Catfish Skin Research Articles

Characteristics of Acid Soluble Collagen from Catfish (Clarias Lazera) Skin

Characteristics of Acid Soluble Collagen from Catfish (Clarias Lazera) Skin

The Characteristic of Gelatin Extracted from The Skin of Adult and Sub-Adult Striped Catfish (Pangasius hypophthalmus) Using Acid-Base Pretreatment: pH and FTIR

The gelatin is the biomaterial that produced by collagen denaturation. The age of animal was reported influences the collagen crosslinks which by that contribute to the gelatin quality. The aims of this study were to determine the characteristics of gelatin that extracted from the skin of adult and sub adult striped catfish (Pangasius hypophthalmus) using acid-base pre-treatment based on pH and FTIR (Fourier Transform Infrared) analysis. The gelatine were extracted from striped catfish skins of adult fish (total body length or TBL = 48.6 ± 1.9 cm) and sub-adult (TBL = 38.9 ± 0.5 cm) using acid-base pre-treatment (CH3COOH and NaOH solution). The pre-treated skin was washed with tap water until neutral. Finally, the swollen skin was mixed with sterile water at a ratio 1/10 (w/v) and extracted using water bath at 40-70 °C for 60 minutes. In general, the pre-treated acid-base of adult and sub adult fish skin resulted the neutral pH gelatin. The FTIR spectra analysis of gelatin from adult and sub adult striped catfish skin exhibited the similar of wavenumbers included amide A, B, I, II, and III region. In both striped catfish skin gelatin adult and sub-adult were shown the functional groups of O-H, C-H, N-H, C = O, C = N, C = C, and N = O.

Histological structure of striped catfish (Pangasius Hypophthalmus) skin from different body size (age) and its relation to the quality of gelatin based on the melting point

Gelatin is a protein derived from collagen denaturation. Currently, fish gelatin has been developed as an alternative to halal gelatin. Fish gelatin can be extracted from the skin of several fish including striped catfish (Pangasius hypophthalmus), because the skin’s connective tissue contains a lot of collagen. In industrial applications, melting point is a very important characteristic of gelatin. The biological factors of raw materials such as the size or age of fish are thought to influence the content of collagen, thereby affecting the melting point of gelatin. The aim of this study was to compare the histological structure of the striped catfish skin at different body sizes, especially the observation of collagen in the skin’s connective tissues and to determine its relationship with the quality of its gelatin product based on melting point. The gelatin pre-treatment was performed using acid-base treatment, extraction with distilled water (55°C) were conducted prior to melting point measurement. The results of histological analysis showed that the connective tissue in the skin of larger fish contained thicker stratum compactum and thinner of stratum spongiosum. The melting point of large catfish skin gelatin has a higher melting point (25.5 °C) than the smaller size (24 °C).

Preparation and evaluation of catfish protein as a wood adhesive

In order to decrease the usage of formaldehyde and petroleum-derived raw materials, there has been a lot of interest in using protein-based wood adhesives as more eco-friendly and less hazardous alternatives. Fish proteins can be extracted from fish and are known to have good adhesive properties. In this work, we extracted the protein from catfish skin and characterized its effectiveness as a wood adhesive. Upon analysis, this protein from catfish skin (a byproduct of catfish processing) performed well as an adhesive, with similar (or slightly better) dry adhesive strength relative to cottonseed protein isolate. The blend of catfish protein and cottonseed protein displayed about the same dry adhesive strength when compared to catfish protein alone. The hot water resistance of catfish protein and cottonseed protein was comparable, but the 1:1 blend exhibited improved performance than the two proteins by themselves. These results suggest that the protein from catfish skin may be a suitable material for wood adhesive applications.

Analysis of Added Value of Catfish Raw Leather Cracker Product (Case Study at CV. Raja Patin, Sugiharjo Village, Deli Serdang Regency, North Sumatra Province)

This study aims to analyze the added value of the catfish skin cracker product in CV. Raja Patin, Sugiharjo Village, North Sumatra Province. The method used in this research is a case study method and quantitative descriptive analysis as data analysis used. The sampling technique was carried out using a purposive sampling method. The added value of the fish skin cracker product is IDR 31,700 / kg with an added value ratio of 67.44%. Fish products that are processed into fish crackers are worth 0.47 times the price of fresh fish. This indicates that processing activities provide a sizeable contribution to economic value added and product added value.

