Enhancement of structural, functional and antioxidant properties of fish gelatin films using Maillard reactions

Tailoring hydrophobicity and strength in spider silk-inspired coatings via thermal treatments

The advent of advanced coatings has transformed material functionalities, extending their roles from basic coverage and visual appeal to include unique properties such as self-healing, superior hydrophobicity, and antimicrobial action. However, the traditional dependency on petrochemical-derived materials for these coatings raises environmental concerns. This study proposes the use of renewable and alternative materials for coating development. We present the use of bioengineered spider silk-inspired protein (SSIP), produced through recombinant technology, as a viable, eco-friendly alternative due to their ease of processing under ambient pressure and the utilization of water as a solvent, alongside their exceptional physicochemical properties. Our research investigates the effects of different thermal treatments and protein concentrations on the mechanical strength and surface water repellency of coatings on silica bases. Our findings reveal a direct correlation between the temperature of heat treatment and the enhancements in surface hydrophobicity and mechanical strength, where elevated temperatures facilitate increased resistance to water and improved mechanical integrity. Consequently, we advocate SSIPs present a promising, sustainable choice for advanced coatings, providing a pathway to fine-tune coating recipes for better mechanical and hydrophobic properties with a reduced ecological footprint, finding potential uses in various fields such as electronics.

Air-Assisted Electrospinning of Dihydromyricetin-Loaded Dextran/Zein/Xylose Nanofibers and Effects of the Maillard Reaction on Fiber Properties

Dihydromyricetin (DMY) has been encapsulated in delivery systems to address the solubility limitations of DMY in water and improve its bioavailability. Air-assisted electrospinning has been used as a novel technology to load DMY. To evaluate the impact of adding DMY to dextran/zein nanofibers and understand the effects of the Maillard reaction (MR) on the physical and functional properties of DMY-loaded nanofibers, dextran/zein/xylose nanofibers with 0%, 1%, 2%, 3%, and 4% DMY were fabricated, followed by MR crosslinking. Scanning electron microscopy (SEM) observations indicated that the addition of DMY and the MR did not affect the morphology of the nanofibers. X-ray diffraction (XRD) results indicated amorphous dispersion of DMY within the nanofibers and a decreased crystalline structure within the nanofibers following the MR, which might improve their molecular flexibility. The nanofibrous film formed after the MR exhibited both increased tensile strength and elastic modulus due to hydrogen bonding within the nanofibers and increased elongation at break attributed to the increased amorphization of the structure after crosslinking. The nanofibers were also found to exhibit improved heat stability after the MR. The antioxidant activity of the nanofibers indicated a dose-dependent effect of DMY on radical scavenging activity and reducing power. The maintenance of antioxidant activity of the nanofibers after the MR suggested heat stability of DMY during heat treatment. Overall, dextran/zein nanofibers with various DMY contents exhibited tunable physical properties and effective antioxidant activities, indicating that dextran/zein nanofibers offer a successful DMY delivery system, which can be further applied as an active package.

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.

Tunable Physical Properties of Electro-Blown Spinning Dextran/Zein Nanofibers Cross-Linked by Maillard Reaction

Electrospinning biopolymer nanofibers have emerged as promising candidates for food packaging applications. In this study, dextran/zein nanofibers were fabricated using electro-blown spinning and subsequently cross-linked via the Maillard reaction (MR) at 60 °C and 50% relative humidity. Compared to traditional electrospinning, the introduction of air-blowing improved the sample preparation speed by 10 times. SEM analysis revealed that the nanofiber morphology remained stable upon MR treatment for 24 h. FTIR spectroscopy confirmed that the MR led to a deformation in the protein conformation and an increase in hydrophilicity and elasticity in the nanofibers cross-linked for 6 h. MR treatment for 18 h considerably enhanced the hydrophobicity and elastic modulus owing to covalent bond formation. Thermal analysis indicated an improved thermal stability with increasing MR duration. Mechanical property analysis revealed an increase in elastic modulus and a decrease in elongation at break for the nanofibers cross-linked for more than 6 h, indicating a trade-off between rigidity and flexibility. Notably, the water vapor permeability of the nanofibers cross-linked for 6 and 18 h was remarkably higher, which can be ascribed to the fiber morphology retention upon water evaporation. Overall, MR-cross-linked dextran/zein/xylose nanofibers showed tunable properties, making them a suitable encapsulation system for bioactive compounds.

