Formation, characterization of gelatine from the scales of Labeo rohita and its comparison with bovine bone gelatine

Comparative study on characteristics of gelatin from the skins of brownbanded bamboo shark and blacktip shark as affected by extraction conditions

The objective of this study was to investigate the effects of the enzymatic aided acid-swelling process on gelatin obtained from fish by-products. For this purpose, gelatin was extracted by an acidic swelling procedure in the presence of protease extracted from Rainbow trout pyloric caeca. The yield of gelatin extraction and the most important physicochemical characteristics of the fish gelatin samples were investigated and compared with those of commercial bovine gelatin (CBG). The yields of gelatin from Epinephelus coioides skin (ESG) either with or without crude protease from pyloric caeca (15 units/g alkaline treated) were 14.98% and 50.89%, respectively. The yields of gelatin from Cyprinus carpio scales (CSG) with crude protease from pyloric caeca (15 units/g) were 49.97%. The gel strength of the CSG (259.66g) was significantly higher than that of CBG (228.30g) and ESG (187.75g). Similarly, the gelling and melting points, foaming capacity and stability, and the SDS-PAGE pattern of gelatins were compared. The electrophoretic pattern confirmed the results of gel strength which was due to the narrower alpha and beta bands in fish skin and commercial bovine gelatins than that of fish scales gelatin. The results of this research showed that the production of high-quality gelatin can be achieved by the enzymatically aided acid-swelling procedure from fish scales and skin.

Gelatin is extracted from animal tissues using heat usually with low yields, but pepsin may increase high quality gelatin yield per unit of tissue. Gelatin from bovine lungs was extracted using heat and pepsin and the resulting gelatins were characterized. Pepsin increased gelatin yield by about 9-fold that of heat extraction alone. All bovine lung gelatin contained protein as the major proximate component, with little ash and non-detectable fat. Bovine lung gelatin had pH, moisture and protein comparable to or less than that of commercial bovine gelatin and decreased ash. Transmittance of bovine lung gelatin was substantially reduced compared to that of commercial bovine gelatin but had increased water and fat-binding capacity, and comparable or increased gelling and melting temperature. Gel strengths of bovine lung gelatin were comparable to or lower than and foam stability and emulsifying activity were lower than commercial bovine gelatin. Increased imino acid (proline and hydroxyproline) content was associated with increased gelling and melting temperatures and was comparable to commercial bovine gelatin. Heat-extracted bovine lung gelatin contained predominantly collagen γ– chains, β– chains and α– chains (α1(I) and α2(I)), with some low molecular weight peptides, while the pepsin-extracted lung gelatins were characterized by comparatively decreased β– and α– chains and increased low molecular weight peptides. The gel strength of heat-extracted bovine lung gelatin was higher than that of pepsin-extracted gelatins, indicating that additional yield was associated with reduced gelatin quality. Bovine lung is a potential source of gelatin for application in diversified industrial fields and use of pepsin is a viable method for extracting additional gelatin after heat extraction of high quality (increased gel strength) gelatin from bovine lung.

Fish skin is a byproduct part and can be converted into value added product like gelatin. The objective of this research was to produce gelatin from two fresh-water fish skins i.e. Nile tilapia (Oreochromis niloticus) and Nile perch (Lates niloticus) and determine the physicochemical characteristics of the obtained gelatin. The physicochemical properties, free amino acids, protein content, pH, viscosity, colour, melting point, clarity, water holing capacity (WHC) and fat binding capacity (FBC), were studied and compared to the commercial bovine gelatin. Nile perch gelatin presented (87.24%) protein content which was resembles to bovine gelatin (88.18%). The viscosity (6.02 cP) of Nile tilapia extracted gelatin was also comparable to the bovine gelatin (6.77 cp). Results showed that the lightness of Nile tilapia gelatin (37.07) was greater than that of bovine gelatin (31.75). Regarding to the WHC, of Nile perch gelatin was higher by 3-fold (687.97%) than bovine gelatin (225.17%). While the Nile tilapia presented 1.4-fold (637.18%) higher than that found in bovine gelatin. Based on obtained results, it could be recomended that fish gelatin could be considered an excellent alternative to mammalian gelatin because of its functional properties similarity with commercial bovine gelatin.

