Properties of films from fish gelatin prepared by molecular modification and direct addition of oxidized linoleic acid

Edible Films Based on Plant and Animal Origin Proteins: Comparison of Some Mechanical and Physicochemical Characteristics

Edible films were manufactured from three different proteins to evaluate their mechanical strength and some physicochemical features. Wheat gluten (WG), cow hide gelatin (CHG), and cow milk casein (CMC) were used at three different concentrations (5%, 6%, and 7% w/v for WG or 2%, 3%, and 4% w/v for both CHG and CMC) for the film samples. Water activity of the film samples varied within a rather narrow gap, which was between 0.26 and 0.36, with the highest values for WG films and the lowest for CMC. WG and CMC gave basic films while CHG resulted in acidic films with a pH value between 5.6 and 5.7. CHG films showed the highest conductivity while pH and conductivity increased as CHG concentration increased. WG resulted in opaque and dark colored films while CHG and CMC led to almost transparent and light colored films. Water vapor permeability of CMC films was slightly higher compared to CHG and WG counterparts with values around 2.0 × 10-14 g m/s Pa m2. In addition, tensile strength of CHG films was significantly higher than CMC and WG counterparts with values over 25 N/mm2 and more flexible with higher values of Young's modulus and elongation at break. It is concluded that CHG may be utilized by the food industry to manufacture edible films with superior mechanical features along with ease of dissolving and transparent visual characteristics, while WG and CMC might be preferred for more rigid, opaque, and dark colored films as needed.

Effect of camellia oil body-based oleogels on the film-forming properties of soy protein isolate

Soybean protein isolate (SPI) was frequently used to make edible films due to its highly degradability and excellent film forming ability. However, the limited barrier properties and low tensile strength of SPI films prevent their application in food packaging. In this study, the SPI film was modified by blending camellia oil body-based oleogel (COBO). COBO improved the mechanical properties of SPI film and increased its light-blocking, water insolubility and barrier properties. Micrograph, particle size distribution, protein conformation and crystalline structure analysis illustrated that camellia saponin in COBO formed hydrogen bonds with SPI, significantly reduced the particle size of the film-forming emulsion, and enhanced the order and uniformity of composite films structure, thus improved the overall performance of the SPI films. The SPI-COBO film packing delayed the weight loss, total soluble solids content increase, and the decrease in hardness of stored strawberries. This study puts forwards a new approach for SPI film modification by blending natural emulsified lipids, contributing to the development of sustainable packaging alternatives.

Intelligent Food Packaging: Quaternary Ammonium Chitosan/Gelatin Blended Films Enriched with Blueberry Anthocyanin-Derived Cyanidin for Shrimp and Milk Freshness Monitoring

Blueberry anthocyanin-derived cyanidin (BAC) was used to prepare a series of responsive food freshness packaging films by compounding it with quaternary chitosan (QC) and gelatin (G). The fundamental properties, pH sensitivity, and functional attributes of the films were examined. The BAC solutions exhibited notable variations in color (from red to pink to violet) under different pH conditions. The incorporation of BAC resulted in improved UV-vis shielding capabilities but compromised the mechanical strength of the films (with tensile strength values from 85.02 to 44.89 MPa, elongation at break from 13.08% to 3.6%, and water vapor transmission rates from 5.24 × 10-9 to 7.80 × 10-9 g m-1 s-1 Pa-1). The QC-G-BAC films, containing 5-15 wt% BAC, exhibited noticeable color changes in acidic/ammonia environments within a short timeframe, easily discernible to the naked eye. Furthermore, the inclusion of BAC significantly enhanced the antioxidant and antimicrobial properties of the films. The addition of 5-15 wt% BAC to QC-G-BAC films could be employed for assessing the freshness of fresh shrimp (from red to dark red) and pasteurized milk (from red to dark earthy yellow). Among them, the total color difference (ΔE) of QC-G-BAC5 film was significantly correlated with the pH, acidity, and total colony count of pasteurized milk (R = 0.846, -0.930, -0.908, respectively). This new concept in smart packaging offers a straightforward and user-friendly freshness indicator.

