The versatility of collagen and chitosan: From food to biomedical applications

Dual cross-linking with tannic acid and transglutaminase improves microcapsule stability and encapsulates lemon essential oil for food preservation

The microencapsulation of essential oils by complex coacervation technology has attracted considerable attention. This paper deals with the preparation of gelatin-chitosan microcapsules through dual cross-linking using transglutaminase (TGase) and tannic acid (TA). Lemon essential oil (LEO) was successfully encapsulated with 82.5 % encapsulation efficiency. Compared to single cross-linking microcapsules (TG), dual cross-linking microcapsules (TG-TA) exhibit superior thermal stability and swell stability. In vitro release studies demonstrated that TG-TA exhibited better controlled-release behavior with a longer duration of action. Meanwhile, the lipid oxidation of TG-TA was 1.45 mg MDA/kg that of control group was 2.23 mg MDA/kg which showed their excellent antioxidant effects. Moreover TG-TA have higher antibacterial rate, more inhibition zone diameters and better effect for preventing the growth of total viable count than TG and LEO. This study has theoretical implications for the use of TG-TA ideal carriers for protecting various active substances, thus facilitating their applications in food preservation.

Chemically modified chitosan as a functional biomaterial for drug delivery system

Chitosan is a natural polymer that can degrade in the environment and support green chemistry. It displays superior biocompatibility, easy access, and easy modification due to the reactive amino groups to transform or improve the physical and chemical properties. Chitosan can be chemically modified to enhance its properties, such as water solubility and biological activity. Modified chitosan is the most effective functional biomaterial that can be used to deliver the drugs to the targeted site. With diverse and versatile characteristics, it can be fabricated into various drug delivery systems such as membranes, beads, fibers, microparticles, composites, and scaffolds, for different drug delivery methods. Integrating nanotechnology with modified chitosan enhanced the delivery attributes of antibacterial, antifungal, antiviral, anticancer, anti-inflammatory, protein/peptides, and nucleic acids for intended use toward desired therapeutic outcomes. The review brings out an overview of the research regarding drug delivery systems utilizing modifying chitosan detailing the properties, functionality, and applications.

Fish collagen mediated alteration of wheat starch thermal properties during multi-species co-fermentation

This study explores the impact of multi-species co-fermentation on the thermal properties of wheat starch, emphasizing the innovative use of fish collagen as an additive. The effects of adding different levels of fish collagen (0 %, 3 %, 6 %, 9 %, 12 %, and 15 %) on the thermal properties of starch were investigated during co-fermentation with Lactobacillus plantarum and Saccharomyces cerevisiae. Utilizing analytical techniques such as X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR), we observed a significant increase in the degree of order from 1.32 to 1.55 and a notable decrease in double helix formation from 1.51 to 0.80 (p < 0.05). The introduction of collagen induced the aggregation of B-starch granules, forming aggregates approximately 16 μm in diameter. Meanwhile, collagen addition shifted the peak thermal impact by +0.91 °C and elevated the maximum mass loss rate temperature from 309.33 °C to 317.09 °C (p < 0.05). Furthermore, a decrease in peak viscosity from 4321 cp to 3123 cp and final viscosity from 4143 cp to 3171 cp (p < 0.05), along with a 3 °C increase in pasting temperature. The results suggest that fish collagen is a potential quality improver for traditional fermented starch-based foods.

Versatile platforms of mussel-inspired agarose scaffold for cell cultured meat

INTRODUCTION

Biomaterial scaffolds are critical for cell cultured meat production. polysaccharide scaffolds lack essential animal cell adhesion receptors, leading to significant challenges in cell proliferation and myogenic differentiation. Thus, enhancing cell adhesion and growth on polysaccharide scaffolds is strongly required to supply the gaps in cell-cultured meat production.

OBJECTIVES

This study aims to develop a multifunctional cell-responsive hydrogel scaffold for the in vitro production of myofibers and structured cell cultured meat through a "cell adhesion-proliferation-differentiation" strategy.

METHODS

A polydopamine coating was applied to agarose hydrogel scaffolds using a dipping technique. The capability of scaffolds for myofiber preparation was assessed by evaluating cell adhesion, proliferation, and myogenic differentiation. Utilizing isolated porcine skeletal muscle satellite cells (PSMSCs), the feasibility of structured cell cultured pork tissue supported by agarose hydrogel film scaffolds was further investigated through three-dimensional imaging and scanning electron microscopy analysis. The physicochemical properties of the structured cell cultured pork tissue were evaluated through staining and texture analysis.

RESULTS

The incorporation of a polydopamine coating facilitated a remarkable 100 % cell adhesion rate on agarose hydrogel scaffolds, which also demonstrated reusability. The agarose hydrogel scaffolds retained adequate mechanical properties, enabling the adhered cells to proliferate effectively and differentiate into myofiber. Moreover, isolated PSMSCs maintained growth potential on the agarose hydrogel scaffolds, thereby imparting the scaffolds with the ability to generate substantial quantities of multinucleated myofibers. Furthermore, we established a structured cell culture pork meat model, characterized by high-density myofibers and agarose hydrogel film scaffolds, which exhibited the texture and color typical of real pork.

CONCLUSION

The innovative agarose/polydopamine scaffold functions as a multifunctional platform for cell culture, offering novel avenues for the diversification and scalable production of cultured meat, and promising significant reductions in production costs for cell cultured meat.

Exploring the influence of different processing conditions on DNA quality of collagen peptides and the feasibility of its raw material traceability

In this work, we have presented a new method for species origin verification of collagen peptides based on DNA techniques. First, we investigate the changes in DNA during the preparation of collagen peptides including the total amount of collagen peptide DNA and the DNA degradation under different processing conditions. Secondly, we discussed the possibility of using polymerase chain reaction (PCR) for follow-up detection of collagen peptides. The results showed that the total amount of DNA decreased as the treatment intensity increased. The size of the cleaved fragments of DNA are mainly concentrated between 200 and 500 bp. On this basis, the combined PCR results finally determined that trace collagen peptide DNA can be effectively amplified with amplicons of about 300 bp to complete the verification of the species origin of collagen peptide. This study provides a new strategy for determining the authenticity of food labels for bovine collagen peptides.

