Physical, mechanical and antimicrobial properties of gelatin based active nanocomposite films containing AgNPs and nanoclay

Biodegradable antibacterial food packaging based on carboxymethyl cellulose from sugarcane bagasse/cassava starch/chitosan/gingerol extract stabilized silver nanoparticles (Gin-AgNPs) and vanillin as cross-linking agent

The increasing issue of plastic waste necessitates improved solutions, and biodegradable food packaging is a promising alternative to traditional plastic. In this study, we prepared packaging films using cassava starch (CV), chitosan (CT) and carboxymethyl cellulose (CMC), with glycerol as a plasticizer. However, these films require modifications to enhance their mechanical properties. Therefore, we modified the films by adding vanillin as the crosslinking agent and gingerol extract stabilized silver nanoparticles. The films were fabricated using the film-casting method and characterized by FTIR, XRD, SEM, TGA, mechanical property test, biodegradability test, anti-bacterial test and food packaging evaluation test. Among these films, CT/CV/V/CMC/Gin-AgNPs1 exhibited superior mechanical properties and demonstrated excellent anti-bacterial property both for gram-positive (S. aureus) and gram-negative (E. coli) bacteria and biodegradability, losing over 50% of its weight after 21 days of burial in soil and effectively preserved grapes at 4 °C for 21 days.

Thermo-Responsive and Electroconductive Nano Au-PNiPAAm Hydrogel Nanocomposites: Influence of Synthesis Method and Nanoparticle Shape on Physicochemical Properties

Hydrogel nanocomposites that respond to external stimuli and possess switchable electrical properties are considered as emerging materials with potential uses in electrical, electrochemical, and biological devices. This work reports the synthesis and characterization of thermo-responsive and electroconductive hydrogel nanocomposites based on poly(N-isopropylacrylamide) (PNiPAAm) and gold nanoparticles (nanospheres-AuNPs and nanorods-AuNRs) using two different synthetic techniques. Method I involved γ-irradiation-induced crosslinking of a polymer matrix (hydrogel), followed by radiolytic in situ formation of gold nanoparticles, while Method II included the chemical synthesis of nanoparticles, followed by radiolytic formation of a polymer matrix around the gold nanoparticles. UV-Vis spectral studies revealed the presence of local surface plasmon resonance (LSPR) bands characteristic of nanoparticles of different shapes, confirming their formation and stability inside the polymer matrix. Morphological, structural, and physicochemical analyses indicated the existence of a stable porous polymer matrix, the formation of nanoparticles with a face-centered cubic structure, increased swelling capacity, and a slightly higher volume phase transition temperature (VPTT) for the hydrogel nanocomposites. Comparative electrochemical impedance spectroscopy (EIS) showed an increase in conductivity for the nano Au-PNiPAAm hydrogel nanocomposites compared to the PNiPAAm hydrogel, with a considerable rise detected above the VPTT. By reverting to room temperature, the conductivity decreased, indicating that the investigated hydrogel nanocomposites exhibited a remarkable reversible "on-off" thermo-switchable mechanism. The highest conductivity was observed for the sample with rod-shaped gold nanoparticles. The research findings, which include optical, structural, morphological, and physicochemical characterization, evaluation of the efficiency of the chosen synthesis methods, and conductivity testing, provide a starting point for future research on the given nanocomposite materials with integrated multifunctionality.

The Effect of Cellulose Nanocrystals on the Molecular Organization, Thermomechanical, and Shape Memory Properties of Gelatin-Matrix Composite Films

Gelatin is a natural hydrocolloid with excellent film-forming properties, high processability, and tremendous potential in the field of edible coatings and food packaging. However, its reinforcing by materials such as cellulose nanocrystals (CNC) is often necessary to improve its mechanical behavior, including shape memory properties. Since the interaction between these polymers is complex and its mechanism still remains unclear, this work aimed to study the effect of low concentrations of CNC (2, 6, and 10 weight%) on the molecular organization, thermomechanical, and shape memory properties in mammalian gelatin-based composite films at low moisture content (~10 weight% dry base). The results showed that the presence of CNCs (with type I and type II crystals) interfered with the formation of the gelatin triple helix, with a decrease from 21.7% crystallinity to 12% in samples with 10% CNC but increasing the overall crystallinity (from 21.7% to 22.6% in samples with 10% CNC), which produced a decrease in the water monolayer in the composites. These changes in crystallinity also impacted significantly their mechanical properties, with higher E' values (from 1 × 104 to 1.3 × 104 Pa at 20 °C) and improved thermal stability at higher CNC content. Additionally, the evaluation of their shape memory properties indicated that while molecular interactions between the two components occur, CNCs negatively impacted the magnitude and kinetics of the shape recovery of the composites (more particularly at 10 weight% CNC, reducing shape recovery from 90% to 70%) by reducing the netting point associated with the lower crystallinity of the gelatin. We believe that our results contribute in elucidating the interactions of gelatin-CNC composites at various structural levels and highlights that even though CNC acts as a reinforcement material on gelatin matrices, their interaction are complex and do not imply synergism in their properties. Further investigation is, however, needed to understand CNC-gelatin interfacial interactions with the aim of modulating their interactions depending on their desired application.

Multifunctional Ag-Poly(N-isopropylacrylamide/itaconic Acid) Hydrogel Nanocomposites Prepared by Gamma Irradiation for Potential Application as Topical Treatment Dressings

Today, hydrogel dressings that can protect injury sites and effectively promote healing have become highly desirable in wound management. Therefore, multifunctional silver-poli(N-isopropylacrylamide/itaconic acid) (Ag-P(NiPAAm/IA)) hydrogel nanocomposites were developed for potential application as topical treatment dressings. The radiolytic method, used for the crosslinking of the polymer matrix as well as for the in situ incorporation of silver nanoparticles (AgNPs) into the polymer matrix, enables the preparation of hydrogel nanocomposites without introducing harmful and toxic agents. Moreover, materials produced using γ-irradiation are simultaneously sterilized, thus fulfilling one of the basic requirements regarding their potential biomedical applications. The NiPAAm/IA ratio and the presence of AgNPs influenced the microstructural parameters of the investigated systems. Increasing the IA content leads to the formation of a more porous polymer matrix with larger pores, while the incorporated AgNPs act as additional junction points, decreasing the porosity and pore size of the resulting nanocomposite hydrogels. Swelling studies showed that most investigated systems uptake the fluids from their surroundings by non-Fick diffusion. Further, the Ag+ ion release, antibacterial activity, and cytotoxicity of Ag-P(NiPAAm/IA) hydrogel nanocomposites were examined to evaluate their biomedical potential. All hydrogel nanocomposites showed an initial burst release of Ag+ ions (useful in preventing bacteria adherence and biofilm formation), followed by a slower release of the same (ensuring sterility for longer use). An antibacterial activity test against Escherichia coli and Staphylococcus aureus showed that Ag-P(NiPAAm/IA) hydrogel nanocomposites, with silver concentrations around 10 ± 1 ppm, successfully prevent bacterial growth. Finally, it was shown that the investigated hydrogel nanocomposites do not exhibit a cytotoxic effect on human keratinocyte HaCaT cells. Therefore, these multifunctional hydrogel nanocomposites may promote wound repair and show promising potential for application as functional wound dressing.