Packaging films based on biopolymers from seafood processing wastes: Preparation, properties, and their applications for shelf-life extension of seafoods-A comprehensive review

Biopolymers derived from seafood processing byproducts are used to prepare active and biodegradable films as the packaging of food products. These films possess bioactivities to enhance the shelf life of packed foods by proactively releasing antimicrobial/antioxidative agents into the foods and providing sufficient barrier properties. Seafood processing byproducts are an eminent source of valuable compounds, including biopolymers and bioactive compounds. These biopolymers, including collagen, gelatin, chitosan, and muscle proteins, could be used to prepare robust and sustainable food packaging with some antimicrobial agents or antioxidants, for example, plant extracts rich in polyphenols or essential oils. These active packaging are not only biodegradable but also prevent the deterioration of packed foods caused by spoilage microorganisms as well as chemical deterioration. Seafood discards have a promising benefit for the development of environmentally friendly food packaging systems via the appropriate preparation methods or techniques. Therefore, the green packaging from seafood leftover can be better exploited and replace the synthetic counterpart.

High-Performance, Degradable, Self-Healing Bio-Based Nanocomposite Coatings with Antibacterial and Antioxidant Properties

The purpose of this study is to obtain a bio-based coating with good functional activity and self-healing ability, demonstrating its potential in food, materials, and other application fields. Plastic coatings can cause serious environmental pollution. It was a good solution to replace plastic coatings with degradable coatings. However, the development of degradable coatings in the fields of food and materials was limited due to their insufficient antibacterial ability and weak comprehensive properties. Therefore, chitosan nanoparticles (NPs) loaded with gallic acid (GA) were self-assembled with gelatin (GE) to prepare high-performance, degradable, self-healing bio-based nanocomposite coatings with antibacterial and antioxidant properties. The oxygen permeability of GE nanocomposite coatings decreased gradually with the addition of NPs, and the barrier properties increased significantly. At the same time, due to the excellent antioxidant and antibacterial ability of GA, the antioxidant effect of the nanocomposite coatings increased by 119%, and the antibacterial rate against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) increased by 32% and 58%, respectively, compared with the pure GE coatings. In addition, the nanocomposite coatings can be repaired within 24 h after being scratched at room temperature. Finally, GA coated with chitosan nanoparticles can significantly delay the escape of GA, and the retardation of gallic acid release exceeded 89% in simulated solutions after 24 h immersion, extending the service life of the nanocomposite coatings.

Effects of pre-emulsion prepared using sucrose esters with different hydrophile-lipophile balances on characteristics of soy protein isolate emulsion films

The preparation of emulsion films using pre-emulsification has received extensive attention due to the enhancement of oil binding capacity. However, the different effects of water in oil (W/O) and oil in water (O/W) pre-emulsions on the physicochemical properties of films are still unclear. Therefore, the soy protein isolate (SPI) based emulsion films were prepared by W/O or O/W pre-emulsion using sucrose esters with different hydrophile-lipophile balances to investigate the properties of SPI emulsion (SPIE) films. The viscosity, storage moduli, and loss moduli of film-forming solutions (FFSs) with O/W pre-emulsion were higher than those of FFSs with W/O pre-emulsion. The oil droplets of FFSs with W/O pre-emulsion were large and uneven, and the oil droplet size increased after drying. Phase separation and macroporous network appeared in cross-sectional of SPIE films with W/O pre-emulsion according to scanning electron microscope images. Meanwhile, the SPIE films with W/O pre-emulsion demonstrated higher oil concentration and hydrophobicity on the upper surface compared with the SPIE films with O/W pre-emulsion. Low tensile strength, glass transition temperature, and high elongation at break and transparency value of SPIE films with O/W pre-emulsions were founded. The water vapor permeability of SPIE films with W/O pre-emulsion increased with the addition of oil, whereas the opposite trend appeared in that with O/W pre-emulsion. In conclusion, the structure and porosity of emulsion films could be affected by the pre-emulsion types, which can determine the application ranges.

