Effect ofin situapatite on performance of collagen fiber film for food packaging applications

Effects of eugenol on physicochemical properties of sturgeon skin collagen-chitosan composite membrane

In this study, a series of collagen-chitosan-eugenol (CO-CS-Eu) flow-casting composite films were prepared using collagen from sturgeon skin, chitosan, and eugenol. The physicochemical properties, mechanical properties, microstructure, as well as antioxidant and antimicrobial activities of the composite membranes were investigated by various characterization techniques. The findings revealed that the inclusion of eugenol augmented the thickness of the film, darkened its color, reduced the transparency, and enhanced the ultraviolet light-blocking capabilities, with the physicochemical properties of the CO-CS-0.25%Eu film being notably favorable. Eugenol generates increasingly intricate matrices that disperse within the system, thereby modifying the optical properties of the material. Furthermore, the tensile strength of the film decreased from 70.97 to 20.32 MPa, indicating that eugenol enhances the fluidity and ductility of the film. Added eugenol also exhibited structural impact by loosening the film cross-section and decreasing its density. The Fourier transform infrared spectroscopy results revealed the occurrence of several intermolecular interactions among collagen, chitosan, and eugenol. Moreover, the incorporation of eugenol bolstered the antioxidant and antimicrobial capabilities of the composite film. This is primarily attributed to the abundant phenolic/hydroxyl groups present in eugenol, which can react with free radicals by forming phenoxy groups and neutralizing hydroxyl groups. Consequently, inclusion of eugenol substantially enhances the freshness retention performance of the composite film. PRACTICAL APPLICATION: ● The CO-CS-Eu film utilizes collagen from sturgeon skin, improving the use of sturgeon resources.● Different concentrations of eugenol altered its synergistic effect with chitosan.● The CO-CS-Eu film is composed of natural products with safe and edible properties.

Collagen processing with mesoscale aggregates as templates and building blocks

Collagen presents a well-organized hierarchical multilevel structure. Microfibers, fibers, and fiber bundles are the aggregates of natural collagen; which achieve an ideal balance of mechanical strength and toughness at the mesoscopic scale for biological tissue. These mesostructured aggregates of collagen isolated from biological tissues retain these inherent organizational features to enable their use as building blocks for constructing new collagen materials with ideal mechanical performance, thermal and dimensional stability. This strategy is distinct from the more common bottom-up or molecular-level design and assembly approach to generating collagen materials. The present review introduces the hierarchical structure of biological collagen with a focus on mesostructural features. Isolation strategies for these collagen aggregates (CAs) are summarized. Recent progress in the use of these mesostructural components for the construction of new collagen materials with emerging applications is reviewed, including in catalysis, environmental applications, biomedicine, food packaging, electrical energy storage, and flexible sensors. Finally, challenges and prospects are assessed for controllable production of CAs as well as material designs.

A rethinking of collagen as tough biomaterials in meat packaging: assembly from native to synthetic

Due to the high moisture-associated typical rheology and the changeable and harsh processing conditions in the production process, packaging materials for meat products have higher requirements including a sufficient mechanical strength and proper ductility. Collagen, a highly conserved structural protein consisting of a triple helix of Gly-X-Y repeats, has been proved to be suitable packaging material for meat products. The treated animal digestive tract (i.e. the casing) is the perfect natural packaging material for wrapping meat into sausage. Its thin walls, strong toughness and impact resistance make it the oldest and best edible meat packaging. Collagen casing is another wisdom of meat packaging, which is made by collagen fibers from hide skin, presenting a rapid growth in casing market. To strengthen mechanical strength and barrier behaviors of collagen-based packaging materials, different physical, chemical, and biological cross-linking methods are springing up exuberantly, as well as a variety of reinforcement approaches including nanotechnology. In addition, the rapid development of biomimetic technology also provides a good research idea and means for the promotion of collagen's assembly and relevant mechanical properties. This review can offer some reference on fundamental theory and practical application of collagenous materials in meat products.

