Fish Gelatin Research Articles

Формирование свойств биодеградируемых пленок на основе рыбного желатина

Nowadays in the food and nutrition industry special attention is paid to the creation of non-toxic, easily recy-clable packaging materials of a new assortment, capable of providing reliable protection of products from harmful factors. The object of the study was biodegradable film compositions based on fish gelatin and agar, with the addition of plasticizing agent - glycerol. Experimental and analytical studies were carried out using standard and original methods. Modeling of the process of thermal treatment of film compositions was carried out, the experimental dependence of moisture absorption of films on temperature (range 120-160 °C) and duration of the thermal modification process (10-30 minutes) was established. The possibility of thermal modification of biodegradable film compositions was determined. The rational mode of thermal treatment of films is the temperature interval of 140 °C for 20 minutes, which allows to keep the moisture absorption index at the maximum level (842%), exceeding the initial index by 8.4 times, during 120 hours. The established parameters of thermal structuring allow to keep organoleptic quality indicators of films at a high level and to obtain a homogeneous, porous and elastic film. Thermally modified films at temperatures of 140 and 160 °C are characterized by increased dissolution time up to 40 and 70 minutes respectively at dissolution temperature of 60 °C and up to 15 and 30 minutes respectively at dissolution temperature of 75 °C. It is shown that thermal modification of biodegradable films will contribute to compliance with safety requirements, environmental friendliness, absence of toxicity. Thermal modification allows to increase functional and technological properties of composite biodegradable films, which can be used to create a wide range of modern packaging barrier materials.

Comparative analysis of red skin Tilapia and bovine gelatins as halal alternatives in food industry

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.

Development and characterization of multifunctional fish gelatin composite films reinforced with ε‐polylysine and zinc oxide nanoparticles

AbstractActive compounds were usually incorporated into biopolymer films to enhance their properties. The tensile strength (TS) and elongation at break (EAB) of the gelatin composite films increased along with the addition of ε‐polylysine (ε‐PL) and zinc oxide nanoparticles (nano‐ZnO). When the concentrations of ε‐PL and nano‐ZnO were 4% and 0.5%, TS and EAB reached to the maximum which were 53.98 ± 2.61 MPa and 16.05 ± 1.76%. The water vapor permeability, water solubility, and water content of the composite films decreased from 2.01 ± 0.04 10−10 g m−1 Pa−1 s−1 to 1.56 ± 0.07 × 10−10 g m−1 Pa−1 s−1, from 45.23 ± 1.54% to 31.39 ± 1.24% and from 23.89 ± 1.41% to 17.34 ± 2.61%, respectively, compared with gelatin film. The light barrier capacity of the composite film was improved. The surface of the film was relatively smooth, and the cross‐section was overall flat. FTIR results indicated that no chemical reaction occurred among ε‐PL, nano‐ZnO and gelatin. The chemical structure of the films remained unchanged throughout the heat‐sealing process. Moreover, the gelatin films containing ε‐PL and nano‐ZnO showed excellent antibacterial activity. Our findings suggest that the gelatin composite films with antibacterial property hold promise for the application in food packaging materials.

Development and characterization of 3D printed fish gelatin and vegetable blends as nutritious meal for dysphagic patients

Dysphagia, increasingly prevalent among the aging population, poses significant nutritional challenges. 3D printing technology offers an innovative solution by creating visually appealing and appetizing dysphagia diets, offering new avenues for enhancing the dining experience of individuals with swallowing difficulties. This study explores the feasibility of using 3D printing to produce nutritionally dense meals for individuals with dysphagia. Techniques like SEM and FTIR were employed to examine ingredient interactions. Rheological properties and printing behavior were analyzed, revealing that xanthan gum (XG) as a thickener increases yield stress, elastic modulus (G′), and apparent viscosities of the ink compositions. Modest additions of XG (0.23% and 0.44%) improved the microstructure and mechanical properties, while higher concentrations (XG-0.77%) caused phase separation and reduced mechanical strength. The 3D printed products were evaluated according to IDDSI guidelines and sensory tests. XG-0.44% samples showed precise printing, excellent self-support, smooth textures, and favorable sensory evaluations, qualifying as level 4-pureed/extremely thick dysphagia diets. This study highlights the potential of 3D printing technology in creating nutritious and appealing meals for individuals with dysphagia.

