• Journal of Dairy Science and Biotechnology
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• 제41권3호
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• pp.149-156
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• 2023

Milk protein is often fractionated/concentrated by using various techniques in dairy industries. Among these techniques, ultrafiltration (UF) is particularly efficient at concentrating the casein fraction of milk protein. The objectives of this study were to produce casein hydrolysates by concentrating the casein fraction in skim milk using the UF technique and to investigate the chemical composition of the casein hydrolysates. The skim milk was concentrated using a UF laboratory test unit equipped with 10 kDa and 30 kDa membranes. After UF, the protein content of the milk was concentrated up to ~7.2% and the Ca was concentrated up to ~196 mg/100 g of milk. Trypsin was then added to the concentrated skim milk to produce the casein hydrolysates. The results of sodium dodecyl sulphate-polyacrylamide gel electrophoresis showed that the casein fraction was not present after hydrolysis, indicating that casein in the milk had been hydrolyzed. The Ca content in the casein hydrolysates was much higher (p<0.05) compared to Ca content in commercial casein phosphopeptides (CPP) indicating that was acidified during the manufacture of commercial CPP. In conclusion, it seems that casein hydrolysates containing large concentrations of protein and Ca can also be made from concentrated UF milk without acidification or renneting.

• Journal of Dairy Science and Biotechnology
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• 제39권1호
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• pp.36-50
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• 2021

This study aimed to evaluate the biological potential of functional food, i.e., specific peptides obtained from the hydrolysis of milk protein, by assessing their antioxidant and antibacterial properties. For the preparation of casein hydrolysates, commercial enzymes were added to 10% casein solution in a 1:200 (w/v) ratio, and samples were collected each hour. Based on the assessment of the degree of hydrolysis (DH) of casein hydrolysates, it was observed that the concentration of all enzymatic hydrolysates increased rapidly from 30 to 40 minutes. However, no change was observed in their concentrations after 150 minutes. Protamex® and Neutrase® exhibited the highest DH when compared to other enzymes. Furthermore, SDS-PAGE was performed for analyzing the proteolytic pattern of each enzyme, except for Flavourzyme®, and peptides in the size range of 20-25 kDa were identified. Subsequently, peptides produced by two enzymes were isolated using a preparative liquid chromatography system. Overall, NF3, NF4, PF5, and PF6 showed higher antioxidant potential than other peptide fractions. Moreover, NF7 and PF3 exhibited the highest antibacterial activity. In this study, we evaluated the biological potential of novel casein-derived peptides that may find application in the food and healthcare industry.

• 한국식품영양과학회지
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• 제39권4호
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• pp.587-594
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• 2010

다양한 기능적 특성을 가지는 단백질 가수분해물의 개발을 위하여, casein, ISP, wheat gluten, gelatin의 4종류 단백질 기질을 alcalase, bromelain, papain, neutrase, trypsin 등의 효소를 이용하여 가수분해물을 제조하였다. 각 단백질에 대한 효소 분해과정을 확인하기 위하여 pH-stat 방법을 이용하여 시간에 따른 단백질 가수분해도(DH)를 측정하였고, 단백질 종류와 효소 종류에 의한 쓴맛 정도와 단백질 가수분해물의 용해성을 검토하고자 DH 10%에서 가수분해를 종결짓고, pH 6.5에서 각각의 용해성과 쓴맛을 NSI(nitrogen soluble index) 측정과 관능검사로 비교하였다. 시간에 따른 가수분해도는 단백질에 따라 다양하게 나타났으며, Casein, ISP, wheat gluten, gelatin의 순으로 높게 나타났다. 모든 단백질에서 alcalase의 가수분해도가 가장 높았으며, neutrase, bromelain, papain의 가수분해도는 비슷한 정도를 보였다. 그러나 trypsin의 경우는 casein에서는 매우 높았지만, ISP에서는 가장 낮았다. DH 10%에서 casein은 trypsin 가수분해물이, ISP와 gluten은 brolmelain과 neutrase 가수분해물이, gelatin의 경우 사용된 모든 효소 가수분해물이 쓴맛이 약하고 용해도가 높아 좋은 기질-효소 조합으로 선택될 수 있었다. 따라서 쓴맛이 적고 용해도가 높은 단백질 가수분해물은 가수분해도의 조절과 단백질과 효소 조합의 선택, 단백질 가수분해물의 농도 조절 등으로 얻을 수 있었다.