Effect of the Ratio of Protein to Water on the Weak Gel Nonlinear Viscoelastic Behavior of Fish Myofibrillar Protein Paste from Alaska Pollock

The linear and nonlinear rheological behaviors of fish myofibrillar protein (FMP) paste with 75%, 82%, and 90% moisture content were evaluated using small-amplitude oscillatory shear (SAOS) and large-amplitude oscillatory shear (LAOS) tests. SAOS revealed pastes with 75% and 82% moisture exhibited solid-like behavior, characterized by higher storage modulus (G') than loss modulus (G″), indicative of weak gel properties with a strong protein interaction. In contrast, the 90% moisture content showed more viscous behavior due to weakened protein-protein entanglements. The frequency exponent (n' and n″) from the power law equation varied slightly (0.24 to 0.36), indicating limited sensitivity to changes in deformation rate during SAOS. LAOS tests revealed significant structural changes, with Lissajous-Bowditch curves revealing early nonlinearities at 10% strain for 90% moisture content. Decomposed Chebyshev coefficients (e3/e1, v3/v1, S, and T) indicated strain stiffening at lower strains for the 75% and 82% moisture pastes (i.e., < 50% strain for 75% and < 10% strain for 82%), transitioning to strain thinning at higher strains. Additionally, numerical model confirmed the predictability of the 3D printing process from the nonlinear rheological data, confirmed the suitability of the 75% and 82% moisture pastes for applications requiring structural integrity. These insights are essential for optimizing processing conditions in industrial applications. The findings suggest that the 75% and 82% moisture pastes are suitable for applications requiring structural integrity, while the 90% moisture paste is ideal for flow-based processes. These insights are essential for optimizing processing conditions in industrial applications.

Prospects and challenges of nanomaterials in sustainable food preservation and packaging: a review

Nanomaterials play a pivotal role in food preservation and its safety, offering ingenious solutions for sustainable food packaging. Nanomaterials enable the creation of packaging materials having unique functional properties. It not only extends the shelf life of the foods by releasing preservatives but also enhances food safety by preventing microbial contamination or food spoilage. In this review, we aim to provide an overview of the various applications of nanotechnology in food packaging, highlighting its key advantages. We also delve into the safety considerations and regulatory issues involved in developing nanotechnology-based food packaging materials. Additionally, advancements in the field of nanotechnology-based packaging have the potential to create safer, more sustainable, and high-quality packaging with greater functionality that delivers essential benefits to manufacturers and consumers.

Phytolacca americana extract as a quality-enhancing factor for biodegradable double-layered films based on furcellaran and gelatin - Property assessment

For the first time, novel active double-layered films based on furcellaran (FUR) and gelatin (GEL) with the addition of Phytolacca americana (PA) extract were obtained. The 1st layer consisted of FUR and GEL, while the aqueous extract of P. americana berries was added in three different concentrations to the 2nd FUR-based layer. The films were characterised by good mechanical (TS range of 0.0011-0.0013 MPa, EAB range between 30.38 %-33.51 %) and water properties (WVTR range of 574.74-588.49 g/m2xd). Structural analysis (SEM and AFM) confirmed good film structure: regular, without cracks or air bubbles. The films showed antioxidant activity tested via the Folin-Ciocâlteu method (4.77-20.70 mg GAExg-1), FRAP assay (0.18-3.40 mM TExg-1) and CUPRAC assay (48.63-53.99 mM TExg-1). The film with the highest PA concentration (6 %) demonstrated the ability to neutralise free radicals, DPPH• and ABTS2+•, at the levels of 1.97 % and 17.34 %, respectively. The ecotoxicity test performed on Lepidium sativum seeds confirmed the lack of ecotoxic film aspects. The biodegradation test indicated that the films are biodegradable. The obtained films can be a good alternative to plastic packaging films (used in the food packaging industry), which are currently a global problem related to the development of post-consumer plastics.

Development of active chitosan film containing bacterial cellulose nanofibers and silver nanoparticles for bread packaging

The objective was to develop an active chitosan-based coating and to evaluate its effect on the shelf life and microbial safety of bread. Bacterial cellulose nanofibers (BCNF) and various levels (0.5%, 1%, and 2%) of silver nanoparticles (AgNPs) were in the chitosan (CS) film. Characterization of films was determined by analyzing WVP, ultraviolet barrier, and opacity as well as FTIR, XRD, DSC, TGA, and SEM. The water vapor permeability (WVP) of CS was remarkably (p < .05) decreased from 3.75 × 10-10 to 0.85 × 10-10 g/smPa when filled with BCNF and 2% AgNPs. Thermal and structural properties were enhanced in nanoparticle-included films. Applying CS/BCNF/AgNPs coatings for bread samples demonstrated a significant improvement in moisture retention and a decrease in the hardness (from 10.2 to 7.05 N for CS and CS/BCNF/1% AgNPs coated samples, respectively). Moreover, microbial shelf life of bread sample increased from 5 to 38 days after packaging with CS/BCNF/2% AgNPs film. After a storage period of 15 days at 25°C, no fungal growth was detected in bread samples which were coated with nanocomposite suspensions containing 1% and 2% AgNPs. However, at the same condition, yeast and mold counts was 7.91 log CFU/g for control sample. In conclusion, the CS/BCNF/2% AgNPs film might have the potential for use as active packaging of bread.

Bioactive chitosan films: Integrating antibacterial, antioxidant, and antifungal properties in food packaging

In this work, chitosan was combined with bio-vanillin (BV) and kaolin clay (KC) to create a novel antifungal and biodegradable food packaging film. The chitosan/KC/BV film exhibited an antioxidant capacity of 80 % as measured by DPPH assay, which was significantly higher than that of the chitosan film which has 55.6 %). The film also demonstrated strong antimicrobial activity with a reduction of 90 % in the growth of E. coli and S. aureus compared to the control. Additionally, the chitosan/KC/BV film showed a 75 % reduction in fungal growth compared to chitosan film. Furthermore, the water vapor permeability of the chitosan film was reduced as 5.38 with the addition of KC/BV. The degradation study revealed that the chitosan/KC film degraded by 88 % within 20 days under composting conditions. Additionally, fresh-cut apple slices were used to examine the effectiveness of chitosan/KC/BV film as a packaging material. The fruit's weight loss and browning index showed satisfactory food preservation. Our research suggests that the chitosan/KC/BV film has great potential for use in the food sector due to its strong antioxidant, antimicrobial, and biodegradable properties.

