Search Results (44)

Eel (Anguilla japonica) is an important and valuable food fish in East Asia and its by-products have been reported to include bioactive and profitable components. This study aimed to extract, characterise, and compare the structure and properties of acid-soluble collagens (ASCs) and pepsin-soluble collagens (PSCs) from the skin and bone of eel (Anguilla japonica), providing insights into their composition, structure, and properties for various applications. The yields of ASC-S (from skin), PSC-S (from skin), ASC-B (from bone), and PSC-B (from bone) were 12.16%, 15.54%, 0.79%, and 1.34% on a dry weight basis, respectively. Glycine, the dominant amino acid, accounted for 16.66% to 22.67% of total amino acids in all samples. SDS-PAGE and FTIR analyses showed the typical triple-helical structure of type I collagen with slight variations in molecular order in extract and intermolecular cross-linking between skin and bone collagens. The denaturation temperature (T_max1) measured by differential scanning calorimetry (DSC) is 81.39 °C and 74.34 °C, respectively, for ASC-B and ASC-S. Bone collagen has higher thermal resistance than skin collagen. Surface morphology imaged using a scanning electron microscope (SEM) showed that the bone collagen had a denser network structure, whilst the skin collagen was more fibrous and porous. The findings suggest that eel-derived collagens from skin and bone can serve as potential alternatives in the food, cosmetic, and healthcare industries. Full article

Recently, there has been a growing interest in collagen peptides derived from marine sources for their notable ability to protect skin cells against apoptosis induced by oxidants. Therefore, the current study aimed to investigate the fundamental properties of collagen peptides, including their physicochemical, thermal, structural, stem-cell-regenerative, and skin-cell-protective effects, in comparison to commercial collagen peptides. The acid-soluble (ASC) and pepsin-soluble (PSC) collagens exhibited three distinct bands on SDS-PAGE, namely α (α₁ and α₂), β, and γ chains, confirming a type I pattern. The thermal profiles obtained from TG and DSC analyses confirmed the denaturation of PSC and ASC at temperatures ranging from 51.94 to 56.4 °C and from 52.07 to 56.53 °C, respectively. The purified collagen peptides were analyzed using SDS-PAGE and MALDI-TOF mass spectrometry, revealing a mass range of 900–15,000 Da. Furthermore, the de novo peptide sequence analysis confirmed the presence of the Gly-X-Y repeating sequence in collagen peptides. Collagen peptide treatments significantly enhanced HFF-1 cell proliferation and migration compared to the control group. ELISA results confirmed the potential interactions between collagen peptides and HFF-1 cells through α₂β₁, α₁₀β₁, and α₁₁β₁ integrin receptors. Notably, collagen peptide treatment effectively restored the proliferation of HFF-1 cells damaged by H₂O₂. Consequently, the advantageous characteristics of squid skin collagen peptides highlight their promising role in regenerative medicine. Full article

The effects of ultrasonic power (0, 150, 300, 450, and 600 W) on the extraction yield and the structure and rheological properties of pepsin-soluble collagen (PSC) from albacore skin were investigated. Compared with the conventional pepsin extraction method, ultrasonic treatment (UPSC) significantly increased the extraction yield of collagen from albacore skin, with a maximum increase of 8.56%. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis revealed that peptides of low molecular weight were produced when the ultrasonic power exceeded 300 W. Meanwhile, secondary structure, tertiary structure, and X-ray diffraction analyses showed that the original triple helix structure of collagen was intact after the ultrasonic treatment. The collagen solutions extracted under different ultrasonic powers had significant effects on the dynamic frequency sweep, but a steady shear test suggested that the collagen extracted at 150 W had the best viscosity. These results indicate that an ultrasonic power between 150 and 300 W can improve not only the extraction yield of natural collagen, but also the rheological properties of the collagen solution without compromising the triple helix structure. Full article

