Cold Water Fish Gelatin Research Articles

Printable embedded pattern designs affect mechanical performance of cold-water fish gelatin cast films

Edible films made of cold-water fish gelatin suffer from suboptimal mechanical strength, limiting their use for sustainable packaging applications. In this study, the use of 3D-printable embedded patterns is investigated as reinforcement for gelatin cast films, aiming for cast films with customizable and enhanced mechanical strength. Various combinations of patterns (i.e. lines, grids, and triangles) and inks (varying concentrations of sodium caseinate, sodium alginate, and cellulose fibers) were 3D-printed. The 3D-printed structures were embedded into cast films and the mechanical properties were subsequently tested. Our results show that films with embedded patterns had an overall higher tensile strength at different stretching directions (i.e. parallel, perpendicular, and diagonal), compared to the plain gelatin films. The strongest mechanical anisotropy was found using the line pattern and the grid showed anisotropy in the parallel and perpendicular direction, highlighting the influence of printing path. Microscopical analysis revealed that embedded patterns affected the fracture mechanics of films. Interestingly, cellulose fibers showed alignment in the printed filaments along the printing direction, which contributes to an increased tensile strength of films after drying. Thus, by using printable embedded pattern design, edible films with customized mechanical performance can be made, contributing to future developments of sustainable packaging solutions.

Extraction and characterization of collagen and gelatin from body wall of sea cucumbers Stichopus horrens and Holothuria arenicola.

Marine invertebrates, including sponges, molluscs, jellyfish, mussels, and sea cucumbers, are abundant sources of high-quality collagen and offer advantages such as availability, ease of processing, lower inflammatory response, and good metabolic compatibility. Approximately 70% of the total protein in the body wall of sea cucumbers is collagen. Gelatin is a water-soluble protein produced from heat-denatured collagen and has various industrial applications. Pepsin-solubilized collagen was extracted from the body wall of two sea cucumber Stichopus horrens and Holothuria arenicola, species found in the Oman Sea and characterized with SDS-PAGE and amino acid composition. Then gelatin was extracted from pepsin-solubilized collagen of S. horrens and some rheological properties were measured. Amino acid composition and SDS-PAGE analysis showed that the collagen from both species was type I, with one α1 chain and β chains, with molecular weights of 125 and 250 kDa, respectively. Glycine was the most abundant amino acid in the collagen from both sea cucumber species. The pepsin-soluble collagens from both species had high levels of glycine, proline, alanine, glutamic acid, and hydroxyproline. The gelatin from S. horrens had a melting point of 30 °C and displayed exceptional thermal stability, surpassing that of mammalian gelatin. Its gelling point was 5 °C, like that of cold-water fish gelatin, with a viscosity of 2.065 cp-lower than mammal gelatins. These findings suggested that collagen and gelatin from sea cucumbers could be useful in nutraceutical, pharmaceutical and cosmetic industries.

3D-printed fish gelatin scaffolds for cartilage tissue engineering.

Knee osteoarthritis is a chronic disease caused by the deterioration of the knee joint due to various factors such as aging, trauma, and obesity, and the nonrenewable nature of the injured cartilage makes the treatment of osteoarthritis challenging. Here, we present a three-dimensional (3D) printed porous multilayer scaffold based on cold-water fish skin gelatin for osteoarticular cartilage regeneration. To make the scaffold, cold-water fish skin gelatin was combined with sodium alginate to increase viscosity, printability, and mechanical strength, and the hybrid hydrogel was printed according to a pre-designed specific structure using 3D printing technology. Then, the printed scaffolds underwent a double-crosslinking process to enhance their mechanical strength even further. These scaffolds mimic the structure of the original cartilage network in a way that allows chondrocytes to adhere, proliferate, and communicate with each other, transport nutrients, and prevent further damage to the joint. More importantly, we found that cold-water fish gelatin scaffolds were nonimmunogenic, nontoxic, and biodegradable. We also implanted the scaffold into defective rat cartilage for 12 weeks and achieved satisfactory repair results in this animal model. Thus, cold-water fish skin gelatin scaffolds may have broad application potential in regenerative medicine.