Expression of Ietalurus punetaus β-defensin based on recombinant Pichia pastoris

β-defensin is a primary protein immune factor in channel catfish's (Ietalurus punetaus) resistance to pathogenic microorganisms. Its primary structure contains a signal peptide composed of 24 amino acid residues at the N-terminal and a mature peptide composed of 43 amino acid residues at the C-terminal. The mature peptide region is responsible for the biological activity of β-defensin. In the present study, a recombinant strain of Pichia pastoris that produces channel catfish β-defensin, was constructed to realize the biosynthesis of channel catfish β-defensin based on eukaryotic expression. First, the β-defensin gene "IPBD" was isolated from the skin of channel catfish by RT-PCR. After linking it with the expression vector pPICZA, pPICZA-IPBD was transferred into competent P. pastoris X-33 cells to obtain recombinant P. pastoris strains. The yeast transformants with multi-copy gene inserts were obtained by using the culture medium containing 1 000 μg/mL zeocin. Using BMM culture medium (without amino nitrogen culture medium) instead of BMMY culture medium (with amino nitrogen culture medium), the fermentation and culture conditions of the recombinant strain were optimized, and the optimal conditions for producing channel catfish β-defensin were determined as follows: the expression was induced for 96 h with 1.0% methanol at 28 °C , 250 r/min. Purified protein with molecular weight of 5.98 kDa was obtained by nickel affinity chromatography, and MALDI-TOF/TOF mass spectrometry proved that it was the expected recombinant IPBD. The antibacterial test results showed that the inhibitory rates of recombinant IPBD on Gram-positive Staphylococcus aureus and Listeria monocytogenes and Gram-negative Pseudomonas aeruginosa were 69.6%, 71.6% and 65.8%, respectively. This study provides a recombinant DNA technique for the development of small molecule natural antibacterial peptide from fish.

Physicochemical Properties and Angiotensin I Converting Enzyme Inhibitory Peptides of Freshwater Fish Skin Collagens

ABSTRACT The objectives of this study were to characterize physicochemical properties of two collagens, tilapia skin (TS) and hybrid catfish skin (HS). Angiotensin-converting enzyme (ACE) inhibitory peptides from extracted TS and HS collagen using pepsin were also determined. HS collagen had a higher amount of imino acid than TS collagen, while TS contained higher amounts of tyrosine (Tyr) and lysine (Lys). Fourier-transform infrared spectra of both collagens showed predominant helix structure. The HS collagen hydrolysate prepared by pepsin was fractionated using sequential ultrafiltration membranes, and the fraction with molecular weight (MW) <5 kDa showed the highest ACE inhibitory activity (p < .05). After cation exchange and two steps size exclusion chromatography, peptides showed ACE inhibitory activity of 72.06%. This study revealed that ACE inhibitory peptides derived from HS collagen could be developed as a functional food with potential antihypertensive properties.

Antibacterial activity and mechanism of the cell-penetrating peptide CF-14 on the gram-negative bacteria, Escherichia coli

In the present study, we characterized CF-14, a novel antimicrobial peptide derived from the catfish skin mucus. The objective of this study was to explore the antimicrobial mechanism of CF-14 against Escherichia coli. The agar-diffusion assay and the microdilution method were used to evaluate the antimicrobial activity and the minimum inhibitory concentration (MIC) of CF-14 against E. coli, respectively. In addition, the absorbance of the bacterial suspension filtrate at 260 nm was measured to quantify the leakage of bacterial cytoplasmic components. The bacterial morphological changes were observed by scanning electron microscopy, while confocal microscopy was used to investigate the localization site of CF-14 in E.coli. The DNA binding ability of CF-14 was evaluated using gel retardation assay and the binding of CF-14 to DnaK was evaluated using Discovery Studio. The results demonstrated that CF-14 exhibited strong antimicrobial activity against E.coli with an MIC of 31.3 μg/mL. Unlike common cationic anti-microbial peptides (AMPs) that target the cellmembrane, CF-14 penetrated the E.coli cell membrane and induced only minormembrane perturbations. Furthermore, the antimicrobial mechanism of CF-14 against E.coli involved DNA binding and competitive inhibition of bacterial DnaK. Finally, by deleting or replacing the amino acid sequence, the antibacterial activity of CF-14 was affected, which helped the optimization of amino acid sequence. Therefore, CF-14 can be a potential antimicrobial peptide.

