Pectin/pullulan blend films for food packaging: Effect of blending ratio

Utilization of cassava peel based cellulose nanofiber for developing functionalized pectin/pullulan/olive oil nanocomposite film for cling wrapping of chicken meat

The current research focused on the utilization of cassava peel for fabricating cellulose nanofiber (CNF) and development of nanocomposite films for cling wrapping of chicken meat. The extraction of cellulose was achieved through the pretreatment method of cassava peel. Further, CNF was fabricated via acid hydrolysis (H2SO4) of cassava peel derived cellulose. Field emission scanning electron microscopy analysis confirmed the formation of CNF with diameters ranging from 25.9 to 50.0 nm. Moreover, X-ray diffraction (XRD) showed the characteristics peak of CNF at 21.66°. Further, the thermal stability of CNF was compared with cellulose. The CNF showed the highest thermal stability with T10, T50 value of 204.30 °C and 336.80 °C respectively, along with the residual weight of 24.19 %. Further, various compositions of films such as CNF incorporated pullulan /pectin (PP) and pullulan /pectin /olive oil (PPO)-based nanocomposite films were developed using solution casting method. The properties of films were investigated in terms of surface morphology, barrier, mechanical and optical properties. Incorporation of CNF reduced the water vapor transmission rate of the nanocomposite films. Moreover, film containing 1.5 wt% CNF exhibited the highest tensile strength (6.90 MPa) and Young's modulus (7.21 MPa), while elongation at break peaked at 1 wt% CNF for PP films but decreased with higher CNF content in PPO films. Further, the developed films were used as a cling wrapper for chicken meat and storage study was checked. The cling wrapper maintained the color of the chicken meat, minimizing weight loss from 42.08 % (unwrapped) to 6.13-11.59 % (cling wrapped) and limits the increase in hardness over 10 days. Microbial analysis revealed a significant reduction in mesophilic and psychrophilic bacterial counts in cling wrapped chicken meat as compared to unwrapped one.

Development and characterization of soluble soybean polysaccharide/pullulan blend films enriched with essential oils

Soluble soybean polysaccharide (SSPS)/pullulan (PUL) blend films enriched with lavender essential oil (LEO) or clove essential oil (CEO) were prepared using the solution casting method. The structural, optical, mechanical, barrier, thermal, antioxidant, and antibacterial properties of the SSPS/PUL/LEO and SSPS/PUL/CEO films were investigated and compared. Scanning electron microscopy micrographs revealed randomly distributed micropores within the SSPS/PUL matrix after enrichment with essential oils (EOs). The addition of EOs significantly improved the UV-blocking performance, elongation at break (EAB), water resistance, antioxidant activity and hydrophobicity of the films. The results showed that the SSPS/PUL/CEO films exhibited nearly 100 % UV-blocking efficiency in the wavelength range of 190-290 nm, while achieving a maximum EAB of 90.6 ± 5.3 %. However, the tensile strength of the films decreased from 10.8 MPa to 5.6 MPa or 4.8 MPa upon the addition of 15 % LEO or CEO, respectively. Thermogravimetric analysis indicated that the addition of EOs had little effect on the thermal properties of the SSPS/PUL films. Both SSPS/PUL/LEO and SSPS/PUL/CEO films exhibited good antioxidant and antibacterial properties, with the SSPS/PUL/CEO film showing superior performance in both aspects. The results preliminarily suggest that the SSPS/PUL/EOs films have great potential to be used as active food packaging materials.

Polysaccharide edible film-the new star in food preservation: A review

Polysaccharide edible film (PEF) plays an important role in protecting food from physical extrusion, chemical hazards and microbial invasion. In recent years, on the basis of ensuring food safety, consumers have put forward higher requirements for maintaining sensory characteristics and nutritional value of food in the process of storage and circulation. As a natural component with convenient preparation and rich sources, polysaccharides have antibacterial, anti-inflammatory, antioxidant and other biological activities. The edible preservative film based on polysaccharide has the advantages of environmental protection, safety and no residue. Considering the health of consumers and the sustainable development of the environment, the environment-friendly, safe and effective PEF has become an important material in the field of food preservation and a creative solution to the problem of food preservation. Based on this, review focuses on the application of PEF in the preservation of different kinds of food, and briefly expounds the mechanism of PEF in the preservation of food, the production methods and different types of PEF. At the same time, it summarizes the existing problems and future development prospects and directions of PEF. After years of in-depth research and application, PEF technology has shown an important role and application potential in the field of food preservation. This paper hopes to provide reference value for the further application of PEF in the field of food preservation.

Citrus wastes as sustainable materials for active and intelligent food packaging: Current advances

Citrus fruits are one of the most popular crops in the world, and around one quarter of them are subjected to industrial processes, aiming at the production of different food products. Citrus processing generates large amounts of waste, including peels, pulp, and seeds. These materials are rich sources of polymers (e.g., pectin, cellulose, hemicellulose, lignin), phenolic compounds, and essential oils. At the same time, the development of food packaging materials using citrus waste is a highly sought strategy for food preservation, and meets the principles of circular economy. This review surveys current advances in the development of active and intelligent food packaging produced using one or more citrus waste components (polymers, phenolics extracts, and essential oils). It highlights the contribution and effects of each of these components on the properties of the developed packaging, as well as emphasizes the current state and challenges for developing citrus-based packaging. Most of the reported investigations employed citrus pectin as a base polymer to produce packaging films through the casting technique. Likewise, most of them focused on developing active materials, and fewer studies have explored the preparation of citrus waste-based intelligent materials. All studies characterized the materials developed, but only a few actually applied them to food matrices. This review is expected to encourage novel investigations that contribute to food preservation and to reduce the environmental impacts caused by discarded citrus byproducts.

Chitosan-pullulan edible coating loaded with dihydromyricetin: Enhanced antioxidant activity and barrier properties to prolong Cantonese sausages' shelf-life

Cantonese sausages are susceptible to oxidative deterioration during storage. Compared with synthetic antioxidants, dihydromyricetin (DMY) is a natural active substance with various functions such as antioxidant and antimicrobial. In this study, edible coating solutions loaded with DMY were prepared based on chitosan (CS) and pullulan (PUL) to prolong the shelf-life of Cantonese sausages. FT-IR and XRD results showed good compatibility between DMY and CS-PUL. It was found that 8 % DMY was physically cross-linked with CS and PUL mainly through hydrogen bonding, which enhanced the barrier and mechanical properties of the films. Meanwhile, the antioxidant property, antimicrobial efficiency and thermal stability of the films were also significantly improved (p < 0.05). The results of storage experiments of Cantonese sausages showed that the 8 % DMY-CP coating solution could effectively retard the lipid oxidation of Cantonese sausages at 25 °C, and maintain the appearance and flavour of products at storage on the 28th d. This study proved DMY's potential as a natural alternative to synthetic additives in polysaccharide-based edible coatings, providing a green and sustainable solution to combat lipid oxidation in meat products.