The processing of fishery resources results in the production of a growing quantity of byproducts, including heads, skins, viscera, intestines, frames, and fillet cutoffs. These byproducts are either wasted or utilized for the production of low-value items and fish oil. Typically, fish processing industries use only 25%, while the remaining 75% is considered as waste by-products. This review presents a comprehensive review on the extraction of collagen from fish byproducts, highlighting numerous techniques including acid-soluble collagen (ASC), enzyme-soluble collagen (ESC), ultrasound extraction, deep eutectic solvent (DES) extraction, and supercritical fluid extraction (SFE). A detailed explanation of various extraction parameters such as time, temperature, solid to liquid (S/L) ratio, and solvent/pepsin concentration is provided, which needs to be considered to optimize the collagen yield. Moreover, this review extends its focus to a detailed investigation of fish collagen applications in the biomedical sector, food sector, and in cosmetics. The comprehensive review explaining the extraction methods, extraction parameters, and the diverse applications of fish collagen provides a basis for the complete understanding of the potential of fish-derived collagen. The review concludes with a discussion of the current research and a perspective on the future development in this research field. Full article

The objective of this study was to isolate and characterize collagen and angiotensin-I-converting enzyme (ACE)-inhibitory (ACEi) peptides from the swim bladders of monkfish (Lophius litulon). Therefore, acid-soluble collagen (ASC-M) and pepsin-soluble collagen (PSC-M) with yields of 4.27 ± 0.22% and 9.54 ± 0.51%, respectively, were extracted from monkfish swim bladders using acid and enzyme methods. The ASC-M and PSC-M contained Gly (325.2 and 314.9 residues/1000 residues, respectively) as the major amino acid, but they had low imino acid content (192.5 and 188.6 residues/1000 residues, respectively) in comparison with collagen from calf skins (CSC) (216.6 residues/1000 residues). The sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) patterns and ultraviolet (UV) absorption spectrums of ASC-M and PSC-M illustrated that they were mainly composed of type I collagen. Subsequently, three ACEi peptides were isolated from a PSC-M hydrolysate prepared via a double-enzyme system (alcalase + neutrase) and identified as SEGPK (MHP6), FDGPY (MHP7) and SPGPW (MHP9), with molecular weights of 516.5, 597.6 and 542.6 Da, respectively. SEGPK, FDGPY and SPGPW displayed remarkable anti-ACE activity, with IC₅₀ values of 0.63, 0.94 and 0.71 mg/mL, respectively. Additionally, a molecular docking assay demonstrated that the affinities of SEGPK, FDGPY and SPGPW with ACE were −7.3, −10.9 and −9.4 kcal/mol, respectively. The remarkable ACEi activity of SEGPK, FDGPY and SPGPW was due to their connection with the active pockets and/or sites of ACE via hydrogen bonding, hydrophobic interaction and electrostatic force. Moreover, SEGPK, FDGPY and SPGPW could protect HUVECs by controlling levels of nitric oxide (NO) and endothelin-1 (ET-1). Therefore, this work provides an effective means for the preparation of collagens and novel ACEi peptides from monkfish swim bladders, and the prepared ACEi peptides, including SEGPK, FDGPY and SPGPW, could serve as natural functional components in the development of health care products to control hypertension. Full article

This study investigated whether oral supplementation with protease-soluble chicken type II collagen (PSCC-II) mitigates the progression of anterior cruciate ligament transection (ACLT)–induced osteoarthritis (OA) in rats. Eight-week-old male Wistar rats were randomly assigned to the following groups: control, sham, ACLT, group A (ACLT + pepsin-soluble collagen type II collagen (C-II) with type I collagen), group B (ACLT + Amano M–soluble C-II with type I collagen), group C (ACLT + high-dose Amano M–soluble C-II with type I collagen), and group D (ACLT + unproteolyzed C-II). Various methods were employed to analyze the knee joint: nociceptive tests, microcomputed tomography, histopathology, and immunohistochemistry. Rats treated with any form of C-II had significant reductions in pain sensitivity and cartilage degradation. Groups that received PSCC-II treatment effectively mitigated the ACLT-induced effects of OA concerning cancellous bone volume, trabecular number, and trabecular separation compared with the ACLT alone group. Furthermore, PSCC-II and unproteolyzed C-II suppressed ACLT-induced effects, such as the downregulation of C-II and upregulation of matrix metalloproteinase-13, tumor necrosis factor-α, and interleukin-1β. These results indicate that PSCC-II treatment retains the protective effects of traditional undenatured C-II and provide superior benefits for OA management. These benefits encompass pain relief, anti-inflammatory effects, and the protection of cartilage and cancellous bone. Full article