• 한국축산식품학회지
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• 제41권4호
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• pp.687-700
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• 2021

This study performed to evaluate the applicability of functional dairy food materials by comparing the calcium solubilization ability and anti-inflammatory effects of hydrolyzed casein protein. Commercial enzyme (Alcalase^®; Neutrase^®; Protamex^®; Flavourzyme^®) was added to the 10% casein solution to prepare the casein hydrolysates. Samples obtained every hour [1:200 (w/v)]. According to results of measuring the degree of hydrolysis (DH), all of four enzymatic hydrolysates increased rapidly from 30 to 40 min, and after 150 min, there were no change. Protamex^® and Neutrase^® had the highest DH compared to others enzymatic hydrolysates. After that, peptides obtained throughout a preparative liquid chromatography system. In the calcium solubility experiments, neutrase fraction (NF) 4 and NF7 showed similar activities with casein phosphopeptide (CPP). In vitro cell experiments showed that no cytotoxicity except for NF6. Also, the production of nitric oxide (NO) inhibited as the concentration of fraction samples increased. The cytokine (IL-1α, IL-6, and TNF-α) production was lower than lipopolysaccharide (+) group significantly. Therefore, the possibility of anti-inflammatory activity found in the hydrolyzed samples. According to the above experiments, NF3 and Protamex Fraction (PF) 3 selected. Amino acids selected throughout an AccQ-Tag system. As a result, 17 species of amino acids and several species of unknown amino acids identified. Both fractions had the highest content of phenylalanine. This study identified the potential of biologically active and functional peptides derived from casein that affect the food and dairy industry.

• Journal of Dairy Science and Biotechnology
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• 제21권2호
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• pp.97-104
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• 2003

본 연구에서는 우유 앨러지의 원인물질중의 하나인 casein단백질을 생체가 알르겐 물질로 인식할 수 없는 수준의 분자로까지 분해하여 항원성을 저감시키고 또한 풍미가 좋은casein분해물을 제조하기 위하여 분해특성이 다른 효소를 사용하여 만들어진 분해물의 특성과 항원성을 조사하였다. 박테리아 효소인 Neutrase, Alcalase, Protamex, Pescalase을 처리한 casein가수분해물의 평균분자량은 1,100~2,300 dalton이었고 곰팡이 효소인 MP, Flavourzyme, LP, Promod경우에는 거의 770 ~ 1,140 dalton범위였다. 항원성 저감정도를 측정하기 위하여 토끼항casein항혈청을 이용하여 ELISA억제시험을 실시한 결과 항체결합을 50%저해하는 미분해casein단백질의 농도는 $10^{3.6}$ng/ml였다. 박테리아 효소인 Neutrase, Alcalase, Protamex, Pescalase에 의한 Casein가수분해물의 값은 각각 $10^{4.8},\;10^{5.5},\;10^{5.9},\;10^{6.1}\;ng/ml$이었고, 곰팡이 효소인 MP, Flavourzyme, LP, Promod경우에는 각각 $10^{6.3},\;10^{6.3},\;10^{6.5},\;10^{6.8}\;ng/ml$로 나타났다. 박테리아와 곰팡이효소의 조합인 Fla+prota, Pro+prota처리구에서는 $10^{7.4},\;10^{7.3}ng/ml$로 나타났다. 따라서 미분해 casein의 항원성을 1로 하면, casein분해물의 항원성은 최고 1/8,000 이하로 저하되었다. 수신피부아나피랙시스반응(PCA)을 이용한 항원성시험에서 casein으로 피하 감작할 경우 푸른색 반점이 나타났으나 효소처리구에서는 이러한 반점이 나타나지 않아 충분히 항원성이 저감화 되었음을 확인하였다.

• 한국식품과학회지
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• 제30권1호
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• pp.218-223
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• 1998

우유 casein단백질을 alcalase로 가수분해시켰을 때, 생성되는 peptide 중 철분과 결합력이 있는 peptide인 IBP가 $immobilized\;Fe^{3+}\;affinity\;chromatography$에 의하여 용이하게 분리되었다. IBP의 분자량은 2,175 dalton이었으며 $pH\;6,\;37^{\circ}C$에서 1시간동안 일정량의 철분과 항온처리하였을 경우, 25, 50, 100 g/mL의 IBP는 각각 4.2, 5.7, 7.1 g의 철분을 가용화시키는 능력을 보였다. IBP는 proline (24.5 Mol%), lysine (15.7 Mol%), glutamic 또는 glutamine (14.9 Mol%) 등의 아미노산으로 구성되어 있었으며 이들의 N-terminal sequence는Met-Ala-Pro-Lys-His의 순으로 이루어져 있었다. 분자량, 아미산 조성, N-terminal sequence등의 결과를 종합해 보면 IBP는 casein 중 -casein의 아미노산 서열 $102{\sim}119$에 해당하는 18개의 아미노산으로 구성된 peptide임을 알 수 있었다.