An Overview of Potential Applications of Environmentally Friendly Hybrid Polymeric Materials

The applications of polymeric materials are being constantly reviewed and improved. In the present world, the word hybrid, and the general idea of combining two or more inherently different approaches, designs, and materials is gaining significant attention. The area of sustainable materials with a low environmental impact is also rapidly evolving with many new discoveries, including the use of materials of a natural origin and countless combinations thereof. This review tries to summarize the current state of knowledge about hybrid polymeric materials and their applications with special attention to the materials that can be considered "environmentally friendly". As the current application field is quite broad, the review was limited to the following topics: packaging, medical applications, sensors, water purification, and electromagnetic shielding. Furthermore, this review points out the new prospects and challenges for the use of the mentioned materials in terms of creating novel solutions with different nano and micro-materials of mostly natural and renewable origin.

A high-strength collagen-based antimicrobial film grafted with ε-polylysine fabrication by riboflavin-mediated ultraviolet irradiation for pork preservation

In this study, a UV-cured collagen-based film (C-P-H film) with high mechanical strength and antimicrobial properties was developed by riboflavin-mediated ultraviolet irradiation of collagen solution containing histidine-modified ε-polylysine. Fourier transform infrared analysis indicated that covalent cross-linking was formed between the collagen molecule and the histidine-grafted ε-polylysine. Compared with the pure collagen film, the C-P-H film containing 5 wt% histidine-modified ε-polylysine showed higher tensile strength (145.98 MPa), higher thermal denaturation temperature (76.5 °C), lower water vapor permeability (5.54 × 10-11 g m-1 s-1 Pa) and excellent antimicrobial activities against Escherichia coli and Staphylococcus aureus. In addition, the wrapping of the C-P-H film effectively inhibited bacterial growth of pork during storage time, successfully prolonging the shelf-life of pork by approximately 4 days compared to that of plastic wrap. These results suggested that collagen-based film grafted with histidine-modified ε-polylysine via riboflavin-mediated ultraviolet irradiation process had a great potential for pork preservation.

Pineapple stem starch-based films incorporated with pineapple leaf carbon dots as functional filler for active food packaging applications

Pineapple leaf waste, a byproduct of agricultural processes, was used as a novel raw material to synthesize carbon dots (CDs) through a simple hydrothermal method. The CDs were subsequently incorporated into pineapple stem starch (PSS)-based active food packaging films. The characterization of the CDs and PSS-CDs films was conducted using various techniques, including UV-light spectroscopy, fluorescence spectroscopy, and transmission electron microscopy. The results revealed that the CDs measured 2.36 ± 0.33 nm and exhibited antioxidant and antibacterial activities. The addition of the CDs led to notable enhancements in both mechanical strength and UV-barrier properties. Thus, PSS-CDs packaging film was successfully prepared, with the incorporation of CDs enhancing the antioxidant and antimicrobial properties of the film, thereby extending the shelf-life of fresh pork.

Chitosan nanoparticles and neem essential oil functionalized pullulan/gum arabic active edible biocomposites for fresh-cut guava preservation

The study demonstrates the preparation of active edible biocomposites using Pullulan (PUL) and Gum Arabic (GA), functionalized with Chitosan Nanoparticles (NCS) and Neem Essential Oil (NEO). These biocomposites addressed the issues of high hydrophilicity and poor barrier properties in packaging. The effects of varying NCS concentrations (1 %, 2 %, and 3 %) on various film properties were studied, while keeping PUL, GA, and NEO concentrations constant. The biocomposite containing NEO and 3 % NCS (PUL/GA/NCS3/NEO), significantly improved surface properties, transforming it from hydrophilic (water contact angle 55.49 ± 2.31°) to hydrophobic (115.01 ± 1.86°). Additionally, tensile strength increased by ∼12.77 MPa, elongation at break by ∼6.26 %, thermal stability (Toffset) by ∼22.49 °C, and water vapour barrier by ∼45.95 %, alongside enhanced UV-shielding, antimicrobial and antioxidant properties. The EDX analysis confirmed the biocomposite safety, with 55.7 % carbon (C), 3.6 % nitrogen (N), and 40.8 % oxygen (O). Moreover, in vitro biocompatibility tests on Human Embryonic Kidney (HEK-293) cells indicated non-cytotoxicity, with 86.82 ± 2.28 % viability after 72 h. Furthermore, the practical application of PUL/GA/NCS3/NEO solution was tested as an edible coating material for fresh-cut guava preservation. The coated guava better maintained storage quality parameters in terms of colour, weight loss, firmness, microbiological shelf-life and antioxidant activity, under both ambient and refrigerated conditions.

Advances in biomaterials based food packaging systems: Current status and the way forward

World hunger is getting worse, while one-third of food produced around the globe is wasted and never consumed. It is vital to reduce food waste to promote the sustainability of food systems, and improved food packaging solutions can augment this effort. The utilization of biomaterials in smart food packaging not only enhances food preservation and safety but also aligns with current demands for eco-friendly technologies to mitigate the impacts of climate change. This review provides a comprehensive overview of the developments in the field of food packaging based on the innovative use of biomaterials. It emphasizes the potential use of biomaterials derived from nature including cellulose, chitosan, keratin, etc. for this purpose. Various smart food packaging technologies such as active and intelligent packaging are discussed in detail including scavenging additives, colour-changing environment indicators, sensors, RFID tags, etc. The article also delves into the utilization of edible films and coatings, nanoparticle fillers and 2D materials in food packaging systems. Furthermore, it outlines the challenges and opportunities in this dynamic domain, emphasizing the ongoing need for research and innovation to shape the future of sustainable and smart food packaging solutions to enhance and monitor the shelf-life of food products.

