flow conditions. In studies on protein-stabilized emulsions, samples which had been subjected to heat treatment(i.e. the protein solution orthe emulsion) have been found to be more prone to orthokinetic coalescene than the untreated ones. The emulsions stabilized with protein heated above the denaturation temperature(i.e. 7$0^{\circ}C$) showed the bigger initial average droplet size, which resulted in an increased orthokinetic coalescenece rate. The storage of the protein-stabilized emulsion at high temperature prior to the shearing experiment also made the emulsion less stable in the shear field. Interestingly. the addition of DATEM has been found to produce a substantial increase in orthokinetic stability of the heat-denatured protein-stabilized emulsion system, although Tween 20 is the opposite case.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2001년도 춘계학술발표대회
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• pp.49-49
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• 2001

To elucidate overall changes in DNA methylation that occurs by inappropriate epigenetic control during ageing, we compared fetal bovine fibroblasts and their aged neomycin-resistant versions using bisulfite-PCR technology. Reduction in DNA methylation was observed in euchromatic repeats (18S-rRNA/art2) and promoter regions of sing1e-copy genes (the cytokeratin/-lactoglobulin/interleukin-13 genes). Contrastingly, a stable maintenance of DNA methylation was revealed in various heterochromatic sequences (satellite I/IIalphoid and Bov-B). The differential inheritance modes of DNA methylation was confirmed through the analysis of individual neomycin-resistant clones. These global, multi-loci analyses provide evidence on the tendency of differential epigenetic modification between genomic DNA regions during ageing.

• 한국식품과학회지
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• 제26권5호
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• pp.532-538
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• 1994

Chymotrypsin, trypsin, pancreatin, 그리고 Aspergillus oryzae 유래 단백질분해효소의 in vitro 처리에 의하여 유청단백질(WPI)의 가수분해물(WPH)중 ${\beta}-LG$유래의 항원성변화를 조사하기 위하여 토끼 항${\beta}-LG$항혈청을 이용한 competitive inhibition ELISA(cELISA)와 heterologous PCA를 실시하였다. cELISA에 의하여 WPH의 monovalent항원성을 분석한 결과, 전체적으로 ${\beta}-LG$유래의 monovalent항원성은 효소처리에 의하여 $10^{-1.7}{\sim}10^{-4.1}$배 또는 그 이하로 저하되었으며, 특히 pepsin전처리후 Asp. oryzae유래의 효소로 가수분해한 경우(OUP)의 항원성은 거의 상실되었다. Guinea pig를 이용한 PCA test에 의하여 ${\beta}-LG$유래의 polyvalent항원성을 분석한 결과, WPH의 항원성은 $1/2{\sim}1/128$ 또는 그 이하로 저하되었다. 특히, WPH중에서 열변성이나 pepsin의 전처리없이 Asp. oryzae유래의 효소로 가수분해한 경우(OUN), 가수분해도(DH)가 그다지 높지 않고 monovalent항원성도 여전히 잔존하였음에도 불구하고($10^{-3.2}$배로 저하) 알레르기의 발증과 밀접한 관련이 있는 polyvalent항원성은 거의 상실되었다. 이는 OUN의 분해효율이 아주 높지는 않으나 ${\beta}-LG$상의 항원결정기가 효과적으로 파괴되어, polyvalent항원성이 제거되었기 때문으로 추측된다. 이 결과는, Asp. oryzae유래의 효소를 WPI에 처리하면 우유 알레르기의 주요 원인물질인 ${\beta}-LG$의 polyvalent항원성이 제거됨으로써 저알레르기성 infant formula용 WPH가 제조될 수 있음을 시사하고 있다.