Preparation of Green Silver Nanoparticles and Eco-Friendly Polymer-AgNPs Nanocomposites: A Study of Toxic Properties across Multiple Organisms

This article focuses on the eco-friendly (green) synthesis of silver nanoparticles (AgNPs) and their incorporation into a polymer matrix. For AgNPs synthesis, Lavandula angustifolia (lavender) leaf extract was used as a reducing and stabilizing agent, and as a silver precursor, AgNO3 solution with different concentrations of silver (50, 100, 250, and 500 mg/L) was used. Prepared AgNPs colloids were characterized using UV-vis spectrophotometry, transmission electron microscopy (TEM), and X-ray diffraction (XRD). The spherical morphology of AgNPs with an average size of 20 nm was confirmed across all samples. Further, the antimicrobial properties of the AgNPs were evaluated using the disk diffusion method on algae (Chlorella kessleri) and the well diffusion method on bacteria (Staphylococcus chromogenes, Staphylococcus aureus, and Streptococcus uberis), along with root growth inhibition tests on white mustard (Sinapis alba). Polymer composite (PVA-AgNPs) was prepared by incorporation of AgNPs into the polymer matrix. Subsequently, non-woven textiles and thin foils were prepared. The distribution of AgNPs within the nanocomposites was observed by scanning electron microscopy (SEM). Antibacterial properties of PVA-AgNPs composites were analyzed on bacteria Streptococcus uberis. It was found that not only AgNPs showed good antimicrobial properties, but toxic properties were also transferred to the PVA-AgNPs nanocomposite.

Effect of montmorillonite (MMT) on the properties of soybean meal protein isolate-based nanocomposite film loaded with debittered kinnow peel powder

The synthetic, non-renewable nature and harmful effects of plastic packaging have led to the synthesis of eco-friendly renewable bio-nanocomposite film. The present work was aimed at the formulation and characterization of bio-nanocomposite film using soybean meal protein, montmorillonite (MMT), and debittered kinnow peel powder. The composition of film includes protein isolate (5% w/v), glycerol (50% w/w), peel powder (20% w/w), and MMT (0.5-2.5% w/w). Incorporation of MMT in soybean meal protein-based film loaded with kinnow peel powder showed lesser solubility (16.76-26.32%), and swelling ability (142.77-184.21%) than the film prepared without MMT (29.41%, & 229.41%, respectively). The mechanical properties like tensile strength of nanocomposite film improved from 9.41 to 38.69% with the increasing concentration of MMT. The water vapor transmission rate of the nanocomposite film was decreased by 3.45-17.85% when the MMT concentration increased. Fourier-transform infrared spectroscopy and X-ray diffraction analysis showed no considerable change in the structural properties of the film after the addition of MMT. Differential scanning colorimeter analysis revealed the increment in melting temperature (85.33-92.67 °C) of the film with a higher concentration of MMT. Scanning electron microscopy analysis indicated an increased distributed area of MMT throughout the film at higher concentrations. The antimicrobial activity of the film was remarkably increased by 4.96-17.18% with the addition of MMT. The results obtained in the current work confirmed that MMT incorporation in soybean meal protein-based film can augment its properties and can be utilized for enhancing the storage period of food products.

Development and characterization of semi-refined iota carrageenan/fish gelatin-based biocomposite film incorporated with SiO2/ZnO nanoparticles

Food packaging based on natural polymers from polysaccharides and proteins can be an alternative to replace conventional plastics. In the present study, semi-refined iota carrageenan (SRIC) and fish gelatin (FG) were used as polymer matrix film with different concentration ratios (0.5:1.5 %, 1.0:1.0 % and 1.5:0.5 % w/w) and SiO2-ZnO nanoparticles were incorporated as fillers with the same concentration in all formulas (0.5:1.5 % w/w carrageenan-fish gelatin). This study aimed to develop films for food packaging applications with desirable physical, mechanical, optical, chemical, and microbiological properties. The results showed that incorporating SiO2-ZnO nanoparticles significantly (p < 0.05) improved the films' elongation at break, UV-screening properties, and antimicrobial activity. Also, the films' thickness, degradability, and transparency significantly (p < 0.05) increased with the higher concentration of fish gelatin addition in the SRIC matrix polymer. The best formula was obtained on the SRIC-FG film at the ratio of 1.5:0.5 % w/w, which performed excellent antimicrobial activity. Thus, semi-refined iota carrageenan/fish gelatin-based biocomposite film incorporated with SiO2-ZnO nanoparticles can be potentially developed as eco-friendly and intelligent food packaging materials to resolve traditional plastic-related issues and prevent food waste.

Development of Plumeria alba extract supplemented biodegradable films containing chitosan and cellulose derived from bagasse and corn cob waste for antimicrobial food packaging

With the increase in global plastic pollution due to conventional plastic packaging (petroleum-derived), bioplastics have emerged as an alternative green source for practising a circular economy. This research aimed to extract cellulose from bagasse and corn cob waste and utilized in mixed form to prepare bioplastic film. The mixed cellulose was further reinforced with natural substances such as chitosan, bentonite, and P. alba extract. These newly developed bioplastics films were characterized by various physical tests like film thickness, moisture content, water solubility and spectroscopic techniques such as Fourier transform infrared (FTIR), scanning electron microscopy-energy dispersive spectroscopic (SEM-EDX), thermal gravimetric analysis (TGA), and ultraviolet-visible (UV-Vis) spectroscopy for opacity testing. The results revealed the enhanced bioplastic thermal and mechanical characteristics through robust interactions between cellulose and bentonite molecules. Moreover, incorporating chitosan solution as reinforcements in bio-composite films resulted in improved water barrier properties. The results indicated lower absorption in the UV range of 250-400 nm, attributed to the absence of UV-absorbing groups. Finally, their biodegradability was tested in soil, and 85.3 % weight loss of bioplastic films was observed after 50 days of the experiment which is the main task of this research. The antimicrobial properties of bioplastic films have been evaluated, and showed an inhibition zone of 16 mm against E. coli. After 12 days of incubation of sherbet berries, complete spoilage is identified in the control group compared to those covered with the bioplastic film. This outcome is attributed to the antioxidant and antimicrobial activities provided by chitosan and P. alba extract in the bioplastic film. The comprehensive outcomes of this study suggest the potential future adoption of these entirely bio-derived, environmentally sustainable and biodegradable bioplastic films as a viable substitute for the plastic packaging currently present in the market.