Gelatin based preservation technologies on the quality of food: a comprehensive review

Gelatin has played a great potential in food preservation because of its low price and superior film forming characteristics. This review provides a comprehensive overview of the latest research progress and application of gelatin preservation technologies (film, coating, antifreeze peptide, etc.), discussing their preservation mechanisms and efficiency through the viewpoints of quality and shelf life of animal and aquatic products as well as fruits and vegetables. It showed that bioactive and intelligent gelatin-based films exhibit antibacterial, antioxidant, water resistance and pH responsive properties, making them excellent for food preservation. In addition, pH responsive properties of films also intuitively reflect the freshness of food by color. Similarly, gelatin and its hydrolysate can be widely used in antifreeze peptides to reduce the mass loss of food during freezing and extend the shelf life of frozen food. However, extensive works are still required to extend their commercial application values.

Sodium alginate/gelatin hydrogel spheres loaded with Fructus Ligustri Lucidi essential oil: Preparation, characterization and biological activity

The application of plant essential oils in the food industry is often hindered by their poor water solubility and high volatilize. Encapsulation has emerged as an effective solution to this problem. This study focuses on the preparation of Fructus Ligustri Lucidi essential oil gel spheres (FEOH) based sodium alginate and gelatin. The optimum formulation for FEOH was established by Box-Behnken Design response surface testing, resulting in a composition of 10 % FEO, 5 % TW20 and 2 % CaCl2. This formulation achieved an encapsulation efficiency of 85.56 %. FTIR and SEM results indicated the successful encapsulation of FEO within the gel spheres. Furthermore, DSC and TGA results showed that encapsulation enhanced the thermal stability of the essential oil. At room temperature, the water content of FEOH exceeded 90 %, and it showed the highest swelling ratio of 62.5 % in an alkaline medium at different pH conditions. The in vitro release behavior showed that FEOH was released up to 85.28 % in oil-based food simulants within 2 h. FEOH showed strong antibacterial activity, with a Minimum Inhibitory Concentration (MIC) of 128 mg/mL against Staphylococcus aureus and 256 mg/mL against Escherichia coli. The gel spheres obtained in this research show significant potential as food preservatives in food matrices.

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.

Synthesis and characterization of polysaccharide- and protein-based edible films and application as packaging materials for fresh fish fillets

The rising packaging industry together with global demand for sustainable production has increased the interest in developing biodegradable packaging materials. The aim of the study was to develop edible films based on pectin, gelatin, and hydroxypropyl methylcellulose and evaluate their applicability as biodegradable packaging materials for gilthead seabream fillets. Mechanical properties, water barriers, wettability of the films through contact angle measurement, optical, and UV-Vis barrier properties were evaluated for food packaging applications. The effective blend of polysaccharide and protein film-forming solutions was confirmed by the produced films with excellent optical properties, acceptable mechanical properties and adequate barriers to water vapor. The contact angle for pectin based and gelatin based films were higher than 90° indicating the hydrophobic films, while HPMC based films had contact angle lower than 90°. The produced films were tested as alternative and environmentally friendly packaging materials for gilthead seabream fillets during refrigerated storage. All tested packaging conditions resulted in similar shelf-life in packed gilthead seabream fillets (i.e. 7-8 days at 2 °C). The results showed that the developed films may reduce the use of conventional petroleum-based food packaging materials without affecting the shelf-life of fish.

Magnetic core-shell cellulose system for the oriented immobilization of a recombinant β-galactosidase with a protein tag

The objective of this study was to immobilize a recombinant β-galactosidase (Gal) tagged with a cellulose-binding domain (CBD) onto a magnetic core-shell (CS) cellulose system. After 30 min of reaction, 4 U/capsule were immobilized (CS@Gal), resulting in levels of yield and efficiency exceeding 80 %. The optimal temperature for β-galactosidase-CBD activity increased from 40 to 50 °C following oriented immobilization. The inhibitory effect of galactose decreased in the enzyme reactions catalyzed by CS@Gal, and Mg2+ increased the immobilized enzyme activity by 40 % in the magnetic CS cellulose system. The relative enzyme activity of the CS@Gal was 20 % higher than that of the soluble enzyme activity after 20 min at 50 °C. The CS support and CS@Gal capsules exhibited an average size of 8 ± 1 mm, with the structure of the shell (alginate-pectin-cellulose) enveloping and isolating the magnetic core. The immobilized β-galactosidase-CBD within the magnetic CS cellulose system retained ∼80 % of its capacity to hydrolyze lactose from skim milk after 10 reuse cycles. This study unveils a novel and promising support for the oriented immobilization of recombinant β-galactosidase using a magnetic CS system and a CBD tag. This support facilitates β-galactosidase reuse and efficient separation, consequently enhancing the catalytic properties of the enzyme.

