• 한국수산과학회지
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• 제40권6호
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• pp.343-349
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• 2007

This study examined the effective utilization of pearl processing by-products. Three extracts of hot-water extract (WE), hydro-cooked extract (HE), and two-step enzymatic hydrolysate (EH) were prepared from pearl oyster muscle, and their characteristics were examined. The moisture, crude protein, volatile basic nitrogen (VBN), and amino-N contents were 97.5-98.0%, 0.5-1.3%, 2.1-4.9 g/100 mL, and 35.0-74.5 g/100 mL, respectively. EH had the lowest VBN and highest amino-N contents. In addition, EH had the highest yields. In terms of its functional properties, EH inhibited angiotensin-I converting enzyme ($IC_{50}$, 1.39 mg/mL) more strongly than the other extracts ($IC_{50}$, 4.17-7.95 mg/mL). The free amino acid contents of WE, HE, and EH were 661, 470 and 1,150 mg/100 mL, respectively. Major amino acids were taurine and glutamic acid. Major inorganic ions were Na, Mg, and Ca. Contents of taste compounds, such as free amino acids, inorganic ions, and quaternary ammonium bases, differed significantly according to the extract methods. Based on the results of chemical experiments and sensory evaluation, the quality of EH was superior to the other extracts, and EH is suitable for use in natural flavoring materials.

• 한국수산과학회지
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• 제53권1호
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• pp.123-131
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• 2020

In this study, we investigated the protective effects of a Neutrase enzymatic hydrolysate derived from Korea pen shell Atrina pectinata (APN) against hydrogen peroxide (H₂O₂)-induced oxidative damage in hepatocytes. First, we confirmed that APN has antioxidant activities by scavenging 2,2-azino-bis (3-ethylbenzthiazoline)-6-sulfonic acid radical (ABTS⁺) and H₂O₂ and increasing oxygen radical absorbance capacity (ORAC) value. Also, the treatment of APN increased the cell viability by reducing the intracellular reactive oxygen species (ROS) production in H₂O₂-stimulated hepatocytes. In addition, APN decreased the sub-G₁ DNA contents and the apoptotic body formation increased by H₂O₂ stimulation. Moreover, APN modulated the protein expression of apoptosis related molecules (Bcl-2, Bax and p53) by suppressing the activation of nuclear factor NFkB and ERK/p38 signaling in H₂O₂-stimulated hepatocytes. Furthermore, APN led to the activation of Nrf2/HO-1signaling known as antioxidant systems. These results suggest APN protects hepatocytes against oxidative damages caused by H₂O₂ stimulation.

• 한국식품영양과학회지
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• 제22권2호
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• pp.226-233
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• 1993

효소에 의한 가수분해로 식품단백질로부터 생리활성 peptide의 생성을 밝히기 위한 연구의 일환으로 효소에 의한 단백질 가수분해물의 ACE 저해작용을 검토한 결과는 다음과 같다. 1. 가수분해에 따른 ACE 저해능은 가수분해 8시간까지는 급격히 증가하다가 그 후로는 완만하게 증가하였으며, 특히 복합효소, bromelain 및 pepsin등에 의해 우수하게 나타났다. 그러나 trypsin 및 $\alpha$-chymotrypsin에 의한 egg albumin 및 casein 가수분해시에는 가수분해 8시간 이후에는 오히려 감소하는 경향을 나타내었다. 2. 단백질 가수분해물의 ACE 저해능은 첨가량의 증가와 함께 우수한 것으로 나타났으며, 가열에 대하여 비교적 안정한 것으로 나타났다. 3. 단백질 가수분해물의 아미노산 조성은 거의 유사한 것으로 나타났으며, 특히 glutamic acid의 함량이 월등히 많은 것으로 나타났다. 그러나 egg albumin 가수분해물의 경우는 glutamic acid의 함량이 적은 반면 alanine 및 cysteine의 함량이 다소 많은 것으로 나타났다 4. Gel 여과에 의한 단백질 가수분해물의 획분별 ACE 저해작용은 서로 비슷한 획 분에서 나타났으며 이 때의 분자량은 1,400부근으로 나타났다. 5. Gel 여과에 의한 ACE 저해작용 획분의 아미노산 조성은 서로 다른 것으로 나타났다.