Active Films of Cassava Starch Incorporated with Carvacrol Nanocapsules

The synthesis of active films with natural antimicrobials from renewable sources offers an alternative to conventional non-biodegradable packaging and synthetic additives. This study aimed to develop cassava starch films with antimicrobial activity by incorporating either free carvacrol or chia mucilage nanocapsules loaded with carvacrol (CMNC) and assess their impact on the physical, mechanical, and barrier properties of the films, as well as their efficacy against foodborne pathogens. The addition of free carvacrol led to a reduction in mechanical properties due to its hydrophobic nature and limited interaction with the polymeric matrix. Conversely, CMNC enhanced elongation at break and reduced light transmission, with a more uniform distribution in the polymeric matrix. Films containing 8% carvacrol exhibited inhibitory effects against Salmonella and Listeria monocytogenes, further potentiated when encapsulated in chia mucilage nanocapsules. These findings suggest that such films hold promise as active packaging materials to inhibit bacterial growth, ensuring food safety and extending shelf life.

Design and characterization of edible chitooligosaccharide/fish skin gelatin nanofiber-based hydrogel with antibacterial and antioxidant characteristics

Antibacterial and active packaging materials have gained significant research attention in response to the growing interest in food packaging. In this investigation, we developed hydrogel packaging materials with antibacterial and antioxidant properties by incorporating chitooligosaccharide (COS) and fish skin gelatin (FSG) nanofiber membranes, which readily absorbed water and exhibited swelling characteristics. The nanofiber membranes were fabricated by electrospinning technology, embedding COS within FSG, and subsequently crosslinked through the Maillard reaction facilitated by the addition of glucose. The behavior of conductivity, viscosity, and surface tension in the spinning solutions was analyzed to understand their variation patterns. Scanning electron microscopy (SEM) results revealed that the crosslinked COS/FSG nanofiber membranes possessed a uniform yet disordered fiber structure, with the diameter of the nanofibers increasing as the COS content increased. Remarkably, when the COS content reached 25 %, the COS/FSG nanofiber membranes (CF-C-25) exhibited a suitable fiber diameter of 437.16 ± 63.20 nm. Furthermore, the thermal crosslinking process involving glucose supplementation enhanced the hydrophobicity of CF-C-25. Upon hydration, the CF-H-25 hydrogel displayed a distinctive porous structure, exhibiting a remarkable swelling rate of 954 %. Notably, the inclusion of COS significantly augmented the antibacterial and antioxidant properties of the hydrogel-based nanofiber membranes. CF-H-25 demonstrated an impressive growth inhibition of 90.56 ± 5.91 % against E. coli, coupled with excellent antioxidant capabilities. In continuation, we performed a comprehensive analysis of the total colony count, pH, TVB-N, and TBA of crucian carp. The CF-H-25 hydrogel proved highly effective in extending the shelf life of crucian carp by 2-4 days, suggesting its potential application as an edible membrane for aquatic product packaging.

Influence of linoleic acid on the immunodetection of shrimp (Litopenaeus vannamei) tropomyosin and the mechanism investigation via multi-spectroscopic and molecular modeling techniques

The effect of linoleic acid (LA) on the IgG/IgE recognition, in vitro digestibility and immunodetection of shrimp tropomyosin (TM) was investigated. Subsequently, the simultaneous binding of LA-TM was explored using multi-spectroscopic and molecular modeling techniques. Our findings reveled that the addition of LA significantly reduced TM's IgG/IgE immunoreactivity, digestibility, and immunodetection. Further analysis using multi-spectroscopic and molecular modeling techniques indicated that while TM's secondary structure remained largely unchanged, its 3-D structure showed significant alterations such as increased particle size and hydrophobic surface area, and a higher number of buried hydrophobic residues exposed due to the binding of LA to TM. These structural changes rendered it difficult for target antibodies and digestive enzymes to interact with related epitopes and cleavage sites buried inside the molecule. The results obtained in this study provide valuable insights into the molecular mechanism of poor immunodetection caused by food matrix interference.

Development of basil seed mucilage (a heteropolysaccharide) - Polyvinyl alcohol biopolymers incorporating zinc oxide nanoparticles

The effect of zinc oxide nanoparticles (ZnONPs) on various properties of basil seed mucilage (a heteropolysaccharide)-polyvinyl alcohol (BSM-PVA) films was investigated. Increasing concentration of ZnONPs in BSM-PVA films reduced moisture content (from 24.73 to 17.09 %), water solubility (from 36.36 to 27.65 %), water vapor permeability (from 4.66 × 10-7 to 2.55 × 10-7 g·m/m2·Pa·h), oxygen permeability (from 2.96 to 2.13 cm3 μm/m2 d kPa), and elongation at break (from 40.34 to 29.44 %), and increased ultimate tensile strength (from 16.81 to 21.48 MPa). Color and light transmission were affected by ZnONPs concentrations. The lack of formation of new peaks, along with the displacement of peaks, indicated the formation of hydrogen bonds between ZnONPs and the film matrix. Dynamic mechanical-thermal analysis showed that storage modulus and glass transition temperature increased with the concentration of ZnONPs. Scanning electron microscopy images illustrated that the addition of ZnONPs improved film integrity. X-ray diffraction pattern showed that the crystal shape of nanoparticles was preserved in the film matrix. Films containing ZnONPs showed good antibacterial activity against Staphylococcus aureus (reductions ≥ 3 log CFU/cm2) and Escherichia coli (reductions ≥ 4 log CFU/cm2). Films containing ZnONPs also showed a suitable antifungal activity during the storage of wheat bread.

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.

The Effect of a Chitosan/TiO2-Nanoparticle/ Rosmarinic Acid-Based Nanocomposite Coating on the Preservation of Refrigerated Rainbow Trout Fillets (Oncorhynchus mykiss)

The aim of this study was to determine the effect of chitosan (CH)-based nanocomposite coating applications [chitosan+TiO2 (CHT) and chitosan+TiO2+rosmarinic acid (CHTRA)] on changes in quality attributes of rainbow trout fillets during cold storage (4°C). Fish fillets were randomly divided into four groups and subjected to treatments (CH, CHT, CHTRA, and control). After treatments, the groups were packaged under a modified atmosphere (40% CO2+30% O2+30% N2) and stored at 4°C for 18 days. During cold storage, the samples were subjected to physico-chemical and microbiological analyses. During storage, CH, CHT, and CHTRA treatments showed lower aerobic mesophilic and psychrotrophic bacteria counts than the control. However, the differences between coating treatments were not significant. The highest mean pH value was determined in the control group. As the storage time increased, the thiobarbituric acid reactive substances value increased. At the end of the storage period, no significant differences were observed between the treatments, including in the control group. The total volatile basic nitrogen (TVB-N) level in the control group was above 25 mg/100 g on day 15 of storage. However, the TVB-N level in the treatment groups was below 20 mg/100 g on day 18. It was also determined that coating application×storage period interaction had a significant effect on all color parameters (p<0.01). At the end of storage, the highest CIE L* was observed in CHTRA treatment. However, the value of this treatment did not differ from that of the CH treatment.