Proteomic profiling of yellow catfish (Pelteobagrus fulvidraco) skin mucus identifies differentially-expressed proteins in response to Edwardsiella ictaluri infection

Fish mucus acts as a physiological and immunological barrier for maintaining normal fish physiology and conferring defense against pathogens infection. Here we report proteomic profiling of skin mucus of yellow catfish before and after E. ictaluri infection by Label-free LC-MS/MS approach. A total of 918 non-redundant proteins were identified from 54443 spectra referring to yellow catfish genome database. Further annotation via GO and KEGG database revealed complex protein composition of yellow catfish mucus. Besides structural proteins in mucus, a lot of immune-related proteins were retrieved, such as lectins, complement components, antibacterial peptides and immunoglobins. 133 differentially-expressed proteins (DEPs), including 76 up-regulated and 57 down-regulated proteins, were identified, most of which were enriched into 17 pathways centering on “immune system” category with 33 proteins involved. Consistently, significant proliferation of mucus-secreting goblet cells and CYPA-expressing cells were observed along outside of yellow catfish skin after E. ictaluri infection, indicating an enhanced immune response to E. ictaluri infection in yellow catfish skin mucus. The proteomic data provide systematic protein information to comprehensively understand the biological function of yellow catfish skin mucus in response to bacterial infection.

Effect of Pre-Treatment on Physical Properties and Sensory Attributes of Gelatin Extracted from Sutchi Catfish (Pangasius sutchi) Skin

This study was conducted to evaluate the effect of pre-treatment on fishy flavor and odor removal of gelatin extracted from sutchi catfish (Pangasius sutchi) skin. Pre-treatment of the skin involved soaking at 4°C in distilled water (GC), lime followed by tamarind (GLT) or salt followed by activated carbon (GSC) prior to extraction in warm distilled water (50°C) for 12 hrs. Yield, physical properties and sensory were determined. Results showed that GLT produced highest yield (19.72%) compared to GSC (15.01%) and GC (15.81%). Although, GLT exhibited lowest gel strength (282.29g), viscoelasticity (14.1ºC) and setting point (10.46ºC) compared to other pre-treatments, fishy flavor and odor of the gelatin were almost absent obtaining the score of 1.68 and 1.74, respectively. These values were below those of reference which are 1.87 (fishy flavor) and 2.71 (fishy odor) denoting from ‘absent to weak’. Since fishy flavor and odor were almost absent, soaking sutchi catfish skin in lime followed by tamarind could be a good method to obtain gelatin with the desired sensory attributes.

Microbiome of Co-cultured Fish Exhibits Host Selection and Niche Differentiation at the Organ Scale.

Fish are the most widespread aquaculture species and maintain complex associations with microbial consortiums. However, the ecology of these associations present in multiple microhabitats in fish remains elusive, especially on the microbial assembly in fish external (skin and gill) and internal (stomach and intestine) niches, and the relationship with the rearing environment. To understand host dependence and niche differentiation of organ-specific microbiome signatures using a 16S rRNA gene-based sequencing technique, we systematically provided characterizations of a comparative framework relevant to the microbiome of stomach, regional intestine, skin, and gill in two important farmed fish species, herbivorous grass carp (Ctenopharyngodon idella) and carnivorous southern catfish (Silurus meridionalis), and of the rearing water. The different feeding habits of grass carp and southern catfish showed a significant separation of microbial community structure, with great compositional differences across body sites within each species. Site-driven divergences relied on host species: the same types of microhabitats between grass carp and southern catfish harbored differential microbiome. Additionally, body sites had remarkably distinct communities and displayed lower alpha diversity compared to rearing water. Unexpectedly, the stomach of southern catfish had the highest microbial diversity in the digestive tract of the two co-cultured fish species. For external sites within each species, a higher diversity occurred in gill of grass carp and in skin of southern catfish. Our results unveil different topographical microbiome signatures of the co-cultured species, indicating host selection in individual-level microbial assemblages and niche differentiation at the organ scale. This work represents a foundation for understanding the comprehensive microbial ecology of cohabiting farmed fish, suggesting potential applications associated with fish microbiome that urgently needs to be assessed in polycultured operations in aquaculture.

Furanoic Lipid F-6, A Novel Anti-Cancer Compound that Kills Cancer Cells by Suppressing Proliferation and Inducing Apoptosis.