The structure, antioxidant activity, and stability of fish gelatin/chitooligosaccharide nanoparticles loaded with apple polyphenols

BACKGROUND

Apple polyphenols (APs) with multiple biological effects have attracted extensive attention due to their broad opportunities for application. However, the use of APs is hampered by their instability in the face of environmental changes. Designing efficient carriers to improve the bioavailability of APs is the key to solving these problems. In this study, gelatin-chitooligosaccharide nanoparticles produced by the Maillard reaction (GCM) were fabricated to encapsulate AP, and the structure, antioxidant activity, and stability of the GMM-AP nanoparticle system were evaluated.

RESULTS

The results of endogenous fluorescence spectrum, Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction, and simultaneous thermal analysis confirmed structural changes and interactions between GCM and AP. Combination with GCM did not adversely affect the antioxidant properties of AP, and the GCM-AP nanoparticles possessed superior temperature and storage stability. In comparison with fish gelatin-apple polyphenol nanoparticles, the GCM-AP nanoparticles were more stable at a wider pH range, and were more resistant to the electrostatic shielding effect of NaCl. After simulating gastric digestion, the particle size and polydispersity index (PDI) of GCM-AP nanoparticles were almost unchanged.

CONCLUSION

The findings suggest that GCM nanoparticles loaded with AP could be used as good carriers with good antioxidant activity and stability. This study therefore provides a theoretical foundation for the development and industrial application of food functional factors. © 2023 Society of Chemical Industry.

Preparation and Characterization of Crosslinked Electrospun Gelatin Fabrics via Maillard Reactions

In this study, nonwoven gelatin (Gel) fabrics crosslinked using N-acetyl-D-glucosamine (GlcNAc) were characterized and compared with those crosslinked using methylglyoxal (MG) and by thermal dehydration. We prepared Gel with 25% concentration along with Gel/GlcNAc and Gel/MG with a GlcNAc-to-Gel ratio of 5% and MG-to-Gel ratio of 0.6%. A high voltage of 23 kV, solution temperature of 45 °C, and distance of 10 cm between the tip and the collector were applied during electrospinning. The electrospun Gel fabrics were crosslinked by heat treatment at 140 and 150 °C for 1 d. The electrospun Gel/GlcNAc fabrics were treated at 100 and 150 °C for 2 d, while the Gel/MG fabrics were heat-treated for 1 d. The Gel/MG fabrics exhibited higher tensile strength and lower elongation than the Gel/GlcNAc fabrics. Overall, Gel/MG crosslinked at 150 °C for 1 d showed a significant enhancement in tensile strength, high hydrolytic degradation, and excellent biocompatibility, with cell viability percentages of 105 and 130% at 1 and 3 d, respectively. Therefore, MG is a promising Gel crosslinker.

Edible pullulan enhanced water-soluble keratin with improved sizing performance for sustainable textile industry

Feather keratin from waste feather has become an attractive target to replace petroleum-based Poly (vinyl alcohol) sizes due to its easy film-forming ability, excellent adhesive property, biodegradability and low cost. However, poor water-solubility and brittleness of pure keratin films have become the bottlenecks and restricted the application of keratin as sizing agents. Therefore, water-soluble keratin was extracted by the reduction-preservation method and enhanced by saccharides in aqueous system to obtain all-green keratin-based slurry. The results showed that the keratin-based slurry exhibited improved sizing performance in the order of sucrose ≤ glucose ≤ pullulan by the moderate Maillard reaction. Among them, the fabricated pullulan-keratin sizes films had 27.86 %, 2684.08 % and 2911.31 % increment in tensile strength, elongation and work of facture compared with pure keratin sizes films. Besides, the addition of pullulan and subsequently moderate Maillard reaction improved the thermo-tenacity of keratin-based sizes, which was expected to tackle with the brittleness of pure keratin size films. In addition, novel pullulan-keratin sizes had good sizing performance and high desizing efficiency to cotton, cotton/polyester and polyester yarns and fabrics. Successful utilization of pullulan-keratin sizes will bring opportunities for high value utilization of waste feather and promote the green and low-carbon development of textile industry.