An investigation of the morphological, thermal, mechanical, and barrier properties of an active packaging containing micro- and nano-sized ZnO particles

Biodegradable films are extremely important for food packaging applications since they minimize environmental effects. However, their application areas are limited due to insufficient characteristics required for particular applications. The objective of the present research was to improve the properties of sago-based biodegradable films embedded with nano- and micro-ZnO (zinc oxide). Nano and micro-ZnO were incorporated in the films at different percentages (1%, 3%, and 5%) in that the films were formed using the solvent casting method. The physicochemical, barrier, thermal, optical, morphology, and mechanical properties of sago-based films were investigated. Adding 5% of micro- and nano-ZnO significantly improved film thickness (0.162 and 0.150 mm, respectively) and WVP (4.40 and 5.64 (kg/s)/(m.Pa), respectively) while the optical properties and thermal stability exhibited superior performance. Micro-ZnO particles improved the mechanical properties of sago-based biodegradable films with the tensile strength reaching 6.173 MPa. Moreover, sago-based nano-ZnO films showed excellent UV-shielding performance and relatively good visible-light transmittance. This study suggested that sago biodegradable film incorporated with micro-ZnO could be an excellent alternative to petroleum-based plastic packaging.

Characteristic Improvement of a Carrageenan-Based Bionanocomposite Polymer Film Containing Montmorillonite as Food Packaging through the Addition of Silver and Cerium Oxide Nanoparticles

Plastic has become an essential ingredient in social life, especially in its function as food packaging. An increase in plastic consumption can have a big impact, especially on environmental issues, because of the plastic waste produced. Substituting petroleum-based plastic with bionanocomposites can be done to reduce the impact of environmental issues caused by plastic waste. The purpose of this study is to produce nanoparticle-incorporated bioplastics, which can be applied as alternative food packaging, especially as petroleum-based plastic substitutes, and as food packaging that has added value in the form of antimicrobial properties. In addition, nanoparticles are also intended to improve the characteristics of bioplastics such as improving mechanical properties and film permeability as well as increasing the barrier properties of bioplastics against ultraviolet rays that can damage packaged food. Bionanocomposites with modified forms were investigated by various characterization such as Fourier transform infrared (FTIR), mechanical property testing of bioplastics as well as analysis of water vapor permeability (WVP), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), UV-visible spectrophotometry (UV-vis), and antimicrobial testing. Visible improvement of mechanical and UV barrier properties was seen in bionanocomposites with the addition of cerium nanoparticles. Furthermore, we have also demonstrated the antibacterial activity properties of nanoparticle-loaded bionanocomposites, which can add value to their use as food packaging. These results indicate that carrageenan-based bionanocomposites have a high potential for positive application in food packaging to ensure food safety and extend the shelf life of packaged foods.

Biofabrication strategy of silver-nanodrug conjugated polyhydroxybutyrate degrading probiotic and its application as a novel wound dressing

Wound infections with rising incidences of multi-drug resistant bacteria are among the public health problems worldwide. The current study describes wound dressing materials made from biodegradable polyhydroxybutyrate (PHB) combined with AgNPs and gelatin (AgNPs/Gelatin/PHB). Microbial PHB was mixed with gelatin (1:2) to form a polymer matrix which was loaded with different concentrations of AgNPs (8.3-133 μg/mL). The statistical results of AgNPs synthesizing based on Box-Behnken design revealed that 1.247 mM silver nitrate and 24.054 % of Corchorus olitorius leaf extract concentration at pH (8.07) were the optimum values for the biosynthesis. UV-Vis spectroscopy, FTIR study and XRD reflects that nanoparticles are formed. The UV-Vis spectroscopy of Gelatin/PHB/AgNPs exhibited two specific bands at 298 nm and 371 nm, which confirm the formation of the conjugate. AgNPs had MICs and MBCs of (24.9, 24.9, and 12.45 μg/mL) and (33.25, 33.25, and 16.6 μg/mL) against (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus). The MIC and MBC of AgNPs/Gelatin/PHB against the same tested bacteria were 31.1 μg and 41.5 μg, respectively. AgNPs/Gelatin/PHB exhibit excellent antimicrobial efficacy against bacteria. Sterilized gauze loaded with 31.1 μg of AgNPs/Gelatin/PHB acted as an effective wound dressing. Thus, the study highlights the importance of wound dressings developed from degradable AgNPs/Gelatin/PHB in enhancing antimicrobial efficiency and facilitating a better wound healing process.

Recent advances in qualitative and quantitative characterization of nanocellulose-reinforced nanocomposites: A review

Nanocellulose has received immense consideration owing to its valuable inherent traits and impressive physicochemical properties such as biocompatibility, thermal stability, non-toxicity, and tunable surface chemistry. These features have inspired researchers to deploy nanocellulose as nanoscale reinforcement materials for bio-based polymers. A simple yet efficient characterization method is often required to gain insights into the effectiveness of various types of nanocellulose. Despite a decade of continuous research and booming growth in scientific publications, nanocellulose research lacks a measuring tool that can characterize its features with acceptable speed and reliability. Implementing reliable characterization techniques is critical to monitor the specifications of nanocellulose alone or in the final product. Many techniques have been developed aiming to measure the nano-reinforcement mechanisms of nanocellulose in polymer composites. This review gives a full account of the scientific underpinnings of techniques that can characterize the shape and arrangement of nanocellulose. This review aims to deliver consolidated details on the properties and characteristics of nanocellulose in biopolymer composite materials to improve various structural, mechanical, barrier and thermal properties. We also present a comprehensive description of the safety features of nanocellulose before and after being loaded within biopolymeric matrices.

Gelatin Improves the Performance of Oregano Essential Oil Nanoparticle Composite Films-Application to the Preservation of Mullet

In this study, the addition of oregano oil chitosan nanoparticles (OEO-CSNPs) was conducted to enhance the comprehensive properties of gelatin films (GA), and the optimal addition ratio of nanoparticles was determined for its application in the preservation of mullet. Oregano oil chitosan nanoparticles were organically combined with gelatin at different concentrations (0%, 2%, 4%, 6% and 8%) to obtain oregano oil-chitosan nanoparticle-GA-based composite films (G/OEO-CSNPs), and thereafter G/OEO-CSNPs were characterized and investigated for their preservative effects on mullet. Subsequent analysis revealed that OEO-CSNPs were uniformly dispersed in the GA matrix, and that G/OEO-CSNPs had significantly improved mechanical ability, UV-visible light blocking performance and thermal stability. Furthermore, the nanoparticles exhibited excellent antioxidant and antibacterial properties, and they improved the films' suitability as edible packaging. The attributes of the G/OEO-CSNPs were optimized, the films had the strongest radical scavenging and lowest water solubility, and electron microscopy also showed nanoparticle penetration into the polymer when the concentration of OEO-CSNPs was 6% (thickness = 0.092 ± 0.001, TS = 47.62 ± 0.37, E = 4.06 ± 0.17, water solubility = 48.00 ± 1.11). Furthermore, the GA-based composite film containing 6% OEO-CSNPs was able to inhibit microbial growth, slow fat decomposition and protein oxidation, reduce endogenous enzyme activity, and delay the spoilage of mullet during the refrigeration process, all of which indicate its excellent potential for meat preservation application.

