• Journal of Dairy Science and Biotechnology
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• v.31 no.2
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• pp.109-125
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• 2013

Recently, functional foods and bioactive components in foods have drawn the attention and interest of food scientists, nutritionists, health professionals, and general consumers. Bioactive whey protein is a highly concentrated milk serum isolate or concentrate, which is high in protein (80~90% protein by weight), carbohydrate- and sugar-free, and nonfat or very low in fat. Bioactive whey protein enhances both healthy and deficient immune systems. In general, ultrafiltered whey protein contains various whey protein concentrate peptides, which could be used for manufacturing probiotics added to health beverages. Hence, the objective of this paper was to review the published literature on research of new functionally improved health beverages using various bioactive components extracted from milk and dairy products.

• Korean Journal of Microbiology
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• v.43 no.3
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• pp.222-226
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• 2007

Proteases are degradative enzymes which hydrolyze a peptide bond between amino acids and they are abundantly applied to commercial field. In order to screen new source of pretense, bacteria secreting extracellular pretense were isolated by enrichment culture from deep sea water samples of East Sea, Korea. A bacterium, named as HJ19, showed the best growth and the largest clear zone in plates supplemented skim milk at $30^{\circ}C$. The partial DNA sequence analysis of the 16S rRNA gene, phenotypic tests and morphology identified that this strain was In genus Micrococcus. The strain HJ19 could not grow at $10^{\circ}C$ but it started growth and showed pretense activity at $20^{\circ}C$. The optimal growth was at $37^{\circ}C$ and the maximal protease activity at $30^{\circ}C$ was about 480unit/ml.

• 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.31 no.2
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• pp.263-270
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• 2002

In the recent studies, many researchers are interested in foods as functional components rather than nutrient sources. Cow's milk is considered as an excellent food sources because of its many nutrients. Casein is a major milk protein and has been reported to have hyperlipidemic and hypercholesterolemic effects. But several reporters have suggested that peptide fractions and hydrolysate of casein have hypolipidemic effects differing from intact protein, casein. Therefore, the objective of the study was to investigate how the casein peptide fractions affect lipid metabolism in rats fed normal or high fat diets. The peptide fractions and hydrolysate of casein were obtained by casein hydrolysis with trypsin. The male rats (Sprague-Dawley), weighing approximately 150 g, were fed each experimental diet containing casein (CAS), casein hydrolysate (CH), casein hydrolysate precipitate (Cpt) and two kinds of peptide fractions (CL & CB) for three weeks, respectively. In the exit I, the male rats were fed normal fat diets (7% soybean oil & cholesterol-free; Expt. I), and in the expt II, fed high fat diets (18% beef tallow & 1% cholesterol; Expt. II). Crude protein contents were calculated from nitrogen contents. Amino acid composition of each fraction was also analyzed. The concentration of total lipid, total cholesterol and triglyceride in serum, liver and feces were measured. As the results of study, tole rats fed peptide fractions with normal fat diets (Expt. I) had no effects on total lipid, total cholesterol and triglyceride concentration in serum and liver and fecal excretion. However, in the rats fed hydrophobic casein peptide fractions (CB) with high fat diet, fecal lipids excretion were significantly increased and the lipids concentration of serum and those of liver tended to decrease, numerically.

• Food Science of Animal Resources
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• v.18 no.2
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• pp.157-163
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• 1998

This study was carried out to examine that pepsin-hydrolyzed bovine lactoferrin has applicabilities which are market milk and dairy products. The stability of pepsin-hydrolyzed bovine apo-lactoferrin and the change of its antibacterial character has been studied under various method for pasteurization (LTLT; 65$^{\circ}C$ / 30min., HTST ; 75$^{\circ}C$ / 15sec., UHT ; 135$^{\circ}C$ / 3sec.) and pH Values (pH 2.0, pH 4.0, pH 6.8). The ehated samples were assayed for minimal bacteriocidal concentrations (MBCs) and bacteriocidal effect against E. coli. The results obtained were summarized as follows: After fractionation of pepsin-hydrolyzed bovine lactofeerin by gel filtration. several peptide fractions were found that had strong antibacterial activity. SDS-PAGE showed that the one of these fractions with strong antibacterial activity, which had a molecular mass a range of 30∼33KDa. The MBCs for pepsin-hydrolyzed bovine lactoferrin fraction No. 2 against E. coli required to cause complete inhibition of growth varied within the range of 200∼400 $\mu\textrm{g}$/ml, depending on heat treatments and pH conditions. The peptide fraction No. 2 showed strong bacteriocidal activity against E. coli at LTLT and HTST treatments under acidic pH conditions. and was reduced activity at UHT treatment under pH 6.8 condition.

