• Journal of the East Asian Society of Dietary Life
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• v.20 no.5
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• pp.680-686
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• 2010

Silk sericin protein was hydrolyzed by seven proteolytic enzymes in order to examine the effectiveness of the hydrolysates in binding calcium. The amino acid nitrogen content of hydrolysates from Flavourzyme was higher than that for other enzymes, and its calcium binding capacity showed a dose-dependent increase. We examined the effects of calcium binding peptide from sericin hydolysates on the bioavailability of Ca-deficient rats. Three-week-old male rats were fed an Ca-deficient diet for three weeks. Rats were divided into four groups (DD: non-treated group on calcium deficient diet; DD+MC: milk-calcium treated group; DD+OC: organic calcium made using sericin hydolysates; and DD+IC: inorganic calcium ($CaCl_2$). After oral administration of calcium supplements for one week, the calcium content of the serum and liver were significantly higher in DD+OC ($101.7{\mu}g$/mL and $49.3{\mu}g$/mL) and DD+MC ($83.6{\mu}g$/mL and $42.8{\mu}g$/mL) than DD ($86.3{\mu}g$/mL and $43.4{\mu}g$/mL). The alkaline phosphatase (ALP) content in the treated groups was significantly lower than DD, but no significant difference among groups was shown. Aspartate aminotransferase (AST) levels did not show any significant difference between groups. Alanine aminotransferase (ALT) levels were significantly reduced compared to the DD group. In conclusion, binding calcium to peptides from sericin hydrolysates seems to improve its bioavailability, and to hasten the cure of calcium deficiency in experimental rats.

• Food Science of Animal Resources
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• v.26 no.4
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• pp.511-516
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• 2006

The objectives of this study was to compare the probiotic characteristics of lactic acid bacteria (LAB) for their ability to assimilate cholesterol, production of bacteriocin, inhibition of angiotensin I-converting enzyme (ACE), and viability under artificial gastrointestinal fluids. Among tested lactic acid bacteria, L167 strain exhibited the highest ACE inhibitory activity (58.75%). The production of ACE inhibitory peptide derived from fermented milk by L167 strain started at the beginning of stationary phase with maximum activity occurring late of the stationary phase. The highest ACE inhibitory activity was observed at 20 h in 10% skim milk medium. L155 strain exhibited cholesterol assimilation activity compared with probiotic strains such as Lactobacillus acidophilus ATCC 43121. With addition of bacteriocin culture, viable cells of Staphylococcus aureus in fermented sausage were slightly decreased during storage. Among selected strains of LAB, 3 strains weve identified as L. plantarum (L155, L165, L167), and two strains were identified as Pediococcus damnosus (L12) and L. paracasei ssp. paracasei (P113) by use of API carbohydrate fermentation pattern and physiological tests.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.5
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• pp.741-746
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• 2005

To investigate the basic information and the possibility of ACE-inhibitory peptides for antihypertension materials, goat's caisin (CN) was hydrolyzed by various proteolytic enzymes and ACE-inhibitory peptides were separated and purified. ACE-inhibition ratios of enzymatic hydrolysates of goat's CN and various characteristics of ACE-inhibitory peptides were determined. ACE-inhibition ratios of goat's CN hydrolysates were shown the highest with 87.84% by pepsin for 48 h. By Sephadex G-25 gel chromatograms, Fraction 3 from goat's CN hydrolysates by pepsin for 48 h was confirmed the highest ACE-inhibition activity. Fraction 3 g and Fraction 3 gh from peptic hydrolysates by RP-HPLC to first and second purification were the highest in ACE-inhibition activity, respectively. The most abundant amino acid was leucine (18.83%) in Fraction 3 gh of ACE-inhibitory peptides after second purification. Amino acid sequence analysis of Fraction 3 gh of ACE-inhibitory peptides was shown that the Ala-Tyr-Phe-Tyr, Pro-Tyr-Tyr and Tyr-Leu. IC$_{50}$ calibrated in peptic hydrolysates at 48 h, Fraction 3, Fraction 3 g and Fraction 3 gh from goat's CN hydrolysates by pepsin for 48 h were 29.89, 3.07, 1.85 and 0.87 g/ml, respectively. Based on the results of this experiment, goat's CN hydrolysates by pepsin were shown to have ACE-inhibitory activity.