Exploring the Potential of Pectin as a Source of Biopolymers for Active and Intelligent Packaging: A Review

The use of fossil-based plastics in food packaging poses a serious environmental concern. Pectin, a natural biodegradable polymer, offers a potential solution for environmentally friendly and sustainable food packaging to replace fossil-based plastics. This article reviews the applications of pectin in active and intelligent packaging and analyzes the latest research trends. Bibliometric analysis was used to review the existing literature on pectin in food packaging. Data were collected from the Scopus database, which covers research on film manufacturing and pectin-based coating. Pectin-based active packaging contains antimicrobial and antioxidant compounds such as ascorbic acid and essential oils, which effectively prevent bacterial growth while absorbing oxygen and water vapor. In contrast, pectin-based intelligent packaging allows real-time monitoring of food quality through integrated color-changing indicators, eliminating the need for open packaging. Research trends have shown a significant increase in publications on pectin-based packaging, reflecting the growing interest in sustainable packaging solutions. With a focus on innovation and sustainability, pectin can replace conventional plastics and provide safer and more durable packaging solutions, thereby supporting global efforts to reduce the environmental impact of plastic waste.

Examining the potential of peppermint essential oil-infused pectin and kappa-carrageenan composite films for sustainable food packaging

Essential oils are key ingredients in the development of edible films and provide a diverse approach to improving food preservation, as well as sensory qualities. The pectin and kappa-carrageenan composite films were obtained by adding peppermint essential oil in different quantities. The films after their fabrication were thoroughly evaluated for their attributes, which included mechanical, barrier, optical, chemical, thermal, and antioxidant properties. The visual assessment of the films demonstrated that PEO-loaded films showed a uniform, homogenous, and slightly yellowish appearance. There was an increase in the thickness (0.045 ± 0.006 to 0.060 ± 0.008 mm), elongation at break (12.73 ± 0.74 to 25.05 ± 1.33 %), and water vapor permeability (0.447 ± 0.014 to 0.643 ± 0.014 (g*mm)/(m2*h*kPa)) was observed with the addition of PEO. However, tensile strength (45.84 ± 3.69 to 29.80 ± 2.10 MPa) and moisture content (25.83 ± 0.046 to 21.82 ± 0.23 %) decreased with the incorporation of PEO. Furthermore, thermal and antioxidant properties were enhanced by the inclusion of PEO. The presented investigation can be employed to synthesize food packaging material with antioxidant properties with potential applications in food packaging.

Preparation of multi-functional active packaging film of Galla chinensis waste CDs/pullulan

In this study, multifunctional green carbon dots (CDs) have been synthesized using Galla chinensis waste (GCW) via hydrothermal method for the first time. An active packaging film has been developed in this work by combining CDs and pullulan (PL), using the solution-casting method. The microscopic morphology revealed that the CDs that were prepared using GCW exhibited good compatibility with PL. In addition, it also led to improvement in the toughness of the PL film (14.01 % to 20.26 %), along with its water vapor permeability value [1.31 to 0.53 (g·mm)/(kPa·h·m2)]. The composite films consisting of CDs exhibited good UV blocking rates for the UVA (90.41 %-7.87 %), UVB (87.76 %-0.08 %), and UVC (83.39 %-0 %) spectral ranges. The composite films exhibited strong antioxidant activity, and the clearance of ABTS and DPPH were obtained to be 93.61 % and 86.30 %, respectively. In addition, the composite films showed good antibacterial activity for E. coli and S. aureus, with a high antibacterial rate of up to 99.99 %. Finally, the non-contact preservation of strawberries over a duration of 10 d at room temperature confirmed that the prepared composite film can help preserve the quality of strawberries, as well as extended their shelf-life.

An insect lac blanket-mimetic and degradable shellac hydrogel/chitosan packaging film with controllable gas permeation for fresh-cut vegetables preservation

Fresh-cut products are extremely perishable due to the processing operations, and the atmosphere environment, especially CO2, O2 and H2O, could profoundly affect their shelf life. Herein, an insect "lac blanket"-mimetic and facile strategy was proposed for fresh-cut vegetables preservation, employing porous shellac hydrogel microparticles as gas "switches" in chitosan film to regulate CO2, O2 and H2O vapor permeability. Thus, the shellac hydrogel/chitosan hybrid film presented the controllable and wide range of gas permeability, compared with the chitosan film. The shellac-COOH nanoscale vesicles aggregated to form shellac hydrogel network via hydrophobic binding. The shellac hydrogel microparticles played a certain lubricating effect on the hybrid film casting solution. The hydrogen bond network between shellac hydrogel and chitosan contributed to the excellent mechanical properties of the hybrid film. The hybrid film also exhibited remarkable water-resistant, antifogging properties, optical transparency and degradability. The hybrid packaging films prepared through this strategy could adjust the internal gas (CO2, O2, H2O and ethylene) contents within the packages, and further exhibited admirable preservation performance on three fresh-cut vegetables with different respiratory metabolisms. This gas permeation-controlled strategy has great potential in fresh food preservation and various other applications that need a modified atmosphere.

Intelligent double-layer film based on gellan gum/modified anthocyanin/curcumin/sodium alginate/zinc oxide for monitoring shrimp freshness

In this study, intelligent double-layer films were prepared using modified black rice anthocyanin (MBRA)-curcumin (CUR)-gellan gum (GG) as the inner indicator layer and sodium alginate (ALG)‑zinc oxide (ZnO) as the outer antimicrobial layer. The bilayer films were successfully prepared, as revealed by scanning electron microscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction measurements. The mechanical characteristics, moisture content, and water vapor resistance of GG-MBRA/CUR1@ALG-ZnO, GG-MBRA/CUR2@ALG-ZnO, and GG-MBRA/CUR3@ALG-ZnO films showed significant enhancement compared to GG-MBRA/CUR3 and ALG-ZnO films. The bilayer films exhibited excellent pH responsiveness and reacted effectively to ammonia. The outer layer significantly improved the antioxidant and antibacterial properties of the inner layer. When the films were applied to shrimp, it was found that the double-layer films not only monitored the freshness of the shrimp in real-time but also were influential in extending the shelf life of the shrimp by about 1 d. Therefore, the double-layer film demonstrated potential as a smart packaging material for real-time monitoring of meat product freshness.