• Journal of Dairy Science and Biotechnology
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• v.41 no.1
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• pp.34-43
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• 2023

Hydrolysis of whey-derived proteins using lactic acid bacteria (LAB) utilizes the mass culture method and fermentation of LAB to produce effective bioactive peptides. Whey protein has the biological potential of its precursors, but the active fragments may not be released depending on the hydrolysis method. As an alternative to these problems, the nutritional and bioactive functionality of the hydrolysis method have been reported to be improved using LAB for whey protein. Peptide fractions were obtained using a sample fast protein liquid chromatography device. Antioxidant activity was verified for each of the five fractions obtained. In vitro cell experiments showed no cytotoxicity and inhibited nitric oxide production. Cytokine (IL [interleukin]-1α, IL-6, tumor necrosis factor-α) production was significantly lower than that of lipopolysaccharides (+). As a result of checking the amino acid content ratio of the fractions selected through the AccQ-Tag system, 17 types of amino acids were identified, and the content of isoleucine, an essential amino acid, was the highest. These properties show their applicability for the production of functional products utilizing dietary supplements and milk. It can be presented as an efficient method in terms of product functionality in the production of uniform-quality whey-derived peptides.

• Analytical Science and Technology
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• v.30 no.6
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• pp.348-354
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• 2017

In this study, patterns of proteome expression were monitored and specifically expressed proteins in human milk were detected in collected human milk after 1 week, 3 weeks, and 6 weeks from delivery. A quantitative shotgun proteomic approach was used to identify human milk proteins and reveal their relative expression amounts. For each sample, two independent human milk samples from two mothers were pooled, and then three replicated shotgun proteomic analyses were carried out. Casein, which is a highly abundant protein in human milk, was removed, and then trypsin was treated to produce a digested peptide mixture. The peptides were loaded in the home-made reversed-phase C18 fused-silica capillary column, and then the eluted peptides were analyzed by using a linear ion-trap mass spectrometer. The relative quantitation of proteins was performed by the normalized spectral count method. For each sample, 81-109 non-redundant proteins were identified. The identified proteins consisted of glycoproteins, metabolic enzyme, and chaperon enzymes such as lactoferrin, carboxylic ester hydrolase, and clusterin. The comparative analysis for the 63 proteins, which were reproducibly identified in all three replications, revealed that 25 proteins were statically significant differentially expressed. Among the differentially expressed proteins, Ig lambda-7 chain C region and tenascin drastically decreased with the delivery time.

• Journal of Dairy Science and Biotechnology
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• v.16 no.2
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• pp.98-105
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• 1998

Various peptides derived from food are among the most potent physiologically active agents known, and include anticancer peptides, angiotensin converting enzyme(ACE) inhibitor exhibiting antihypertension action, opioid peptides, antithrombotic peptides, hypocholesterolemic peptides, immunomodulators, calcium absorption enhancers, and other peptides. Hydrophobic peptides extracted from a Cheddar-type cheese slurry were fractionated by gel chromatography and repeated HPLC. A peptide fraction from HPLC showed high cytotoxicity on the tumor cell lines such as a human colon carcinoma, and comprised of Tyr, Ser, Leu, Gly, and others. Hypocholesterolemic peptides were isolated from peptic hydrolyzates of casein and soy proteins. Macropeptides of 1,000${\sim}$5,000 dalton were effective on reducing the cholesterol level of mouse serum. Peptides showing high Krigbaum hydrophobicity and ANS surface hydrophobicity resulted in high hypocholesterolemic effect and fecal steroid concentrations. Caseinomacropeptides(CMP) were isolated from whey powder and treated with soluble and immobilized trypsin to obtain antithrombotic peptides. One fraction from the CMP hydrolyzed with immobilized trypsin for 24h exhibited high antithrombotic activity with 52.5% inhibition of platelet aggregation. These result suggested that peptides from various milk products could be utilized as a good bioactive agents for developing health functional foods.

• 한국유가공학회:학술대회논문집
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• 1998.05a
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• pp.22-29
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• 1998

Various peptides derived from food are among the most potent physiologically active agents known, and include anticancer peptides, angiotensin converting enzyme(ACE) inhibitor exhibiting antihypertension action, opioid peptides, antithrombotic peptides, hypocholesterolemic peptides, immunomodulators, calcium absorption enhancers, and other peptides. Hydrophobic peptides extracted from a Cheddar-type cheese slurry were fractionated by gel chromatography and repeated HPLC. A peptide fraction from HPLC showed high cytotoxicity on the tumor cell lines such as a human colon carcinoma, and comprised of Tyr, Ser, Leu, Gly, and others. Hypocholesterolemic peptides were isolated from peptic hydrolyzates of casein and soy proteins. Macropeptides of 1,000${\sim}$5,000 dalton were effective on reducing the cholesterol level of mouse serum. Peptides showing high Krigbaum hydrophobicity and ANS surface hydrophobicity resulted in high hypocholesterolemic effect and fecal steroid concentrations. Caseinomacropeptides (CMP) were isolated from whey powder and treated with soluble and immobilized trypsin to obtain antithrombotic peptides. One fraction from the CMP hydrolyzed with immobilized trypsin for 24h exhibited high antithrombotic activity with 52.5% inhibition of platelet aggregation. These results suggested that peptides from various milk products could be utilized as a good bioactive agents for developing health functional foods.

• Journal of Dairy Science and Biotechnology
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• v.39 no.1
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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.