Effects of citric acid crosslinking on the structure and properties of ovotransferrin and chitosan composite films

In this study, ovotransferrin/chitosan (OVT/CS) composite films cross-linked by citric acid (CA) were prepared and the effects of CA cross-linking on the structure and physicochemical properties of the composite films were investigated. The cross-linking degree measured by 2,4,6-trinitrobenzenesulfonic acid (TNBS) method confirmed that CA was cross-linked with the matrix, and Fourier transform infrared spectroscopy confirmed that more hydrogen bonds and electrostatic interactions were formed between CA and the matrix. Differential scanning calorimetry, X-ray diffraction and Scanning electron microscope images revealed the compatibility between substances. The synergistic inhibition between the matrix results in a significantly higher antibacterial activity of the composite film than the pure film. Compared with uncross-linked films, the mechanical properties, barrier properties and water resistance of the cross-linked films were significantly improved. When the concentration of CA was 5 wt% (W/W, on a dry basis of the weight of OVT and CS), the most significant improvement in film performance was obtained. The tensile strength of the film increased from 32.05 MPa without cross-linking to 61.99 MPa and the swelling degree decreased from 51.5 % to 24.23 %. The observed phenomena suggest that cross-linking OVT and CS with CA can obtain functional edible films with improved properties.

Influence of the Maillard Reaction on Properties of Air-Assisted Electrospun Gelatin/Zein/Glucose Nanofibers

To develop biodegradable, sustainable, and environment-friendly functional food-packaging materials, gelatin/zein/glucose nanofibers were fabricated through air-assisted electrospinning and then crosslinked by the Maillard reaction under mild conditions (60 °C and 50% relative humidity) in this study. Compared to traditional electrospinning, air-assisted electrospinning increased the yield of nanofibers by 10 times, and the average diameter from 263 nm to 664 nm, while the airflow facilitated uniform and smooth nanofiber formation. During the Maillard reaction in 0-5 days, the gelatin/zein/glucose showed no morphology change. Fourier transform infrared spectra analysis indicated that gelatin interacted with zein through hydrogen bonding and the occurrence of the Maillard reaction among the protein and glucose molecules. After four days of Maillard reaction, the nanofibers presented higher thermal stability, the most hydrophobic surface (water contact angle: 133.6°), and stiffer network structure (elastic modulus of 38.63 MPa, tensile strength of 0.85 MPa). Overall, Maillard-reaction-crosslinked gelatin/zein/glucose nanofibers showed favorable physical properties, which suggests their potential for application in food-active packaging.

The Preparation of Anti-Ultraviolet Composite Films Based on Fish Gelatin and Sodium Alginate Incorporated with Mycosporine-like Amino Acids

Mycosporine-like amino acids (MAAs) are ultraviolet-absorbing compounds and have antioxidant functions. In this paper, MAAs were added into fish gelatin/sodium alginate films as an anti-ultraviolet additive. The effects of 0–5% MAAs (w/w, MAAs/fish gelatin) on the physical properties, antioxidant properties, antibacterial properties and anti-ultraviolet properties of fish gelatin/sodium alginate films were investigated. The results suggest that the content of the MAAs influenced the mechanical properties. The water content, swelling and water vapor permeability of the films were not altered with the addition of MAAs. In addition, the composite films showed effective antioxidant activity and antimicrobial activity. The incorporation of MAAs significantly improved the DPPH radical scavenging activity of the films from 35.77% to 46.61%. Moreover, the block ultraviolet rays’ ability was also greatly improved when the film mixed with the MAAs and when the value of the light transmission was 0.6% at 350 nm. Compared with the pure composite film, the growth of E. coli covered by the composite film with 3.75% and 5% MAAs exhibited the best survival rate. These results reveal that MAAs are a good film-forming substrate, and MAAs have good potential to prepare anti-ultraviolet active films and antioxidant active films for applications. Overall, this project provides a theoretical basis for the study of active composite films with anti-ultraviolet activities, and it provides new ideas for the application of MAAs.

Synthesis and Rheological Characterization of a Novel Salecan Hydrogel

Salecan (Sal) is a novel microbial polysaccharide. In the present research, thermal treatment was performed to fabricate Sal hydrogel. The effect of Sal concentration on water holding capacity, swelling properties, texture properties, and microstructure of the hydrogels was discussed. It was found that the equilibrium degree of swelling (EDS) of Sal hydrogels was above 1500%, inferred Sal was a highly hydrophilic polysaccharide. As Sal concentration increased from 3.5 to 8.0 wt%, the hardness increased from 0.88 to 2.07 N and the water hold capability (WHC) increased from 91.3% to 98.2%. Furthermore, the internal network structure of Sal hydrogel also became denser and more uniform. Rheological studies suggested that elastic hydrogel formed under the gelation process. All these results demonstrated that Sal hydrogel prepared by thermal treatment had good gelling properties, which opened up a new safe way for the preparation of Sal hydrogel and broadened the application range of Sal.