Study of Physicochemical and Gelation Properties of Fish Gelatin from Different Sources

Fish gelatin has been increasingly used as a safe alternative to cattle and pig gelatin due to its similar structure, avoiding the health and socio-cultural issues associated with the use of materials of mammalian origin. Fish gelatin can be produced from processed fish products to achieve a high yield at a low cost. Recent studies show that although fish gelatin comes from a wide range of sources, the protein content and amino acid composition of fish gelatin from different sources are different, and some fish gelatin is soft and unstable transglutaminase (TGase) can catalyze the γ-amide group of glutamine residues and the ε-amino group of lysine residues in proteins to form covalent bonds to form a stable protein network structure, improve the strength of the gel so that it can be applied in a more special environment. In this experiment, after screening the raw materials of cold-water fish gelatin M06 and M08, warm-water fish gelatin M03 and M04, a strong fish gelatin was successfully prepared by catalytic modification of cold-water fish gelatin by transglutaminase (TGase), and the excellent performance of TG enzyme-catalyzed modified gelatin was proved through the application effect of chicken salt soluble protein. In this experiment, the protein content of cold-water fish M08 was the highest, which was up to 99.9%, 1.09 times that of warm-water fish. The gelatin content of cold-water fish M08 was the highest of the four kinds of fish gelatin, with a wide proportion of components and rich amino acid composition. Cold-water fish M08 gelatin-derived gel had the highest strength of 253 ± 1 g/cm at 4 °C. It was found that fish gelatin with protein molecular weight distribution and rich amino acid composition had higher gel strength. M08 gelatin is cross-linked by transglutaminase (TGase), which increases the strength of enzyme gels by approximately 200% compared to self-assembled gels. Fish gelatin catalyzed by the TG enzyme improves the gel strength of raw material and makes it more applicable. M08 gelatin also showed good application performance at low temperatures in compound chicken salt-soluble protein gel, with a water retention rate of 95.84% and gel strength of 198.5 g/cm. This study expanded the application range of fish gelatin by TG enzyme and improved the application potential of fish gelatin.

Application of Poultry Gelatin to Enhance the Physicochemical, Mechanical, and Rheological Properties of Fish Gelatin as Alternative Mammalian Gelatin Films for Food Packaging.

This study aimed to describe the properties of cold water fish gelatin (FG) blended with poultry gelatin (PG) for a production of a sachet containing olive oil. To find a desirable film, the different ratio of FG-PG-based films were characterized in terms of mechanical properties. As the proportion of PG in PG-FG-based increased, the tensile strength and Young's modulus were increased, and the elongation at break and heat seal strength of the films were decreased. The 50-50 film had favorable characteristics to use as a sachet. The amount of acid index and peroxide of the oil stored in the sachets after 14 days showed that there is a significant difference (p < 0.05) between the films. The barrier properties of the films including the water vapor permeability and oxygen permeability of films were increased from 1.21 to 4.95 × 10-11 g m-1 Pa-1 s-1 and 48 to 97 cm3 mµ/m2 d kPa, respectively. Dark, red, yellow, and opaque films were realized with increasing PG. Fourier transform infrared (FTIR) spectra approved a wide peak of approximately 2500 cm-1. The rheological analysis indicated that, by adding PG, viscosity, elastic modulus (G') and loss modulus (G'') were increased significantly (p < 0.05) about 9.5, 9.32 and 18 times, respectively. Therefore, an easy modification of FG with PG will make it suitable for oil sachet packaging applications for the food industry.