Evaluation of Gelatin-Based Poly(Ester Urethane Urea) Electrospun Fibers Using Human Mesenchymal and Neural Stem Cells.

Previously, a new biodegradable poly(ester urethane urea) was synthesized based on polycaprolactone-diol and fish gelatin (PU-Gel). In this work, the potential of this new material for neural tissue engineering is evaluated. Membranes with randomly oriented fibers and with aligned fibers are produced using electrospinning and characterized regarding their mechanical behavior under both dry and wet conditions. Wet samples exhibit a lower Young's modulus than dry ones and aligned membranes are stiffer and more brittle than those randomly oriented. Cyclic tensile tests are conducted and high values for recovery ratio and resilience are obtained. Both membranes exhibited a hydrophobic surface, measured by the water contact angle (WCA). Human mesenchymal stem cells from umbilical cord tissue (UC-MSCs) and human neural stem cells (NSCs) are seeded on both types of membranes, which support their adhesion and proliferation. Cells stained for the cytoskeleton and nucleus in membranes with aligned fibers display an elongated morphology following the alignment direction. As the culture time increased, higher cell viability is obtained on randomfibers for UC-MSCs while no differences are observed for NSCs. The membranes support neuronal differentiation of NSCs, as evidenced by markers for a neuronal filament protein (NF70) and for a microtubule-associated protein (MAP2).

Rheological Properties of Fish and Mammalian Gelatin Hydrogels as Bases for Potential Practical Formulations.

Hydrogels have the ability to retain large amounts of water within their three-dimensional polymer matrices. These attractive materials are used in medicine and the food industry; they can serve as the basis for structured food products, additives, and various ingredients. Gelatin is one of widely used biopolymers to create hydrogels that exhibit biocompatibility and tunable rheological properties. In this study, we offer a comparative analysis of rheological properties of gelatin-based hydrogels (C = 6.67%), including mammalian gelatins from bovine and porcine skins and fish gelatins from commercial samples and samples extracted from Atlantic cod skin. Mammalian gelatins provide high strength and elasticity to hydrogels. Their melting point lies in the range from 22 to 34 °C. Fish gelatin from cod skin also provides a high strength to hydrogels. Commercial fish gelatin forms weak gels exhibiting low viscoelastic properties and strength, as well as low thermal stability with a melting point of 7 °C. Gelatins were characterized basing on the analysis of amino acid composition, molecular weight distribution, and biopolymer secondary structure in gels. Our research provides a unique rheological comparison of mammalian and fish gelatin hydrogels as a tool for the re-evaluation of fish skin gelatin produced through circular processes.

Complex coacervation of low methoxy pectin with three types of gelatins for the encapsulation of fish oil

Herein, the complex coacervation of low methoxy pectin (LMP) with three types of gelatins was explored to encapsulate fish oil. The fish oil@gelatin-LMP complex coacervates with good precipitation separation could be obtained at low gelatin concentrations (Fish gelatin, FG: 10–80 mg/mL; porcine skin gelatin, PSG: 10–40 mg/mL; bovine skin gelatin, BSG: 10–80 mg/mL), high gelatin: fish oil mass ratios (4:1–1:1), appropriate gelatin: LMP mass ratios (3:1–12:1 for FG and PSG, 6:1 for BSG), and appropriate pH (FG: 4.90–5.50; PSG: 4.80–5.40; BSG: 4.10–4.50). FG induced similar loading ability, lower encapsulation ability, and comparable peroxide values to the mammalian gelatins. FG induced higher or similar free fatty acid released percentages to mammalian gelatins in the in vitro gastrointestinal model at low gelatin concentrations (10–40 mg/mL). These results provided useful information to understand the protein-polysaccharide complex coacervation to encapsulate oil-based bioactive substances.

