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1.
ABSTRACT

Krill (Euphausia superba) was hydrolyzed by proteolytic enzymes in order to produce multifunctional bioactive peptides, and their functional properties were evaluated. Krill protein hydrolysate (KPH) by pepsin with 4-h hydrolysis showed the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging and angiotensin I converting enzyme (ACE) inhibitory activities. The solubility and foaming properties of KPH were higher than those of the unhydrolyzed krill protein at a wide range of pHs. KPH was further fractionated based on molecular weight. The 1- to 3-kDa peptide fraction exhibited the highest DPPH scavenging activity (IC50 value of 0.5 mg/mL), oxygen radical absorbance capacity (497.39 ± 4.31 µM TE/mg fraction), 2,2-azino-bis(3-ethylbenzthiazoline)-6-sulfonic acid cation radical scavenging activity (48.41 ± 0.23 µM TE/mg fraction), and reducing power (110.40 ± 2.07 µM TE/mg fraction). However, the < 1-kDa peptide fraction exhibited a higher ACE inhibitory activity than that of other fractions. The 1- to 3- and < 1-kDa peptide fractions are rich in aromatic and hydrophobic amino acids, respectively.  相似文献   

2.
为增加暗纹东方鲀附加值,考察不同处理方法对提取暗纹东方鲀鱼皮胶原蛋白的影响,实验以暗纹东方鲀鱼皮为对象,通过热水法、酸法和胃蛋白酶、木瓜蛋白酶、无花果蛋白酶处理鱼皮提取胶原蛋白。通过对不同胶原蛋白的提取率、氨基酸组成、傅里叶红外光谱(FTIR)、紫外光谱(UV)、扫描电镜、十二烷基硫酸钠—聚丙烯酰胺凝胶电泳(SDS-PAGE)进行研究,对暗纹东方鲀鱼皮胶原蛋白特性进行表征和比较。结果显示,用胃蛋白酶得到的胶原蛋白提取率最高;氨基酸组成相似但含量不同;3种酶制备的胶原蛋白中,脯氨酸含量显著低于酸和热水制备的胶原蛋白;FTIR扫描结果表明,5种处理方法得到的胶原蛋白都存在Amide A、Amide B、AmideⅠ、AmideⅡ和AmideⅢ,均保持了胶原蛋白三螺旋结构;紫外光谱显示在235 nm左右有强吸收峰,结合FTIR确定其为典型的胶原蛋白,经过SDS-PAGE分析,确定暗纹东方鲀鱼皮胶原蛋白为Ⅰ型胶原蛋白。酸法和胃蛋白酶较好地保留了胶原蛋白的β、α1和α2链,木瓜蛋白酶作用化学键比其他酶广泛,得到小分子量的胶原蛋白分子;扫描电镜结果显示,酸法提取的胶原蛋白最适合应用在生物医学材料上运载药物。由此可见,不同处理方法提取的胶原蛋白理化特性存在一定差异,不同的酶制备的胶原蛋白分子量分布会产生明显差别,可根据研究需要选用不同处理方法开发胶原蛋白产品。  相似文献   

3.
ABSTRACT

Basa fish skin free from fat and noncollagenous proteins was hydrolyzed by different proteinases to produce angiotensin-converting enzyme (ACE) inhibitory peptides. Protamex hydrolysates were found to have the highest ACE inhibitory activity. Response surface methodology (RSM) was applied to optimize the hydrolysis conditions of Protamex—including enzyme-to-substrate ratio, hydrolysis time, and solid (fish skin)-to-liquid (water for hydrolysis)—at a temperature of 50°C and a pH of 7.0. The mathematical model demonstrated a good fit with the experimental data. An enzyme-to-substrate ratio of 6,108 U/g, a hydrolysis time of 1.24 h, and a solid-to-liquid ratio of 1:8.05 g/mL were found to be the optimal conditions to achieve the highest value of ACE inhibitory activity. The IC50 of the hydrolysates for ACE inhibitory activity was 1.417 mg/mL under these conditions.  相似文献   