Ultrasound-assisted alkaline hydrolysis of fish(Cyprinus carpio L.) scale gelatin: A possible curcumin delivery system with increased water solubility and sustained release

Biodegradable films containing different concentrations of duck feet gelatin (DFG) (2.0, 2.5, 3.0, and 3.5%) were produced, and their mechanical and physicochemical properties were measured and compared to those of biodegradable films made from commercial bovine gelatin (CBG). Gel strength of DFG (306.96 g) was significantly higher than that of CBG (216.78 g). Elongation at break (EAB), thickness, and water vapour permeability of DFG films significantly increased as the concentration of gelatin increased. Films with DFG concentration of 3.5% had the EAB value 33.00, compare to CBG with EAB value 25.56%. DFG films exhibit significantly lower water solubility compared to CBG films. Water solubility of films with DFG concentration of 3.5% is 32.37%, meanwhile for CBG is 48.74%. Both of the gelatin films prepared from DFG and CBG were transparent, as indicated by the high L*, ranging from 94.64 to 96.01 for DFG and 95.54 to 96.06 for CBG sources. These results indicate that DFG has great potential for future application as a source material for production of gelatin-based biodegradable films.

Bovine and porcine gelatin sensitivity in children sensitized to milk and meat

The poultry industry produces many by-products such as chicken feet. These by-products contain a relatively high amount of protein, especially collagen, which is effective for producing gelatin. Gelatin is a biopolymer with unique properties widely used in food and pharmaceutical industries. This study aimed to determine the physicochemical properties of chicken feet gelatin extracted using acidic and microwave treatment, and compared them with a commercial bovine gelatin. The results showed color (L*, a*, b*), gel strength, viscosity, turbidity, gelling and melting temperature, and amino acid composition of chicken feet gelatin were significantly higher quality than those of the commercial one. FTIR analysis showed all the amide bands in acidic gelatin and microwave-extracted gelatin, but not in commercial bovine gelatin (band B). In temperature scanning and gel formation analysis, the highest melting temperature and gel formation were related to gelatin extracted by acidic treatment. Moreover, the gelatin obtained through microwave extraction exhibited improved quality compared to acidic extraction, showing higher viscosity and gel strength. The microscopic structure of microwave-extracted gelatin compared to acidic and bovine gelatin had numerous holes and showed the highest turbidity. The structural stability of chicken feet gelatin is more potent than that of commercial bovine gelatin. Therefore, it presents a viable alternative to mammalian gelatins. Furthermore, microwave-extracted gelatin demonstrated enhanced gel strength, viscosity, and thermal properties, leading to an overall improvement in the quality of chicken feet gelatin.

Effects of gelatins on calcium phosphate precipitation: a possible application for distinguishing bovine bone gelatin from porcine skin gelatin

We investigated relationship between porcine skin (PS) and bovine bone (BB) gelatins in their actions on proliferation of murine benign and malignant cells in this study. We previously observed that BB gelatin enhanced spleen cell proliferation. The present study showed that such an activity of BB gelatin was not exerted in a serum-free medium. On the other hand, PS gelatin suppressed proliferation of normal spleen cells and of those stimulated by concanavalin A (Con A). It is not known whether or not such an activity of PS gelatin on Con A-stimulated spleen cells is exerted in the serum-free medium since Con A was unable to augment proliferation of spleen cells in that medium. BB gelatin as well as PS gelatin suppressed proliferation of RL male symbol 1 cells, a T cell lymphoma cell line of Balb/c mice, and such an activity of BB gelatin was not exerted in the serum-free medium whereas PS gelatin exerted its activity in the same medium. Mitomycin C (MMC)-treated spleen cells as well as MMC-treated RL male symbol 1 cells partly released RL male symbol 1 cells from the inhibition of proliferation by PS gelatin. MMC-treated RL male symbol 1 cells as well as MMC-treated spleen cells suppressed the proliferation of spleen cells augmented by BB gelatin. Inhibition of RL male symbol 1 cell proliferation by PS gelatin was not affected by BB gelatin, but enhancement of spleen cell proliferation by BB gelatin was attenuated by PS gelatin regardless of the sequence of treating the spleen cells with PS gelatin. Enhancement of spleen cell proliferation by BB gelatin was time-dependent but suppression of RL male symbol 1 cell proliferation by PS gelatin was not. In conclusion, BB gelatin enhanced proliferation of spleen cells and suppressed proliferation of RL male symbol 1 cells. In both cases, fetal calf serum (FCS) was required. PS gelatin suppressed proliferation of spleen cells and of RL male symbol 1 cells without FCS.