• YAKHAK HOEJI
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• v.38 no.3
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• pp.351-357
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• 1994

The levels of maternal immunity enhancing factor(MIEF), which is an immunomodulatory protein identified from bovine colostrum, were determined by indirect competitive enzyme-linked immunosorbent assay(ELISA) for the colostrum and normal milk collected during the first two weeks of lactation. The mean concentration of MIEF in the colostrum of the first day of lactation was $109\;{\mu}g/ml$, and fell from the third day of lactation to $3{\sim}4\;{\mu}g/ml$. The molecular weight of the purified MIEF determined by reducing SDS-PAGE and TSK G2000SW column chromatography was 22,000 and 24,000 daltons, respectively, showing that MIEF is a monomeric peptide in its native form. To examine the capacity of MIEF to induce differentiation of B Lymphocytes, human tonsillar Iymphocytes were cultured in the presence of different concentrations of MIEF, and then antibody secreting cells were enumerated by enzyme-linked immunospot(ELISPOT) assay. When added to cultures of human tonsillar Lymphocytes, MIEF induced differentiation of resting B Iymphocyte to antibody secreting plasma cells as efficiently as LPS.

• Food Science of Animal Resources
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• v.25 no.2
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• pp.244-249
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• 2005

To investigate the effect of Holstein colostrum peptide fraction on proliferation of immune cell, polypeptide fractions were separated from acid whey into 3 fractions depending on molecular weight by ultrafiltration: Fraction I, which contains the polypeptide larger than 10,000 Da, Fraction n, which contains the polypeptide ranging from 1,000 Da to 10,000 Da and Fraction III, which contains the polypeptide smaller than 1,000 Da. EL-4 cell (murine T lymphoma cell) was used to evaluate immune enhancing effect of each fraction from Holstein colostrum. Fraction n showed the highest proliferative effect of the colostrum whey fractions on EL-4 cell at 1mg/mL compared with whole whey and other fractions and this proliferative activity was shown in dose dependent manner. Fraction n showed the highest proliferative effect on PMA (Phorbol 12-myristate 13-acetate) stimulated EL-4 cell. Heated Fraction n showed similar effect to native one on proliferation of both EL-4 cell and PMA stimulated EL-4 cell.

• Korean Journal of Agricultural Science
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• v.39 no.4
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• pp.561-568
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• 2012

The aim of this study was to introduce a simple method for isolation of ${\alpha}$-lactalbumin, ${\beta}$-lactoglobulin and bovine serum albumin from cow's milk, and peptides produced by enzymatic hydrolysis of ${\alpha}$-lactalbumin, ${\beta}$-lactoglobulin and bovine serum albumin with alcalase. Whey protein were precipitated from whey by ammonium sulfate and, ${\alpha}$-lactalbumin and ${\beta}$-lactoglobulin were isolated using Hi Prep 26/60 Sephacryl S-100 column gel filtration chromatography. Bovine serum albumin and ${\beta}$-lactoglobulin were isolated by Mono-Q 5/50 GL column anion exchange chromatography of the 50% Ammonium Sulfate-supernatant. Isolated whey proteins were hydrolyzed by proteolytic alcalase. Tricine SDS-PAGE and reverse-phase HPLC analyses revealed that almost hydrolyzed all the ${\alpha}$-lactalbumin, ${\beta}$-lactoglobulin and bovine serum albumin with alcalase. Molecular weight of various peptides derived from alcalase hydrolysate were small molecular weight than 3.5 kDa.

• Korean Journal of Microbiology
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• v.46 no.1
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• pp.63-67
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• 2010

Proteases catalyze hydrolytic cleavage of a peptide bond between amino acids and occupy pivotal positions in application in physiological and commercial fields. During the screening for novel bacteria producing extracellular protease, two bacterial strains, WD12 and WD32, were isolated from rotten trees and they made clear zone on LB plates supplemented with 1% skim milk. The similarities of 16S rRNA gene sequence of either WD12 or WD32 to GenBank database showed the highest to Pseuoxanthomonas mexicana as 97.8 and 99.8%, respectively. Phylogenetic analysis showed that both isolated was located within the cluster comprising P. mexicana and P. japonesis. WD12 and WD32 were catalase- and oxidase-positive, Gram-negative rod strains. In case of WD12, it could assimilate malate, but could not assimilate D-mannose, which were different characteristics from P. mexicana. Both Pseuoxanthomonas sp. WD12 and WD32 optimally produced extracellular protease at $35-37^{\circ}C$, and maximal activity showed as 656 unit/ml and 267 unit/ml, respectively.