Characterization of glycosylated gelatin/pullulan nanofibers fabricated by multi-fluid mixing solution blow spinning

In this work, multi-fluid mixing solution blow spinning was applied to develop gelatin/pullulan composite nanofibers, and then the nanofibers were glycated to enhance the physical properties. The results show that the grafting degree of the nanofibers increased significantly from 17.5 % to 36.0 % as the glycation time increased, and the morphology results indicated that 72 h of glycation did not destroy the structure of the nanofibers. FTIR results show that the glycation consumed the the-NH₂ groups, cleaved sugar units of polysaccharide, and affected the secondary structure of the protein. The glycation enhanced the thermal stability and improved the rigidity of the nanofibers. Besides, after 120 h of glycation, the water contact angle of nanofibers increased from 0° to 79.1°, and the water vapor transmission rates decreased from 12.49 to 8.97 g mm/m² h kPa, indicating the enhanced hydrophobicity and barrier properties. In addition, the glycation improved the water stability of the nanofibers, which increased the applicability of the gelatin/pullulan nanofibers in food packaging. The present work provides a green and efficient method for improving the physical properties of gelatin/pullulan nanofibers.

Colorimetric food spoilage monitoring with carbon dot and UV light reinforced fish gelatin films using a smartphone application

The objective of this study was to develop novel colorimetric films for food freshness monitoring. UV light irradiation (365 nm) and carbon dots (CDs) were tested as the potential crosslinkers in the fabrication of anthocyanins doped fish gelatin (FG) films. The effect of crosslinkers on the optical, surface, structural, barrier and mechanical properties of FG films was investigated. The incorporation of CD under UV irradiation improved the tested properties of FG films. The kinetic colorimetric responses of FG films against ammonia vaporwere studied to simulate the food spoilage and determine the ammonia sensitivity of the films. Among the tested films, UV-treated FG films containing 100 mg/l (FG-UV-CD100) indicated the best properties. Later, the color difference of FG-UV-CD100 films was observed to correlate well with microbial growth and TVB-N release in skinless chicken breast samples. At the same time, a custom-designed smartphone application (SmartFood) was also developed to be used with the FG-UV-CD100 film for quantitative estimation of food freshness in real-time. The proposed food freshness monitoring platform reveals a great potential to minimize global food waste and the outbreak of foodborne illness.

A soft Pickering emulsifier made from chitosan and peptides endows stimuli-responsiveness, bioactivity and biocompatibility to emulsion

Polymeric Pickering emulsifiers may bring new insights to emulsion theory and practice due to their soft characters. Herein, a group of soft Pickering emulsifiers, chitosan-casein hydrophobic peptides nanoparticles (CS-CHP NPs) were prepared with a non-covalent anti-solvent procedure. The CS-CHP NPs provided the contact angles of 37.2°-87.4°, stabilizing O/W or W/O emulsions with enhanced thermal stability, endowing the emulsion with pH and CO₂/N₂ responsiveness. The emulsifying behavior and mechanism presented by CS-CHP NPs were different from that of ordinary hard Pickering emulsifiers, where the appropriate contact angle was 37.2° instead of 87.4° for stabilizing O/W emulsions. Moreover, the nanoparticles possess antioxidant, antibacterial activities and excellent biocompatibility. DPPH and ABTS scavenging activity of the CS-CHP NPs were >220% of that of CS NPs. The last, the emulsion provided high-efficient encapsulation of curcumin, making the soft Pickering emulsifiers a group candidate for drug delivery in food, cosmetics and pharmaceutical industry.

Application of Gelatin in Food Packaging: A Review

Owing to the increasing environmental concerns and requirements for high-quality foods, edible films and coatings (based on proteins, polysaccharides, natural phenolic active substances, etc.) are being developed as effective alternatives to traditional plastic packaging. Gelatin is extracted from collagen. It is an ideal material for food packaging due to its versatile advantages such as low price, polymerization, biodegradability, good antibacterial and antioxidant properties, etc. However, gelatin film exists poor waterproof and mechanical properties, which limit its developments and applications in food packaging. Previous studies show that pure gelatin can be modified by adding active ingredients and incorporating them with bio-polymers to improve its mechanical properties, aiming to achieve the desirable effect of preservation. This review mainly shows the preparation and molding ways of gelatin-based edible films and the applications of gelatin modified with other biopolymers. Furthermore, this review provides the latest advances in gelatin-based biodegradable packaging and food applications that exhibit outstanding advantages in food preservation.