Identifying novel anti-cancer drugs is important for devising better cancer treatment options. In a series of studies designed to identify novel therapeutic compounds, we recently showed that a C-20 fatty acid (12,15-epoxy-13,14-dimethyleicosa-12,14-dienoic acid, a furanoic acid or F-6) present in the lipid fraction of the secretions of the Arabian Gulf catfish skin (Arius bilineatus Val.; AGCS) robustly induces neutrophil extracellular trap formation. Here, we demonstrate that a lipid mix (Ft-3) extracted from AGCS and F-6, a component of Ft-3, dose dependently kill two cancer cell lines (leukemic K-562 and breast MDA MB-231). Pure F-6 is approximately 3.5 to 16 times more effective than Ft-3 in killing these cancer cells, respectively. Multiplex assays and network analyses show that F-6 promotes the activation of MAPKs such as Erk, JNK, and p38, and specifically suppresses JNK-mediated c-Jun activation necessary for AP-1-mediated cell survival pathways. In both cell lines, F-6 suppresses PI3K-Akt-mTOR pathway specific proteins, indicating that cell proliferation and Akt-mediated protection of mitochondrial stability are compromised by this treatment. Western blot analyses of cleaved caspase 3 (cCasp3) and poly ADP ribose polymerase (PARP) confirmed that F-6 dose-dependently induced apoptosis in both of these cell lines. In 14-day cell recovery experiments, cells treated with increasing doses of F-6 and Ft-3 fail to recover after subsequent drug washout. In summary, this study demonstrates that C-20 furanoic acid F-6, suppresses cancer cell proliferation and promotes apoptotic cell death in leukemic and breast cancer cells, and prevents cell recovery. Therefore, F-6 is a potential anti-cancer drug candidate.

Environmental conditions and neutral processes shape the skin microbiome of European catfish (Silurus glanis) populations of Southwestern France.

Teleost fishes interact with diverse microbial communities, playing crucial functions for host fitness. While gut microbiome has been extensively studied, skin microbiome has been overlooked. Specifically, there is no assessment of the relative impact of host and environmental factors on microbiome variability as well as neutral processes shaping fish skin microbiome. Here, we assessed the skin microbiome of a Siluriforme, the European catfish (Silurus glanis) sampled in four sites located in Southwestern France. We assessed the relative roles of individual features (body size and genetic background), local environment and neutral processes in shaping skin microbiome. Catfish skin microbiome composition was distinct to that of other freshwater fish species previously studied with high abundances of Gammaproteobacteria and Bacteroidetes. We found no effect of catfish individual genotype and body size on the structure of its associated skin microbiome. Geographical location was the best catfish skin microbiome structure predictor, together with neutral models of microbiome assembly.

Evaluation of a Recombinant Flavobacterium columnare DnaK Protein Vaccine as a Means of Protection Against Columnaris Disease in Channel Catfish (Ictalurus punctatus).

Flavobacterium columnare causes substantial losses among cultured finfish species. The Gram-negative bacterium is an opportunistic pathogen that manifests as biofilms on the host's mucosal surfaces as the disease progresses. We previously demonstrated that the dominant mucosal IgM antibody response to F. columnare is to the chaperone protein DnaK that is found in the extracellular fraction. To establish the efficacy of using recombinant protein technology to develop a new vaccine against columnaris disease, we are reporting on two consecutive years of vaccine trials using a recombinant F. columnare DnaK protein (rDnaK). In year one, three groups of channel catfish (n = 300) were immunized by bath immersion with a live attenuated F. columnare isolate, rDnaK or sham immunized. After 6 weeks, an F. columnare laboratory challenge showed a significant increase in survival (>30%) in both the live attenuated and rDnaK vaccines when compared to the non-immunized control. A rDnaK-specific ELISA revealed significant levels of mucosal IgM antibodies in the skin of catfish immunized with rDnaK at 4- and 6-weeks post immunization. In the second year, three groups of channel catfish (n = 300) were bath immunized with rDnaK alone or with rDnaK after a brief osmotic shock or sham immunized. After 6 weeks a laboratory challenge with F. columnare was conducted and showed a significant increase in survival in the rDnaK (> 25%) and in rDnaK with osmotic shock (>35%) groups when compared to the non-immunized control. The rDnaK-specific ELISA demonstrated significant levels of mucosal IgM antibodies in the skin of catfish groups immunized with rDnaK at 4- and 6-weeks post immunization. To further understand the processes which have conferred immune protection in the rDnaK group, we conducted RNA sequencing of skin samples from the non-immunized (n = 6) and rDnaK treated channel catfish at 1-week (n = 6) and 6 weeks (n = 6) post immunization. Significantly altered gene expression was identified and results will be discussed. Work to further enhance the catfish immune response to F. columnare rDnaK is underway as this protein remains a promising candidate for additional optimization and experimental trials in a production setting.