The objective of this study was to evaluate the effect of ultrasound pre-treatment on the characterization from Bactrian camel skin. It was possible to produce and characterize collagen extracted from Bactrian camel skin. The results showed that the yield of collagen was higher in ultrasound pre-treatment (UPSC) (41.99%) than the pepsin-soluble collagen extraction (PSC) (26.08%). All extracts were identified as type I collagens using sodium dodecyl sulfate polyacrylamide gel electrophoresis and retained their helical structure, as confirmed through Fourier transform infrared spectroscopy. The scanning electron microscopy analysis of UPSC revealed that some physical changes were caused by sonication. UPSC had smaller particle size than PSC. The viscosity of UPSC always plays a leading role in the range of 0–10 Hz. However, the contribution of elasticity to the solution system of PSC increased in the range of 1–10 Hz. Moreover, ultrasound-treated collagen had superior solubility property at pH 1–4 and at <3% (w/v) NaCl than non-ultrasound treated collagen. Therefore, the utilization of ultrasound for the extraction of pepsin soluble collagen is a good alternative technology to expand the application at industrial level. Full article

The current study aimed to determine the effects of extraction time on the extractability and physicochemical properties of collagen from the skin of silver catfish (Pangasius sp.). Pepsin soluble collagen (PSC) was extracted for 24 and 48 h and analysed in terms of chemical composition, solubility, functional group, microstructure, and rheological properties. The yields of PSC at 24 h and 48 h extraction time were 23.64% and 26.43%, respectively. The chemical composition exhibited significant differences, with PSC extracted at 24 h showing better moisture, protein, fat, and ash content. Both collagen extractions indicated the highest solubility at pH 5. In addition, both collagen extractions exhibited Amide A, I, II, and III as fingerprint regions for collagen structure. The morphology of the extracted collagen appeared porous with a fibril structure. The dynamic viscoelastic measurements of complex viscosity (η*) and loss tangent (tan δ) decreased as temperature increased, and the viscosity increased exponentially as the frequency increased, whereas the loss tangent decreased. In conclusion, PSC extracted at 24 h showed similar extractability to that extracted at 48 h but with a better chemical composition and shorter extraction time. Therefore, 24 h is the best extraction time for PSC from silver catfish skin. Full article

Finding strategies to use the swim bladder of farmed totoaba (Totoaba macdonaldi) is of the utmost need to reduce waste. Fish swim bladders are rich in collagen; hence, extracting collagen is a promising alternative with benefits for aquaculture of totoaba and the environment. The elemental biochemical composition of totoaba swim bladders, including their proximate and amino acid compositions, was determined. Pepsin-soluble collagen (PSC) was used to extract collagen from swim bladders, and its characteristics were analyzed. Alcalase and papain were used for the preparation of collagen hydrolysates. Swim bladders contained 95% protein, 2.4% fat, and 0.8% ash (on a dry basis). The essential amino acid content was low, but the functional amino acid content was high. The PSC yield was high, at 68% (dry weight). The amino acid composition profile, electrophoretic pattern, and structural integrity analyses of the isolated collagen suggested it is a typical type-I collagen with high purity. The denaturalization temperature was 32.5 °C, probably attributable to the imino acid content (205 residues/1000 residues). Papain-hydrolysates (≤3 kDa) of this collagen exhibited higher radical scavenging activity than Alcalase-hydrolysates. The swim bladder from the farmed totoaba could be an ideal source to produce high-quality type I collagen and may be considered an alternative to conventional collagen sources or bioactive peptides. Full article