In Vitro Hemostatic Activity of Novel Fish Gelatin-Alginate Sponge (FGAS) Prototype.

A hemostatic sponge prototype was successfully synthesized from fish gelatin as an alternative to mammalian gelatin; it was mixed with alginate in certain combinations, double cross-linked with calcium ions, and gamma irradiated at a dose of 20 kGy to improve the characteristics and effectiveness of its function as a local hemostatic agent. There were improvements in the physicochemical and mechanical properties, porosity index, absorption capacity, biodegradation properties, biocompatibility, and hemocompatibility of the fish gelatin-alginate sponge (FGAS) prototypes compared with the pure fish gelatin sponge. Hemostatic activity tests showed that the means for clotting time, prothrombin time, and activated partial thromboplastin time were shorter in the FGAS prototype than in the negative control, and there was no significant difference compared with the commercial gelatin sponge. The hemostatic mechanism of the FGAS prototype combined a passive mechanism as a concentrator factor and an active mechanism through the release of calcium ions as a coagulation factor in the coagulation cascade process.

Rheological and textural properties of fish gelatine-microbial transglutaminase gel microparticles as thickener for texture-modified food

Gel microparticles are tiny, soft particles made from proteins or polysaccharides using particle size reduction. In creating texture-modified food and thickened liquids, gel microparticles are frequently employed to customise the rheological and textural features of foods or thin liquids. Gel microparticles aid by lowering flow behaviour, and modifying the taste perception of the texture-modified food. By cross-linking fish gelatine with the microbial transglutaminase enzyme (mTGA) using the homogenisation process, fish gelatine has tremendous potential to be used to create gel microparticles. The size measurements, texture profile, viscoelastic characteristics, and impact of sugar content on the texture profile of gel microparticles were all examined in the present work for the developed gel microparticles. The results of a particle size investigation revealed that gel microparticle sizes, which ranged from 18 to 1445 µm, increased with higher enzyme concentrations. With increasing mTGA concentration, the texture profile analysis (TPA) also revealed increasing values for hardness, adhesiveness, springiness, cohesiveness, gumminess, and chewiness parameters. The cross-linked gel microparticles had higher dominance on elastic behaviour than viscous behaviour from the rheological investigation, as evidenced by a higher G' compared to G". Additionally, larger TPA values were seen as the sugar concentration increased. These outcomes are anticipated because sugar will strengthen fish gelatine’s hydrogen bond. Based on all completed analyses, fish gelatine cross-linked with 0.7% mTGA to create gel microparticles has shown encouraging results, which can be used as a thickener in texture-modified food to aid those who have trouble swallowing.

Effects of dietary tryptophan levels on growth performance, serotonin metabolism, brain 5-HT and cannibalism activities in tiger puffer, Takifugu rubripes fingerlings