Cellulosic films reinforced by chitosan-citric complex for meat preservation: Influence of nonenzymatic browning

The methods to obtain cellulose-chitosan composite films exhibiting excellent water-resisting and antibacterial abilities have been widely explored. Cellulose-chitosan-citric films (C-Chx-F) were successfully obtained by a facile coating of chitosan-citric complex on the surface of cellulose. The occurrence of nonenzymatic browning at 80 °C improved the thermal stability, water-resistance, mechanical property and oxygen-barrier ability of C-Chx-F membranes. C-Ch3-F hydrogel showed excellent breaking stress of 6.03 ± 0.25 MPa, and elastic module of 27.09 ± 1.21 MPa, probably assigned to nonenzymatic browning. Under different test temperatures, the nonenzymatic browning and the content of chitosan-citric complex will significantly improve the oxygen barrier property of membranes (P < 0.05), and C-Ch3-F membrane represented the value of oxygen permeation below the detection level. Excellent antibacterial capability of C-Chx-F hydrogels demonstrated that polycationic chitosan-citric complex immobilized in films still retained excellent antibacterial ability. The excellent decontamination in meat preservation endowed C-Chx-F films with potential application in food packaging.

Progress in the Valorization of Fruit and Vegetable Wastes: Active Packaging, Biocomposites, By-Products, and Innovative Technologies Used for Bioactive Compound Extraction

According to the Food Wastage Footprint and Climate Change Report, about 15% of all fruits and 25% of all vegetables are wasted at the base of the food production chain. The significant losses and wastes in the fresh and processing industries is becoming a serious environmental issue, mainly due to the microbial degradation impacts. There has been a recent surge in research and innovation related to food, packaging, and pharmaceutical applications to address these problems. The underutilized wastes (seed, skin, rind, and pomace) potentially present good sources of valuable bioactive compounds, including functional nutrients, amylopectin, phytochemicals, vitamins, enzymes, dietary fibers, and oils. Fruit and vegetable wastes (FVW) are rich in nutrients and extra nutritional compounds that contribute to the development of animal feed, bioactive ingredients, and ethanol production. In the development of active packaging films, pectin and other biopolymers are commonly used. In addition, the most recent research studies dealing with FVW have enhanced the physical, mechanical, antioxidant, and antimicrobial properties of packaging and biocomposite systems. Innovative technologies that can be used for sensitive bioactive compound extraction and fortification will be crucial in valorizing FVW completely; thus, this article aims to report the progress made in terms of the valorization of FVW and to emphasize the applications of FVW in active packaging and biocomposites, their by-products, and the innovative technologies (both thermal and non-thermal) that can be used for bioactive compounds extraction.

Fabrication of fish gelatin / sodium alginate double network gels for encapsulation of probiotics

BACKGROUND

To improve the environmental resistance of probiotics, and particularly their survival in the gastrointestinal environment, a fish gelatin (FG) / sodium alginate (SA) double network gelation (FSDN) was developed to encapsulate them. Thermal treatment and calcium ion inducement were adopted to fabricate fish gelatin and sodium alginate gels. It was feasible to scale up this process. The effects of FG concentration (0-60 g/L) on FSDN properties, including morphology, water-holding capacity, and encapsulation efficiency were evaluated.

RESULTS

The results indicated that the addition of FG could improve the transparency, rehydration, and water-holding capacity of FSDN. Scanning electronic microscope (SEM) images revealed that FSDN had a denser and more complete structure than SA. Encapsulation efficiency improved from 15.85% to 91.91% as the FG concentration ranged from 0 to 50 g/L. Bifidobacterium longum embedded by FSDN showed better thermal stability than when it was free. Compared with bare probiotics (1.7%), the encapsulated ones exhibited higher viability (above 15%) in simulated gastric fluid.

CONCLUSION

In conclusion, interpenetrating FSDN is an effective barrier constituent and could achieve the targeted delivery of probiotics. It is a potential new delivery carrier for the oral administration of probiotics. © 2021 Society of Chemical Industry.

Recent Applications of Biopolymers Derived from Fish Industry Waste in Food Packaging

Fish waste is attracting growing interest as a new raw material for biopolymer production in different application fields, mainly in food packaging, with significant economic and environmental advantages. This review paper summarizes the recent advances in the valorization of fish waste for the preparation of biopolymers for food packaging applications. The issues related to fishery industry waste and fish by-catch and the potential for re-using these by-products in a circular economy approach have been presented in detail. Then, all the biopolymer typologies derived from fish waste with potential applications in food packaging, such as muscle proteins, collagen, gelatin, chitin/chitosan, have been described. For each of them, the recent applications in food packaging, in the last five years, have been overviewed with an emphasis on smart packaging applications. Despite the huge industrial potential of fish industry by-products, most of the reviewed applications are still at lab-scale. Therefore, the technological challenges for a reliable exploitation and recovery of several potentially valuable molecules and the strategies to improve the barrier, mechanical and thermal performance of each kind of biopolymer have been analyzed.