Pyrolized Diatomaceous Biomass Doped with Epitaxially Growing Hybrid Ag/TiO2 Nanoparticles: Synthesis, Characterisation and Antibacterial Application

In the pursuit of innovative solutions for modern technologies, particularly in the design and production of new micro/nanostructured materials, microorganisms acting as "natural microtechnologists" can serve as a valuable source of inspiration. This research focuses on harnessing the capabilities of unicellular algae (diatoms) to synthesize hybrid composites composed of AgNPs/TiO₂NPs/pyrolyzed diatomaceous biomass (AgNPs/TiO₂NPs/DBP). The composites were consistently fabricated through metabolic (biosynthesis) doping of diatom cells with titanium, pyrolysis of the doped diatomaceous biomass, and chemical doping of the pyrolyzed biomass with silver. To characterize the synthesized composites, their elemental and mineral composition, structure, morphology, and photoluminescent properties were analysed using techniques such as X-ray diffraction, scanning and transmission electron microscopy, and fluorescence spectroscopy. The study revealed the epitaxial growth of Ag/TiO₂ nanoparticles on the surface of pyrolyzed diatom cells. The antimicrobial potential of the synthesized composites was evaluated using the minimum inhibitory concentration (MIC) method against prevalent drug-resistant microorganisms, including Staphylococcus aureus, Klebsiella pneumonia, and Escherichia coli, both from laboratory cultures and clinical isolates.

Effect of Kaolin clay and Ficus carica mediated silver nanoparticles on chitosan food packaging film for fresh apple slice preservation

In this work, a novel antioxidant, antibacterial, and biodegradable food packaging film was elaborated, by incorporating natural kaolin clay (KC) and Ficus carica mediated silver nanoparticles (AgNPs) into Chitosan (Cht). A comparison of the physico-chemical and functional characteristics of the Cht/KC/AgNPs film was performed with those of Cht, Cht/KC, and Cht/AgNPs. SEM analysis showed a rough surface in the composite films containing KC particles because of their large diameter (50-120 μm) compared to AgNPs (20-80 nm). The FTIR analysis suggested that the interactions between Cht and AgNPs were stronger than those between Cht and KC. The tensile strength of Cht film increased from 16 MPa to ∼24 MPa in Cht/KC/AgNPs film. The introduction of KC and/or AgNPs considerably improved the light and moisture barrier capacity of the Cht film. The UV light transmittance decreased by 50 % for Cht film when incorporated by KC and AgNPs. Moreover, Cht/AgNPs was better in terms of antioxidant, antibacterial, and mechanical compared to Cht/KC, which was superior in biodegradability and water vapor barrier capacity. In particular, the Cht/KC/AgNPs film presented good barrier, antioxidants, antibacterial, mechanical, and biodegradable properties, owing to the synergistic effect between KC and AgNPs. For the packaging properties, all the films were tested for their ability to keep the freshness of apple slices as wrapping material. The films exhibited good results, and the Cht/KC/AgNPs showed promising performance regarding the moisture loss, browning index, total phenolic compound, and antioxidant activity of the apple slices. Moreover, the Cht/KC/AgNPs film exhibited a migration of silver meeting the standards set by EFSA and ECHA, which makes this film safe for food packaging.

Cross-linked CMC/Gelatin bio-nanocomposite films with organoclay, red cabbage anthocyanins and pistacia leaves extract as active intelligent food packaging: colorimetric pH indication, antimicrobial/antioxidant properties, and shrimp spoilage tests

Multifunctional food packaging films were produced from crosslinked carboxymethyl cellulose/gelatin (CMC/Ge) bio-nanocomposites incorporated with Ge-montmorillonite (OM) nanofiller, anthocyanins (ATH) from red cabbage as colorimetric pH-indicator, and pistacia leaves extract (PE) as active agent. The influence of additives on the structural, physical, and functional properties of the films was investigated. The results showed that ATH and PE caused color alteration and reduced transparency. However, they improved the UV light barrier ability by 98 %, with less impact from OM, despite its well-dispersed state in the matrix. Increasing PE content in the bio-nanocomposite films caused an increase in compactness and surface roughness, reduction in moisture content (15.10-12.33 %), swelling index (354.55-264.58 %), surface wettability (contact angle 80.1-92.49°), water vapor permeability (7.37-5.69 × 10¹⁰ g m^-1s^-1Pa^-1), and nano-indentation mechanical parameters, without affecting the thermal stability. ATH-included films demonstrated color pH-sensitivity with improved ATH color stability through the ATH-Al³⁺ chelates formation. PE-added films exhibited effective antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical, reaching 93 % of inhibition, and antimicrobial properties with biocidal effects for PE-rich film. The shrimp spoilage test showed that the T-1.5PE film offered the strongest active intelligent response. The CMC/Ge-based bio-nanocomposite films endowed with antioxidant/antimicrobial properties and colorimetric pH-sensitivity have promising potential for food packaging application.

Food packaging composite film based on chitosan, natural kaolinite clay, and Ficus. carica leaves extract for fresh-cut apple slices preservation

The problem of environmental plastic contamination is one of the most serious issues facing our world today. The majority of the packaging materials used to preserve food are made of plastic which is considered an environmental issue. Natural kaolinite clay (KC) and Ficus leaf extract (FLE) were combined with chitosan in this work to create a novel antioxidant and biodegradable food packaging film. Chitosan/KC/FLE film was compared to chitosan film, Chitosan/KC, and Chitosan/FLE films in terms of structural, physical, and functional aspects. The addition of FLE and/or KC significantly improved the light and moisture barrier characteristics, mechanical properties, and antioxidant capabilities of chitosan film. Moreover, KC addition had a remarkable impact on the water vapor permeability and the biodegradability of the chitosan film. Because of the synergistic action of FLE and KC, the Chitosan/KC/FLE film delivered strong barrier and antioxidant capabilities. Furthermore, Chitosan/KC/FLE film was tested as packaging material on fresh-cut apple slices and demonstrated good food preservation regarding the weight loss, browning index, and total phenolic content of the fruit. According to our findings, Chitosan/KC/FLE film might be employed as a possible food packaging material in the food industry.