Development of innovative active packaging films using gelatin/pullulan-based composites incorporated with cinnamon essential oil-loaded metal-organic frameworks for meat preservation

This study aimed to investigate the effect of cinnamon essential oil (CEO)-loaded metal-organic frameworks (CEO@MOF) on the properties of gelatin/pullulan (Gel/Pull)-based composite films (Gel/Pull-based films). The incorporation of CEO@MOF into Gel/Pull-based films demonstrated significant antimicrobial activity against S. aureus, S. enterica, E. coli, and L. monocytogenes. Additionally, CEO@MOF integrated film exhibited a 98.16 % ABTS radical scavenging, with no significant change in the mechanical properties of the neat Gel/Pull film. The UV blocking efficiency of the composite films increased significantly from 81.38 to 99.56 % at 280 nm with the addition of 3 wt% CEO@MOF. Additionally, Gel/Pull/CEO@MOF films effectively extended the shelf life of meat preserved at 4 °C by reducing moisture loss by 3.35 %, maintaining the pH within the threshold limit (6.2), and inhibiting bacterial growth by 99.9 %. These results propose that CEO@MOF has significant potential as an effective additive in active packaging to improve shelf life and food safety.

Recyclable bactericidal packaging films for emperor banana preservation

Food safety issues and food waste have always been hot topics of concern. This study aimed to develop a recyclable bactericidal packaging film that combines polylactic acid (PLA), graphitic carbon nitride (CN) and carbon nanotubes (CNT) to extend food shelf life. This film exhibited compactness and thermostability, as observed by scanning electron microscope and differential scanning calorimeter. The temperature of P/CN/CNT film could still reach 54 ± 4 °C after being used for 3 times. The film still has bactericidal activity on the 5th cycle use except for L. monocytogenes revealed by morphological characterization on bacteria. This film effectively extended the shelf life of banana to 7 days, as confirmed by measurements of hardness, pH value and total bacterial count of banana. This study provides a packaging film with recyclable bactericidal ability.

Soft and flexible polyvinyl alcohol/pullulan aerogels with fast and high water absorption capacity for facial mask substrates

Facial mask substrates commonly used in skincare are often considered unhealthy and environmentally unfriendly due to their composition of premoistened nonwovens containing various preservatives. This study aims to address this issue by developing a preservative-free degradable aerogel made from polyvinyl alcohol (PVA)/pullulan (PUL) using a unidirectional freeze-drying method. The aerogels had ordered three-dimensional porous structures and exhibited desirable mechanical properties. They were soft and flexible in both dry and wet states, and their Young's moduli were comparable to that of human skin. The aerogels had high porosity, ranging from 93.0 % to 95.1 %, and exhibited a high water absorption rate and water absorption capacity (ranging from 7.5 g/g to 10.1 g/g). After 30 min of water evaporation, the aerogels showed excellent moisture retention, ranging from 88 % to 93 %. Additionally, the PVA/PUL aerogel efficiently loaded and released active ingredients, such as rapidly releasing ascorbic acid (> 90 % within 30 min). These findings suggest that the PVA/PUL aerogel has potential as a material for facial mask substrates.

Preparation and characterization of biodegradable food packaging films using lemon peel pectin and chitosan incorporated with neem leaf extract and its application on apricot fruit

The present study aims to develop and characterize biodegradable packaging films from lemon peel-derived pectin and chitosan incorporated with a bioactive extract from neem leaves. The films (PCNE) contained varying concentrations of neem leaf extract and were comprehensively assessed for their physical, optical, mechanical, and antimicrobial attributes. The thickness, moisture content, water solubility, and water vapor permeability of the biodegradable packaging films increased with the increasing concentration of neem leaf extract. Comparatively, the tensile strength of the films decreased by 42.05 % compared to the control film. The Scanning Electron Microscopy (SEM) confirmed that the resultant blended pectin-chitosan films showed a uniform structure without cracks. Furthermore, the analysis targeting Staphylococcus aureus and Aspergillus niger indicated that the films had potent antimicrobial activity. Based on these results, the optimum films were selected and subsequently applied on apricot fruits to increase their shelf life at ambient temperature. The findings, after examining factors such as colour, firmness, total soluble solids, shrinkage, weight loss, and appearance, concluded that the apricots coated by PCNE-5 had the most delayed signs of spoilage and increased their shelf life by 50 %. The results showed the potential applicability of lemon peel pectin-chitosan-neem leaf extract blend films in biodegradable food packaging.

Recent innovations (2020-2023) in the approaches for the chemical functionalization of curdlan and pullulan: A mini-review

Chemical modification represents a highly efficacious approach for enhancing the physicochemical characteristics and biological functionalities of natural polysaccharides. However, not all polysaccharides have considerable pharmacologic activity; so, appropriate chemical modification strategies can be selected in accordance with the distinct structural properties of polysaccharides to aid in improving and encouraging the presentation of their biological activities. Hence, there has been a growing interest in the chemical alteration of polysaccharides due to their various properties such as antioxidant, anticoagulant, antiviral, anticancer, biomedical, antibacterial, and immunomodulatory effects. This paper offers a comprehensive examination of recent scientific advancements produced over the past four years in the realm of unique chemical and functional modifications in curdlan and pullulan structures. This review aims to provide readers with an overview of the structural activity correlations observed in the backbone structures of curdlan and pullulan, as well as the diverse chemical modification processes employed for these polysaccharides. Additionally, the review aims to examine the effects of combining various bioactive molecules with chemically modified curdlan and pullulan and explore their potential applications in various important fields.

Biopolymer films incorporated with chlorogenic acid nanoparticles for active food packaging application

Food packaging is innovating towards more environmental-friendly polymers and broader applications of bioactive compounds. In this study, active packaging materials were successfully prepared by incorporating chlorogenic acid (CGA) nanoparticles into pullulan/gelatin polymer matrixes. The rhamnolipid (RL) and/or CGA were combined with chitosan (CS) to synthesize active nanoparticles by the ionic crosslinking method. The film containing CS/RL/CGA nanoparticles (F/CRC) exhibited both ultrahigh visible light (400-760 nm) transmittance (approximately 90%) and UVA (320-400 nm)-blocking efficiency (89.06%). Its fluorescent properties can be used for anti-counterfeiting. Significantly, the bacterial inhibition rates of F/CRC against E. coli and S. aureus were 92.14% and 98.72%. F/CRC also showed good antioxidant capability and biosafety. Finally, the packaging test further indicated that F/CRC could delay the browning of bananas and the bacteria growth of chicken samples. This work presents a green and feasible route to produce functional materials with UV-shielding properties for packaging applications.