Impact of glycation on physical properties of composite gluten/zein nanofibrous films fabricated by blending electrospinning

In this study, the gluten/zein nanofibrous films were fabricated by blending electrospinning and then glycated with xylose via Maillard reaction. The average fiber diameter of the gluten film decreased from 551 to 343 nm with the increasing ratio of zein, but increased significantly to a range of 717-521 nm after glycation, which induced a higher thermal stability of the nanofibers with an order to disorder transition. The glycated composite films showed the reduced water vapor permeability and improved water stability with a stiffer and more elastic network structure, due to the enhanced intermolecular entanglements and interactions between polymer chains. The results from this work suggested that the composite gluten/zein electrospun films may be glycated via Maillard reaction to obtain desirable physical properties for active food-packaging applications.

Effect of glucose substitution by low-molecular weight chitosan-derivatives on functional, structural and antioxidant properties of maillard reaction-crosslinked chitosan-based films

In this study, the effects of different temperatures, incubation times and types of reducing sugars, including glucose and different low molecular weight (Mw) chito-oligosaccharides (COS) with varying acetylation degree (AD), on the extent of Maillard reaction (MR) on chitosan-based films were studied. Interestingly, an improvement of structural and functional properties of all MR-crosslinked films was noted, which is more pronounced by heating at higher temperature and exposure time. These findings were proved through Fourier-transform infrared and X-ray diffraction analyses. In addition, color change and Ultraviolet spectra demonstrate that glucose addition provides the high extent of MR, followed by COS1 (Mw < 4.4 kDa; AD, 18.20%) and COS2 (Mw < 4.4 kDa; AD, 10.63%). These results were confirmed by enhanced water resistance and thermal properties. Moreover, MR-chitosan/COS films showed the highest mechanical properties, whereas, glucose-loaded films were brittle, as demonstrated by scanning electron microscopy micrographs. Furthermore, MR-chitosan/COS1 films exhibited the better antioxidant behavior followed by chitosan/glucose and chitosan/COS2 films, mainly at higher heating-conditions. Thereby, MR-crosslinked chitosan/COS based films were attractive to be applied as functional and active coating-materials in various fields.

Hermetia illucens Protein Conjugated with Glucose via Maillard Reaction: Antioxidant and Techno-Functional Properties

The food industry is considering novel sources of proteins with enhanced functionalities to meet the increasing demand and population growth. Edible insect proteins have emerged as an alternative that is environmentally friendly and economically viable and thus could make a significant contribution to global food security. This study was aimed to establish the effect of conjugation via the Maillard reaction on the antioxidant and techno-functional properties of black soldier fly larvae protein concentrate. Reaction mixtures containing black soldier fly larvae protein concentrate and glucose (2 : 1 weight ratio) were wet-heated at 50, 70, and 90°C for 2, 4, 6, 8, and 10 h, respectively, with an initial pH of 9. The results showed that the browning indices of the black soldier fly larvae-glucose (BSFL-Glu) model system increased with an increase in reaction time and temperature, with conjugates formed at 90°C exhibiting the highest browning intensity at 420 nm. At 50°C, the DPPH-RS of the conjugates ranged from 15.47 to 32.37%. The ABTS⁺ radical scavenging activity of BSFL-Glu conjugates produced at 90°C exhibited significantly (p < 0.05) higher scavenging activity as a function of reaction time. The foaming capacity of BSFL-Glu conjugates produced at 70°C showed a significant increase (p < 0.05) as a function of reaction time. Principal component analysis was applied to browning and antioxidant indices. Component 1 of the score plot accounted for 89%, while component 2 accounted for 8% of the observed variability and allowed discrimination/differentiation of the samples based on the heating temperature. These findings provide a practical means to improve the functionality of novel edible insect proteins for food application.