• Asian-Australasian Journal of Animal Sciences
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• 제16권3호
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• pp.417-424
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• 2003

Inhibitory activities against angiotensin I-converting enzyme (ACE) of enzymatic hydrolysates of porcine skeletal muscle proteins were investigated. Myosin B, myosin, actin, tropomyosin, troponin and water-soluble proteins extracted from pork loin were digested by eight kinds of proteases, including pepsin, $\alpha$-chymotrypsin, and trypsin. After digestion, hydrolysates produced from all proteins showed ACE inhibitory activities, and the peptic hydrolysate showed the strongest activity. In the case of myosin B, the molar concentration of peptic hydrolysate required to inhibit 50% of the activity increased gradually as digestion proceeded. The hydrolysates produced by sequential digestion with pepsin and $\alpha$-chymotrypsin, pepsin and trypsin or pepsin and pancreatin showed weaker activities than those by pepsin alone, suggesting that ACE inhibitory peptides from peptic digestion might lose their active sequences after digestion by the second protease. However, the hydrolysates produced by sequential digestion showed stronger activities than those by $\alpha$-chymotrypsin, trypsin or pancreatin alone. These results suggested that the hydrolysates of porcine meat were able to show ACE inhibitory activity, even if they were digested in vivo, and that pork might be a useful source of physiologically functional factors.

• 한국수산과학회지
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• 제44권2호
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• pp.118-125
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• 2011

In this study, an angiotensin I-converting enzyme (ACE) inhibitor from squid skin was purified and characterized. Squid (Todarodes pacificus) skin protein isolates were hydrolyzed using six commercial proteases: alcalase, ${\alpha}$-chymotrypsin, neutrase, papain, pepsin, and trypsin. The peptic hydrolysate had the highest ACE inhibitory activity. The ACE inhibitory peptide was purified using Sephadex G-25 column chromatography and reverse phase high-performance liquid chromatography (HPLC) with a $C_{18}$ column. The purified ACE inhibitory peptide was identified and sequenced, and found to consist of seven amino acid residues: Ser-Ala-Gly-Ser-Leu-Val-Pro (657Da). The $IC_{50}$ value of the purified ACE inhibitory peptide was 766.2 ${\mu}M$, and Lineweaver-Burk plots suggested that the purified peptide acts as a noncompetitive ACE inhibitor. These results suggest that the ACE inhibitory peptide purified from the peptic hydrolysate of squid skin may be of benefit in developing antihypertensive drugs and functional foods.

• Journal of Animal Science and Technology
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• 제52권5호
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• pp.435-440
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• 2010

유청단백질농축물(WPC)은 풍부한 단백질 및 다양한 생리활성 물질들을 함유하고 있음으로 식품의 단백질 보충 및 건강 기능성 향상을 위해 식품산업에서 널리 사용되고 있는 유용한 식품소재 중에 하나이다. 본 연구는 유용 기능성 식품소재로 활용이 가능한 유청단백질의 산업화와 관련된 사항들을 조사하고자 수행하였다. 한외여과를 이용한 WPC 제조과정에서 WPC-30을 포함한 한외여과 기의 국산화 가능성을 확인했다. 한외여과, 분무건조 및 단백질분해 효소를 이용하여 제조한 WPC-30 가수분해물의 이화학적 기능성을 검토한 결과 단백질 가수분해능 및 관능성에 대한 평가는 alcalase 처리했을 때 가장 높은 것으로 나타났으며 거품 형성능은 flavourzyme 처리한 WPC-30 가수분해물에서 가장 높은 결과를 보였다. 또한 다양한 pH조건에서의 단백질의 용해도를 측정한 결과, protamex 처리한 WPC-30 가수분해물에서 가장 높은 용해도를 나타내었다. 그러나 모든 WPC-30 가수분해물의 용해도는 알차리 조건에서는 유의적으로 개선되는 효과를 보였다. 이들 결과들을 총체적으로 검토한 결과, 효소를 이용한 유청단백질의 가수분해는 알카리조건에서 alcalase를 사용하는 것이 가장 효과적인 것으로 나타났다.