Since gelatin-containing foods pose a risk for eliciting allergic reactions in sensitized individuals, a novel sandwich enzyme linked-immunosorbent assay (ELISA) for the detection and quantification of bovine and porcine gelatin in processed foods was developed. Rabbits and goats were immunized with bovine gelatin, and three antisera (pAb1 and pAb2 from rabbits, and pAb3 from goats) were obtained. We established a sandwich ELISA method based on a combination of these antibodies. In this study, two sandwich ELISA methods, rabbit pAb2-pAb1 and goat pAb3-pAb3, were evaluated for sensitivity, specificity, cross-reactivity, and applicability. Both ELISA methods were highly specific for bovine and porcine gelatin but had little reactivity with fish gelatin. The detection and quantification limits for porcine gelatin were found to be 0.78 ng/mL and 1.56 ng/mL, respectively. The established sandwich ELISA methods produced no false-positives, except for heated meat products or false negatives when various commercial foods were analyzed for their gelatin content. The rabbit pAb2-pAb1 ELISA cross-reacted with boiled squid, while the goat pAb3-pAb3 ELISA did not. Thus, the proposed goat pAb3-pAb3 ELISA method is a reliable tool for the detection of gelatin contaminants present in processed foods.

Gelatin plays a vital role in the food industry, serving as a thickening agent, emulsifier, wetting agent, and stabiliser. However, conventional sources like mammalian gelatin pose health and societal issues, while poultry gelatin can present risks related to avian flu. Our work was motivated by recent studies focusing on alternative gelatin sources, which prompted further investigation. Our study aimed to extract gelatin from red-skin Tilapia and bovine sources. Both types of gelatin underwent pre-treatment using 0.2 M sodium hydroxide (NaOH) and 0.05 M acetic acid (CH3COOH) at 27ºC, followed by water extraction at 60°C for 3 hours. Fourier-transform infrared (FTIR) analysis confirmed that the extracted gelatins exhibited peaks similar to commercial gelatin. The extracted fish gelatin (EFG) demonstrated superior gel strength compared to commercial fish gelatin (CFG), whereas commercial bovine gelatin (CBG) exhibited superior gel strength than extracted bovine gelatin (EBG). The protein content of EFG and EBG was comparable, but the fat content was significantly higher in EFG. The foaming capacity was also evaluated, with EFG showing greater capacity than EBG. Our work demonstrates excellent potential of alternative gelatin for usage in various applications and creates new opportunities for the food sector, particularly for halal food production.

Physicochemical properties of giant salamander skin gelatin (GSSG) prepared at 45, 50, 55, 60, 65 °C were studied in comparison with those of tiger puffer skin gelatin (TPSG) and commercial bovine gelatin (CBG). It is showed that GSSG contained lower content of imino acid (179–181 residues/1000) than CBG (204 residues/1000) and TPSG (188 residues/1000). GSSG45 exhibited a protein pattern with α1- and β-chain, which attenuated along with the formation of fragments with molecule weight < 97.2 KD when extraction temperature increased. Amide I and II of GSSG were shifted to higher wavenumber while amide A and B to lower wavenumber in parallel with declined peak (7.3°) intensity by X-ray analysis as temperature increased. Gel strength, gelling temperature and melting temperature of GSSG (47–122 g, 9.30–12.18 °C and 16.87–21.34 °C) were lower than those of CBG (160 g, 22.01 °C and 28.70 °C) and TPSG (151 g, 13.90 °C and 21.34 °C) (p < 0.05). They decreased as temperature elevated in consistent with their gel microstructure with big size voids. These also coincided with their longer relaxation time showed by low field-nuclear magnetic resonance. GSSG50 (62.3 m2/g, 57.5 min) and GSSG55 (55.6 m2/g, 60.8 min) showed higher emulsion activity index and emulsion stability index (p < 0.05) as well as smaller size emulsion droplets than others. Results indicate that GSSG has poor gelling properties, but excellent emulsifying properties. They are greatly affected by extraction temperature. GSSG is proposed to be extracted at a temperature between 45 and 50 °C.