A family of chitosan-peptide conjugates provides broad HLB values, enhancing emulsion's stability, antioxidant and drug release capacity

Strong hydrophilicity of polysaccharide and physicochemical instability of peptides limit application of polysaccharide-peptide mixtures in food industry. In this study, a natural resource platform of polysaccharide-peptide conjugates was constructed through Maillard reaction from chitosan and casein hydrophobic peptide. By choosing the molecular weight and deacetylation degree of chitosan and other reaction parameters, the conjugated chitosan-peptides possess extensive HLB values from 6 to 14 were obtained with grafting degree of 3.10%-15.08%. The conjugates have gained dramatically improved emulsifying ability, and endowed the emulsion higher antioxidant capacity than the peptide, chitosan and the mixture of peptide-chitosan has. Emulsions prepared with all conjugates exhibited long-term stability and strengthened tolerance towards temperature and electrolyte stimuli. This stable emulsion system also provided an effective encapsulation, protection and controlled release of curcumin, which may provide a method for transfer polysaccharides to stable emulsifiers with broader HLB values and application.

Active biopackaging produced from by-products and waste from food and marine industries

The agro-food industry cannot today do without packaging to preserve and above all market its products. Plastic materials coming mainly from petrochemicals have taken a predominant place in the food packaging sector. They have become indispensable in many sectors, from fresh to frozen products, from meat and dairy products to fruit and vegetables or almost-ready meals. Plastics are cheap, their lightness reduces transport costs, and their convenience is fundamental for out-of-home catering. However, plastics pose serious end-of-life issues. The development of materials that are more respectful of the consumer and the environment has become a major issue. In addition, the agro-food industries generate significant quantities of waste or by-products that are poorly or not at all recovered. However, these contain constituents that can be extracted or transformed to be compatible with packaging uses. Many molecules from waste materials are of particular interest for the development of active packaging such as biopolymers, bioactive agents, inorganic compounds, fibers, or nano- and micro-objects. Providing bioactive functions such as antioxidants or antimicrobials can extend the shelf life of food while reducing the sophistication of plastic materials and thus improving their recycling. This article summarizes the main materials and constituents that can be recovered from waste and illustrates through several examples what could be the applications of such new, sustainable, and active packaging.

Gum Arabic/Gelatin and Water-Soluble Soy Polysaccharides/Gelatin Blend Films as Carriers of Astaxanthin-A Comparative Study of the Kinetics of Release and Antioxidant Properties

Polymer blending and incorporation of active substances offer a possibility of generation of novel packaging materials with interesting features. Astaxanthin is one of the most powerful antioxidants. Hence, in this study, water-soluble AstaSana astaxanthin (AST) was incorporated into 75/25 gum arabic/gelatin (GAR75/GEL25) and water-soluble soy polysaccharides/gelatin (WSSP75/GEL25) blend films in different concentrations (0, 0.25%, 0.5%, 1%). Microscope images showed good compatibility between the polysaccharides and GEL. Basing on time required for 50% release, the WSSP-based film exhibited an approximately four-fold slower release rate (t_50% = 65.16–142.80 min) than the GAR-based film (t_50% = 14.64–34.02 min). This result was mainly ascribed to the slower dissolution of the WSSP-based carrier. The faster release rate of the GAR-based films resulted in stronger antioxidant activity (quarter-scavenging time (t_25%ABTS) = 0.22–7.51 min) in comparison to the WSSP-based films (t_25%ABTS = 0.91–12.94 min). The increase in the AST concentration was accompanied by gradually reduced solubility and the release rate. It is possible that the increasing number of starch granules (from the AST formulation) acted as a dissolution blocking agent. In general, the WSSP75/GEL25 film displayed the most linear (the Zero-order similar) release profile. So, this carrier has potential for release of AST at a quasi-constant speed.

Improving the functional properties of fish gelatin by conjugation with the water-soluble fraction of bitter almond gum

Maillard-based conjugation may be a useful way of improving the functional properties of food biopolymers. In this study, covalent attachment of fish gelatin (FG) and the water-soluble fraction of bitter almond gum (SBAG) was performed through dry heating of FG-SBAG mixtures (1:1, 1:2, and 2:1) for 2 days at 60 °C and 80% relative humidity. The formation of the FG-SBAG conjugates was confirmed by FTIR spectroscopy and the degree of glycosylation (DG). The changing color observed in all FG-SBAG conjugates was indicative of Maillard reactions. Heat stability of conjugates increased with increasing SBAG ratio, and denaturation temperatures were consistent with DG. Conjugation improved radical scavenging activity, water holding capacity, emulsifying, and foaming properties of the FG (p < 0.05). Overall, the FG: SBAG (1:2) conjugate was the optimum combination for improving examined functional properties. The results suggest that this conjugate can potentially serve as a new ingredient in food formulations.