Essential amino acid (EAA) requirements of aquaculture fish species can be used as a guideline for commercial feed formulation. Several EAA requirements have been quantified in tiger puffer (Takifugu rubripes). However, as the third limiting amino acid (AA) of many plant protein sources, tryptophan requirement of this species has yet to be quantified. This study was conducted to determine dietary tryptophan requirement of tiger puffer, and investigate the effect of dietary tryptophan supplementation on the cannibalism, brain serotonin (5-hydroxytryptpamine, 5-HT) metabolism and serum cortisol levels. Six experimental diets were prepared using fish meal, gelatin and corn protein concentrate as intact protein, and then supplemented with crystalline AA premix. The analyzed tryptophan levels in the experimental diets were 3.5, 4.1, 4.5, 5.5, 7.0 and 11.8 g/kg of dry diet. Experimental diets were randomly fed in triplicate to tiger puffer (initial average weight of 17.5 g) for 58 days. The weight gain (WG), feed conversion ratio (FCR) and protein efficiency ratio (PER) were significantly affected by dietary tryptophan, and the break points were observed at 5.07, 4.82 and 4.99 g/kg of dry diet, respectively. Compared to the basal diet, the cannibalism (the rate of bite mark appearance) was significantly lower and survival rate was significantly higher when fish were given diets containing 7.0 and 11.8 g/kg tryptophan. The concentrations of free tryptophan and phenylalanine in the brain exhibited a nonlinear increase in response to the incremental levels of dietary tryptophan. Brain 5-HT concentration was significantly affected by dietary tryptophan levels, but did not show a significant dose-dependent response. The expression of genes related to 5-HT metabolism (tph1a, ddc and aldh) and serotonin reuptake (sert) in the brain varied significantly and exhibited a nonlinear relationship with the graded levels of dietary tryptophan. In addition, serum cortisol levels showed a decreasing trend till the 5.5 g/kg tryptophan inclusion level, at which point there appeared to be the lowest level. In conclusion, based on nonlinear regression analysis of the WG, FCR and PER, dietary tryptophan requirement of tiger puffer was determined to be range between 4.82 and 5.07 g/kg of dry diet (10.48–11.03 g/kg of dietary protein). Dietary tryptophan supplementation above requirement could mitigate cannibalism and improve the survival of tiger puffer, which may be attributed to regulating the synthesis and catabolism of 5-HT and its availability in the synaptic cleft, and subsequently the reduction of serum cortisol content.

Anti-skin-aging effect of fish gelatin from Cynoscion acoupaby maintaining collagen matrix homeostasis on D-galactose induced aging mice

Anti-skin-aging effect of fish gelatin from <em>Cynoscion acoupa</em>by maintaining collagen matrix homeostasis on D-galactose induced aging mice

Complex Characterization of Nanofiber Biomaterials Based on Chitosan, Collagen and Fish Gelatine Produced by Electrospinning*

Electrospinning is an increasingly used technique for producing nanofibers from various types of polymers and biopolymers. These fibers are suitable for applications in tissue engineering, wound healing and drug delivery. In this study, we focused on biomaterials produced from raw marine fish collagen, fish gelatin and chitosan. Various collagen/chitosan and fish gelatin/chitosan in several ratios were dissolved in acetic acid. The formed solutions have concentrations in the range from 5 to 90% (g/ml). The effect of different molecular formats (native and denatured collagen) was studied. The prepared solutions were used in electrospinning experiments. The order degree of various phases of raw materials was established from x-ray diffraction (XRD) measurements. The raw materials, bio-polymeric solutions and finite nanofibers biomaterials were characterized using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), low-field 1D NMR (nuclear magnetic resonance) relaxometry, 2D NMR T1-T2 COSY (correlation spectroscopy), T1-T2 EXSY (exchange spectroscopy) maps, and high field localized 1H NMR spectroscopy. The T 2-T 2 EXSY experiments showed that the number of components characterized by distinct dynamics is larger than those that can by estimated from 1D T 2-distributions due to molecular exchange. Moreover, the full complexity was also revealed by T 1-T 2 COSY maps. The study provides a better understanding of the nanofiber properties, demonstrates the potential of electrospinning for producing nanofibers, and highlights the importance of using multiple characterization methods for a better understanding of the properties of biological nanofibers.