Multilayer Structure Ammoniated Collagen Fibers for Fast Adsorption of Anionic Dyes

Dye wastewater has become one of the difficult industrial wastewaters due to its significant characteristics such as high chroma and poor biodegradability. Here, we use collagen fibers (CFs) as the matrix, glutaraldehyde as the cross-linking agent, and polyethyleneimine (PEI) as the ammoniating modifier to prepare cationic-modified collagen fibers (CF-PEI). The CF-PEI still maintained the original fibrous structure with a larger adsorption area. The content of primary amino groups on CF-PEI was significantly increased, which not only improved the hydrophilic swelling performance of CFs but also improved the adsorption capacity. The adsorption capacity of CF-PEI for soap yellow and acid red could reach 538.2 and 369.7 mg g-1, respectively. The adsorption rate was fast, and the adsorption equilibrium could be reached in about 60 min. Desorption regeneration studies have shown that 0.1 mol L-1 HCl could achieve a better desorption effect, and the CF-PEI had a good recycling performance. The ammoniated modified CF-PEI was an excellent adsorption treatment material for anionic dye wastewater. It is expected to become an effective way for high-value resource utilization of waste dander in the leather industry.

Excellent coating of collagen fiber/chitosan-based materials that is water- and oil-resistant and fluorine-free

Collagen fiber has attracted much attention due to its good biocompatibility and biodegradability. In the present research, we prepared a type of non-fluorine hydrophobic and oil-resistant material using collagen fiber, chitosan, and polydimethylsiloxane (PDMS) as raw materials. To improve oil/grease resistance, the first layer filled the porous matrix and was made from the cross-linking product of collagen fiber/chitosan and glutaraldehyde. This was followed by a simple coating of PDMS, to increase hydrophobicity and water resistance. Notably, 10 g/m² of cross-linking product and 6 g/m² of PDMS had a low pore size as well as a smooth and uniform surface, which made the composites exhibit excellent hydrophobic and oil-resistant properties (water contact angles of 141°), water and oil resistance (kit rating value of 12/12) and mechanical properties. Fluorine-free environment-friendly materials with high water and oil resistance play an important role in promoting the development of high-performance materials for food packaging.

Biodegradable Packaging Materials from Animal Processing Co-Products and Wastes: An Overview

Biodegradable polymers are non-toxic, environmentally friendly biopolymers with considerable mechanical and barrier properties that can be degraded in industrial or home composting conditions. These biopolymers can be generated from sustainable natural sources or from the agricultural and animal processing co-products and wastes. Animals processing co-products are low value, underutilized, non-meat components that are generally generated from meat processing or slaughterhouse such as hide, blood, some offal etc. These are often converted into low-value products such as animal feed or in some cases disposed of as waste. Collagen, gelatin, keratin, myofibrillar proteins, and chitosan are the major value-added biopolymers obtained from the processing of animal's products. While these have many applications in food and pharmaceutical industries, a significant amount is underutilized and therefore hold potential for use in the generation of bioplastics. This review summarizes the research progress on the utilization of meat processing co-products to fabricate biodegradable polymers with the main focus on food industry applications. In addition, the factors affecting the application of biodegradable polymers in the packaging sector, their current industrial status, and regulations are also discussed.

Evaluation of a novel nano-size collagenous matrix film cross-linked with gallotannins catalyzed by laccase

The effect of hydrolysis degree of gallotannins (GT, 1 mg/g) on cross-linking of nano-size collagen catalyzed by laccase (12 U/g) was studied, and the antibacterial properties of GT hydrolysates (HGT)-laccase (Lac) collagen films on minced cod were also investigated. The results showed that the tensile strength of HGT-Lac films (87.23-100.77 MPa) was higher than those added HGT alone (85.59-95.58 MPa) under the same hydrolysis degree of GT. Compared to the denaturation temperature (78.05 °C) of pure nano-size collagen film without addition of HGT and laccase, the denaturation temperature of HGT (80.75-86.30 °C) and HGT-Lac (91.97-101.64 °C) films increased greatly, especially for HGT-Lac films. Moreover, both HGT and HGT-Lac films showed some mild antibacterial properties for minced cod during storage at 4 °C for 8 days. Therefore, the combination of HGT and laccase could improve the performance of nano-size collagen film and extend the application of collagen in biodegradable/edible packaging.