There is a growing demand for the identification of alternative sources of collagen not derived from land-dwelling animals. The present study explored the use of pepsin- and acid-based extraction protocols to isolate collagen from the swim bladders of Megalonibea fusca. After extraction, these acid-soluble collagen (ASC) and pepsin-soluble collagen (PSC) samples respectively were subjected to spectral analyses and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) characterization, revealing both to be comprised of type I collagen with a triple-helical structure. The imino acid content of these ASC and PSC samples was 195 and 199 residues per 1000 residues, respectively. Scanning electron microscopy demonstrated that samples of freeze-dried collagen exhibited a compact lamellar structure, while transmission electron microscopy and atomic force microscopy confirmed the ability of these collagens to undergo self-assembly into fibers. ASC samples exhibited a larger fiber diameter than the PSC samples. The solubility of both ASC and PSC was highest under acidic pH conditions. Neither ASC nor PSC caused any cytotoxicity when tested in vitro, which met one of the requirements for the biological evaluation of medical devices. Thus, collagen isolated from the swim bladders of Megalonibea fusca holds great promise as a potential alternative to mammalian collagen. Full article

The present study used acetic acid, sodium hydroxide, and pepsin extract acid-soluble collagen (ASC), alkali-soluble collagen (ALSC), and pepsin-soluble collagen (PSC) from the bones of spent-hens, and the effects of three extraction methods on the characteristics, processing properties, antioxidant properties and acceptability of chicken bone collagen were compared. The results showed that the extraction rates of ASC, ALSC and PSC extracted from bones of spent-hens were 3.39%, 2.42% and 9.63%, respectively. The analysis of the amino acid composition, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), Fourier transform infrared spectroscopy (FTIR), and ultraviolet full spectrum showed that the collagen extracted by the three methods had typical collagen characteristics and stable triple-helix structure, but the triple helical structure of PSC is more stable, and acid and alkaline extraction seems to have adverse effects on the secondary structure of chicken bone collagen. Differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) scanning showed that PSC had higher thermal stability and more regular, loose, and porous microstructure. In addition, PSC has good processing properties, in vitro antioxidant activity, and organoleptic acceptability. Therefore, enzymatic hydrolysis was still one of the best methods to prepare collagen from bones of spent-hens, and enzyme-soluble collagen has wider application prospects in functional food and medicine and also provides an effective way for the high-value comprehensive utilization of waste chicken bone by-products. Full article

The tail tendons of skipjack tuna (Katsuwonus pelamis), a by-product from the meat-separation process in canned-tuna production, was used as an alternative source of collagen extraction. The acid-solubilized collagens using vinegar (VTC) and acetic-acid (ATC) extraction and pepsin-solubilized collagen (APTC) were extracted from tuna-tail tendon. The physiochemical properties and characteristics of those collagens were investigated. The obtained yield of VTC, ATC, and APTC were 7.88 ± 0.41, 8.67 ± 0.35, and 12.04 ± 0.07%, respectively. The determination of protein-collagen solubility, the effect of pH and NaCl on collagen solubility, Fourier-transform infrared spectroscopy (FTIR) spectrum, and microstructure of the collagen-fibril surface using a scanning electron microscope (SEM) were done. The protein solubility of VTC, ATC, and APTC were 0.44 ± 0.03, 0.52 ± 0.07, and 0.67 ± 0.12 mg protein/mg collagen. The solubility of collagen decreased with increasing of NaCl content. These three collagens were good solubility at low pH with the highest solubility at pH 5. The FTIR spectrum showed absorbance of Amide A, Amide B, Amide I, Amide II, and Amide III groups as 3286–3293 cm⁻¹, 2853–2922 cm⁻¹, 1634–1646 cm⁻¹, 1543–1544 cm⁻¹, and 1236–1237 cm⁻¹, respectively. The SEM analysis indicated a microstructure of collagen surface as folding of fibril with small pore. Full article