Elucidating the rheological and thermal properties of mixed fish and pork skin gelatin gels: Effects of cooling conditions and incubation times

Gelatin is an important hydrocolloid in food and biotechnological applications. There are two basic sources of gelatins; mammalian and fish-derived gelatins, but fish gelatins are less appreciated due to their weak gel properties. Hence, to reinforce the gel properties of fish gelatin, mixtures of gelatins are used. In this study, the mixtures of cold-water ocean fish scale (OFS) and pork skin (PS) gelatin were studied via rheological measurements, micro differential scanning calorimetry (DSC), and particle tracking at different cooling conditions and incubation times to understand the gelation mechanism and the network structure of the gels. The rheological and micro-DSC measurements provide a detailed understanding of the gelation mechanism of gelatin gels under different cooling conditions while particle tracking revealed the local physical properties of the gels. A single or two-step melting was demonstrated in the mixed gelatin gels depending on the cooling conditions suggesting that the aggregation of PS in the mixtures influences the physical and thermal properties of the gels. Under rapid cooling, co-aggregation of OFS and PS chains is considered to cause a single-step melting of the mixed gels. Under gradual cooling, conversely, the PS may form aggregates independently before the OFS. This is evidenced by a two-step decrease in moduli and two clear endothermic peaks in the micro-DSC measurement. Particle tracking further reveals information on the local physical properties of pure and mixed gelatin gels on reheating, indicating that the local structures of mixed gels resemble those of pure PS gels. This suggests that mixed OFS and PS gels may form a cooperative aggregation, thereby improving the physical and thermal properties of the mixed gelatin gels.

Spatiotemporal responsive hydrogel microspheres for the treatment of gastric cancer

AbstractThe development of tumor drug microcarriers has attracted considerable interest due to their distinctive therapeutic performances. Current attempts tend to elaborate on the micro/nano‐structure design of the microcarriers to achieve multiple drug delivery and spatiotemporal responsive features. Here, the desired hydrogel microspheres are presented with spatiotemporal responsiveness for the treatment of gastric cancer. The microspheres are generated based on inverse opals, their skeleton is fabricated by biofriendly hyaluronic acid methacrylate (HAMA) and gelatin methacrylate (GelMA), and is then filled with a phase‐changing hydrogel composed of fish gelatin and agarose. Besides, the incorporated black phosphorus quantum dots (BPQDs) within the filling hydrogel endow the microspheres with outstanding photothermal responsiveness. Two antitumor drugs, sorafenib (SOR) and doxorubicin (DOX), are loaded in the skeleton and filling hydrogel, respectively. It is found that the drugs show different release profiles upon near‐infrared (NIR) irradiation, which exerts distinct performances in a controlled manner. Through both in vitro and in vivo experiments, it is demonstrated that such microspheres can significantly reduce tumor cell viability and enhance the efficiency in treating gastric cancer, indicating a promising stratagem in the field of drug delivery and tumor therapy.

The generation of islet-like insulin-producing cells from Wharton's jelly-derived mesenchymal stem cells on the PES/fish gelatin scaffold

Diabetes Mellitus (DM) disrupts the body's capability to control blood glucose statuses. Type 1 diabetes mellitus (T1DM) arises from inadequate insulin production and is treated with insulin replacement therapy. Stem cell therapy is a hopeful treatment for T1DM that involves using adult stem cells to generate insulin-producing cells (IPCs). Mesenchymal stem cells (MSCs) are particularly advantageous for generating IPCs. The islet cells require interactions with the extracellular matrix for survival, which is lacking in conventional 2D culture systems. Natural or synthetic polymers create a supportive 3D microenvironment in tissue engineering. We aim to construct superior differentiation conditions employing polyethersulfone (PES)/Fish gelatin scaffolds to differentiate Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs) to IPCs. In this study, the PES/fish gelatin scaffold (3D) was manufactured by electrospinning, and then its biocompatibility and non-toxicity were investigated by MTT assay. After that, scaffold-supportive effects on WJ-MSCs differentiation to IPCs were studied at the gene and protein levels. After exposure to the differentiation media, 2D and 3D (PES/Fish gelatin) cultured cells were slowly aggregated and developed spherical-shaped clusters. The viability of cells was found to be comparable in both 2D and 3D cultures. The gene expression analysis showed that efficiency of differentiation was more elevated in 3D culture. Additionally, ELISA results indicated that C-peptide and insulin release were more significant in 3D than in 2D culture. In conclusion, the PES/fish gelatin scaffold is highly promising for pancreatic tissue engineering because it supports the viability, growth, and differentiation of WJ-MSCs into IPCs.