• Journal of Microbiology and Biotechnology
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• 제34권5호
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• pp.1082-1091
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• 2024

The antioxidant capacity and protective effect of peptides from protein hydrolysate of Cordyceps militaris cultivated with tussah pupa (ECPs) on H₂O₂-injured HepG2 cells were studied. Results indicated ECP1 (<3 kDa) presented the strongest antioxidant activity compared with other molecular weight peptides. Pretreated with ECPs observably enhanced survival rates and reduced apoptosis rates of HepG2 cells. ECPs treatment decreased the ROS level, MDA content and increased CAT and GSH-Px activities of HepG2 cells. Besides, the morphologies of natural peptides from C. militaris cultivated with tussah pupa (NCP1) and ECP1 were observed by scanning electron microscopy (SEM). Characterization results suggested the structure of NCP1 was changed by enzymatic hydrolysis treatment. Most of hydrophobic and acidic amino acids contents (ACC) in ECP1 were also observably improved by enzymatic hydrolysis. In conclusion, low molecular weight peptides had potential value in the development of cosmetics and health food.

• Food Science and Biotechnology
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• 제15권1호
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• pp.128-132
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• 2006

This study was undertaken to investigate the effect of peptic and chymotryptic hydrolyses of 7S globulin, the major allergen of soybean protein, on its allergenicity, as measured by enzyme linked immunosorbent assay (ELISA), and to identify the allergenic hydrolyzed fragments of 7S globulin using SDS-PAGE. When 7S globulin was hydrolyzed by pepsin, the allergenicity was reduced by over 50%. However, the allergenicity of 7S globulin reduced by peptic hydrolysis was recovered in the sera from 5 out of 10 patients following sequential chymotryptic hydrolysis. Two fragments, with molecular weights 20-25 and 13-16 kDa, among the hydrolysate of 7S globulin by sequential pepsin and chymotrypsin showed reactivity with sera from 10 soybean-allergenic patients. As a result of the theoretical hydrolyses of ${\beta}$-conglycinin, which is a major protein of 7S globulin, it is suggested that the 20-25 kDa fragments were the fragments of the ${\alpha}$-subunit of ${\beta}$'-conglycinin and that the 10-16 kDa fragments were from the ${\alpha}$'-subunit.

• 한국축산식품학회지
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• 제44권3호
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• pp.723-737
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• 2024

Yeast protein can be a nutritionally suitable auxiliary protein source in livestock food. The breakdown of proteins and thereby generating high-quality peptide, typically provides nutritional benefits. Enzyme hydrolysis has been effectively uesed to generate peptides; however, studies on the potential applications of different types of enzymes to produce yeast protein hydrolysates remain limited. This study investigated the effects of endo- (alcalase and neutrase) and exotype (flavourzyme and prozyme 2000P) enzyme treatments on yeast protein. Endotype enzymes facilitate a higher hydrolysis efficiency in yeast proteins than exotype enzymes. The highest degree of hydrolysis was observed for the protein treated with neutrase, which was followed by alcalase, prozyme 2000P, and flavourzyme. Furthermore, endotype enzyme treated proteins exhibited higher solubility than their exotype counterparts. Notably, the more uniform particle size distribution was observed in endotype treated yeast protein. Moreover, compared with the original yeast protein, the enzymatic protein hydrolysates possessed a higher content of β-sheets structures, indicating their higher structural stability. Regardless of enzyme type, enzyme treated protein possessed a higher total free amino acid content including essential amino acids. Therefore, this study provides significant insights into the production of protein hydrolysates as an alternative protein material.

• Preventive Nutrition and Food Science
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• 제5권2호
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• pp.65-69
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• 2000

Hen egg-white lysozyme was conjugated with 7~9 mers xyloglucan hydrolysates(MW-1,400) at 6$0^{\circ}C$ and 79% relative humidity for 3 days. SDS-PAGE showed that the conjugation between lysozyme and the oligosaccharide began from 1-day incubation, and three molecules of carbohydrate chains were attached to a protein molecule after 30day incubation. The enzymatic activity of lysozyme was totally conserved in the neoglycoprotein, when measured by using glycol chitin as substrate. Besides, the emulsifying properties of lysozyme were vastly improved by the conjugation with the oligosaccharide, in which emulsifying activity of the neoglycoprotein was five times higher than that of native one.