Physicochemical properties of silver catfish (Pangasius sp.) skin collagen as influenced by acetic acid concentration

The aim of this study was to investigate the physicochemical properties of silver catfish skin collagen as affected by acetic acid concentration (0.5M and 0.7M). Acid solubilised collagen (ASC) were isolated from the skin of silver catfish (Pangasius Sp.) and were compared with commercial collagen. The yields of extracted collagen using 0.5M and 0.7M acetic acid were 10.94±0.38% and 5.47±0.20%, respectively. The pH values for commercial collagen and extracted collagen for 0.5M and 0.7M acetic acid values were 6.52±0.04, 4.04±0.06 and 3.79±0.28, respectively. The functional group of collagen was successfully detected, along with a flaky and fibrous morphology structure. The relative viscosity for all samples decreased with an increase in temperature. Collagen extracted with 0.5M acetic acid is more efficient for use as a solvent for collagen extraction since it produces a higher yield and higher fibrous collagen thickness. This study found that collagen extracted from silver catfish (Pangasius sp.) had the potential to be used as alternative fish collagen in various fields.

Catfish (Arius bilineatus, Val.) skin protein preparation ameliorates neurobehavioral and axonal and neuronal histopathological alterations in a sciatic nerve crush injury rat model: a novel approach

Preliminary investigations showed that soluble protein fraction‐Fraction C (SPF‐FC) from catfish skin preparations (CSP) from the Arabian Gulf catfish (Arius bilineatus, Val.) exhibit potent anti‐inflammatory and healing properties as shown in our previous clinical trials for the healing of non‐healing diabetic foot ulcers, chronic back pain, and some other neurological disorders. The present study was designed to investigate the neuroprotective and neuroregenerative properties of SPF‐FC derived from CSP on the spinal neurons, regeneration of sciatic nerve fibers, and recovery of sensory‐motor functions in the sciatic nerve crush injury model. Male Wistar rats (weight 250–300 g) were randomly assigned to four groups: (I) SHAM, (II) CRUSH, (III) CRUSH+SPF treated intraperitoneally (IP) and (IV) CRUSH+SPF treated subcutaneously (SC) groups. Rats in CRUSH groups underwent surgery, where the sciatic nerve was crushed, followed by treatment with saline (II) or with 3–12 mg/Kg SPF IP (III) or SC (IV) daily for 14 days. All animals were tested for the neurobehavioral parameters throughout the 6 weeks of the study. Sciatic nerve and spinal cord tissues were processed for light and electron histological examinations, stereological analysis, immunohistochemical and biochemical examinations at Week 4 and Week 6 post‐injury. Administration of SPF IP or SC significantly (p&lt;0.05–0.0001) enhanced the sensory and motor performance on different neurobehavioral functional tests of the nerve‐injured rats. The stereological evaluation revealed significant (p&lt;0.000) histomorphological evidence of neuroregeneration in the sciatic nerve of the CRUSH+ SPF groups compared to controls at week 4 and 6. SPF‐FC treatment significantly prevented the decrease in the number of the NeuN‐immunoreactive spinal neurons ipsilateral to the crush injury, decreased the GFAP immunoreactive astrocytes and increased the GAP‐43 immunoreactivity. The data analysis supports our hypothesis that SPF‐FC immunoreactivity treatment lessens neurobehavioral deficits, enhances axonal regeneration and ameliorate histomorphological nerve alterations following nerve injury. Further, SPF‐FC protects spinal neurons and enhances subcellular recovery by decreasing the astrocytic activity and GAP‐43, thus improves nerve regeneration and functional recovery.Support or Funding InformationThis work was supported by Kuwait University Research Administration (KU Grants No. SL03/14 and SL04/09 and RCF/OMICSRU project SRUL02/13) and Kuwait Foundation for the Advancement of Sciences (Grant No. KFAS 2013‐1207‐01A‐D).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Extraction and characterization of collagen from the skin of Pterygoplichthys pardalis and its potential application in food industries.

The primary objective of this study was to extract collagen from underutilized fish species owing to its cost effective nature and also its ability to address the demand of type I collagen arising from food and pharmaceutical industries. Acid and pepsin soluble collagen (ppASC and ppPSC) were extracted from the skin of sucker catfish (Pterygoplichthys pardalis) with a yield of 19.6 and 23.8% on wet weight basis respectively. The same were characterized and confirmed as type I collagen by SDS-PAGE, FTIR and UV-Vis spectroscopy, amino acid analysis, and Zeta potential. Taking into consideration the application of collagen in food industry, a food product was developed by incorporating with fresh cheese. This fortification was found to be acceptable and had not altered the taste, odor and other sensory properties of the product.