Development and characterization of semi-refined iota carrageenan/fish gelatin-based biocomposite film incorporated with SiO2/ZnO nanoparticles

Food packaging based on natural polymers from polysaccharides and proteins can be an alternative to replace conventional plastics. In the present study, semi-refined iota carrageenan (SRIC) and fish gelatin (FG) were used as polymer matrix film with different concentration ratios (0.5:1.5 %, 1.0:1.0 % and 1.5:0.5 % w/w) and SiO2-ZnO nanoparticles were incorporated as fillers with the same concentration in all formulas (0.5:1.5 % w/w carrageenan-fish gelatin). This study aimed to develop films for food packaging applications with desirable physical, mechanical, optical, chemical, and microbiological properties. The results showed that incorporating SiO2-ZnO nanoparticles significantly (p < 0.05) improved the films' elongation at break, UV-screening properties, and antimicrobial activity. Also, the films' thickness, degradability, and transparency significantly (p < 0.05) increased with the higher concentration of fish gelatin addition in the SRIC matrix polymer. The best formula was obtained on the SRIC-FG film at the ratio of 1.5:0.5 % w/w, which performed excellent antimicrobial activity. Thus, semi-refined iota carrageenan/fish gelatin-based biocomposite film incorporated with SiO2-ZnO nanoparticles can be potentially developed as eco-friendly and intelligent food packaging materials to resolve traditional plastic-related issues and prevent food waste.

Preparation of films based on reticulated fish gelatin containing garlic essential oil

Agro-industrial co-products, such as fish gelatin, stand out for their capacity in forming biopolymeric films, being biocompatible and non-toxic; however, its hydrophilicity poses a challenge. Essential oils, rich in bioactives, attract research interest aiming to enhance the protective barrier of films and enable their application in packaging. This study produced films based on cross-linked Nile tilapia skin gelatin, incorporating garlic essential oil. Gelatin obtained through partial collagen hydrolysis from the fish skin and cross-linked with gallic acid had hydroxyproline content of 10.02 g 100 g−1 and gel strength of 287 g, which were consistent with other studies. Oil extraction used supercritical CO2 as a solvent and ethanol as a cosolvent, following a factorial experimental design, evaluating the extraction temperature (40 °C and 70 °C) and cosolvent ratio (1:1 and 1:3), with three central points. Extraction was successful, with higher yields on a dry basis at 70 °C (88.35 %), using a 1:1 cosolvent ratio. Films incorporated with oil exhibited lower water vapor permeability (WVP) than those with only cross-linked gelatin (1.59 (g m−1 s−1 Pa−1) 1011). The film with the most suitable tensile strength (19.07 MPa), elongation (120.91 %), and WVP (1.09 (g m−1 s−1 Pa−1) 1011) properties contained garlic oil extracted at the central point (55 °C and 1:2). Thermal analysis indicated increased melting temperatures in films with added oil, suggesting low thermal degradation. These results suggest that garlic oil addition can improve the properties of fish gelatin-based films, making them promising for biodegradable packaging.

Characterization and molecular docking of sustainable wine lees and gelatin-based emulsions: innovative fat substitution.