Gelatins derived from aronia-supplemented fish diets: Structural effect and molecular simulation

Fish gelatin, a sustainable substitute for mammalian gelatin, frequently exhibits weaker gel strength and thermal stability, limiting its industrial uses. This study investigated an in vivo method to improve functional characteristics by supplementing Nile tilapia diets with Aronia extract. The control diet (A0) contained no Aronia extract, while the remaining four diets consisted of commercial pelleted feed enriched with 250 mg/kg (A250), 500 mg/kg (A500), 750 mg/kg (A750), and 1000 mg/kg (A1000) of Aronia extract. The gelatin samples revealed thermo-reversible behavior with increasing temperature. A250 exhibited the highest melting temperature of 29.65 °C, compared to 27.43 °C for A0. The gelation temperature for A250 was 17.56 °C, indicating a relatively stable gelatin structure. The elastic modulus (G') was the highest in A250, suggesting an improved gel network compared to the other samples. The gelation rate constant (kgel) was highest in A250 (540.67 Pa), followed by A750 (447.32 Pa), A500 (393.85 Pa), and A1000 (370.97 Pa), compared to 391.15 Pa for A0. The gel strength was improved, with A250 showing the highest value at 133.9 g, followed by A750, A1000, and A500, while A0 was 102.1 g. The glass transition temperatures (Tg) for A250, fish gelatin (FG), bovine gelatin (BG), and A0 were 76.72 °C, 74.31 °C, 70.71 °C, and 73.52 °C, respectively. Molecular docking studies revealed strong binding interactions between A250 and phenolic compounds, which contributed to the observed structural enhancements. These findings suggest that supplementing fish diets with Aronia extract can substantially enhance gelatin quality, offering a promising alternative to traditional gelatin sources.

Aminated graphene oxide reinforced gelatin-chitosan composite films toward biopackaging: Preparation and properties

Developing high-performance biobased composite films has garnered increasing attention in recent years. Herein, a new nano-reinforcement strategy for gelatin-chitosan composite film (GCCF) was proposed. Aminated graphene oxide (AGO) was first prepared via the modification of GO using ethylenediamine, and subsequently incorporated into GCCF to finally fabricate an AGO modified GCCF composite film (AGCCF). FTIR and XPS indicated that GO underwent partial reduction upon interaction with ethylenediamine. XRD, SEM and AFM suggested that AGO contributed to a more amorphous and even network structure of AGCCF. Notably, at an AGO concentration of 1.0 %, the moisture content decreased to 9.09 %, the swelling ratio was reduced by approximately 38.62 %, and water vapor permeability diminished by about 22.60 %. Furthermore, as the concentration of AGO increased, there was a corresponding decrease in transparency and a darkening in color observed for AGCCF. Specifically, the transmittance at 280 nm for AGCCF with the highest AGO dosage (1.0 %) decreased by 55.96 %, indicating improved UV shielding efficiency compared to GCCF. Additionally, the tensile strength of AGCCF reached up to 23.88 MPa, representing an increase of 359.23 % relative to that of GCCF (5.20 MPa). These findings suggest that the developed high-performance AGCCF holds considerable promise for applications in biopackaging.

Identification of a human type XVII collagen fragment with high capacity for maintaining skin health

Collagen XVII (COL17) is a transmembrane protein that mediates skin homeostasis. Due to expression of full length collagen was hard to achieve in microorganisms, arising the needs for selection of collagen fragments with desired functions for microbial biosynthesis. Here, COL17 fragments (27-33 amino acids) were extracted and replicated 16 times for recombinant expression in Escherichia coli. Five variants were soluble expressed, with the highest yield of 223 mg/L. The fusion tag was removed for biochemical and biophysical characterization. Circular dichroism results suggested one variant (sample-1707) with a triple-helix structure at >37 °C. Sample-1707 can assemble into nanofiber (width, 5.6 nm) and form hydrogel at 3 mg/mL. Sample-1707 was shown to induce blood clotting and promote osteoblast differentiation. Furthermore, sample-1707 exhibited high capacity to induce mouse hair follicle stem cells differentiation and osteoblast migration, demonstrating a high capacity to induce skin cell regeneration and promote wound healing. A strong hydrogel was prepared from a chitosan and sample-1707 complex with a swelling rate of >30 % higher than simply using chitosan. Fed-batch fermentation of sample-1707 with a 5-L bioreactor obtained a yield of 600 mg/L. These results support the large-scale production of sample-1707 as a biomaterial for use in the skin care industry.

Diffusion model assisted designing self-assembling collagen mimetic peptides as biocompatible materials

Collagen self-assembly supports its mechanical function, but controlling collagen mimetic peptides (CMPs) to self-assemble into higher-order oligomers with numerous functions remains challenging due to the vast potential amino acid sequence space. Herein, we developed a diffusion model to learn features from different types of human collagens and generate CMPs; obtaining 66% of synthetic CMPs could self-assemble into triple helices. Triple-helical and untwisting states were probed by melting temperature (Tm); hence, we developed a model to predict collagen Tm, achieving a state-of-art Pearson's correlation (PC) of 0.95 by cross-validation and a PC of 0.8 for predicting Tm values of synthetic CMPs. Our chemically synthesized short CMPs and recombinantly expressed long CMPs could self-assemble, with the lowest requirement for hydrogel formation at a concentration of 0.08% (w/v). Five CMPs could promote osteoblast differentiation. Our results demonstrated the potential for using computer-aided methods to design functional self-assembling CMPs.

Photocrosslinkable Biomaterials for 3D Bioprinting: Mechanisms, Recent Advances, and Future Prospects

Constructing scaffolds with the desired structures and functions is one of the main goals of tissue engineering. Three-dimensional (3D) bioprinting is a promising technology that enables the personalized fabrication of devices with regulated biological and mechanical characteristics similar to natural tissues/organs. To date, 3D bioprinting has been widely explored for biomedical applications like tissue engineering, drug delivery, drug screening, and in vitro disease model construction. Among different bioinks, photocrosslinkable bioinks have emerged as a powerful choice for the advanced fabrication of 3D devices, with fast crosslinking speed, high resolution, and great print fidelity. The photocrosslinkable biomaterials used for light-based 3D printing play a pivotal role in the fabrication of functional constructs. Herein, this review outlines the general 3D bioprinting approaches related to photocrosslinkable biomaterials, including extrusion-based printing, inkjet printing, stereolithography printing, and laser-assisted printing. Further, the mechanisms, advantages, and limitations of photopolymerization and photoinitiators are discussed. Next, recent advances in natural and synthetic photocrosslinkable biomaterials used for 3D bioprinting are highlighted. Finally, the challenges and future perspectives of photocrosslinkable bioinks and bioprinting approaches are envisaged.

