A state-of-the-art review on the elaboration of fish gelatin as bioactive packaging: Special emphasis on nanotechnology-based approaches

[Background]: The last decade has noticed the expansion of green materials, which aims to reduce the human impact on the environment. Green polymers are clearly tendency subdivision of this stream and numerous bio-sourced plastics have been developed. Recent research has further focused on the development of new bio-based materials such as edible/biodegradable films for food products.[Scope and approach]: Fish gelatin (FG), a protein with recreatable reserve, biodegradability, and processability, has a remarkable potential in bio-packaging. However, there have been noticeable issues concerning the use of FG as packing material, including its low mechanical strength, poor moisture stability, and poor water barrier properties. This paper aims to review the state-of-the-art in development of FG-based films and highlights how they play a crucial role in modifying the properties of such films. Various types of nanofillers that have been included into FG to fabricate bio-nanocomposite films, such as nanoclays (montmorillonite, sepiolite), polysaccharide nanofillers (nanowhiskers/nanofibers), metal ions (silver, copper) and metal oxides nanoparticles (ZnO, TiO2) are reviewed.[Key findings and conclusions]: Cross-linking is a promising technique to improve the performance and applicability of FG-based biomaterials, particularly respecting their water sensitivity, which hinders many of their potential uses as food contact materials. Bio-nanocomposite technology may help to make high-performance materials with extra bio-functional properties, and it is anticipated to be a dynamic research in the future. In general, more research is required to ameliorate application processes of FG films, especially physical aspects, to be suitable for bio-packaging application.Financial support from the Iran Nanotechnology Initiative council (INIC) and Iran National Science Foundation Grant No. 95837482 is gratefully acknowledged.Peer reviewe

Production of Omega-3 Fatty Acid Concentrates from Common Kilka Oil: Optimization of the Urea Complexation Process

There has been an increase in interest in the application of ω-3 PUFAs, especially EPA and DHA, in the development of various food products owing to their myriad health benefits. However, most fish oils do not contain more than 30% combined levels of EPA and DHA. In this study, through the urea complexation procedure, the production of EPA and DHA concentrate in their free fatty acids (FFAs) form was achieved from an enzymatic oil extracted from common kilka (Clupeonella cultriventris caspia). To gain the maximum value of EPA and DHA, the response surface methodology (RSM), which is an effective tool to categorize the level of independent variables onto the responses of an experimental process, was also used. Different variables including the urea–fatty acids (FAs) ratio (in the range of 2–6, w/w), the temperature of crystallization (in the range of −24–8 °C), and the time of crystallization (in the range of 8–40 h) were investigated by response surface methodology (RSM) for maximizing the EPA and DHA contents. Following the model validation, the levels of the variables at which the maximum desirability function (0.907 score) was obtained for response variables were 5:1 (urea–FAs ratio), −9 °C (the temperature of crystallization), and 24 h (the time of crystallization). Under these optimal conditions, increases of 2.2 and 4.4 times in the EPA and DHA concentrations were observed, respectively, and an increase in the concentrations of EPA and DHA from 5.39 and 13.32% in the crude oil to 12.07 and 58.36% in the ω-3 PUFA concentrates were observed, respectively. These findings indicate that the urea complexation process is efficient at optimizated conditions

Enhancing hot oxidation resistance of the HVOF-sprayed NiCoCrAlTaY coating by alumina nanoparticles via a modified suspension route