Enzymatic modification of Fish Gelatin and Beet Pectin using Horseradish peroxidase

The Fish Gelatin (FG), a good alternative for unhealthy and limited socio-cultural mammalian gelatin appears to possess endogenous structural limitations. The goal of this work was to use enzymatic crosslinking to modify cold-water Fish Gelatin (FG) with Beet Pectin. Reaction conditions were optimized by a single factorial experiment and covalent crosslinking was measured by ultraviolet (UV)-Vis spectroscopy at 340 nm to indicate Horseradish Peroxidase (HRP) catalyzes Beet Pectin (BP). At 50 °C for 4 h, the highest weight ratio of heterologous adducts between FG-BP was 1:3, with HRP and Hydrogen peroxide (H2O2) of 2 µg/mL and 0.067%, (v/v), respectively. Intermolecular cross-linking was found between treated samples using ATR-FTIR and Sodium Dodecyl Sulphur and Polyacrylamide Gel Electrophoresis (SDS-PAGE). The heterologous product, control FG, and BP as well as a mixture of untreated FG-BP had a β-sheet of 41.14%, 39.65%, 39.9%, and 40.0%, respectively. The maximum reduction in elution was obtained in heterogeneous FG-BP complex. Furthermore, a schematic mechanism for Cold-water Fish Gelatin and Beet Pectin was proposed. Overall, peroxidase crosslinked BP was able to modify cold-water Fish Gelatin. The use of Horseradish peroxidase on Fish Gelatin could provide a practical way of building the FG-BP complex as a basis for understanding the FG functionalities comprehensively.

Antimicrobial Activity of Ovotransferrin Loaded Fish Gelatin Electrospun Nanofibers Against Some Pathogens Originated from Fish Products

Fish and fishery products rich in nutrients are sensitive to microbial spoilage even at cold temperatures. Cold water fish gelatin including various amounts of ovotransferrin was electrospun in order to obtain antimicrobial nanofibers. The obtained electrospun nanofibers were subjected to disc diffusion method to determine antimicrobial activity against Shewanella putrefaciens, Pseudomonas spp., Flavobacterium psychrophilum and E. coli originated from fish. Morphological characterization as well as mechanical strength of electrospun nanofibers were determined. High amounts of ovotransferrin exhibited elevated antimicrobial activity. Mostly inhibited bacteria by 15% ovotransferrin was E. coli with an inhibition zone diameter of 19±0.2 mm. Mats containing 15% ovotransferrin showed an inhibition zone diameter of 18±0.5 mm, 19±0.5 mm and 18±1.0 mm against Pseudomonas florescens, Flavobacterium psychrophilum and Shewanella putrefaciens respectively. Ovotransferrin content of 5% showed an inhibition zone diameter of 14±0.3 mm, 12±1.0 mm and 11±0.5 mm against Pseudomonas florescens, Flavobacterium psychrophilum and Shewanella putrefaciens respectively. Fish gelatin had a hydrophilic character according to the contact angle measurements which got worse by incorporating ovotransferrin. Ovotransferrin including nanofibers exhibited poor mechanical characterization which is attributed to weakened fish gelatin molecular bonding in presence of higher amounts of ovotransferrin. Neat gelatin had reasonable tensile strength comparing to other specimens. As a result, ovotransferrin incorporated fish gelatin electrospun nanofibers are promising in inhibiting fish originated microorganisms.

The effects of tannic and caffeic acid as cross-linking agents on the physicochemical, barrier, and mechanical characteristics of cold-water fish gelatin films

The effects of tannic and caffeic acid as cross-linking agents on the physicochemical, barrier, and mechanical characteristics of cold-water fish gelatin films

Reducing cherry rain-cracking: Development and characterization of cold-water fish gelatin films reinforced by dual rod-spherical nanoscale structures formed under magnetic fields