Self-Assembly Behavior of Collagen and Its Composite Materials: Preparation, Characterizations, and Biomedical Engineering and Allied Applications

Collagen is the oldest and most abundant extracellular matrix protein and has many applications in biomedical, food, cosmetic, and other industries. Previous reviews have already introduced collagen's sources, structures, and biosynthesis. The biological and mechanical properties of collagen-based composite materials, their modification and application forms, and their interactions with host tissues are pinpointed. It is worth noting that self-assembly behavior is the main characteristic of collagen molecules. However, there is currently relatively little review on collagen-based composite materials based on self-assembly. Herein, we briefly reviewed the biosynthesis, extraction, structure, and properties of collagen, systematically presented an overview of the various factors and corresponding characterization techniques that affect the collagen self-assembly process, and summarize and discuss the preparation methods and application progress of collagen-based composite materials in different fields. By combining the self-assembly behavior of collagen with preparation methods of collagen-based composite materials, collagen-based composite materials with various functional reactions can be selectively prepared, and these experiences and outcomes can provide inspiration and practical techniques for the future development directions and challenges of collagen-based composite biomaterials in related applications fields.

Collagen as the extracellular matrix biomaterials in the arena of medical sciences

Collagen is a multipurpose material that has several applications in the health care, dental care, and pharmaceutical industries. Crosslinked compacted solids or lattice-like gels can be made from collagen. Biocompatibility, biodegradability, and wound-healing properties make collagen a popular scaffold material for cardiovascular, dentistry, and bone tissue engineering. Due to its essential role in the control of several of these processes, collagen has been employed as a wound-healing adjunct. It forms a major component of the extracellular matrix and regulates wound healing in its fibrillar or soluble forms. Collagen supports cardiovascular and other soft tissues. Oral wounds have been dressed with resorbable forms of collagen for closure of graft and extraction sites, and to aid healing. This present review is concentrated on the use of collagen in bone regeneration, wound healing, cardiovascular tissue engineering, and dentistry.

Review of Bio-Based Biodegradable Polymers: Smart Solutions for Sustainable Food Packaging

Conventional passive packaging plays a crucial role in food manufacturing by protecting foods from various external influences. Most packaging materials are polymer-based plastics derived from fossil carbon sources, which are favored for their versatility, aesthetic appeal, and cost-effectiveness. However, the extensive use of these materials poses significant environmental challenges due to their fossil-based origins and persistence in the environment. Global plastic consumption for packaging is expected to nearly triple by 2060, exacerbating the ecological crisis. Moreover, globalization has increased access to a diverse range of foods from around the world, heightening the importance of packaging in providing healthier and safer foods with extended shelf life. In response to these challenges, there is a growing shift to eco-friendly active packaging that not only protects but also preserves the authentic qualities of food, surpassing the roles of conventional passive packaging. This article provides a comprehensive review on the viability, benefits, and challenges of implementing bio-based biodegradable polymers in active food packaging, with the dual goals of environmental sustainability and extending food shelf life.

Hydrogel delivery systems of functional substances for precision nutrition

Hydrogel delivery systems based on polysaccharides and proteins have the ability to protect functional substances from chemical degradation, control/target release, and increase bioavailability. This chapter summarizes the recent progress in the utilization of hydrogel delivery systems for nutritional interventions. Various hydrogel delivery systems as well as their preparation, structure, and properties are given. The applications for the encapsulation, protection, and controlled delivery of functional substances are described. We also discuss their potential and challenges in managing chronic diseases such as inflammatory bowel disease, obesity, liver disease, and cancer, aiming at providing theoretical references for exploring novel hydrogel delivery systems and their practical prospects in precise nutritional interventions.

A review of advancements in chitosan-essential oil composite films: Better and sustainable food preservation with biodegradable packaging

In response to the environmental pollution caused by non-degradable and non-recyclable plastic packaging films (PPFs) and the resulting health concerns due to the migration of microplastics into food, the development of biodegradable food packaging films has gained great attention. Chitosan has been extensively utilized in the food industry owing to its abundant availability, exceptional biocompatibility, degradability, and antimicrobial properties. Chitosan-essential oil composite films (CEOs) represent a promising avenue to replace conventional PPFs. This review provides an overview of the advancements in CEOs over the past decade, focusing on the effects of essential oils (EOs) on CEOs in terms of antimicrobial activity, antioxidant effect, gas barrier, light barrier, and mechanical properties. It also offers insights into the controlled release of EOs in CEOs and summarizes the application of CEOs in fresh food preservation.

Unraveling Endothelial Cell Migration: Insights into Fundamental Forces, Inflammation, Biomaterial Applications, and Tissue Regeneration Strategies

Cell migration is vital for many fundamental biological processes and human pathologies throughout our life. Dynamic molecular changes in the tissue microenvironment determine modifications of cell movement, which can be reflected either individually or collectively. Endothelial cell (EC) migratory adaptation occurs during several events and phenomena, such as endothelial injury, vasculogenesis, and angiogenesis, under both normal and highly inflammatory conditions. Several advantageous processes can be supported by biomaterials. Endothelial cells are used in combination with various types of biomaterials to design scaffolds promoting the formation of mature blood vessels within tissue engineered structures. Appropriate selection, in terms of scaffolding properties, can promote desirable cell behavior to varying degrees. An increasing amount of research could lead to the creation of the perfect biomaterial for regenerative medicine applications. In this review, we summarize the state of knowledge regarding the possible systems by which inflammation may influence endothelial cell migration. We also describe the fundamental forces governing cell motility with a specific focus on ECs. Additionally, we discuss the biomaterials used for EC culture, which serve to enhance the proliferative, proangiogenic, and promigratory potential of cells. Moreover, we introduce the mechanisms of cell movement and highlight the significance of understanding these mechanisms in the context of designing scaffolds that promote tissue regeneration.

Food applications of bioactive biomaterials based on gelatin and chitosan

Food packaging must guarantee the products' quality during the different operations including packing and maintenance throughout transportation and storage until to consumption. Thus, it should satisfy, both, food freshness and quality preservation and consumers health safety. Natural bio-sourced polymers have been explored as safe edible materials for several packaging applications, being interestingly carrier of bioactive substances, once added to improve films' properties. Gelatin and chitosan are among the most studied biomaterials for the preparation of edible packaging films due to their excellent characteristics including biodegradability, compatibility and film-forming property. These polymers could be used alone or in combination with other polymers to produce composite films with the desired physicochemical and mechanical properties. When incorporated with bioactive substances (natural extracts, polyphenolic compounds, essential oils), chitosan/gelatin-based films acquired various biological properties, including antioxidant and antimicrobial activities. The emerging bioactive composite films with excellent physical attributes represent excellent packaging alternative to preserve different types of foodstuffs (fruits, meat, fish, dairy products, …) and have shown great achievements. This chapter provides the main techniques used to prepare gelatin- and chitosan- based films, showing some examples of bioactive compounds incorporated into the films' matrix. Also, it illustrates the outstanding advantages given by these biomaterials for food preservation, when used as coating and wrapping agents.