Development of pH-responsive intelligent and active films based on pectin incorporating Schiff base (Phenylalanine/syringaldehyde) for monitoring and preservation of fruits

This study aimed to develop pectin-based films by incorporating Schiff base compounds (SPS) synthesized by phenylalanine and syringaldehyde. The SEM images showed good compatibility between SPS and pectin matrix. The interaction of SPS and pectin matrix was analyzed by FTIR and XRD. Results indicated that the cross-linking effects between SPS and pectin matrix improved the thermal stability, water resistance and light shielding ability of the films. The incorporation of SPS in the films scavenged more than 80% of DPPH and ABTS free radicals, exhibited sustained antimicrobial ability against S. aureus, E. coli and B. cinerea, and showed significant color changes as pH-responsive films. Especially, the intelligent active coating/films inhibited the quality deterioration of cherry tomatoes and fresh-cut mangoes, and monitored the freshness of fresh-cut mangoes during storage. Therefore, the SPS/PE films have a potential application in maintaining fruit quality and monitoring the freshness of fresh-cut fruit.

Fabrication of jamun seed starch/tamarind kernel xyloglucan bio-nanocomposite films incorporated with chitosan nanoparticles and their application on sapota (Manilkara zapota) fruits

The present work develops bio-nanocomposite packaging films by valorizing agricultural byproducts jamun seed starch (JaSS) and tamarind kernel xyloglucan (XG), and adding varying concentrations of chitosan nanoparticles (ChNPs). The blending of JaSS and XG promotes a dense polymer network in the composite films with enhanced packaging attributes. However, ChNPs incorporation significantly reduced the viscosity and dynamic moduli of the JaSS/XG film-forming solutions. The FTIR and XRD results reveal improved intermolecular interactions and crystallinity. The DSC and TGA thermograms showed improved thermal stability in the ChNP-loaded JaSS/XG films. The addition of 3 % w/w ChNPs significantly enhanced the tensile strength (20.42 MPa), elastic modulus (0.8 GPa), and contact angle (89°), along with reduced water vapor transmission rate (13.26 g/h.m2) of the JaSS/XG films. The films exhibited strong antimicrobial activity against Bacillus cereus and Escherichia coli. More interestingly, the JaSS/XG/ChNPs coating on the sapota fruits retarded the weight loss and color change up to 12 days of storage. Overall, the JaSS/XG/ChNP bio-nanocomposites are promising packaging materials.

Exploring the potential of pullulan-based films and coatings for effective food preservation: A comprehensive analysis of properties, activation strategies and applications

Pullulan is naturally occurring polysaccharide exhibited potential applications for food preservation has gained increasing attention over the last half-century. Recent studies focused on efficient preservation and targeted inhibition using active composite ingredients and advanced technologies. This has led to the emergence of pullulan-based biofilm preservation. This review extensively studied the characteristics of pullulan-based films and coatings, including their mechanical strength, water vapor permeability, thermal stability, and potential as a microbial agent. Furthermore, the distinct characteristics of pullulan, production methods, and activation strategies, such as pullulan derivatization, various compounded ingredients (plant extracts, microorganisms, and animal additives), and other technologies (e.g., ultrasound), are thoroughly studied for the functional property enhancement of pullulan-based films and coatings, ensuring optimal preservation conditions for diverse food products. Additionally, we explore hypotheses that further illuminate pullulan's potential as an eco-friendly bioactive material for food packaging applications. In addition, this review evaluates various methods to improve the efficiency of the film-forming mechanism, such as improving the direct coating process, bioactive packaging films, and implementing layer-by-layer coatings. Finally, current analyses put forward suggestions for future advancement in pullulan-based bioactive films, with the aim of expanding their range of potential applications.

Design and preparation of novel antioxidant and antibacterial films containing procyanidins and phycocyanin for food packaging

The purpose of this study was to design a novel antioxidant and antibacterial film for food packaging using food-grade raw materials. The films were designed and fabricated based on carboxymethyl chitosan and pectin incorporated with procyanidins (PCs) and phycocyanin (Phy) by the tape casting method. The effects of different proportions of PCs and Phy on the properties and functions of the prepared films were studied. The results showed that the thickness of films could range from 55 to 70 μm, with dense network structure and uniform distribution of elements. Compared with C-Film group, the film loaded with PCs and Phy had lower water solubility and swelling rate, and higher tensile strength and elongation at break. FITR and XRD spectra revealed the molecular interaction mechanism among carboxymethyl chitosan, pectin, PCs and Phy, which could effectively endow the films with ultraviolet barrier properties. Moreover, the addition of PCs and Phy could effectively improve the antioxidant capacity and antibacterial effect of films, for example, the free radical scavenging abilities of most films were above 80% when the concentration of PCs was 40 μg mL-1. In view of these functional properties, the prepared film containing PCs and Phy have been successfully used in food packaging, which was proved by the preservation experiment of grapes. This study can provide theoretical and technical guidance for the preparation of biodegradable antibacterial films, and their application in the food packaging field.

Exploring novel organocatalytic-acetylated pea starch blends in the development of hot-pressed bioplastics

Acetylated starch shows enhanced thermal stability and moisture resistance, but its compatibilization with other more hydrophilic polysaccharides remains poor or unknown. In this study, the feasibility of thermomechanically compounding organocatalytically acetylated pea starch (APS), produced at two different degrees of substitution with alkanoyl groups (DSacyl, 0.39 and 1.00), with native pea starch (NPS), high (HMP) and low methoxyl (LMP) citrus pectin, and sugar beet pectin (SBP, a naturally acetylated pectin) for developing hot-pressed bioplastics was studied. Generally, APS decreased hydrogen bonding (ATR-FTIR) and crystallinity (XRD) of NPS films at different levels, depending on its DSacyl. The poor compatibility between APS and NPS or HMP was confirmed by ATR-FTIR imaging. Contrariwise, APS with DSacyl 1 was effectively thermomechanically mixed with the acetylated SBP matrix, maintaining homogeneous distribution within it (ATR-FTIR imaging). APS (any DSacyl) significantly increased the visible/UV light opacity of NPS-based films and decreased their water vapor transmission rate (WVTR, by ca. 11 %) and surface water wettability (by ca. 3 times). In comparison to NPS-APS films, pectin-APS showed higher visible/UV light absorption, tensile strength (ca.2.9-4.4 vs ca.2.4 MPa), and Young's modulus (ca.96-116 vs ca.60-70 MPa), with SBP-APS presenting significantly lower water wettability than the rest of the films.