In order to solve the problem of cherry rain-cracking, cold-water fish gelatin (CFG)-based edible films (CFG, CFG-CNC [cellulose nanocrystals], CFG-CA [chitosan hydrochloride-sodium alginate nanoparticles], CFG–CNC–CA, and their magnetic field [MF] films) were prepared with reinforcement by rod-spherical dual-nanoscale structures. Here, the spherical nanoparticles CA were formed based on static electricity interaction between chitosan hydrochloride and sodium alginate according to pre-gel method, whereas the rods consisted of CNC extracted from sugarcane bagasse. Studies were conducted in laboratory to determine the coating-ductility, hydrophobic, water-vapor barrier, mechanical, and retention properties, and in the field to determine cracking index (CI) and cracking ratio (CR). MF treatment was found to induce the rod-spherical dual-nanoparticles to arrange into C–O–C linkages. Compared to the other films, the CFG–CNC–CA (MF) film showed superior coating-ductility properties (surface tension: 61.8 mN m−1), hydrophobicity (water contact angle: 111.6°), and water-vapor barrier (water-vapor permeability: 7.43 × 10−10 gm−1Pa−1s−1), as well as superior mechanical (Young's modulus: 351 MPa; tensile strength: 30.1 MPa) and retention properties on cherry (water solubility: 38.4%; swelling degree: 876%). Compared with the experimental control, the total CI of cherries treated with CFG–CNC–CA (MF) was reduced from 43.3% to 11.8%, and the total CR was reduced from 34.8% to 11.1%, type Ⅰ’ cracking in particular experienced a greater reduction (from 26.7% to 9.16%) than did type Ⅱ’ (13.7%–4.96%) or Ⅲ’ (8.90%–3.48%). Thus, this study successfully provided a reference for edible CFG–CNC–CA (MF) coatings that prevent and control cherry rain-cracking disasters worldwide in a timely, safe, and efficient manner.

Visible light-induced crosslinking of unmodified gelatin with PEGDA for DLP-3D printable hydrogels

The possibility to 3D shape hydrogels is attracting an enormous interest in the biomedical field both for their application as scaffold or for the design of new medical hydrogels. Digital light processing (DLP) printing can create layer-by-layer models with high resolution and printing speed. Herein, a hybrid natural-synthetic hydrogel is propsed using cold-water fish gelatin as innovative co-initiating species of a camphorquinone photo-initiator instead of the traditional aliphatic or aromatic amines, for the crosslinking of PEGDA monomer. Such system allows to chemically bound gelatin to the PEGDA monomer without any previous modification and leads to the production of DLP-3D printable hydrogels. The real-time photorheological measurements showed that Gelatin behave as a binder during photopolymerization and ATR-FTIR spectroscopy proved that gelatin segments were chemically incorporated within PEGDA network. Mechanical and biological properties were improved by increasing gelatin content. Furthermore, the 3D digital light processing of this material leads to the creation of precise and rapidly printed structures that are biocompatible and able to support cell viability and proliferation. Considering those features, the proposed hydrogel may be a promising candidate in 3D-printed devices for cell culture.

Visible light-induced cross-linking of unmodified gelatin with PEGDA for DLP-3D printable hydrogels

The 3D printability of cold-water fish gelatin used as co-initiating species for the crosslinking of PEGDA monomers in presence of camphorquinone (through a Norrish II reaction) is evaluated. The 3D digital light processing leads to the creation of biocompatible printed structures able to support cell viability and proliferation.

Visible light-induced crosslinking of unmodified gelatin with PEGDA for DLP-3D printable hydrogels

The 3D printability of cold-water fish gelatin used as co-initiating species for the crosslinking of PEGDA monomers in presence of camphorquinone (through a Norrish II reaction) is evaluated. The 3D digital light processing (DLP) leads to the creation of biocompatible printed structures able to support cell viability and proliferation.

The effects of caffeic acid and tannic acid on physicochemical, morphological and hydrogel properties of cold-water fish gelatin

The effects of caffeic acid and tannic acid on physicochemical, morphological and hydrogel properties of cold-water fish gelatin

Fish gelatin as an alternative to mammalian gelatin for food industry: A meta-analysis

Gelatin is prepared from heat denaturation and partial hydrolysis of collagen from mammalian sources and is a common ingredient in the food industry. Diet restrictions of porcine gelatin due to culture and/or religion, and the health safety concerns due to an onset of zoonotic disease in cattle from earlier period, have led to the search for alternative gelatin sources. The most extensively studied alternatives with high potential are fish and fish by-products. However, fish gelatin application in the food industry is still limited due to inferior performance in gelling ability. The gel strength values of the warm-water and cold-water fish gelatin compared to mammalian gelatin, were evaluated by meta-analysis to determine their potential as an alternative. Through rigorous screening of the extraction and gel strength determination methods, a total of 13 studies were included in the analysis. The mean gel strength of fish gelatin was significantly lower in comparison to mammalian gelatin (p < 0.05). Interestingly, the warm-water fish skin gelatin was the only sample group with a combined effect estimate point that overlapped and extended pass the null effect line, making it the most suitable substitute of mammalian gelatin in food gel preparation when compared to other fish gelatins.