Green Synthesis of Silver Nanoparticles for Preparation of Gelatin Films with Antimicrobial Activity

Silver nanoparticles were successfully synthesized using Thuja orientalis aqueous extract and AgNO3 as a precursor. UV-Vis showed a distinct absorption peak at 424 nm attributed to silver nanoparticles due to their surface plasmon resonance. Atomic absorption analysis reflected an increase in the concentration of nanoparticles in relation to the progress of the synthesis, obtaining a peak concentration value of 15.7 mg/L at 50 min. The FTIR spectra revealed the characteristic functional groups of phytomolecules involved in the silver-ion binding process, such as R-O-H (3335 cm-1) O=C-OH (2314 cm-1) and C-C=C (1450 cm-1). At 50 min, zeta potential showed the stability of the nanoparticles with the value of -21.73 mV. TEM micrographs revealed the formation of spherical nanoparticles with an average size of about 85.77 nm. Furthermore, films incorporated with nanoparticles exhibited a Tg from 66.42 °C to 73.71 °C and Tm at 103.31 °C. Films from the G22 formulation presented excellent antibacterial properties inhibiting the growth of Staphylococcus aureus. Thuja orientalis aqueous extract could be a low-cost, eco-friendly, and efficient reducing and capping agent for the synthesis of nanometric-sized Ag particles. Gelatin films with nanoparticles are expected to have high potential as an active food packaging system.

Effect of polyvinyl alcohol and carboxymethylcellulose on the technological properties of fish gelatin films

The objective of this work was to develop biodegradable films by mixing gelatin/carboxymethylcellulose (FG/CMC) and gelatin/polyvinyl alcohol (FG/PVOH) and to evaluate the effect of adding these polymers on the properties of fish gelatin films. The films FG/CMC and FG/PVOH were produced in the proportions 90/10, 80/20 and 70/30 and characterized their physical, chemical and functional properties. The addition of CMC and PVOH improved the mechanical strength, barrier property and water solubility of gelatin films. FG/CMC films showed greater tensile strength and greater solubility than FG/PVOH. The maximum concentration of CMC promoted the highest mechanical resistance, while the highest PVOH content produced the film with the lowest solubility. The proposed mixing systems proved to be adequate to improve the properties of fish gelatin films, with potential for application in the packaging sector.

Characterization and Application of Gelatin Films with Pecan Walnut and Shell Extract (Carya illinoiensis)

Phenolic compounds that come from natural products are a good option for minimizing lipid oxidation. It should be noted that these are not only introduced directly into the food, but also incorporated into edible biofilms. In contact with food, they extend its useful life by avoiding contact with other surface and preventing deterioration air, one of the main objectives. In particular, gelatin is a biopolymer that has a great potential due to its abundance, low cost and good film-forming capacity. The aim of this study has been to design and analyse gelatin films that incorporate bioactive compounds that come from the walnut and a by-product, the walnut shell. The results showed that mechanical and water vapor barrier properties of the developed films varied depending on the concentration of the walnut, shell and synthetic antioxidant. With increasing walnut concentration (15%) the permeability to water vapor (0.414 g·mm/m2·day·Pascal, g·mm/m2·day·Pa) was significantly lower than the control (5.0368 g·mm/m2·day·Pa). Furthermore, in the new films the elongation at the break and Young's modulus decrease by six times with respect to the control. Films with pure gelatin cannot act as an antioxidant shield to prevent food oxidation, but adding pecan walnut (15% concentration) presents 30% inhibition of the DPPH stable radical. Furthermore, in the DSC, the addition of walnut (15 and 9% concentrations), showed the formation of big crystals; which could improve the thermal stability of gelatin films. The use of new gelatin films has shown good protection against the oxidation of beef patties, increasing the useful lifetime up to nine days, compared to the control (3-4 days), which opens up a big field to the commercialization of meat products with lower quantities of synthetic products.