Fluorescence and pectinase double-triggered chitosan/pectin/calcium propionate/curcumin-β-cyclodextrin complex film for pork freshness monitoring and maintenance

An intelligent and active food packaging film based on chitosan (CS), pectin (P), calcium propionate (CP), and curcumin-β-cyclodextrin complex (Cur-β-CD) was prepared. The CS/P/CP/Cur-β-CD film exhibited improved hydrophobicity (74.78 ± 0.53°), water vapor (4.55 ± 0.16 × 10-11 g·(m·s·Pa)-1), and oxygen (1.50 ± 0.06 × 10-12 g·(m·s·Pa)-1) barrier properties, as well as antioxidant (72.34 ± 3.79 % for DPPH and 86.05 ± 0.14 % for ABTS) and antibacterial (79.41 ± 2.89 % for E. coli and 83.82 ± 3.96 % for S. aureus) activities. The release of CP and Cur could be triggered by pectinase, with their cumulative release reaching 92.62 ± 1.20 % and 42.24 ± 1.15 %, respectively. The CS/P/CP/Cur-β-CD film showed delayed alterations in surface color, pH value, total volatile bases nitrogen, total viable counts, thiobarbituric acid reactive substance, hardness, and springiness of pork. Additionally, the fluorescence intensity of the film gradually decreased. In conclusion, we have developed a pH-responsive film with pectinase-triggered release function, providing a new concept for the design of multi-signal responsive intelligent food packaging.

The reduce of water vapor permeability of polysaccharide-based films in food packaging: A comprehensive review

Polysaccharide-based films are favored in the food packaging industry because of their advantages of green and safe characters, as well as natural degradability, but due to the structural defects of polysaccharides, they also have the disadvantages of high water vapor permeability (WVP), which greatly limits their application in the food packaging industry. To break the limitation, numerous methods, e.g., physical and/or chemical methods, have been employed. This review mainly elaborates the up-to-date research status of the application of polysaccharide-based films (PBFs) in food packaging area, including various films from cellulose and its derivatives, starch, chitosan, pectin, alginate, pullulan and so on, while the methods of reducing the WVP of PBFs, mainly divided into physical and chemical methods, are summarized, as well as the discussions about the existing problems and development trends of PBFs. In the end, suggestions about the future development of WVP of PBFs are presented.

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.

Preparation and characterization of self-standing biofilms from compatible pectin/starch blends: Effect of pectin structure

Pectin structure-miscibility-functionality relationships in starch films remain unknown. In this study, five citrus pectins (CPs) with 17 to 63 % of degree of methyl esterification (DM) and sugar beet pectin (SBP, rich in acetyl moieties and rhamnogalacturonan-I domains) were investigated for composition and structure and, further, blended with pea starch (3:1 starch-pectin weight ratio) to fabricate self-standing films. The incorporation of pectin resulted in a two- to three-fold increase in tensile strength and Young's modulus (up to 52.2 and 1837 MPa, respectively, using CP with low DM) without compromising elongation at break. Starch-SBP films presented the lowest strength among pectin films. Lower film moisture and water vapor permeability were attained with CP of high DM, or with SBP, whereas surface wettability was explained by counteracting factors affecting film compositional heterogeneity. Films made with high methoxyl CP, or with SBP, showed lower overall H-bonding (FTIR) and starch crystallinity (XRD). A DM above 57 % negatively affected the mixing and interfacial adhesion of pectin with starch, as shown by Attenuated Total Reflection-FTIR imaging. Pectins with the lowest purity, presumably with the greatest content in xyloglucan, as suggested by HPAEC, presented ~20 % higher elongation at break than the other films.

Recent advances in edible coatings and their application in food packaging

The food packaging industries are facing the challenge of food waste generation. This can be addressed through the use of edible coating materials. These coatings aid in extending the shelf life of food products, reducing waste. The key components of these coatings include food-grade binding agents, solvents, and fillers. The integration of polysaccharide, protein, lipids, bioactive and composite-based materials with edible coating matrix aids to combat substantial post-harvest loss of highly perishable commodities and elevates the quality of minimally processed food. The aim of this review is to introduce the concept of edible coatings and discuss the different coating materials used in the food industry, along with their properties. Additionally, this review aims to classify the coating types based on characteristic features and explore their application in various food processing industries. This review provides a comprehensive overview of edible coatings, including the integration of polysaccharides, proteins, lipids, bioactive, and composite-based materials into the coating matrix. This review also addresses the significant post-harvest loss of highly perishable commodities and emphasizes the enhancement of quality in minimally processed food. Furthermore, the antimicrobial, anti-corrosive, and edible characteristics are highlighted, showcasing their potential applications in different food packaging industries. Moreover, it also discusses the challenges, safety and regulatory aspects, current trends, and future perspectives, aiming to shed light on the commercialization and future investigation of edible coatings.

Study of the Physical, Chemical, and Structural Properties of Low- and High-Methoxyl Pectin-Based Film Matrices Including Sunflower Waxes

The development of bio-based materials remains one of the most important alternatives to plastic materials. Although research in this field is growing, reporting various materials and methodologies, it is still necessary to increase exploration. The aim of this work was to expand and complement previous research on the preparation and characterization of high- and low-methoxyl pectin films obtained by casting, with the addition of commercial and recovered sunflower waxes. The results showed that the addition of sunflower waxes to the pectin matrix generated some discontinuity in the aggregate, increasing the thickness and roughness of the film. However, due to their hydrophobic nature, the waxes contributed to lower vapor transmission rate values of the films. On the other hand, the low-methoxyl pectin films had a more crystalline structure, which could help to diminish water vapor permeability values, mechanical resistance and rigidity, and improve their elongation. Regarding chemical characteristics, most of the raw materials' chemical groups were found in the resulting films, and the presence of C-H bending due to pectin gelation was observed. Finally, the compatibility and contribution of pectin and sunflower waxes to the production of the films were demonstrated, as well as the possibility of using materials from industrial waste in food packaging applications.

Role of biotechnology in the advancement of biodegradable polymers and functionalized additives for food packaging systems

Biodegradable polymers have shown enormous potential for application in food packaging systems and offer solutions to mitigate the challenges of single-use plastics. Over the past decade, advances in fermentation technology, metabolic engineering of microorganisms, and synthetic biology have enabled the optimization and functionalization of biodegradable polymers for food packaging application. This article provides an overview of the biotechnological approaches/methods used in advancing the production of biopolymers and summarizes the recent developments in the application of functionalized biopolymers for decision-making and quality control. It discusses the current applications and future perspectives of extracellular biopolymers in food systems. Finally, this review highlights the complexities of public acceptance, safety, and government regulations and legislations.