Fabrication and characterisation of collagen/pullulan ultra-thin fibers by electrospinning

Collagen electrospun fibers are promising materials for food packaging and tissue engineering. The conventional electrospinning of collagen, however, is usually carried out by dissolving it in organic reagents, which are toxic. In this study, collagen/pullulan (COL/PUL) ultra-thin fibers were prepared by electrospinning using acetic acid as a solvent. Compared to the conventional preparation method, the proposed method is safe and does not produce toxic solvent residues. The introduction of PUL increased the degree of molecular entanglement in the solution, so the viscosity of the COL/PUL electrospun solution increased from 0.50 ± 0.01 Pa∙s to 4.40 ± 0.08 Pa∙s, and the electrical conductivity decreased from 1954.00 ± 1.00 mS/cm to 1372.33 ± 0.58 mS/cm. Scanning electron microscopy analysis confirmed that PUL improved the spinnability of COL, and smooth, defect-free COL/PUL ultra-thin fibers with diameters of 215.32 ± 40.56 nm and 240.97 ± 53.93 nm were successfully prepared at a viscosity of greater than 1.18 Pa∙s. As the proportion of PUL increased, intramolecular hydrogen bonds became the dominant interaction between COL and PUL. The intermolecular hydrogen bonding content decreased from 52.05 % to 36.45 %, and the intramolecular hydrogen bonding content increased from 46.11 % to 62.95 %. The COL was gradually unfolded, the content of α-helices decreased from 33.57 % to 25.91 % and the random coils increased from 34.22 % to 40.09 %. More than 36 % of the triple helix fraction of COL was retained by the COL/PUL ultra-thin fibers, whereas only 16 % of the triple helix fraction of COL was retained by the COL nanofibers prepared with 2.2.2-trifluoroethanol. These results could serve as a reference for the development of green food COL-based fibers.

Collagen-decorated electrospun scaffolds of unsaturated copolyesters for bone tissue regeneration

Many efforts have been devoted to bone tissue to regenerate damaged tissues, and the development of new biocompatible materials that match the biological, mechanical, and chemical features required for this application is crucial. Herein, a collagen-decorated scaffold was prepared via electrospinning using a synthesized unsaturated copolyester (poly(globalide-co-pentadecalactone)), followed by two coupling reactions: thiol-ene functionalization with cysteine and further conjugation via EDC/NHS chemistry with collagen, aiming to design a bone tissue regeneration device with improved hydrophilicity and cell viability. Comonomer ratios were varied, affecting the copolymer's thermal and chemical properties and highlighting the tunable features of this copolyester. Functionalization with cysteine created new carboxyl and amine groups needed for bioconjugation with collagen, which is responsible for providing biological and structural integrity to the extra-cellular matrix. Bioconjugation with collagen turned the scaffold highly hydrophilic, decreasing its contact angle from 107 ± 2° to 0°, decreasing the copolymer crystallinity by 71%, and improving cell viability by 85% compared with the raw scaffold, thus promoting cell growth and proliferation. The highly efficient and biosafe strategy to conjugate polymers and proteins created a promising device for bone repair in tissue engineering.

Biodegradable and biocompatible collagen-based hybrid materials for force sensing applications

With the aim of replacing synthetic macromolecules by biological macromolecules for advanced applications, collagen films were produced with two different ionic liquids (ILs), choline dihydrogen phosphate ([Ch][DHP]) and choline serinate ([Ch][Seri]), added in order to modulate the electrical responses. The films were prepared by casting, varying IL content between 0 and 6 wt%. The morphology and thermal properties of the resulting films were found to be independent of both IL type and content. However, the highest direct curret (d.c.) electrical conductivity (1.4 × 10-8 S·cm-1) was achieved for collagen films containing 3 wt% [Ch][DHP]. Furthermore, it was demonstrated that IL/collagen films were non-cytotoxic, with cell activity values exceeding 70 %. These collagen films were proven to be suitable for force sensing applications, displaying excellent sensitivity and stability upon repeated testing.

Polysaccharides and proteins based bionanocomposites as smart packaging materials: From fabrication to food packaging applications a review

Food industry is the biggest and rapidly growing industries all over the world. This sector consumes around 40 % of the total plastic produced worldwide as packaging material. The conventional packaging material is mainly petrochemical based. However, these petrochemical based materials impose serious concerns towards environment after its disposal as they are nondegradable. Thus, in search of an appropriate replacement for conventional plastics, biopolymers such as polysaccharides (starch, cellulose, chitosan, natural gums, etc.), proteins (gelatin, collagen, soy protein, etc.), and fatty acids find as an option but again limited by its inherent properties. Attention on the initiatives towards the development of more sustainable, useful, and biodegradable packaging materials, leading the way towards a new and revolutionary green era in the food sector. Eco-friendly packaging materials are now growing dramatically, at a pace of about 10-20 % annually. The recombination of biopolymers and nanomaterials through intercalation composite technology at the nanoscale demonstrated some mesmerizing characteristics pertaining to both biopolymer and nanomaterials such as rigidity, thermal stability, sensing and bioactive property inherent to nanomaterials as well as biopolymers properties such as flexibility, processability and biodegradability. The dramatic increase of scientific research in the last one decade in the area of bionanocomposites in food packaging had reflected its potential as a much-required and important alternative to conventional petroleum-based material. This review presents a comprehensive overview on the importance and recent advances in the field of bionanocomposite and its application in food packaging. Different methods for the fabrication of bionanocomposite are also discussed briefly. Finally, a clear perspective and future prospects of bionanocomposites in food packaging were presented.

Applications and safety aspects of bioactives obtained from by-products/wastes

Due to the negative impacts of food loss and food waste on the environment, economy, and social contexts, it is a necessity to take action in order to reduce these wastes from post-harvest to distribution. In addition to waste reduction, bioactives obtained from by-products or wastes can be utilized by new end-users by considering the safety aspects. It has been reported that physical, biological, and chemical safety features of raw materials, instruments, environment, and processing methods should be assessed before and during valorization. It has also been indicated that meat by-products/wastes including collagen, gelatin, polysaccharides, proteins, amino acids, lipids, enzymes and chitosan; dairy by-products/wastes including whey products, buttermilk and ghee residue; fruit and vegetable by-products/wastes such as pomace, leaves, skins, seeds, stems, seed oils, gums, fiber, polyphenols, starch, cellulose, galactomannan, pectin; cereal by-products/wastes like vitamins, dietary fibers, fats, proteins, starch, husk, and trub have been utilized as animal feed, food supplements, edible coating, bio-based active packaging systems, emulsifiers, water binders, gelling, stabilizing, foaming or whipping agents. This chapter will explain the safety aspects of bioactives obtained from various by-products/wastes. Additionally, applications of bioactives obtained from by-products/wastes have been included in detail by emphasizing the source, form of bioactive compound as well as the effect of said bioactive compound.