4.
ABSTRACT

Pepsin enzyme from skipjack tuna was extracted for the production of kawakawa (Euthynnus affinis) fish protein hydrolysate. Using ultra-fractionation, Kawakawa protein hydrolysates were separated into four different fractions, including fractioned protein hydrolysate I (FPH I) (< 1 kDa), FPH-II (1–3 kDa), FPH-III (3–10 kDa), and FPH-IV (> 10 kDa). The antioxidant activity was assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity, inhibition of linoleic acid oxidation, reducing power tests, and chelating activity of metal ions. Results indicated that FPH II fraction peptides had higher antioxidant activity in comparison with the other fractions, followed by FPH I. Further, the fractions were evaluated for angiotensin converting enzyme (ACE) inhibition, and IC50 value ranged from 0.45 to 1.86 mg/ml with higher activity in FPH I (IC50 0.45). Finally, the amino acid profile of different fractions was analyzed. The fractions exhibited significant amounts of hydrophobic amino acids, which could perform as hydrogen donors, frustrate the free radicals, and inhibit the ACE. The recovered pepsin from the viscera was used to produce hydrolysates with good biological activities. Peptides lower than 3 KDa had antioxidant activity as positive controls and significant ACE activity. These are very important findings that could be used to conduct further research in a preclinical study of these peptides.  相似文献   

5.
ABSTRACT

Skin collagen of six discarded fish species was analyzed and compared. Acid soluble collagen (ASC) was extracted; a characteristic sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) profile for type I collagen was obtained, except for Chimaera mostrosa. Contents of collagen calculated from HPro (31.85% average) were higher than those determined from ASC extracts (17.75% average), with Galeus spp. being the species with the higher percentage. Amino acid analysis revealed the typical composition of collagen, with very few differences among species. Specific profiles were obtained after protease digestion. Denaturation temperature of ASC correlated well with imino and hydroxyproline contents.

Results demonstrate the feasibility of using the obtained collagens in different industrial applications.  相似文献   

6.
The effects of different hydrolysis conditions on the angiotensin-I converting enzyme (ACE) inhibitory properties of giant red sea cucumber (Parastichopus californicus) collagen hydrolysates were investigated. Optimal conditions predicted by central composite rotatable design (CCDR) modeling for producing ACE inhibitory peptides were found to be 54.9°C, 1.76 h and an enzyme to substrate (E/S) ratio of 0.064. Compared with experiments performed under these optimal conditions, the predicted degree of hydrolysis (DH) and ACE inhibitory activities had error rates of 3 to 6%. Under optimum conditions, the molecular weights of collagen hydrolysates were less than 6.5 kDa. Lineweaver-Burk plots suggest that the collagen hydrolysates acted as competitive inhibitors with an inhibition constant (Ki) value of 0.706 mg/mL.  相似文献   

7.
Acid soluble collagen (ASC) and pepsin soluble collagen (PSC) were isolated from rohu skin with the yield of 64.2 and 6.8% (dry weight basis), respectively. Both collagens had glycine as the major amino acid with imino acid content of 196–202 residues/1,000 residues and were characterized as type I collagen with molecular composition of (α1)2α2-heterotrimer. Fourier transform infrared spectra of both collagens were similar, with no shift in wavenumber of all amide bands. The Tmax value of ASC and PSC was 36.40 and 35.48°C, respectively. The zero surface net charge of ASC and PSC was found at pH 5.9 and 5.3, respectively.  相似文献   

8.
In order to study the similarities and differences of physical-chemical properties of collagens from different parts of the fish body, acid-soluble collagens and pepsin-soluble collagens were isolated from skin, scale, and bone of grass carp (Ctenopharyngodon idellus), with yields ranging from 0.7 to 25.5% on the basis of dry weight. The content of acid-soluble collagen in skin and scale was much higher than that in bone according to the data of extraction yield. Collagens from grass carp have similar amino acid composition, protein patterns, and sequences of primary structure. Thermal transition temperatures of collagens from different parts of grass carp body decreased in the order of bone > skin > scale. The pepsin-soluble collagens showed more resistance to collagenase, compared to acid-soluble collagens extracted from the same part of the grass carp body. All grass carp collagens did not induce a significant cytotoxic effect according to the results of in vitro cytotoxicity test.  相似文献   