A critical review on valorization of food processing wastes and by-products for pullulan production

Pullulan is a commercially available exopolymer biosynthesized by Aureobasidium pullulans supplemented with nitrogen, carbon and other vital components through submerged and solid-state fermentation. These nutrients are very expensive and it raises the cost for the production of pullulan. Hence, the need of alternative cost-effective raw materials for its production is a prerequisite. Owing to its unique physicochemical features, pullulan has various applications in the food, pharmacological, and biomedical domains. Food industrial wastes generate a considerable number of by-products which accumulates and has a negative influence on the environment. These by-products are made up of proteins, carbohydrates, and other components, can be employed as substrates for the production of pullulan. The present review briefs on the pullulan production using food processing waste and by-products and the elements that impact it. It provides an insight into versatile applications of pullulan in food industries. Various challenges and future prospects in the field of research on pullulan production have been uncovered.

Light calcium carbonate improves pullulan biosynthesis by Aureobasidium pullulans under high concentration of sugar

The effects of light calcium carbonate (CaCO₃) on pullulan biosynthesis by Aureobasidium pullulans NCPS2016 were investigated. Light CaCO₃ enhanced pullulan production by 12.4 % when added to the low concentration of fructose broth compared with K₂HPO₄. Pullulan production was further improved when increasing both the concentrations of light CaCO₃ and fructose. Compared to K₂HPO₄, light CaCO₃ improved the activities of UDP-glucose pyrophosphorylase, α-phosphoglucose mutase, UDP-glucosyltransferase, and glucosyltransferase relevant to pullulan biosynthesis, and the gene transcriptional levels of UDP-glucose pyrophosphorylase, α-phosphoglucose mutase, UDP-glucosyltransferase, and glucose kinase were enhanced. During 30-liter fermentation, 144.3 g/L of purified pullulan was produced from 200 g/L of fructose and 15 g/L of light CaCO₃ within 168 h, with the yield and productivity of 0.72 g/g and 0.86 g/L/h respectively. This is the first report that light CaCO₃ improves pullulan production significantly.

Physicochemical, structural and in vitro gastrointestinal tract release properties of ι-carrageenan/sodium caseinate synbiotic microgels produced by double-crosslinking with calcium ions and transglutaminase

The aim of this study was to develop ι-carrageenan (ιC)/sodium caseinate (NaCas) synbiotic microgels loading Lacticasebacillus paracasei produced by double-crosslinking with calcium ions and different concentrations (0, 5, 10, and 15 U/g protein) of transglutaminase (TGase). The synbiotic microgels were coated/filled with pectic oligosaccharide (POS). Field emission scanning electron microscope (FE-SEM) and X-ray diffraction (XRD) analyses indicated that L. paracasei was successfully microencapsulated in synbiotic microgels. In Fourier transform infrared (FT-IR) analysis, the new formation of covalent and ionic crosslinking was observed in double-crosslinked synbiotic microgels. The encapsulation efficiency of L. paracasei was significantly increased from 87.82 to 97.68 % by increasing the concentration of TGase from 0 to 15 U/g protein, respectively. After exposure to simulated gastric fluid for 2 h and simulated intestinal fluid for 4 h, the survival rate of L. paracasei was significantly increased as the concentration of TGase increased.

Recent advances in prevailing antifogging surfaces: structures, materials, durability, and beyond

In past decades, antifogging surfaces have drawn more and more attention owing to their promising and wide applications such as in aerospace, traffic transportation, optical devices, the food industry, and medical and other fields. Therefore, the potential hazards caused by fogging need to be solved urgently. At present, the up-and-coming antifogging surfaces have been developing swiftly, and can effectively achieve antifogging effects primarily by preventing fog formation and rapid defogging. This review analyzes and summarizes current progress in antifogging surfaces. Firstly, some bionic and typical antifogging structures are described in detail. Then, the antifogging materials explored thus far, mainly focusing on substrates and coatings, are extensively introduced. After that, the solutions for improving the durability of antifogging surfaces are explicitly classified in four aspects. Finally, the remaining big challenges and future development trends of the ascendant antifogging surfaces are also presented.

Biopolymer-Based Sustainable Food Packaging Materials: Challenges, Solutions, and Applications

Biopolymer-based packaging materials have become of greater interest to the world due to their biodegradability, renewability, and biocompatibility. In recent years, numerous biopolymers-such as starch, chitosan, carrageenan, polylactic acid, etc.-have been investigated for their potential application in food packaging. Reinforcement agents such as nanofillers and active agents improve the properties of the biopolymers, making them suitable for active and intelligent packaging. Some of the packaging materials, e.g., cellulose, starch, polylactic acid, and polybutylene adipate terephthalate, are currently used in the packaging industry. The trend of using biopolymers in the packaging industry has increased immensely; therefore, many legislations have been approved by various organizations. This review article describes various challenges and possible solutions associated with food packaging materials. It covers a wide range of biopolymers used in food packaging and the limitations of using them in their pure form. Finally, a SWOT analysis is presented for biopolymers, and the future trends are discussed. Biopolymers are eco-friendly, biodegradable, nontoxic, renewable, and biocompatible alternatives to synthetic packaging materials. Research shows that biopolymer-based packaging materials are of great essence in combined form, and further studies are needed for them to be used as an alternative packaging material.

Pectin from plantain peels: Green recovery for transformation into reinforced packaging films

Plantain peels as agro-waste are generated in the millions of tons per year with no profitable management strategies. On the other hand, the excessive use of plastic packaging threatens the environment and human health. This research aimed to address both problems via a green approach. High-quality pectin was recovered from plantain peels via an enzyme-assisted and ethanol-recycling process. The yield and galacturonic acid (GalA) content of the recovered low methoxy pectin was 12.43% and 25.0%, respectively, when cellulase was added at 50 U per 5 g peel powder, with a significantly higher recovery rate and purity than the pectin products extracted with no cellulase (P ≤ 0.05). The recovered pectin was further integrated and reinforced with beeswax solid-lipid nanoparticles (BSLNs) to fabricate films as a potential alternative packaging material to single-use plastics. The reinforced pectin films showed improved light barrier, water resistance, mechanical, conformational, and morphological properties. This study presents a sustainable strategy to transform plantain peels into pectin products and pectin-based packaging films with broad applications.