Effects of collagen, chitosan and mixture on fibroblast responses and angiogenic activities in 2D and 3D in vitro models

Despite accumulating evidences have demonstrated the potential of collagen and chitosan on tissue repair, it remains unclear on their combination effects. Here, we examined the regenerative effects of single collagen, chitosan and their mixture on fibroblasts and endothelial cells at cellular levels. The results showed that fibroblast responses, as indicated by high proliferative rate, increased spheroid diameter and migrated area existing from spheroid edge, and decreased wound area, were significantly promoted by either collagen or chitosan stimulation. Similarly, both collagen and chitosan resulted in increased endothelial cell proliferation and migration with accelerated tube-like network formation and upregulated VE-cadherin expression, although collagen strongly provided this effect. While the 1:1 mixture (100:100 μg/mL of chitosan to collagen) treatment caused a reduction in fibroblast viability, the lower ratio of chitosan (1:10 mixture; 10:100 μg/mL) did not produce any impact on both fibroblast and endothelial cell viabilities. The 1:10 mixture also significantly enhanced the additional effects on fibroblast responses and angiogenic activities as shown by higher endothelial growth, proliferation and migration with accelerated capillary-like network formation than those treated with the single substance. Further investigation of signaling proteins found that collagen significantly increased expressions of p-Fak, p-Akt and Cdk5 whereas chitosan upregulated p-Fak and Cdk5 expressions. Comparing to the single treatments, p-Fak, p-Akt and Cdk5 were higher expressed in the 1:10 mixture. These observations indicate that proper collagen-chitosan mixture provides the combination effects on fibroblast responses and angiogenic activities when a high concentration of collagen is used, possibly through Fak/Akt and Cdk5 signaling pathways. Therefore, this study helps to define the clinical use of collagen and chitosan as promising biomaterials for tissue repair.

Sustainable Collagen Composites with Graphene Oxide for Bending Resistive Sensing

This work reports on the development of collagen films with graphene oxide nanoparticles (GO NPs), aiming toward the development of a new generation of functional sustainable sensors. For this purpose, different GO NP contents up to 3 wt % were incorporated into a collagen matrix, and morphological, thermal, mechanical and electrical properties were evaluated. Independently of the GO NP content, all films display an increase in thermal stability as a result of the increase in the structural order of collagen, as revealed by XRD analysis. Further, the inclusion of GO NPs into collagen promotes an increase in the intensity of oxygen characteristic absorption bands in FTIR spectra, due to the abundant oxygen-containing functional groups, which lead to an increase in the hydrophilic character of the surface. GO NPs also influence the mechanical properties of the composites, increasing the tensile strength from 33.2 ± 2.4 MPa (collagen) to 44.1 ± 1.0 MPa (collagen with 3 wt % GO NPs). Finally, the electrical conductivity also increases slightly with GO NP content, allowing the development of resistive bending sensors.

Green biomanufacturing in recombinant collagen biosynthesis: trends and selection in various expression systems

Collagen, classically derived from animal tissue, is an all-important protein material widely used in biomedical materials, cosmetics, fodder, food, etc. The production of recombinant collagen through different biological expression systems using bioengineering techniques has attracted significant interest in consideration of increasing market demand and the process complexity of extraction. Green biomanufacturing of recombinant collagen has become one of the focus topics. While the bioproduction of recombinant collagens (type I, II, III, etc.) has been commercialized in recent years, the biosynthesis of recombinant collagen is extremely challenging due to protein immunogenicity, yield, degradation, and other issues. The rapid development of synthetic biology allows us to perform a heterologous expression of proteins in diverse expression systems, thus optimizing the production and bioactivities of recombinant collagen. This review describes the research progress in the bioproduction of recombinant collagen over the past two decades, focusing on different expression systems (prokaryotic organisms, yeasts, plants, insects, mammalian and human cells, etc.). We also discuss the challenges and future trends in developing market-competitive recombinant collagens.

Characteristics of Chitosan Films with the Bioactive Substances-Caffeine and Propolis

Chitosan is a natural and biodegradable polymer with promising potential for biomedical applications. This study concerns the production of chitosan-based materials for future use in the medical industry. Bioactive substances-caffeine and ethanolic propolis extract (EEP)-were incorporated into a chitosan matrix to increase the bioactivity of the obtained films and improve their mechanical properties. Acetic and citric acids were used as solvents in the production of the chitosan-based films. The obtained materials were characterized in terms of their antibacterial and antifungal activities, as well as their mechanical properties, including tensile strength and elongation at break. Moreover, the chemical structures and surface morphologies of the films were assessed. The results showed that the solution consisting of chitosan, citric acid, caffeine, and EEP exhibited an excellent antiradical effect. The activity of this solution (99.13%) was comparable to that of the standard antioxidant Trolox (92.82%). In addition, the film obtained from this solution showed good antibacterial activity, mainly against Escherichia coli and Enterococcus faecalis. The results also revealed that the films produced with citric acid exhibited higher activity levels against pathogenic bacteria than the films obtained with acetic acid. The antimicrobial effect of the chitosan-based films could be further enhanced by adding bioactive additives such as caffeine and propolis extract. The mechanical tests showed that the solvents and additives used affected the mechanical properties of the films obtained. The film produced from chitosan and acetic acid was characterized by the highest tensile strength value (46.95 MPa) while the chitosan-based film with citric acid showed the lowest value (2.28 MPa). The addition of caffeine and propolis to the film based on chitosan with acetic acid decreased its tensile strength while in the case of the chitosan-based film with citric acid, an increase in strength was observed. The obtained results suggested that chitosan films with natural bioactive substances can be a promising alternative to the traditional materials used in the medical industry, for example, as including biodegradable wound dressings or probiotic encapsulation materials.