Characterisation of Collagen from the Skin of Catfish (Pangasius sp) for Innovative PVA-Collagen Nanofiber

Preparation of PVA-Collagen nanofiber plaster production begin by repairing the skin of catfish, then collagen is extracted with distilled water. Extracted collagen need to be frozen dry so that collagen can be obtained in the form of sheets, powder, or crystals. The next step is the production of PVA-Collagen nanofiber, a 10% solution of polyvinyl alcohol (PVA) is mixed with a previously prepared extracted collagen and stirred until it forms a homogeneous mixture. Next, PVA-Collagen nanofiber is formed by the electrospinning method. The results of characterization using FTIR found three main groups in six variations: amide group A; amide I; and amide II. Amide A has a wave number in the range 3300-3440 cm-1, amide I is in the range 1625-1690 cm-1, and amide II is in the range of 1480-1575 cm-1. Characterization was carried out to determine the surface morphology of the observation in the sample using Photomicrograph (200 µm) with magnification 10x, produced fiber diameter formed in variations of PVA-Collagen 1% 116-120 µm while in the variation of PVA-Collagen 1% + Chitosan 10 drops in diameter 41-50 µm.

Furanoid F-Acid F6 Uniquely Induces NETosis Compared to C16 and C18 Fatty Acids in Human Neutrophils.

Various biomolecules induce neutrophil extracellular trap (NET) formation or NETosis. However, the effect of fatty acids on NETosis has not been clearly established. In this study, we focused on the NETosis-inducing ability of several lipid molecules. We extracted the lipid molecules present in Arabian Gulf catfish (Arius bilineatus, Val) skin gel, which has multiple therapeutic activities. Gas chromatography–mass spectrometry (GC-MS) analysis of the lipid fraction-3 from the gel with NETosis-inducing activity contained fatty acids including a furanoid F-acid (F6; 12,15-epoxy-13,14-dimethyleicosa-12,14-dienoic acid) and common long-chain fatty acids such as palmitic acid (PA; C16:0), palmitoleic acid (PO; C16:1), stearic acid (SA; C18:0), and oleic acid (OA; C18:1). Using pure molecules, we show that all of these fatty acids induce NETosis to different degrees in a dose-dependent fashion. Notably, F6 induces a unique form of NETosis that is rapid and induces reactive oxygen species (ROS) production by both NADPH oxidase (NOX) and mitochondria. F6 also induces citrullination of histone. By contrast, the common fatty acids (PA, PO, SA, and OA) only induce NOX-dependent NETosis. The activation of the kinases such as ERK (extracellular signal-regulated kinase) and JNK (c-Jun N-terminal kinase) is important for long-chain fatty acid-induced NETosis, whereas, in F-acid-induced NETosis, Akt is additionally needed. Nevertheless, NETosis induced by all of these compounds requires the final chromatin decondensation step of transcriptional firing. These findings are useful for understanding F-acid- and other fatty acid-induced NETosis and to establish the active ingredients with therapeutic potential for regulating diseases involving NET formation.

Recycling fish skin for utilization in food industry as an effective emulsifier and foam stabilizing agent

Abstract Background Indian fish industry produces a staggering amount of waste every year part of which is dumped as landfill leading to pollution. Objective This study aims to extract collagen from fish skin, a major component of this waste, hydrolyze it and use the hydrolysate as emulsifiers to increase the shelf life of food products. Materials and methods Collagen was purified from the skin of Catfish, Mullet and Indian Salmon were characterized through infrared and diffraction studies. The samples were hydrolyzed enzymatically. The hydrolysates were assayed for emulsifying, foam stabilizing and hemolytic properties. Results The samples displayed an electrophoretic and infrared spectral profile corresponding to that of collagen type I. X-ray diffraction patterns revealed the presence of triple helix and traces of phosphate. The hydrolysates (6 kDa) exhibited the highest emulsion at 2.74±0.20 m2/g (for 57.00±0.50 min) and foam stability in the range of 75–78%, respectively. The hydrolysates were able to stabilize drug and food formulations successfully and two of the samples exhibited less than 3% toxicity as determined through hemolytic assay. Conclusion Collagen hydrolysates from fish skin, a common fish industry waste, were found to be bioactive and non-toxic making them suitable replacements for synthetic emulsifiers.