9.
Angiotensin-converting enzyme (ACE) inhibitory capacity was evaluated in hydrolysates from sea cucumber Isostichopus badionotus. The pepsin-pancreatin and Alcalase®-Flavorzyme® sequential systems were used. Hydrolysates were characterized in terms of degree of hydrolysis (DH), electrophoretic profile, and inhibitory activity. The Alcalase®-Flavorzyme® system produced hydrolysates with the highest DH, with that produced at 90 min exhibiting the highest ACE inhibitory action (86%). This hydrolysate was chosen for purification by ultrafiltration with five molecular weight cut-offs (< 1, 1–3, 3–5, 5–10, and > 10). The > 10-kDa fraction exhibited the highest ACE inhibitory action (80.7%) and was fractionated by gel fractionation chromatography. Of the 11 resulting fractions, IX had the highest ACE inhibitory action (73.4%) and lowest IC50 value (2-μg prot/mL). Hydrolysis of sea cucumber I. badionotus with the Alcalase®-Flavorzyme® system produced hydrolysates with ACE inhibitory action. These contained a peptide with an IC50 value comparable to those of synthetic ACE inhibitors.  相似文献   

10.
Enzymatic solubilization of collagen from the skin tissue of diamond squid Thysanoteuthis rhombus, an underutilized resource in Japan, was attempted using an acid protease from the fungus Rhizopus niveus. This novel approach was compared with the conventional method using porcine pepsin. Both proteases were able to solubilize most of the skin collagen (>90 % of the total collagen) by performing the treatment in 0.5 M acetic acid at 4 °C for 72 h and at an enzyme/substrate ratio (w/w) of 1/10. The SDS-PAGE patterns of the solubilized collagen preparations were quite similar to each other, and two types of collagen (major and minor collagens) were purified from each preparation by cation-exchange column chromatography. These collagen types from the porcine pepsin-solubilized collagen showed similar features to those from the Rhizopus acid protease-solubilized collagen. These results suggest that the Rhizopus acid protease, a protease of non-animal origin, is applicable for solubilizing collagen in the skin of diamond squid.  相似文献   

11.
Eight isolipidic diets containing 0, 20, 40, and 60 g/kg oxidized fish oil (OFO) or oxidized soybean oil (OSO) were fed to triplicate groups of channel catfish, Ictalurus punctatus, for 8 weeks to investigate the effects of oxidized oils on growth, body color, and antioxidative capacity. Lower weight gain (WG) was observed in fish fed high levels of oxidized oils (40 and 60 g/kg) (p < .05). At the inclusion of 40 g/kg, OFO group showed lower WG than the OSO group (p < .05). With the increase of dietary oxidized oils, the serum levels of malondialdehyde, total bilirubin, direct bilirubin, and activity of alanine aminotransferase and aspartate aminotransferase significantly increased (p < .05), but the glutathione level decreased (p < .05). Serum superoxide dismutase and catalase activity showed the maximum values at 20 g/kg OFO group and 40 g/kg OSO group, respectively. Compared to the 0 g/kg oxidized oil groups, both dietary oxidized oils increased the b* value (yellowness) of dorsal skin and caudal skin at 40 and 60 g/kg inclusion (p < .05). In conclusion, dietary oxidized oil (≥40 g/kg) decreased the growth and the antioxidative capacity and increased the yellowness of skin. OFO caused more negative effects on channel catfish than OSO at the inclusion of 40 g/kg.  相似文献   

12.
ABSTRACT

Peptic hydrolysates were prepared by digesting the cutlassfish muscle protein using pepsin for 1, 3, and 6 h, and their inhibitory activity against angiotensin-I converting enzyme (ACE) was studied. The ACE-inhibitory effect of the peptic hydrolysate of cutlassfish muscle generated at the 3 h time point exhibited the strongest activity. After identifying the optimal hydrolysate, the active peptide was isolated by ultrafiltration, gel permeation, and high performance liquid chromatography (HPLC). The resulting purified peptide was characterized using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/TOF MS/MS) and was identified to be a 496.44 Da pentapeptide (Phe-Ser-Gly-Gly-Glu). The ACE-inhibitory activity of the active peptide exhibited an IC50 value of 0.033 ± 0.003 mg/ml. A molecular docking program was used to simulate the interaction between the peptide and ACE, which revealed that the inhibitory effect was mainly due to the hydrogen bonds between ACE and the peptide. Based on the ACE-inhibitory properties and the molecular docking study of the resulting active peptide, we demonstrated an increase in nitric oxide (NO) production in a dose-dependent manner. In conclusion, cutlassfish protein hydrolysate and the resulting active peptide could be used as active ingredients in functional food as anti-hypertensive agents.  相似文献   