Surimi industry produces a large quantity of byproducts that are currently being utilized to produce low-value commodities. This study aims to extract gelatin from pink perch skin and bone obtained from the surimi industry using a green single-step extraction method. In addition to using a green solvent, that is, acetic acid, the new method combines the multiple steps of pre-treatment and hydrolysis into one single-step extraction process. Response surface methodology was used to optimize extraction parameters (pH, temperature, and time) to maximize yield and l-hydroxyproline (l-hyp) content. The optimum condition for gelatin extraction was obtained at pH 3, 75°C, and 30min. At optimum conditions, gelatin yield and l-hyp content were observed to be 16.07% and 41.26mgg-1 , respectively. The gelatin obtained at optimized condition was further compared with commercial bovine gelatin (BG) in terms of chemical composition and textural, functional, and rheological properties. The results suggested that the optimized pink perch gelatin had higher protein content (92.06%), better gel strength (251.08g), higher imino acid (18.01%), and improved textural and functional properties than the commercially available BG. The optimized single-step gelatin extraction method from pink perch skin and bones is a promising, rapid, and efficient method for the production of good-quality gelatin, which can be further used for the development of high-value products such as food formulations. PRACTICAL APPLICATION: Fish gelatin is widely used in food product development. Most of the existing methods of the development of high-value product such as gelatin, use multi-step process and harsh mineral acid, therefore, are time-consuming and harmful to the environment. This study provides a green single-step gelatin extraction method that provides an efficient, rapid, and convenient method of gelatin extraction and a sustainable solution for fish industry byproduct utilization. The data obtained with this laboratory-scale study provides a strong basis for scale-up studies.

The development of biomaterial inks suitable for biofabrication and mimicking the physicochemical properties of the extracellular matrix is essential for the application of bioprinting technology in tissue engineering (TE). The use of animal-derived proteinous materials, such as jellyfish collagen, or fish scale (FS) gelatin (GEL), has become an important pillar in biomaterial ink design to increase the bioactivity of hydrogels. However, besides the extraction of proteinous structures, the use of structurally intact FS as an additive could increase biocompatibility and bioactivity of hydrogels due to its organic (collagen) and inorganic (hydroxyapatite) contents, while simultaneously enhancing mechanical strength in three-dimensional (3D) printing applications. To test this hypothesis, we present here a composite biomaterial ink composed of FS and alginate dialdehyde (ADA)-GEL for 3D bioprinting applications. We fabricate 3D cell-laden hydrogels using mouse pre-osteoblast MC3T3-E1 cells. We evaluate the physicochemical and mechanical properties of FS incorporated ADA-GEL biomaterial inks as well as the bioactivity and cytocompatibility of cell-laden hydrogels. Due to the distinctive collagen orientation of the FS, the compressive strength of the hydrogels significantly increased with increasing FS particle content. Addition of FS also provided a tool to tune hydrogel stiffness. FS particles were homogeneously incorporated into the hydrogels. Particle-matrix integration was confirmed via scanning electron microscopy. FS incorporation in the ADA-GEL matrix increased the osteogenic differentiation of MC3T3-E1 cells in comparison to pristine ADA-GEL, as FS incorporation led to increased ALP activity and osteocalcin secretion of MC3T3-E1 cells. Due to the significantly increased stiffness and supported osteoinductivity of the hydrogels, FS structure as a natural collagen and hydroxyapatite source contributed to the biomaterial ink properties for bone engineering applications. Our findings indicate that ADA-GEL/FS represents a new biomaterial ink formulation with great potential for 3D bioprinting, and FS is confirmed as a promising additive for bone TE applications.