• 동아시아식생활학회지
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• 제19권1호
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• pp.45-51
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• 2009

In this study, food protein hydrolysates were prepared from six types of food protein: purified meat protein, whole egg protein, casein, isolated soy protein, concentrated rice protein, and gluten. Food proteins were hydrolyzed with pepsin and ethanol (80%)-soluble fractions of pepsin hydrolysates were employed for analysis. The products were colorless and odorless powders with low fat content and good solubility. The MW (molecular weight) of the protein hydrolysates was confirmed to be $200{\sim}1,800$ via gel filtration. Free amino acid contents accounted for less than 5% of the samples. The results of our amino acid analysis revealed that all food protein hydrolysates preserved their original amino acid compositions and nutritional values of their source proteins with highly pure oligopeptide mixtures. These results show that the food protein hydrolysates prepared in these investigations should prove excellent dietary nitrogen sources for a variety of applications.

• 한국축산식품학회지
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• 제35권3호
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• pp.360-369
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• 2015

Milk proteins have many potential sequences within their primary structure, each with a specific biological activity. In this study, we compared and investigated the bioactivities of hydrolysates of the domestic (A, B) and imported (C, D) skim milk powders generated using papain digestion. MALDI-TOF analysis revealed that all milk powder proteins were intact, indicating no autolysis. Electrophoretic analysis of hydrolysates showed papain treatment caused degradation of milk proteins into peptides of various size. The antioxidant activity of the hydrolysates, determined using 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and total phenolic contents (TPC) assays, increased with incubation times. In all skim milk powders, the antioxidant activities of hydrolysates were highest following 24 h papain treatment (TPC: A, 196.48 μM GE/L; B, 194.52 μM GE/L; C, 194.76 μM GE/L; D, 163.75 μM GE/L; ABTS: A, 75%; B, 72%; C, 72%; D, 57%). The number of peptide derived from skim milk powders, as determined by LC-MS/MS, was 308 for A, 283 for B, 208 for C, and 135 for D. Hydrolysate A had the highest antioxidant activity and the most potential antioxidant peptides amongst the four skim milk powder hydrolysates. A total of 4 β-lactoglobulin, 4 α_s1-casein, and 56 β-casein peptide fragments were identified as potential antioxidant peptides in hydrolysate A by LC-MS/MS. These results suggest that domestic skim milk could have applications in various industries, i.e., in the development of functional foods.

• 한국축산식품학회지
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• 제22권1호
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• pp.87-93
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• 2002

최근 고혈압을 예방하기 위한ACE 저해 펩타이드에 대한 연구는 주로 여러 가지 식품 단백질의 효소 가수분해물로부터 얻어진 펩타이드를 중심으로 이루어지고 있다. 본 연구에서는 케이신을 여러 가지 상업용 단백질분해 효소를 사용하여 ACE저해 효과가 높은 가수분해물 제조시 가수분해 조건이 ACE저해효과에 미치는 영향을 알아보자 하였으며 적정 가수분해 조건을 설정하고자 하였다. ACE 저해효과를 가지는 케이신 가수분해 물을 제조하기 위한 효소 종류, 첨가량 및 가수분해시간은 효소는 Aspergillus oryzae 유래의 promod 192를 사용하고, 효소의 첨가량은 케이신에 대하여 1%, 반응시간은 47$^{\circ}C$에서 12시간으로 하는 것이 적당하였다. 이 때 케이신 가수분해물의 $IC_{50}$/값은 248.71ug/m1(통상법), 265.84ug/ml(전처리법)로서 ACE 저해효과가 높았다.

• Journal of Nutrition and Health
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• 제30권6호
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• pp.614-621
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• 1997

The experiments were performed to investigate the effects of protein and protein hydrolysates on lipid metabolism in the hyperlipidemic/hypercholesterolemic rat model induced by feeding fat-enriched diet. In Except 1 male rats were fed four semi-purified high fat and cholesterol diets that contained different nitrogen source, casein(C), casein hydrolysate(CH), corn gluten(G) and corn gluten hydrolysate(GH), for 6 weeks. In Expt. 2 rats were fed high fat and cholesterol diet for 4 weeks to induce hyperlipidemia and hypercholesterolemia. Then the rats were divided into 4 groups and were fed the four kinds of above experimental diets for 4 weeks consecutively. The contents of total lipid , cholesterol and triglyceride in blood, liver and feces were determined. Serum lipid concentrations of CH, G and GH were significantly lower than that of C. Serum cholesterol concentrations of hydrolysate groups(CH and GH) were significantly lower than those of intact protein groups(C and G). Serum HDL -cholesterol concentration tended to increase by hydrolysate intake. The total lipid, cholesterol contents in liver showed similarity results as above. Fecal lipid excretions of CH, G, and GH groups were significantly higher than that of C group. These results indicate that hypolipidemic and /or hypocholesterolemic effect of corn gluten or protein hydrolysates were detected in the process of inducing hyperlipidemia by high-fat and cholesterol diet or after inducing hyperlipidemia.