13.
Angiotensin-I-converting enzyme (ACE) plays a crucial role in the crisis of hypertension. Some peptides that originate from protease hydrolysates are known to suppress ACE activity in vitro and in vivo. Here, we investigated whether trypsin hydrolysate of oyster Crassostrea gigas showed hypotensive activity and ACE inhibition. The hydrolysate significantly suppressed systolic blood pressure and ACE activity in spontaneously hypertensive rats following a one-shot oral administration and a long-term feeding experiment lasting 9 weeks. Each hydrolysate from oyster tissue showed ACE inhibitory activity, indicating the hypotensive effect was due to synergism. One potent ACE inhibitory peptide, Asp-Leu-Thr-Asp-Tyr, was identified from the hydrolysate of the striate muscle, and the peptide exhibited hypotensive activity in vivo. Protease digestion analysis suggested that Asp-Tyr could be the real effector of this penta-peptide in vivo.  相似文献   

14.
ABSTRACT

A liquid fermentation process to bioconvert shrimp by-products was developed with two species of fungi, Boletus edulis and Suillus bovinus. Angiotensin I-converting enzyme (ACE) inhibitory, antioxidant activities of bioconverted products and the deodorization effect of fungal bioconversion were determined. Two species of fungi could grow quickly in shrimp by-products medium and deodorize shrimp by-products. Bioconverted products had higher ACE inhibitory and antioxidant activities than control medium. Water extracts without crude polysaccharides from mycelia of B. edulis had the highest ACE inhibitory activity (IC50 = 0.084 ± 0.011 mg/mL). Crude exopolysaccharides of B. edulis had higher antioxidant activity. Bioconversion with the fungus was proven to be a novel, practicable way to recycle shrimp by-products.  相似文献   

15.
ABSTRACT

Squid tunics were divided in two batches: freeze-dried and air-dried. Dried squid tunics were directly hydrolyzed with pepsin, Alcalase, and Esperase. Freeze-dried tunics showed better aptitude for hydrolysis than air-dried tunics. Pepsin showed the lowest efficiency in protein breakdown and gave hydrolysates with low antioxidant activity, whereas Alcalase and Esperase peptide fractions showed strong radical scavenging ability, ACE-inhibitory activity, and noticeable antimicrobial properties. B. cereus, B. coagulans, and D. hansenii were found to be the most sensitive bacteria. Dried squid tunics proved to be an alternative to a previously extracted gelatin for obtaining bioactive peptides.  相似文献   

16.
Pepsin-soluble collagen (PSC) was extracted and purified from wasted skin and bone of the golden pompano by acetic acid-pepsin method. The result showed that the PSCs extraction yields of skin and bone were 21.81% and 1.25% (wet weight), 62.21% and 1.78% (on the basis of lyophilized dry weight), respectively. Golden pompano skin and bone PSCs contained the typical chain of α and β dimers, and they were preliminarily judged to belong to type I collagen. The skin PSC had similar amino acid composition to bone PSC, which is rich in glycine, alanine, proline, and hydroxyproline. After addressing the pepsin, three helical structure of PSCs were intact, and their natural structures largely remained. The denaturation temperatures of skin and bone PSCs were 37.04°C and 38.23°C, respectively. Solubility results showed that the skin and bone PSCs solubility was the largest at pH = 3. The solubility of skin and bone PSCs was stable at NaCl concentrations lower than 3%. In addition, two PSCs in acid and low salt conditions had good solubility. This study demonstrated that golden pompano skin and bone could be used as good materials to extract PSC, representing an economic benefit and added value.

Abbreviations: SDS-PAGE: Sodium dodecyl sulfate polyacrylamide gel electrophoresis; FTIR: Fourier transform infrared; DSC: Differential scanning calorimetry; XRD: X-ray diffraction  相似文献   

17.
ABSTRACT

The present study examined whether bioactive peptides and omega-3 fatty acids-containing phopholipids could be recovered from squid processing by-product (SPB) hydrolysate. The hydrolysate was produced at 55°C for varying times with endogenous proteases and centrifuged to yield peptides-containing supernatant and phospholipids-containing precipitate. The supernatant showed angiotensin I-converting enzyme (ACE) inhibitory activity with half maximal inhibitory concentration (IC50) values decreasing with hydrolysis time from 2.11 mg (0 h) to 1.71 mg (1 h), 1.38 mg (1.5 h), and 1.34 mg (2 h). Two-hour squid hydrolysate was further fractionated to isolate the most active fraction whose molecular weight was found to be below 10 kDa with IC50 of 0.32 mg. The phospholipids-containing precipitate (45.6 g/100 g oil) was analyzed for a fatty acid profile, with the levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) being 16.86 and 29.24 g/100 g oil, respectively. The ACE inhibition by hydrolysate peptides and omega-3 fatty acid recovery support the nutraceutical potential of the SPB hydrolysate.  相似文献   