Instead of molecularly imprinting a whole protein molecule, imprinting protein epitopes is gaining popularity due to cost and solubility issues. Belonging to the matrix metalloproteinase protein family, MMP-1 is an interstitial collagenase that degrades collagen and may be involved in cell migration, cell proliferation, the pro-inflammatory effect, and cancer progression. Hence, it can serve as a disease protein biomarker and thus be useful in early diagnosis. Herein, epitopes of MMP-1 were identified by screening its crystal structure. To identify possible epitopes for imprinting, MMP-1 was cleaved in silico with trypsin, pepsin at pH = 1.3, and pepsin at pH > 2.0 using Peptide Cutter, generating peptide fragments containing 8 to 12 amino acids. Five criteria were applied to select the peptides most suitable as potential epitopes for MMP-1. The triphenylamine rhodanine-3-acetic acid (TPARA) functional monomer was synthesized to form a stable pre-polymerization complex with a selected template epitope. The complexed functional monomer was then copolymerized with 3,4-ethoxylenedioxythiophene (EDOT) using potentiodynamic electropolymerization onto indium–tin–oxide (ITO) electrodes. The composition of the molecularly imprinted poly(TPARA-co-EDOT) (MIP) was optimized by maximizing the film’s electrical conductivity. Cyclic voltammetry was used to determine MMP-1 concentration in the presence of the Fe(CN)₆³⁻/Fe(CN)₆⁴⁻ redox probe actuating the “gate effect.” A calibration curve was constructed and used to determine the usable concentration range and the limit of detection as ca. 0.001 to 10.0 pg/mL and 0.2 fg/mL MMP-1, respectively. Finally, the MMP-1 concentration in the A549 human lung (carcinoma) culture medium was measured, and this determination accuracy was confirmed using an ELISA assay. Full article

In search of alternative and sustainable sources of collagenous materials for biomedical applications, the scales of five Mediterranean fish species—fished in high tonnage in the Mediterranean region since they represent popular choices for the local diet—as well as those of the Atlantic salmon for comparison purposes, were comparatively studied for their acid- and pepsin-soluble collagen content. Fish scales that currently represent a discarded biomass of no value could be efficiently exploited for the production of a high added-value biomaterial. The isolated collagenous materials, which showed the typical electrophoretic patterns of type I collagen, were morphologically and physicochemically characterized. Using scanning electron microscopy the fibrous morphology of the isolated collagens was confirmed, while the hydroxyproline content, in conjunction with infrared spectroscopy and X-ray diffraction studies verified the characteristic for collagen amino acid profile and its secondary structure. The acid- and pepsin-soluble collagens isolated from the fish scales were blended with the bioactive sulfated marine polysaccharide ulvan and polyethylene oxide and electrospun to afford nanofibrous scaffolds that could find applications in the biomedical sector. Full article

Fish processing waste is a prospective source of collagen and a cost-effective environmental pollutant. The skin of the purple-spotted bigeye snapper (Priacanthus tayenus) was extracted utilising various acid soluble collagens (ASC) including acetic acid (AAC), lactic acid (LAC), citric acid (CAC) and pepsin soluble collagens (PSC). In this study, PSC (6.65%) had the highest collagen yield, followed by AAC (5.79%), CAC (4.15%), and LAC (3.19%). The maximum temperatures (T_max) denaturation of AAC, LAC, CAC, and PSC were 31.4, 31.7, 31.5, and 33.2 °C, respectively. UV-VIS absorption spectra showed all extracted collagens had a range of absorbance at 230 nm, due to the presence of glycine, proline, hydroxyproline, and triple-helical collagen. Additionally, they exhibited amide A, B, amide I, II, and III peaks. SDS–PAGE identified all extracted collagens as type I. The PSC had a significantly higher (p < 0.05) hydroxyproline content than acidic extraction 66.3 ± 1.03 (mg/g sample). Furthermore, all samples were extremely soluble in acetic conditions at pH 5, and all collagen was soluble in NaCl up to 3% (w/v). Therefore, PSC was the best treatment since it did not impact collagen triple helical and acetic acid yielded the most collagen in ASC extraction. Overall, the analysis revealed that fish skin waste might be used as an alternate source of collagen in diverse applications, particularly in food applications. Full article