Fish Gelatin Antimicrobial Electrospun Nanofibers for Active Food-Packaging Applications

A protein-based electrospun nanofiber from cold water fish gelatin (FG) including bovine lactoferrin (L) as an antimicrobial substance for food packaging applications was developed. Various amounts of L (0, 5, 10, 15, and 20%) were incorporated into FG electrospun nanofibers in order to test antimicrobial activity by disc diffusion method against Pseudomonas fluorescens, Acinetobacter johnsonii, Aeromonas hydrophila, Flavobacterium psychrophilum, Shewanella putrefaciens, and Escherichia coli commonly cause problems in food safety especially in fish products. It was obviously seen that 15% and 20% wt L incorporated FG electrospun nanofibers had significant inhibition zone against all bacterial strains while 5% and 10% L-FG had lower antimicrobial effects. In order to recommend fish gelatin as a food packaging material, mechanical properties should be enhanced to be competitive with synthetic polymers. It was revealed that mechanical strength of gelatin electrospun nanofibers depended on both fiber morphology and bioactive substance content. Neat FG (N-FG ) bead-free electrospun mats had higher fiber diameter (815 ±40 nm) while 15% and 20% L-FG had relatively lower diameter with beaded morphology, i.e., 348 ±32 nm, 229 ± 44 nm respectively. The tensile strength of 20% L-FG mats was significantly lower than the N-FG mats due to beady and thinner morphology. It can be concluded that L-FG electrospun nanofibers with high antimicrobial activity and improvable tensile strength is promising for active packaging applications.Keywords: Electrospinning, Pseudomonas spp., Escherichia coli, Shewanella spp., biodegradable, active packaging

Investigation of Carboxymethyl Cellulose (CMC) on Mechanical Properties of Cold Water Fish Gelatin Biodegradable Edible Films.

The tendency to use biocompatible packages, such as biodegradable films, is growing since they contain natural materials, are recyclable and do not cause environmental pollution. In this research, cold water fish gelatin and carboxymethyl cellulose were combined for use in edible films. Due to its unique properties, gelatin is widely used in creating gel, and in restructuring, stabilizing, emulsifying, and forming foam and film in food industries. This research for the first time modified and improved the mechanical properties of cold water fish gelatin films in combination with carboxymethyl cellulose. Cold water fish gelatin films along with carboxymethyl cellulose with concentrations of 0%, 5%, 10%, 20% and 50% were prepared using the casting method. The mechanical properties were tested by the American National Standard Method. Studying the absorption isotherm of the resulting composite films specified that the humidity of single-layer water decreased (p < 0.05) and caused a reduction in the equilibrium moisture of these films. In the mechanical testing of the composite films, the tensile strength and Young’s modulus significantly increased and the elongation percent significantly decreased with the increase in the concentration of carboxymethyl cellulose. Considering the biodegradability of the films and the improvement of their mechanical properties by carboxymethyl cellulose, this kind of packaging can be used in different industries, especially the food industry, as an edible coating for packaging food and agricultural crops.

Cold Water Fish Gelatin Methacryloyl Hydrogel for Tissue Engineering Application.

Gelatin methacryloyl (GelMA) is a versatile biomaterial that has been used in various biomedical fields. Thus far, however, GelMA is mostly obtained from mammalian sources, which are associated with a risk of transmission of diseases, such as mad cow disease, as well as certain religious restrictions. In this study, we synthesized GelMA using fish-derived gelatin by a conventional GelMA synthesis method, and evaluated its physical properties and cell responses. The lower melting point of fish gelatin compared to porcine gelatin allowed larger-scale synthesis of GelMA and enabled hydrogel fabrication at room temperature. The properties (mechanical strength, water swelling degree and degradation rate) of fish GelMA differed from those of porcine GelMA, and could be tuned to suit diverse applications. Cells adhered, proliferated, and formed networks with surrounding cells on fish GelMA, and maintained high initial cell viability. These data suggest that fish GelMA could be utilized in a variety of biomedical fields as a substitute for mammalian-derived materials.