The present study aimed to determine how various amounts (0.00, 0.58, 1.52 and 4.50 g 100 g-1) of wine lees (WL), which contains numerous essential components, impact the emulsifying properties of fish gelatin (FG) at a low concentration (0.5 g 100 g-1) in the high-fat phase (65 g 100 g-1). This study conducted rheology, physicochemical technical and characterization analyses on the emulsions to provide sustainable and innovative approaches for spreadable oils. The addition of WL to FG emulsions improved oxidative stability, emulsion stability and bioactive compounds. The zeta potential (-101 ± 5.62 mV) of 0.58 g 100 g-1 WL-containing emulsion (PE1) was found to be high, whereas particle size (347.6 ± 5.25 nm) and polydispersity index (0.50) were statistically low. It was also found that the addition of WL improved the intermolecular interactions, crystallinity and microstructural properties of the emulsions. All these results were supported by simulating the molecular configuration between FG and WL. The compounds gallic acid, caffeic acid, myricetin, quercetin and resveratrol showed a strong affinity to FG, with free binding energies of -5.50, -5.88, -6.53, -6.68 and -6.66 kcal mol-1, respectively. As a result, WL-supported FG has the potential to be used as an alternative to egg proteins to develop sustainable low-cost spreadable emulsions. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Fabrication of smart film based on fish gelatin incorporating phycoerythrin and cellulose nanofibrils to monitor fish freshness

Phycoerythrin (PE) extract from red algae Laver (Pyropia dentata) was used in the fabrication of a smart packaging film. The PE showed pH sensitivity, implying unique color shifts at different pH. The film colors altered from red through purple-brown to colorless with increasing pH. The smart packaging films were prepared by casting method composed of gelatin (GE), sodium alginate (SA), and cellulose nanofibrils (CNF). The films were coded as GE/SA (control), GE/SA/PE, and GE/SA/CNF/PE. The thickness of the films ranged from 0.24 ± 0.02 mm to 0.33 ± 0.01 mm. The mechanical properties tensile strength (TS) (12.24 ± 0.30 MPa to 17.65 ± 0.33 MPa) and elongation at break (EAB) (79.34% ± 1.02%–93.36% ± 0.69%) significantly increased after addition of CNF. The synthesized films showed water contact angle ranged from 84.55 ± 2.12 to 69.41 ± 1.21, suggesting that films were hydrophobic. The Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis demonstrated strong interaction among PE, CNF, and biopolymers. The film with GE/SA/CNF/PE exhibited higher thermal stability compared with control film. Then, the films were applied for checking real time application for the freshness of salmon fish. The significant color change of the film occurred and the number of bacterial colony and TVB-N were increased from 3.81 Log CFU/g to 6.94 Log CFU/g and from 4.78 mg/100 g to 32.27 mg/100 g after incubation for 48 h. Therefore, the film with PE and CNF was intended as an excellent candidate for smart packaging film.

Optimization of cobia fish (Rachycentron canadum) gelatin extraction with response surface methodology

Cobia fish or often called sea cork fish, is a fish that has thick meat which is nutritionally equivalent to salmon meat. Cobia fish is usually sold in the form of fish fillets and the bones becomes solid waste, which has the potential to be a raw material for fish gelatin. Gelatin is a bone and skin collagen hydrolysis product that can be used for food and nonfood industries. The quality of fish gelatin is influenced by the extraction process, such as acid concentration, temperature, and extraction time. This study aims to determine the effect of hydrochloric acid concentration, temperature, extraction time, and the optimal process of making cobia fish bone gelatin using the response surface methodology with the Box Behnken model. The data was processed using Design Expert 11 software. The model suggested by the software was the cubic model. The optimum extraction conditions obtained were using a concentration of 5.53% hydrochloric acid, a temperature of 90oC, and a stirring time of 6.42 mins would produce a yield of 12.38% and gel strength of 229.14 bloom. The verification results by extracting cobia fish gelatin with optimum conditions obtained a yield of 11.22% and gel strength of 227.60 bloom. The proximate analysis of cobia fish gelatin extracted under optimum conditions was found to contain 6.43% water content, 8.27% ash content, 4.65% fat content, 68.47% protein content, and 12.18% carbohydrate by different. Cobia fish gelatin microstructure is in the form of thick strands with a soft sponge.