In Situ Polymerization of Linseed Oil-Based Composite Film: Enhancement of Mechanical and Water Barrier Properties by the Incorporation of Cinnamaldehyde and Organoclay

Linseed oil-based composite films were prepared with cinnamaldehyde (Cin) using a modified clay (organoclay) through in situ polymerization, which is the result of the interaction between Cin and organoclay. The incorporation of organoclay reduces the polymer chain's mobility and, therefore, increases the thermal stability of the composite films. In some experimental conditions, the clay is located both inside and on the surface of the film, thus, affecting the mechanical and thermal properties as well as the surface properties of the composite films. The incorporation of organoclay decreases the water contact angle of the composite film by more than 15%, whatever the amount of cinnamaldehyde. However, the incorporation of cinnamaldehyde has the opposite effect on film surface properties. Indeed, for the water vapor permeability (WVP), the effect of cinnamaldehyde on the film barrier properties is much higher in the presence of organoclay. The incorporation of hydrophobic compounds into the polymer films reduces the water content, which acts as a plasticizer and, therefore, decreases the WVP by more than 17%. Linseed oil has a natural antioxidant activity (~97%) due to the higher content of unsaturated fatty acids, and this activity increased with the amount of organoclay and cinnamaldehyde.

Biobased polymer resources and essential oils: a green combination for antibacterial applications

To fight nosocomial infections, the excessive use of antibiotics has led to the emergence of multidrug-resistant microorganisms, which are now considered a relevant public health threat by the World Health Organization. To date, most antibacterial systems are based on the use of petro-sourced polymers, but the global supplies of these resources are depleting. Besides, silver NPs are widely accepted as the most active biocide against a wide range of bacterial strains but their toxicity is an issue. The growing interest in natural products has gained increasing interest in the last decade. Therefore, the design of functional antibacterial materials derived from biomass remains a significant challenge for the scientific community. Consequently, attention has shifted to naturally occurring substances such as essential oils (EOs), which are classified as Generally Recognized as Safe (GRAS). EOs can offer an alternative to the common antimicrobial agents as an inner solution or biocide agent to inhibit the resistance mechanism. Herein, this review not only aims at providing developments in the antibacterial modes of action of EOs against various bacterial strains and the recent advances in genomic and proteomic techniques for the elucidation of these mechanisms but also presents examples of biobased polymer resource-based EO materials and their antibacterial activities. Especially, we describe the antibacterial properties of biobased polymers, e.g. cellulose, starch, chitosan, PLA PHAs and proteins, associated with EOs (cinnamon (CEO), clove (CLEO), bergamot (BEO), ginger (GEO), lemongrass (LEO), caraway (CAEO), rosemary (REO), Eucalyptus globulus (EGEO), tea tree (TTEO), orange peel (OPEO) and apricot (Prunus armeniaca) kernel (AKEO) essential oils). Finally, we discuss the influence of EOs on the mechanical strength of bio-based materials.

From Classical to Advanced Use of Polymers in Food and Beverage Applications

Polymers are extensively used in food and beverage packaging to shield against contaminants and external damage due to their barrier properties, protecting the goods inside and reducing waste. However, current trends in polymers for food, water, and beverage applications are moving forward into the design and preparation of advanced polymers, which can act as active packaging, bearing active ingredients in their formulation, or controlling the head-space composition to extend the shelf-life of the goods inside. In addition, polymers can serve as sensory polymers to detect and indicate the presence of target species, including contaminants of food quality indicators, or even to remove or separate target species for later quantification. Polymers are nowadays essential materials for both food safety and the extension of food shelf-life, which are key goals of the food industry, and the irruption of smart materials is opening new opportunities for going even further in these goals. This review describes the state of the art following the last 10 years of research within the field of food and beverage polymer's applications, covering present applications, perspectives, and concerns related to waste generation and the circular economy.

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

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

The Improved Properties of Carboxymethyl Bacterial Cellulose Films with Thickening and Plasticizing

This study aims to improve the thermal stability and mechanical properties of carboxymethyl bacterial cellulose (CMBC) composite films. Experiments were conducted by preparing bacterial cellulose (BC) into CMBC, then parametrically mixing sodium alginate/starch/xanthan gum/gelatin and glycerin/sorbitol/PEG 400/PEG 6000 with CMBC to form the film. Scanning electron microscopy, X-ray diffractometry, infrared spectroscopy, mechanical tests, and thermogravimetric analysis showed that the composite films had better mechanical properties and thermal stability with the addition of 1.5% CMBC (% v/v), 1% sodium alginate, and 0.4% glycerin. Tensile strength was 38.13 MPa, the elongation at break was 13.4%, the kinematic viscosity of the film solution was 257.3 mm²/s, the opacity was 4.76 A/mm, the water vapor permeability was 11.85%, and the pyrolysis residue was 45%. The potential causes for the differences in the performance of the composite films were discussed and compared, leading to the conclusion that CMBC/Sodium alginate (SA)/glycerin (GL) had the best thermal stability and mechanical properties.

Surfactin effectively improves bioavailability of curcumin by formation of nano-capsulation

To improve the bioavailability of curcumin, surfactin was used to prepare curcumin-loaded nanoemulsions (Cur-NEs). Moreover, the physicochemical properties, digestive characteristics, as well as inhibition activity to Caco-2 cells of Cur-NEs were measured. Furthermore, the morphological analysis revealed that Cur-NEs with 320 mg/L surfactin appeared spherical nanoparticale (23.23 ± 2.86 nm) and uniform distribution. The encapsulation efficiency of Cur-NEs with 320 mg/L surfactin was 97.25 ± 1.28%. Simulated gastrointestinal digestion results indicated that surfactin elevated the sustained-release characteristics and higher bioaccessibility (40.92 ± 2.84%) of curcumin. Besides, Cur-NEs with 320 mg/L surfactin exhibited excellent stability in different temperature, pH and light irradiation. In addition, the inhibition of Cur-NEs with 320 mg/L surfactin to Caco-2 cells was 71.29%. Biochemical analysis showed that Cur-NEs enhanced the activity of lactate dehydrogenase, superoxide dismutase, catalase and glutathione peroxidase, as well as the reactive oxygen species content. RT-PCR and ELISA results also revealed that Cur-NEs inhibited Caco-2 cells through the activated mitochondria-mediated pathway. This study provided a strategy to encapsulate curcumin in nanoparticles with surfactin for improving bioavailability.

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

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

Preparation of sodium alginate/konjac glucomannan active films containing lycopene microcapsules and the effects of these films on sweet cherry preservation

In this study, lycopene microcapsules (LMs) were prepared using chitosan (CS) and carboxymethyl CS (CMCS) as the wall materials. Sodium alginate (SA) and konjac glucomannan (KGM) were used as substrates to fabricate LM/SA/KGM composite films. Results showed that when 2.0 % CMCS was employed, the resulting LMs had the maximum embedding rate of 83.17 %, smallest particle sizes, and stable zeta potentials. The LMs still had a high retention rate after 10 days of storage at 4 and 25 °C. When 2.0 % LMs were used, the corresponding composite film exhibited the best antibacterial properties, oxidation resistance, a high transparency (82.3 %), and a strong water vapor barrier (2.39 × 10^-10 g/m·s·Pa). Finally, the effects of the as-prepared composite films on the preservation of sweet cherries stored at 0 °C for 15 days were investigated. The results indicated that the LM/SA/KGM composite film effectively prolonged the shelf lives of sweet cherries and efficiently delayed the decline in the decay rate, pH, contents of soluble solids, and other indicators. The application of LM/SA/KGM composite films in fruit and vegetable preservation has development prospects and provides a reference for expanding the application range of lycopene and enhancing fruit and vegetable preservation.