Fabrication of Delivery Gels with Micellar Casein Concentrates (MCC) Using Microfiltration Embedding Lactobacillus Rhamnosus GG (LGG): Effect of Temperature on Structure, Rheological Behavior, and Texture

To obtain natural protein gels as delivery systems loading with probiotics and protect the probiotics from heat treatment, we fabricated casein-based gels using micellar casein concentrates (MCC) via microfiltration and then embedded with Lactobacillus Rhamnosus GG (LGG). Rheological analysis indicated that MCC with a protein concentration of 12% would form gels greatly. The results of SDS-polyacrylamide gel electrophoresis showed that the contents of macromolecule in the gels increased as the heat treatment time is prolonged. After heat treatment, a fibrillated structure and a more stable structure were obtained in MCC-LGG gels by scanning electron microscopy and Fourier transform infrared spectroscopy, respectively. The different changes of rheological behavior and texture of the gels were evaluated using a rheometer and texture analyzer, respectively. Similarly, centrifugation could reduce the property modified by heat inducing and contribute to LGG embedding completely. Importantly, LGG with a survival rate of 7.12% was in the gels after heat treatment at 75 °C for 10 min. Results showed that MCC could offer a protecting circumstance for living LGG cells from heat treatment. Therefore, MCC-LGG gels would be a potential healthy food for improving intestinal microflora in the dairy industry.

Improved structure-stability and packaging characters of crosslinked collagen fiber-based film with casein, keratin and SPI

BACKGROUND

To improve the structure-stability and packing characters of collagen fiber, we manufactured crosslinked collagen fiber (CColF)-based edible films using transglutaminase (TGase). Then we made a comparison on structure-stability and packing characteristics among the CColF-based films loaded with casein (CN), keratin (KRT) and soy protein isolate (SPI), respectively.

RESULTS

Observed from scanning electron microscopy (SEM), the CColF loaded with CN, KRT and SPI showed some unique morphology of the additional proteins. The CColF-protein films performed better packing characteristics including barrier properties, mechanical properties and thermal-stability properties, compared with CColF films. Importantly, with 500 g kg^-1 CN (of CColF) addition, CColF-based films possessed a greater thermal stability than the other films judged from differential scanning calorimetry (DSC). Meanwhile, the CColF loaded with 100 g kg^-1 CN provided a higher value of tensile strength (TS) and the CColF loaded with 100 g kg^-1 KRT showed a higher value in elongation-at-break (EAB) than the other films.

CONCLUSION

In conclusion, the collagen fiber-based edible films with better structure-stability and packing characteristics for food packaging was obtained which could be an advantage to promote the development of the application of collagen in packing products. © 2019 Society of Chemical Industry.

Improved mechanical properties and thermal-stability of collagen fiber based film by crosslinking with casein, keratin or SPI: Effect of crosslinking process and concentrations of proteins

This study utilized three different thermo-stable proteins of casein, keratin and soy protein isolate (SPI) to improve the thermal stabilities and mechanical properties of collagen fiber films using transglutaminase (TGase) crosslinking. The crosslinking greatly enhanced the thermal- stability of collagen fiber films, especially that of the collagen fiber crosslinking with 50% casein composite films, judged from thermogravimetric analysis (TGA). Furthermore, the TGase treatment improved the mechanical properties of the collagen fiber films interms of tensile strength (TS) and elongation at break (EAB). Importantly, a prominent improvement in EAB at wet and heated state was noted when collagen fiber crosslinked with 50% keratin or 50% casein, respectively. Moreover, different addition patterns of proteins in the collagen fiber films offered altered morphology as observed by scanning electron microscopy (SEM). Meanwhile, the conformational changes of the films revealed by fourier transform infrared spectroscopy (FTIR) confirmed a greater stabilization of film in the group of collagen fiber crosslinking with other proteins. In conclusion, the crosslinking action induced by TGase between collagen fiber and higher thermo-stable proteins promoted heat-resistance and mechanical properties of collagen fiber based film.