The effect of alumina (Al2O3) nanoparticles on the hot oxidation behavior of NiCoCrAlTaY coating is investigated. High velocity oxygen fuel (HVOF) technique was employed to deposit coatings on a single crystal CMSX-4 Ni-based superalloy. Different amounts of α-Al2O3 nanoparticles (3, 6 and 9 wt%) were added to NiCoCrAlTaY powder via a modified suspension route. By this modification, the Al2O3 nanoparticles were adhered on the surface of the atomized metallic NiCoCrAlTaY powders with a relatively uniform distribution. The composite powder was then sprayed on the superalloy substrate by an industrial HVOF route. The cyclic hot oxidation resistance of the coatings was evaluated at 1100 °C. Results showed that the coating with 6 wt% nano-Al2O3 experienced significantly better oxidation performance. The presence of nano-Al2O3 in the coating accelerated the formation of α-Al2O3 dense oxide layer and, thereby, delayed diffusion of other elements to the surface. Adding more Al₂O₃ nanoparticles up to 9 wt% led to an increase in porosity and surface roughness of the coating which decreased oxidation resistance

trans-Cinnamaldehyde-doped quadripartite biopolymeric films: Rheological behavior of film-forming solutions and biofunctional performance of films

Biofunctional quadripartite films were developed by adding trans-Cinnamaldehyde (CIN) (0.4, 0.8, and 1.6% w/v) into chitosan (CH)/poly(vinyl alcohol) (PVA)/fish gelatin (FG) matrices. Rheological data revealed that all solutions exhibited shear-thinning and typical entangle polymers solutions behavior. Mechanical results showed that the incorporation of CIN caused a significant increase (p < 0.05) in tensile strength, while a significant decrease was observed in elongation-at-break. With increasing CIN content, the WVP of the films, which were in the range of 0.785–0.995 g mm/kPa h m2, increased to some extent, whereas the water solubility and water absorption were reduced up to 47 and 87%, respectively. Moreover, water contact angle analysis showed that the inclusion of CIN made the quadripartite film more hydrophobic, in which the highest value achieved was 86.6 ± 0.75° at θt=10. ATR/FT-IR spectroscopy demonstrated the formation of Schiff-base and intermolecular hydrogen bonds between components' functional groups, which enhanced the quadripartite films' thermal stability and mechanical properties. X-ray diffraction analysis suggested compatibility among the components, and changes of the surface of the films were confirmed by SEM and AFM analyses. Likewise, the antimicrobial activity of the CIN-loaded films were proved against Staphylococcus aureus, Listeria monocytogenes, Salmonella enteritidis, and Escherichia coli. The quadripartite films exhibited in vitro DPPH radical scavenging activity (~35.8%) and ferric reducing power at the maximum CIN testing concentration. The findings of this study proved that CIN-doped films could be used as promising inner functional packaging for food products.The study has been carried out with the financial support from Research Council of Tarbiat Modares University.Peer reviewe

Tailoring physico-mechanical and antimicrobial/antioxidant properties of biopolymeric films by cinnamaldehyde-loaded chitosan nanoparticles and their application in packaging of fresh rainbow trout fillets

In this study, cinnamaldehyde (CIN)-loaded chitosan nanoparticles (CCNPs) were fabricated and embedded into chitosan/poly(vinyl alcohol)/fish gelatin (CPF) ternary matrices to improve the physico-mechanical and biofunctional performances of the films. The particle size and ζ-potential values of the CCNPs were 370.3 nm and +32.2 mV, respectively. SEM images revealed that the CCNPs were homogeneously dispersed in the CPF ternary film matrices, thereby filling void spaces in the composite matrix, and significantly improving the bionanocomposite films tensile properties (from 28.33 ± 2.17 MPa to 33.0 ± 1.28 MPa) (p < 0.05). However, the water barrier properties and water contact angle of the CPF films were not significantly influenced by the nanofiller embedding. Although the incorporation of the NPs decreased the light transmittance of the films, it provided the CPF-CCNPs nanocomposite films with excellent UV-barrier properties. ATR/FT-IR spectroscopy and X-ray diffraction analysis demonstrated the formation of hydrogen bonds between the NPs and polymer molecules. TGA and DSC studies revealed that CPF-CCNPs nanocomposite films presented better thermal stability than the neat CPF film. AFM imaging also indicated a re-organization of the surface of the nanocomposite films due to the incorporation of the NPs. Release studies suggested that the CPF-CCNPs bionanocomposite film exhibited sustained release behavior of CIN. Likewise, the bioactive nanocomposites displayed antibacterial activity against food-borne pathogens such as Gram-positive (Staphylococcus aureus and Listeria monocytogenes) and Gram-negative bacteria (Escherichia coli and Salmonella enteritidis). The bionanocomposite films exhibited in vitro DPPH radical scavenging activity (∼16.4%) and ferric reducing power at the maximum CIN loading concentration. Additionally, analysis of storage quality indices (pH, TBARS values, color, and microbiological analyses) revealed the shelf-life of rainbow trout fillets wrapped in CPF-CCNPs0.25 was extended to 12 days.The study has been carried out with the financial support from Research Council of Tarbiat Modares University (IG-39804) and from Agencia Estatal de Investigación (AEI), through project AGL2017-84161.Peer reviewe