Cross-linking oppositely charged oil-in-water emulsions to enhance heteroaggregate stability

The formation and subsequent enzymatic and chemical cross-linking of heteroaggregates from oppositely charged oil-in-water (O/W) emulsions was investigated. For this purpose, 10% (w/w) oil-in-water emulsions (d43<1μm) were prepared at pH 4 using a positively charged emulsifier (Nα-lauroyl-L-arginine ethyl ester (LAE), cold water fish gelatin, or whey protein isolate) or a negatively charged one (sugar beet pectin or Quillaja saponins). The oppositely charged emulsions were then combined at a volume ratio of 1:1 and treated with laccase or glutaraldehyde in order to further stabilize the electrostatically attached aggregates by covalently cross-linking the oppositely charged membranes. Emulsions and heteroaggregates were characterized by their rheological properties, their surface charge, particle size distribution, and microstructure using dynamic and static light scattering as well as confocal laser scanning microscopy. Prior to cross-linking, the emulsifiers’ stabilization mechanism were found to greatly influence the formation of heteroaggregates. Laccase treatment (1.34mU/mL) increased aggregate expansion by ca. 30% for the combined emulsions stabilized by Quillaja saponins/whey protein isolate, while combined Quillaja saponins/fish gelatin stabilized emulsions remained unaffected. When combined emulsions were treated with 50mM glutaraldehyde, aggregate size significantly increased 2- and 3-fold, respectively. Thus, our study provides novel insights into the enzymatic and chemical cross-linking of heteroaggregates composed of oppositely charged O/W emulsions.

The effects of sugars on moisture sorption isotherm and functional properties of cold water fish gelatin films

Sugars were incorporated into CWFG solutions at different ratios (0%, 2%, 4%, and 6% w/w). Functional properties of the modified films were characterized following American standard test methods, and moisture sorption isotherm was characterized by polynomial and GAB models. Permeation to water vapor and oxygen of the modified films decreased compared to that of the control CWFG films. Moisture content, solubility, and monolayer water content of CWFG films decreased with the increase of sugar content. The addition of sugars significantly increased the Tensile strength of CWFG films from 30 to 40MPa for ribose, and 30 to 35MPa for fructose whereas elongation at the breaks decreased from 60% to 30% for ribose, and from 60% to 45% for that which incorporated fructose sugars. Moisture sorption isotherm curve significantly shifted to lower moisture content in aw<0.6. In aw>0.6, ribose-incorporated CWFG films, had similar function to hydrogel materials. In all the characterizations, the effects of ribose were significantly higher than those of fructose. Results of this research can be explored for commercial use, depending on the application for either packaging purposes or in the cosmetics industries.

Cold water fish gelatin modification by a natural phenolic cross-linker (ferulic acid and caffeic acid).

Nowadays use of edible films and coatings is increasing due to their biodegradability and environment friendly properties. Fish gelatin obtained from fish skin wastage can be used as an appropriate protein compound for replacing pork gelatin to produce edible film. In this study films were prepared by combination of fish gelatin and different concentration (0%, 1%, 3%, and 5%) of two phenolic compounds (caffeic acid and ferulic acid). The film was prepared at pH > 10 and temperature of 60˚c under continuous injection of O2 and addition of the plasticizer sorbitol/glycerol. Results showed that solubility, oxygen permeability, and water vapor permeability were decreased for caffeic acid and the highest effect was observed at concentration of 5%. Solubility had a linear relationship with concentration of phenolic compound in film containing ferulic acid, however, no significant change was observed in vapor and O2 permeability. A comparison between two phenolic compounds showed that caffeic acid had the highest effect in decreasing solubility, water vapor permeability, and oxygen permeability. Caffeic acid is more effective phenolic compound compared with Ferulic acid that can increase safety of biodegradable packaging by improving their barrier and physicochemical properties.