Peptide-triggered self-assembly of collagen mimetic peptides into nanospheres by electrostatic interaction and π-π stacking

Collagen is the most abundant protein in various connective tissues, providing mechanical integrity as well as regulating cellular activities. Self-assembled peptides have been extensively explored to develop collagen mimetic materials, due to their attractive features such as easy synthesis, selective sequences and low immunogenicity. Metal ion-triggered self-assembly of collagen mimetic peptides has recently received increasing interests, since the addition of external stimuli offers programmable control of the self-assembly process. We have for the first time reported a peptide-stimulated self-assembly of collagen mimetic peptides into nanospheres by electrostatic interaction and π-π stacking. We have accidentally discovered that FAM-modified positively-charged triple helical peptide FAM-PRG was highly soluble, while the addition of a single-stranded negatively-charged peptide EOG-10 efficiently drove its self-assembly into well-ordered spherical nanomaterials. Peptide EOG-10 has been shown to mediate similar self-assembly of TPE-modified triple-helical peptide TPE-PRG into luminescent exquisite nanospheres, consistently demonstrating the robustness of this peptide-triggered strategy. Fluorescence monitoring of the interaction of EOG-10 and TPE-PRG at different ratios indicated that EOG-10 specifically binds to TPE-PRG to form a 3 : 1 complex. High salt concentration was shown to inhibit the self-assembly of TPE-PRG with EOG-10, suggesting that their self-assembly was controlled by electrostatic interaction. The self-assembly of TPE-PRG with EOG-10 has been further revealed to require the exact lengths of both peptides as well as complementary sequences without mutations, indicating a pairwise "side-by-side" binding mode. Notably, the identity of the N-terminal residues of X-PRG has been found to play a determinant role in the self-assembly, while non-aromatic residues lost the self-assembling capability, suggesting that π-π stacking and electrostatic interactions collectively modulate the self-assembly of X-PRG and EOG-10. To conclude, we have developed a highly biocompatible and programmably controlled peptide-triggered self-assembly approach to create novel collagen mimetic nanomaterials, which may have great potential in advanced functional materials.

Recent Advances in Collagen Antimicrobial Biomaterials for Tissue Engineering Applications: A Review

Biomaterial-based therapies have been receiving attention for treating microbial infections mainly to overcome the increasing number of drug-resistant bacterial strains and off-target impacts of therapeutic agents by conventional strategies. A fibrous, non-soluble protein, collagen, is one of the most studied biopolymers for the development of antimicrobial biomaterials owing to its superior physicochemical, biomechanical, and biological properties. In this study, we reviewed the different approaches used to develop collagen-based antimicrobial devices, such as non-pharmacological, antibiotic, metal oxide, antimicrobial peptide, herbal extract-based, and combination approaches, with a particular focus on preclinical studies that have been published in the last decade.

Collagen, protein hydrolysates and chitin from by-products of fish and shellfish: An overview

Waste processing from fish and seafood manufacturers represents a sustainable option to prevent environmental contamination, and their byproducts offer different benefits. Transforming fish and seafood waste into valuable compounds that present nutritional and functional properties compared to mammal products becomes a new alternative in Food Industry. In this review, collagen, protein hydrolysates, and chitin from fish and seafood byproducts were selected to explain their chemical characteristics, production methodologies, and possible future perspectives. These three byproducts are gaining a significant commercial market, impacting the food, cosmetic, pharmaceutical, agriculture, plastic, and biomedical industries. For this reason, the extraction methodologies, advantages, and disadvantages are discussed in this review.

Antimicrobial Nano-Zinc Oxide Biocomposites for Wound Healing Applications: A Review

Chronic wounds are a major concern for global health, affecting millions of individuals worldwide. As their occurrence is correlated with age and age-related comorbidities, their incidence in the population is set to increase in the forthcoming years. This burden is further worsened by the rise of antimicrobial resistance (AMR), which causes wound infections that are increasingly hard to treat with current antibiotics. Antimicrobial bionanocomposites are an emerging class of materials that combine the biocompatibility and tissue-mimicking properties of biomacromolecules with the antimicrobial activity of metal or metal oxide nanoparticles. Among these nanostructured agents, zinc oxide (ZnO) is one of the most promising for its microbicidal effects and its anti-inflammatory properties, and as a source of essential zinc ions. This review analyses the most recent developments in the field of nano-ZnO–bionanocomposite (nZnO-BNC) materials—mainly in the form of films, but also hydrogel or electrospun bandages—from the different preparation techniques to their properties and antibacterial and wound-healing performances. The effect of nanostructured ZnO on the mechanical, water and gas barrier, swelling, optical, thermal, water affinity, and drug-release properties are examined and linked to the preparation methods. Antimicrobial assays over a wide range of bacterial strains are extensively surveyed, and wound-healing studies are finally considered to provide a comprehensive assessment framework. While early results are promising, a systematic and standardised testing procedure for the comparison of antibacterial properties is still lacking, partly because of a not-yet fully understood antimicrobial mechanism. This work, therefore, allowed, on one hand, the determination of the best strategies for the design, engineering, and application of n-ZnO-BNC, and, on the other hand, the identification of the current challenges and opportunities for future research.

Recent progressions in biomedical and pharmaceutical applications of chitosan nanoparticles: A comprehensive review

Nowadays, the most common approaches in the prognosis, diagnosis, and treatment of diseases are along with undeniable limitations. Thus, the ever-increasing need for using biocompatible natural materials and novel practical modalities is required. Applying biomaterials, such as chitosan nanoparticles (CS NPs: FDA-approved long-chain polymer of N-acetyl-glucosamine and D-glucosamine for some pharmaceutical applications), can serve as an appropriate alternative to overcome these limitations. Recently, the biomedical applications of CS NPs have extensively been investigated. These NPs and their derivatives can not only prepare through different physical and chemical approaches but also modify with various molecules and bioactive materials. The potential properties of CS NPs, such as biocompatibility, biodegradability, serum stability, solubility, non-immunogenicity, anti-inflammatory properties, appropriate pharmacokinetics and pharmacodynamics, and so forth, have made them excellent candidates for biomedical applications. Therefore, CS NPs have efficiently applied for various biomedical applications, like regenerative medicine and tissue engineering, biosensors for the detection of microorganisms, and drug delivery systems (DDS) for the suppression of diseases. These NPs possess a high level of biosafety. In summary, CS NPs have the potential ability for biomedical and clinical applications, and it would be remarkably beneficial to develop new generations of CS-based material for the future of medicine.