Bovidae-based gelatin: Extractions method, physicochemical and functional properties, applications, and future trends

Gelatin is one of the most important multifunctional biopolymers and is widely used as an essential ingredient in food, pharmaceutical, and cosmetics. Porcine gelatin is regarded as the leading source of gelatin globally then followed by bovine gelatin. Porcine sources are favored over other sources since they are less expensive. However, porcine gelatin is religiously prohibited to be consumed by Muslims and the Jewish community. It is predicted that the global demand for gelatin will increase significantly in the future. Therefore, a sustainable source of gelatin with efficient production and free of disease transmission must be developed. The highest quality of Bovidae-based gelatin (BG) was acquired through alkaline pretreatment, which displayed excellent physicochemical and rheological properties. The utilization of mammalian- and plant-based enzyme significantly increased the gelatin yield. The emulsifying and foaming properties of BG also showed good stability when incorporated into food and pharmaceutical products. Manipulation of extraction conditions has enabled the development of custom-made gelatin with desired properties. This review highlighted the various modifications of extraction and processing methods to improve the physicochemical and functional properties of Bovidae-based gelatin. An in-depth analysis of the crucial stage of collagen breakdown is also discussed, which involved acid, alkaline, and enzyme pretreatment, respectively. In addition, the unique characteristics and primary qualities of BG including protein content, amphoteric property, gel strength, emulsifying and viscosity properties, and foaming ability were presented. Finally, the applications and prospects of BG as the preferred gelatin source globally were outlined.

Production of Innovative Essential Oil-Based Emulsion Coatings for Fungal Growth Control on Postharvest Fruits

This work assessed the antimicrobial potential of natural essential oils (EOs) from cinnamon (CEO), zataria (ZEO), and satureja (SEO), applied natively or as coatings against Penicillium expansum and Botrytis cinerea during both in vitro and in vivo (on apple fruits) experiments. The induced inhibitory effect towards fungal growth, as a function of both EO type and concentration (75–1200 μL/L), was preliminarily investigated to select the most suitable EO for producing bacterial cellulose nanocrystals (BCNCs)/fish gelatin (GelA)-based emulsions. CEO and ZEO exhibited the best performances against P. expansum and B. cinerea, respectively. None of the pristine EOs completely inhibited the fungal growth and “disease severity”, properly quantified via size measurements of lesions formed on fruit surfaces. As compared to pristine CEO, coating emulsions with variable CEO concentration (75–2400 µL/L) curbed lesion spreading on apples, owing to the controlled CEO release during a 21-day temporal window. The strongest effect was displayed by BCNCs/GelA-CEO emulsions at the highest CEO concentration, upon which lesions on fruit skins were barely detectable. This work demonstrated the capability of EOs embedded in BCNCs/GelA-based nanocapsules to efficiently slow down microbial spoilage on postharvest fruits, thus offering viable opportunities for developing innovative antimicrobial packaging systems.

Poly(Lactic Acid) (PLA)-Based Nanocomposites: Impact of Vermiculite, Silver, and Graphene Oxide on Thermal Stability, Isothermal Crystallization, and Local Mechanical Behavior

The structural, thermal, and mechanical properties of unreinforced and reinforced polylactic acid (PLA) were investigated. The PLA was a biopolymer that was reinforced with four fillers (i.e., graphene oxide (GO) and silver (Ag); vermiculite (VMT) and silver (Ag); and two organically modified vermiculites). The processing technique for the production of the composite materials were carefully planned. The PLA nanocomposites were investigated by examining their morphological aspects, changes in PLA phases and transitions and, most importantly, the effect on certain final properties. X-ray diffraction and differential scanning calorimetry (DSC) analysis indicated that the sample was completely amorphous. Thermogravimetric analysis (TGA) results indicated that the presence of reinforcing particles in the PLA matrix did not affect the thermal degradation of these composites. Furthermore, the local mechanical properties were investigated using the microindentation method to evaluate the effect of different nanofillers. Scanning electron microscopy (SEM) and a VHX-500 optical digital microscope (Keyence International, Mechelen, Belgium) were also used to examine the surface morphology of the PLA polymer composites. These results can help to select suitable fillers to enhance the PLA performance of biopolymers.

Rheological properties of wood/bacterial cellulose and chitin nano-hydrogels as a function of concentration and their nano-films properties

In this study, rheological properties of the Wood Cellulose NanoFibers (WCNF), Bacterial Cellulose NanoFibers (BCNF), and Chitin NanoFibers (ChNF) as well as physical properties of films prepared from each nano‐hydrogel were investigated. Each nano‐hydrogel was prepared in 2 concentrations of 0.5 and 1 wt% for rheological study. Rheological properties were measured using a rotational rheometer. The flow behaviour data were fitted with rheological models. Apparent viscosity was higher in higher concentrations of nano‐hydrogels. Herschel‐Bulkley model was the best model for flow behaviour data fitting. BCNF nano‐hydrogels had the highest hysteresis loop while WCNF nano‐hydrogels had the best structure recovery and lowest hysteresis loop. At LVE (Linear Viscoelastic Region), G′ (storage modulus) and G″ (loss modulus) had a constant value, but as strain increased their values decreased. Storage modulus was found to be greater than loss modulus in all samples during frequency sweep test. BCNF nano‐hydrogel showed the lowest frequency dependency. Chitin nanofilms had the highest elongation and stress value.

Silver-sepiolite (Ag-Sep) hybrid reinforced active gelatin/date waste extract (DSWE) blend composite films for food packaging application

In this study, date syrup waste extract (DSWE) (15 wt%) and different content of silver doped sepiolite hybrid (Ag-Sep, 0.25-3 wt%) were incorporated into gelatin matrix to develop a series of active composite packaging films. Incorporating 2 wt% of Ag-Sep increased the modulus of blend film by 98% compared to unmodified gelatin/DSWE blend film. The active gelatin composite film exhibited superior active compounds migration to aqueous food simulants. Besides, Ag-Sep provided a tortuous pathway to the composite film, resulting in high 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical inhibition efficiency (91%) and slow-release kinetics of active compounds to the food simulant. The Ag-Sep hybrid was improved the antimicrobial property of the gelatin/DSWE blend film against both gram-negative and gram-positive microbes. Thus, this study demonstrated that the Ag-Sep hybrid exhibits significant properties in the active gelatin composite films, implying that this hybrid could be an effective additive for various active packaging films.