Effect of chitosan‐based coatings enriched with savory and/or tarragon essential oils on postharvest maintenance of kumquat (Fortunella sp.) fruit

The present study assessed the ability of chitosan‐based coatings incorporating savory and/or tarragon essential oils (EOs) to preserve the postharvest quality of kumquats. Changes in weight loss, titratable acidity, total soluble solids, and vitamin C content were determined over 30 days of storage at 7°C. Savory (Satureja hortensias L.) essential oil was characterized by thymol (29.1%), carvacrol (26.6%), and γ‐terpinene (24.72%) as major constituents. While, in the tarragon (Artemisia dracunculus L.) essential oil, estragol (81.89%), β‐cis‐Ocimene (4.62%), and β‐trans‐Ocimene (3.44%) were the main ones. The CH‐EOs coatings were effective in reducing weight loss of kumquats fruits during storage. Moreover, the tested composite coatings showed positive effects in maintaining vitamin C and fruits treated with CH‐oil coatings retained good sensory acceptability. The obtained results demonstrate the potential of the combined application of chitosan and savory and/or tarragon EOs as a promising postharvest treatment for maintaining the postharvest quality of kumquats fruits

Polymer blending effects on the physicochemical and structural features of the chitosan/poly(vinyl alcohol)/fish gelatin ternary biodegradable films

Films with appropriate mechanical properties and low permeability are very important for food packages. The aim of this research was to develop and characterize the ternary films made from chitosan (CH), poly(vinyl alcohol) (PVA), and fish gelatin (FG) at different blend compositions (50/50/0, 40/40/20, 35/35/30, 30/30/40, and 25/25/50, CH/PVA/FG) via a simple casting method. Stress-strain curves showed that the incorporation of 20% FG into the films made them tougher as well as making them more elastic; optimum ternary films were obtained using CH/PVA/FG ratio of 40/40/20, giving maximum values of TS and EAB as 41.93 ± 3.24 MPa and 133.13 ± 13.23%, respectively. The water vapor permeability (WVP) values of the ternary films were in the range of 0.686–0.818 g mm/kPa h m2. With increasing FG content, the WVP of the films increased to some extent, whereas the water solubility was reduced up to 23%. Water absorption increased with increasing FG concentration up to 874%. Meanwhile, the ultraviolet–visible-light barrier of the resultant ternary films was significantly improved with the addition of FG; at the same time, an increase in FG concentrations also made the films more opaque and improved their thermal stability. FT-IR spectra showed interactions through hydrogen bonding between the polar groups of FG and hydroxyl moieties of CH and PVA in the blends, which enhanced the compatibility between the three polymers. X-ray diffraction analysis suggested compatibility among the polymeric-blends, and changes of the surface of the films was confirmed by SEM and AFM analyses. The obtained results suggested the effectiveness of blending approach in improving the compatibility of polymers and overall functionality of films.The study has been carried out with the financial support from Research Council of Tarbiat Modares University.Peer reviewe