Understanding fish waste management using bibliometric analysis: A supply chain perspective

Food loss and waste have become an issue of global significance, considering their concurrent effects on the socioeconomic and environmental facet of society. Despite this domain gaining prolific attention recently, issues hampering the effective utilization of residues from fish processing usually go unidentified in developing economies such as India. This occurs mainly owing to fragmented supply chains, inappropriate handling, discontinuous cold chains, inadequate temperature monitoring and so on, affecting quality and causing underuse. Any researcher trying to understand the prospects of utilizing these fish processing co-streams in a developing economy with the vision of improving consumption, economic sustainability, reducing discards and promoting circularity faces a lacuna. The authors address this demand in research by identifying the validity of this domain both in the global and native research community by conducting a detailed review using bibliometric analysis and content analysis. Data from Scopus with 717 documents, comprising 612 research articles from 78 countries, 1597 organizations and 2587 authors, are analysed. Results signify (i) developing a focus on hydroxyapatite production, bio-methane generation, transesterification processes, biomass and the rest raw material generated from fish processing, and (ii) reduced research on supply chain-related aspects despite their considerable importance. To comprehend this deficiency, especially in the Indian stance, barriers hindering the utilization of generated by-products are identified, and recommendations for improvements are proposed. The results will provide the struts for a circular and sustainable supply chain for processed seafood in developing economies.

Biopolymer - A sustainable and efficacious material system for effluent removal

Undesired discharge of various effluents directly into the aquatic ecosystem can adversely affect water quality, endangering aquatic and terrestrial flora and fauna. Therefore, the conceptual design and fabrication of a sustainable system for alleviating the harmful toxins that are discharged into the atmosphere and water bodies using a green sustainable approach is a fundamental standpoint. Adsorptive removal of toxins (∼99% removal efficacy) is one of the most attractive and facile approaches for cleaner technologies that remediate the environmental impacts and provide a safe operating space. Recently, the introduction of biopolymers for the adsorptive abstraction of toxins from water has received considerable attention due to their eclectic accessibility, biodegradability, biocompatibility, non-toxicity, and enhanced removal efficacy (∼ 80-90% for electrospun fibers). This review summarizes the recent literature on the biosorption of various toxins by biopolymers and the possible interaction between the adsorbent and adsorbate, providing an in-depth perspective of the adsorption mechanism. Most of the observed results are explained in terms of (1) biopolymers classification and application, (2) toxicity of various effluents, (3) biopolymers in wastewater treatment and their removal mechanism, and (4) regeneration, reuse, and biodegradation of the adsorbent biopolymer.

Collagen Derived from Fish Industry Waste: Progresses and Challenges

Fish collagen garnered significant academic and commercial focus in the last decades featuring prospective applications in a variety of health-related industries, including food, medicine, pharmaceutics, and cosmetics. Due to its distinct advantages over mammalian-based collagen, including the reduced zoonosis transmission risk, the absence of cultural-religious limitations, the cost-effectiveness of manufacturing process, and its superior bioavailability, the use of collagen derived from fish wastes (i.e., skin, scales) quickly expanded. Moreover, by-products are low cost and the need to minimize fish industry waste's environmental impact paved the way for the use of discards in the development of collagen-based products with remarkable added value. This review summarizes the recent advances in the valorization of fish industry wastes for the extraction of collagen used in several applications. Issues related to processing and characterization of collagen were presented. Moreover, an overview of the most relevant applications in food industry, nutraceutical, cosmetics, tissue engineering, and food packaging of the last three years was introduced. Lastly, the fish-collagen market and the open technological challenges to a reliable recovery and exploitation of this biopolymer were discussed.

Natural Compounds and Biopolymers-Based Hydrogels Join Forces to Promote Wound Healing

Rapid and complete wound healing is a clinical emergency, mainly in pathological conditions such as Type 2 Diabetes mellitus. Many therapeutic tools are not resolutive, and the research for a more efficient remedial remains a challenge. Wound dressings play an essential role in diabetic wound healing. In particular, biocompatible hydrogels represent the most attractive wound dressings due to their ability to retain moisture as well as ability to act as a barrier against bacteria. In the last years, different functionalized hydrogels have been proposed as wound dressing materials, showing encouraging outcomes with great benefits in the healing of the diabetic wounds. Specifically, because of their excellent biocompatibility and biodegradability, natural bioactive compounds, as well as biomacromolecules such as polysaccharides and protein, are usually employed in the biomedical field. In this review, readers can find the main discoveries regarding the employment of naturally occurring compounds and biopolymers as wound healing promoters with antibacterial activity. The emerging approaches and engineered devices for effective wound care in diabetic patients are reported and deeply investigated.

PCL/Collagen/UA Composite Biomedical Dressing with Ordered Microfiberous Structure Fabricated by a 3D Near-Field Electrospinning Process

In this work, a functionalized polycaprolactone (PCL) composite fiber combining calf-type I collagen (CO) and natural drug usnic acid (UA) was prepared, in which UA was used as an antibacterial agent. Through 3D near-field electrospinning, the mixed solution was prepared into PCL/CO/UA composite fibers (PCUCF), which has a well-defined perfect arrangement structure. The influence of electrospinning process parameters on fiber diameter was investigated, the optimal electrospinning parameters were determined, and the electric field simulation was conducted to verify the optimal parameters. The addition of 20% collagen made the composite fiber have good hydrophilicity and water absorption property. In the presence of PCUCF, 1% UA content significantly inhibited the growth rate of Gram-positive and negative bacteria in the plate culture. The AC-PCUCF (after crosslinking PCUCF) prepared by crosslinking collagen with genipin showed stronger mechanical properties, water absorption property, thermal stability, and drug release performance. Cell proliferation experiments showed that PCUCF and AC-PCUCF had no cytotoxicity and could promote cell proliferation and adhesion. The results show that PCL/CO/UA composite fiber has potential application prospects in biomedical dressing.

Advanced application of collagen-based biomaterials in tissue repair and restoration

In tissue engineering, bioactive materials play an important role, providing structural support, cell regulation and establishing a suitable microenvironment to promote tissue regeneration. As the main component of extracellular matrix, collagen is an important natural bioactive material and it has been widely used in scientific research and clinical applications. Collagen is available from a wide range of animal origin, it can be produced by synthesis or through recombinant protein production systems. The use of pure collagen has inherent disadvantages in terms of physico-chemical properties. For this reason, a processed collagen in different ways can better match the specific requirements as biomaterial for tissue repair. Here, collagen may be used in bone/cartilage regeneration, skin regeneration, cardiovascular repair and other fields, by following different processing methods, including cross-linked collagen, complex, structured collagen, mineralized collagen, carrier and other forms, promoting the development of tissue engineering. This review summarizes a wide range of applications of collagen-based biomaterials and their recent progress in several tissue regeneration fields. Furthermore, the application prospect of bioactive materials based on collagen was outlooked, aiming at inspiring more new progress and advancements in tissue engineering research.