• Food Science of Animal Resources
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• v.29 no.6
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• pp.659-667
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• 2009

Casein is considered to be the main source of protein in milk; therefore, many studies have been conducted to identify casein-derived bioactive peptides and their physiological effects. Casein is inactive within the parent protein but can be liberated by various proteases and enzymatic hydrolysis during microbial fermentation and gastrointestinal digestion. Once absorbed, casein exhibits different bioavailabilities in the body. Specifically, casein-derived peptides function as angiotensin converting enzyme (ACE) inhibitor in the cardiovascular system; thus, they are expected to reduce and prevent hypertension. Additionally, casein-derived peptides behave as opioid-like peptides in the nervous system, which impacts relaxation. These peptides are also expected to modulate various aspects of immune functions. Finally, caseinophosphopeptide (CPP) and glycomacropeptide (GMP) may exhibit a number of nutritional effects such as the absorption of calcium, iron or zinc. Many studies have been conducted to evaluate casein-derived peptides due to their multifunctional properties and the results of these studies have contributed to the development of a wide variety of functional dairy products. The purpose of this paper was to review the generation of bioactive peptides, their absorption and metabolism, and their specific bioactive effects.

• Journal of Dairy Science and Biotechnology
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• v.39 no.1
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• pp.27-35
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• 2021

The aim of this research was to investigate the potential application of casein phospho-peptide (CPP)/chitosan oligosaccharide (CSO) nanocomplexes to dairy foods. The physical stability of CPP/CSO nanocomplexes during storage in model dairy foods including milk and yogurt was assessed by measuring the size and polydispersity index of the nanocomplexes. Encapsulation efficiency and in vitro vitamin D release from CPP/CSO nanocomplexes during gastrointestinal digestion were determined using HPLC. CPP/CSO nanocomplexes with increased CPP concentrations and decreased pH displayed significantly increased average particle size. During storage in model dairy foods, CPP/CSO nanocomplexes prepared with lower CPP concentrations and raised pH exhibited excellent physical stability. Vitamin D encapsulation efficiency increased significantly (p<0.05) as CPP concentration and/or pH decreased. Less than 3% vitamin D were released under gastric digestion conditions in vitro, while 91% of encapsulated vitamin D was released by 2 h of incubation under intestinal conditions, indicating that CPP/CSO nanocomplexes could effectively protect vitamin D from gastric conditions for delivery to the intestines. In conclusion, CPP/CSO nanocomplexes can be applied to dairy foods as an effective vitamin D delivery system.

• Food Science of Animal Resources
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• v.36 no.4
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• pp.558-565
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• 2016

The aim of this study was to investigate the influence of proteolytic pork hydrolysate (PPH) on yoghurt production by Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. Fresh lean pork was cut into pieces and mixed with deionized water and dealt with protease, then the resulting PPH was added to milk to investigate the effects of PPH on yoghurt production. The fermentation time, the viable cell counts, the flavor, free amino acids compounds, and sensory evaluation of yoghurt were evaluated. These results showed that PPH significantly stimulated the growth and acidification of the both bacterial strains. When the content of PPH reached 5% (w/w), the increased acidifying rate occurred, which the fermentation time was one hour less than that of the control, a time saving of up to 20% compared with the control. The viable cell counts, the total free amino acids, and the scores of taste, flavor and overall acceptability in PPH-supplemented yoghurt were higher than the control. Furthermore, the contents of some characteristic flavor compounds including acids, alcohols, aldehydes, ketones and esters were richer than the control. We concluded that the constituents of PPH such as small peptide, vitamins, and minerals together to play the stimulatory roles and result in beneficial effect for the yoghurt starter cultures growth.