UV-blocking biodegradable film based on flaxseed mucilage/pectin impregnated with titanium dioxide and calcium chloride for food packaging applications

A UV blocking and potentially biodegradable composite films are fabricated from flax seed mucilage and pectin with different concentrations of titanium dioxide (TiO₂) and crosslinked with calcium chloride (CaCl₂). This study aimed to evaluate the physical, surface, and optical properties including color, potential biodegradability, and absorption kinetics of the developed film. From the observations made, addition of 5 wt% TiO₂ enhanced UV barrier property with a total color change (ΔE) of 23.441 ± 0.54 and increased its crystallinity to 54.1 % from 43.6 %. Crosslinking agent and TiO₂ resulted in a prolonged period of biodegradation of >21 days when compared to neat film. Also, swelling index of crosslinked film was reduced by 3 times of non-crosslinked films. Surface of the developed films has no cracks and agglomerates as observed from scanning electron microscope. Moisture absorption kinetic study reveals that all the films have best-fit data following a pseudo-second-order kinetic model with a correlation coefficient ≥0.99 and the rate was controlled by inter-particle diffusion. The film with 1 wt% TiO₂ and 5 wt% CaCl₂ showed the lowest rate constants (k₁) of 0.27 and (k₂) of 0.029. The results suggest that this film can be potentially used in food packaging as a UV-blocking layer with potential biodegradability and good moisture resistance as compared to pure flax seed mucilage or pectin films.

Recent progress in pectin extraction, characterization, and pectin-based films for active food packaging applications: A review

Pectin is an abundant complex polysaccharide obtained from various plants. Safe, biodegradable, and edible pectin has been extensively utilized in the food industry as a gelling agent, thickener, and colloid stabilizer. Pectin can be extracted in a variety of ways, thus affecting its structure and properties. Pectin's excellent physicochemical properties make it suitable for many applications, including food packaging. Recently, pectin has been spotlighted as a promising biomaterial for manufacturing bio-based sustainable packaging films and coatings. Functional pectin-based composite films and coatings are useful for active food packaging applications. This review discusses pectin and its use in active food packaging applications. First, basic information and characteristics of pectin, such as the source, extraction method, and structural characteristics, were described. Then, various methods of pectin modification were discussed, and the following section briefly described pectin's physicochemical properties and applications in the food sector. Finally, the recent development of pectin-based food packaging films and coatings and their use in food packaging were comprehensively discussed.

Plasma etching effect on the molecular structure of chitosan-based hydrogels and its biological properties

To reasonably use hydrogels in healthcare field, this study four kinds of chitosan (CTS)-based hydrogels with different molecular structures. With plasma etching, the morphology, chemical groups' proportion, and hydrophilicity of the hydrogel surface were changed. At 40 min of modification, the ratios of CO and NH₂ on the CTS40-based hydrogel surface increased and reached their maximum values of 40.31 % and 89.17 %, respectively. Combined with the changes in hydrophilic chemical groups and the hydrogel's network structure, the hydrogel surface's wettability changed after plasma etching. From the results, CTS40-based hydrogel showed the lowest contact angle (77.40 ± 3.89°) with 80 min modification due to its dense network structure of CTS and appropriate ratio of hydrophilic groups on the surface. With these molecular structural changes, the antibacterial properties of CTS-based hydrogels against Staphylococcus aureus were improved. Moreover, the functional components delivery system coating with these CTS-based hydrogels showed colon-site controlled-release property. The hydrogels also facilitated the growth of Caco2 and Hic cells, which had 72.74 %-453.27 % cell viability of Caco2 cells on the surface. Therefore, the antibacterial property and biocompatibility of plasma modified CTS-based hydrogels have been demonstrated. The mechanism between molecular structure changes of CTS with plasma etching and its properties was discussed, which would provide a promising carrier material for utilizing healthcare field.

Carboxymethylcellulose/agar-based functional film incorporated with nitrogen-doped polyethylene glycol-derived carbon dots for active packaging applications

The present investigation demonstrates the role of nitrogen doping on polyethylene glycol (PEG)-derived carbon dots on optical, antibacterial, and antioxidant activity. CDs' average size and surface charge were determined using transmission electron microscopy (TEM) and a zeta sizer with 2.14 ± 0.6 nm and -20 mV, respectively. Though CDs without N-doping (PCD) did not show any significant antioxidant and antimicrobial activities, the CDs doped with nitrogen (NPCD) showed potent antioxidant (25% and 100% DPPH and ABTS radical scavenging activity) and significant antimicrobial activity against Gram-positive (1.8 cm inhibition zone) and Gram-negative (1.4 cm) bacteria. Both carbon dots were loaded into the carboxymethyl cellulose (CMC)/agar-based film with different concentrations (4 and 8%) and showed a significant increase in the physicochemical properties, and UV-blocking property was increased from 53.7 to 79.9% without sacrificing the transparency. The NPCD-loaded film also showed high antioxidant (DPPH 12.7% and ABTS 67%) and potent antibacterial activity. In particular, the CMC/agar film loaded with 8% NPCD destroyed Escherichia coli and Listeria monocytogenes completely after 6 h of incubation.

3D-Printed Pectin/Carboxymethyl Cellulose/ZnO Bio-Inks: Comparative Analysis with the Solution Casting Method

Bio-inks consisting of pectin (Pec), carboxymethyl cellulose (CMC), and ZnO nanoparticles (ZnO) were used to prepare films by solution casting and 3D-printing methods. Field emission scanning electron microscopy (FE-SEM) was conducted to observe that the surface of samples made by 3D bioprinter was denser and more compact than the solution cast samples. In addition, Pec/CMC/ZnO made by 3D-bioprinter (Pec/CMC/ZnO-3D) revealed enhanced water vapor barrier, hydrophobicity, and mechanical properties. Pec/CMC/ZnO-3D also showed strong antimicrobial activity within 12 h against S. aureus and E. coli O157: H7 bacterial strains compared to the solution cast films. Further, the nanocomposite bio-inks used for 3D printing did not show cytotoxicity towards normal human dermal fibroblast (NDFB) cells but enhanced the fibroblast proliferation with increasing exposure concentration of the sample. The study provided two important inferences. Firstly, the 3D bioprinting method can be an alternative, better, and more practical method for fabricating biopolymer film instead of solution casting, which is the main finding of this work defining its novelty. Secondly, the Pec/CMC/ZnO can potentially be used as 3D bio-inks to fabricate functional films or scaffolds and biomedical applications.