Graphical Abstract

Production of biopolymers from food waste: Constrains and perspectives

Food is an essential commodity for the survival of any form of life on earth. Yet generation of plethora of food waste has significantly elevated the global concern for food scarcity, human and environment deterioration. Also, increasing use of polymers derived from petroleum hydrocarbons has elevated the concerns towards the depletion of this non-renewable resource. In this review, the use of waste food for the production of bio-polymers and their associated challenges has been thoroughly investigated using scientometric analysis. Various categories of food waste including fruit, vegetable, and oily waste can be employed for the production of different biopolymers including polyhydroxyalkanoates, starch, cellulose, collagen and others. The advances in the production of biopolymers through chemical, microbial or enzymatic process that increases the acceptability of these biopolymers has been reviewed. The comprehensive compiled information may assist researchers for addressing and solving the issues pertaining to food wastage and fossil fuel depletion.

Recent insights into polysaccharide-based hydrogels and their potential applications in food sector: A review

Hydrogels are ideal for various food applications because of their softness, elasticity, absorbent nature, flexibility, and hygroscopic nature. Polysaccharide hydrogels are particularly suitable because of the hydrophilic nature, their food compatibility, and their non-immunogenic character. Such hydrogels offer a wide range of successful applications such as food preservation, pharmaceuticals, agriculture, and food packaging. Additionally, polysaccharide hydrogels have proven to play a significant role in the formulation of food flavor carrier systems, thus diversifying the horizons of newer developments in food processing sector. Polysaccharide hydrogels are comprised of natural polymers such as alginate, chitosan, starch, pectin and hyaluronic acid when crosslinked physically or chemically. Hydrogels with interchangeable, antimicrobial and barrier properties are referred to as smart hydrogels. This review brings together the recent and relevant polysaccharide research in these polysaccharide hydrogel applications areas and seeks to point the way forward for future research and interventions. Applications in carrying out the process of flavor carrier system directly through their incorporation in food matrices, broadening the domain for food application innovations. The classification and important features of polysaccharide-based hydrogels in food processing are the topics of the current review study.

'Multiple and short-range' cross-linking of dialdehyde carboxymethyl cellulose contributes to regulating the physicochemical property of collagen fibril

Collagen fibril hydrogel (CH), with controllable micro-structure, sufficient modifying sites and excellent biocompatibility, has received widely attention in the regulation of biomacromolecules. Herein, dialdehyde carboxymethyl cellulose (DCMC) in different -CHO contents and molecular weights demonstrated two types of cross-linking behaviors to CH, 'limited and long-range' or 'multiple and short range' cross-linking, corresponding to -CHO content ranged from 0 to  53 % and 53- 90 %, respectively. In regard of structure, non-destroying effect of DCMC on collagen was supported by FT-IR and XRD analysis. CH cross-linked by DCMC (CH-DC) showed declining porosity and aggregating fibrils as -CHO content of DCMC rising. In regard of physicochemical properties, DCMC with >53 % -CHO strengthened the hydrophilicity, thermal stability and degradation resistance of CH-DC. Also, there was 110 % growth on gel strength, 86 Pa enhancements on storage modulus, and 4.6 times decrease on the swelling ratio of CH-DC. Results indicated that DCMC with 79 % -CHO remarkably improved the physicochemical properties of CH via developing sufficient Schiff-base bonds with collagen fibril in a short distance. This study distinguished two patterns of DCMC cross-linking from physicochemical view. In other words, DCMC is potential to meet the requirement of protein-based materials with different expectations by adjusting its -CHO content and molecular weight.

Chitosans and Nanochitosans: Recent Advances in Skin Protection, Regeneration, and Repair

Chitosan displays a dual function, acting as both an active ingredient and/or carrier for pharmaceutical bioactive molecules and metal ions. Its hydroxyl- and amino-reactive groups and acetylation degree can be used to adjust this biopolymer's physicochemical and pharmacological properties in different forms, including scaffolds, nanoparticles, fibers, sponges, films, and hydrogels, among others. In terms of pharmacological purposes, chitosan association with different polymers and the immobilization or entrapment of bioactive agents are effective strategies to achieve desired biological responses. Chitosan biocompatibility, water entrapment within nanofibrils, antioxidant character, and antimicrobial and anti-inflammatory properties, whether enhanced by other active components or not, ensure skin moisturization, as well as protection against bacteria colonization and oxidative imbalance. Chitosan-based nanomaterials can maintain or reconstruct skin architecture through topical or systemic delivery of hydrophilic or hydrophobic pharmaceuticals at controlled rates to treat skin affections, such as acne, inflammatory manifestations, wounds, or even tumorigenesis, by coating chemotherapy drugs. Herein, chitosan obtention, physicochemical characteristics, chemical modifications, and interactions with bioactive agents are presented and discussed. Molecular mechanisms involved in chitosan skin protection and recovery are highlighted by overlapping the events orchestrated by the signaling molecules secreted by different cell types to reconstitute healthy skin tissue structures and components.

Sustainable Applications of Animal Waste Proteins

Currently, the growth of the global population leads to an increase in demand for agricultural products. Expanding the obtaining and consumption of food products results in a scale up in the amount of by-products formed, the development of processing methods for which is becoming an urgent task of modern science. Collagen and keratin make up a significant part of the animal origin protein waste, and the potential for their biotechnological application is almost inexhaustible. The specific fibrillar structure allows collagen and keratin to be in demand in bioengineering in various forms and formats, as a basis for obtaining hydrogels, nanoparticles and scaffolds for regenerative medicine and targeted drug delivery, films for the development of biodegradable packaging materials, etc. This review describes the variety of sustainable sources of collagen and keratin and the beneficial application multiformity of these proteins.

Chitosan as a Tool for Sustainable Development: A Mini Review

New developments require innovative ecofriendly materials defined by their biocompatibility, biodegradability, and versatility. For that reason, the scientific society is focused on biopolymers such as chitosan, which is the second most abundant in the world after cellulose. These new materials should show good properties in terms of sustainability, circularity, and energy consumption during industrial applications. The idea is to replace traditional raw materials with new ecofriendly materials which contribute to keeping a high production rate but also reducing its environmental impact and the costs. The chitosan shows interesting and unique properties, thus it can be used for different purposes which contributes to the design and development of sustainable novel materials. This helps in promoting sustainability through the use of chitosan and diverse materials based on it. For example, it is a good sustainable alternative for food packaging or it can be used for sustainable agriculture. The chitosan can also reduce the pollution of other industrial processes such as paper production. This mini review collects some of the most important advances for the sustainable use of chitosan for promoting circular economy. Hence, the present review focuses on different aspects of chitosan from its synthesis to multiple applications.