18.
The characteristics and functional properties of gelatin obtained from Chinese giant salamander (Andrias davidianus) skin were investigated. After alkaline and acetic acid pre-treatment, yield of the gelatin by hot water extraction (60°, 8 h) was 17.63 g/100 g (wet basis), and the gelatin contained 89.46 g/100 g protein, 0.3 g/100 g fat, and 0.41 g/100 g ash (dry basis). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) results of the gelatin showed clear band pattern for collagen subunits,β- and α-chains. The gelatin contained 18.85% imino acids, 28.62% hydrophobic amino acids, and 19.68% essential amino acids, which is slightly lower than porcine skin gelatin (PSG). The gelatin exhibited thermo-reversible properties, with gel strength of 192.50 ± 11.47 g, rupture distance of 10.17 ± 0.20 mm, gelling temperature of 4.98°, and melting temperature of 18.04°, Emulsifying activity index (EAI) of the gelatin diminished with increasing concentrations from 10 to 40 mg/mL (p < .05), whereas the emulsifying stability index (ESI) improved significantly (p < .05). Higher concentrations (30 and 40 mg/mL) could significantly enhance the gelatin’s foam expansion (FE) and foam stability (FS) (p < .05). Water absorption ability and oil absorption ability of the gelatin were 7.1 g water/g gelatin and 9.8 g oil/g gelatin, respectively. These results imply that the gelatin with good interfacial properties could potentially be used as a novel ingredient in food emulsion systems.

Abbreviations: CGSS, Chinese giant salamander skin; CSG, Chinese giant salamander skin gelatin; PSG, porcine skin gelatin; EAI, emulsion activity index; ESI, emulsion stability index; FE, foam expansion; FS, foam stability; WAC, water absorption capacity; OAC, oil absorption capacity.  相似文献   

19.
Type I collagen was extracted from walleye pollock (Theragra chalcogramma) skin and purified by DEAE-52 cellulose chromatography and gel filtration chromatography with Sephacryl S-300 HR. Fourier transform infrared spectroscopy spectra and X-ray diffraction pattern showed the existence of a helical arrangement, with the distance between the molecular chains of 1.18 nm and the unit height, typical of the triple helix, of 0.27 nm. Scanning electron microscopy (SEM) revealed the collagen had a filamentary structure. Peptide mapping, obtained by matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), indicated that peptides with the molecular weight of 1,470, 1,565, 1,570, 2,150, and 2,470 Da were the major products of trypsin digestion of pollock skin collagen.  相似文献   

20.
The aim of this study was to investigate effects of dietary geniposide (GP) on growth performance, flesh quality, and lipid metabolism of grass carp, Ctenopharyngodon idella (95.2 ± 0.6 g), fed seven different diets, including a control diet; Eucommia ulmoides (EU)–supplemented diet (20 g/kg); and GP‐supplemented diets containing 100, 200, 400, 600, and 800 mg/kg GP, respectively. Weight gain rate was significantly improved (P < 0.05) and feed conversation ratio was significantly decreased (P < 0.05) by supplementation of EU. Grass carp fed 100–800 mg/kg GP‐supplemented diets showed significantly higher total collagen and alkaline‐insoluble collagen content in muscle than control (P < 0.05). Contents of total collagen and the alkaline‐insoluble collagen content in the skin of grass carp were significantly increased by dietary 600–800 mg/kg GP and EU (P < 0.05). Fish fed diets containing 600–800 mg/kg GP showed significantly lower muscle crude lipid content than the EU, control, and 100–400 mg/kg GP groups (P < 0.05). Fish fed 400–800 mg/kg GP diets had significantly higher muscle fiber density and lower muscle fiber diameter and serum triglyceride level than the control (P < 0.05). In conclusion, supplementation of GP could improve flesh quality, but not growth of grass carp. The supplemental level of GP for improving flesh quality was estimated to be a 400–600 mg/kg diet.  相似文献   

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