Preparation and Physiochemical Characterization of Bitter Orange Oil Loaded Sodium Alginate and Casein Based Edible Films

Fabrication of bamboo nanocellulose fibril-based food packaging with dual-antimicrobial property

The development of cellulose-based packaging films with excellent antimicrobial properties and biocompatibility has garnered significant attention. In this work, nanocellulose fibrils (NCFs) derived from from bamboo parenchyma cells were utilized to fabricate nanocomposite film with antimicrobial properties. This system exhibited distinct release behaviors for two antimicrobial agents, with the slow release of Ag nanoparticle (AgNP) in the initial stage contributed to delaying food spoilage, while the subsequent pH change in the microenvironment facilitated the release of essential oil of sour orange blossoms (SEO) for secondary antimicrobial activity. Additionally, the composite film demonstrated improved thermal stability and UV blocking capacity. Moreover, AgNP has been proven to enhance the mechanical properties, with the tensile strength of the novel composite film increasing by 34.85 % compared to control group. The water vapor permeability and oxygen permeability of the novel composite film were reduced, which could potentially reduce weight loss and slow down the rate of after-ripening. Following the acidification treatment, the films containing EO@MPN (essential oil encapsulated with metal-polyphenol network) component performed different antimicrobial patterns, indicating their pH-responsive antimicrobial capabilities, and they are effective against both Gram-positive and Gram-negative bacteria. After a 24-h exposure to a food simulant, the release amount of Ag was measured at 67.6 μg/dm2, within the acceptable limit, and the release profile of Ag was characterized. Cytotoxicity and Live/Dead staining tests confirmed that the novel composite film film had no significant toxicity, thus making it safe for application in food preservation. Furthermore, in a 15-day preservation experiment with mangoes, the novel composite film demonstrated the best performance, underscoring its potential as a sustainable antimicrobial packaging material.

Sausage Preservation Using Films Composed of Chitosan and a Pickering Emulsion of Essential Oils Stabilized with Waste-Jujube-Kernel-Derived Cellulose Nanocrystals

The purpose of this study was to prepare Pickering emulsions stabilized by waste jujube kernel cellulose nanocrystals (CNC) using composite essential oils (EOs) (i.e., cinnamon essential oil [CIN] combined with clove essential oil [CL]). The Pickering emulsions were blended with chitosan (CS) to generate a composite film (CS/CNC/EOs Pickering emulsions). We evaluated the mechanical properties, barrier properties, and microstructures of CS/CNC/EOs bio-based packaging films containing different concentrations of EOs. In addition, the fresh-keeping effects of the composite membranes on beef sausages were evaluated over a 12-day storage period. Notably, the EOs exhibited good compatibility with CS. With the increase in the EOs concentration, the droplet size increased, the composite films became thicker, the elongation at break decreased, the tensile strength increased, and the water vapor permeability decreased. When the composite films were used for preserving beef sausages, the antioxidant and antibacterial activity of the membranes improved as the concentration of EOs increased, effectively prolonging the shelf life of the sausages. Composite membranes with an EOs concentration of 2% exerted the best fresh-keeping effects. Overall, owing to their antioxidant and antimicrobial properties, the bio-based composite films prepared using CS/CNC/EOs Pickering emulsions demonstrated immense potential for application in the packaging of meat products.

Biocompatible film based on protein/polysaccharides combination for food packaging applications: A comprehensive review

Protein and polysaccharides are the mostly used biopolymers for developing packaging film and their combination-based composite produced better quality film compared to their single counterpart. The combination of protein and polysaccharides are superior owing to the better physical properties like water resistance, mechanical and barrier properties of the film. The protein/polysaccharide-based composite film showed promising result in active and smart food packaging regime. This work discussed the recent advances on the different types of protein/polysaccharide combinations used for making bio-based sustainable packaging film formulation and further utilized in food packaging applications. The fabrication and properties of various protein/polysaccharide combination are comprehensively discussed. This review also presents the use of the multifunctional composite film in meat, fish, fruits, vegetables, milk products, and bakery products, etc. Developing composite is a promising approach to improve physical properties and practical applicability of packaging film. The low water resistance properties, mechanical performance, and barrier properties limit the real-time use of biopolymer-based packaging film. The combination of protein/polysaccharide can be one of the promising solutions to the biopolymer-based packaging and thus recently many works has been published which is suitable to preserve the shelf life of food as well trace the food spoilage during food storage.

Novel hydroxyl-terminated hyperbranched polymer as a synergistic modifier with tannin for preparation of casein-based films with superior performance

A hyperbranched poly (titanium oxide) (HBPTi) with hydroxyl terminal groups was synthesized via polycondensation reaction as a synergistic modifier with tannin to promote performance of casein-based composite film. The synergistic effects of HBPTis, acquiring different hyperbranched structures, with tannin on the microstructure, mechanical characteristics, barrier against water vapor, and thermal stability of casein-based film were investigated in this work. The tensile strength of the composite films increased from 7.6 MPa to 22.1 MPa, which accounts for 190.79 % increase after the addition of HBPTi compared to casein-tannin films modified with glycerol. The casein-tannin films with the help of HBPTi presented excellent water vapor permeation, thermal stability, and showed nearly 100 % UV absorption in the range 200-400 nm. Additionally, the microstructure of HBPTi modified casein-tannin films tend to be more compact due to the promoted interaction of casein-tannin composite aided by covalent bonding and/or other types of bonding between casein, tannin and HBPTi. Therefore, associative modification using such hyperbranched polymers and tannins provides extendable application value for casein-based films especially as food packaging materials and for other fields as well.

New insights into essential oil nano emulsions loaded natural biopolymers recent development, formulation, characterization and packaging applications: A comprehensive review

Customer demand for wholesome diets has spurred researchers to explore preservative-free methods for maintaining food product quality. Nano emulsion-based coatings and films are seen as sustainable solutions for extending the shelf life of fresh produce. These innovations are driving progress in various industries. Nano emulsion techniques offer effective encapsulation of bioactive compounds due to their small droplet size, stability, and enhanced activity. This review highlights the preparation and manufacturing methods of biopolymer-based nano emulsions containing essential oils, which are used as edible coatings and films over the past decade, representing the first comprehensive review paper on this topic to encompass research from the past ten years. The characterization and application of these coatings and films are also discussed. It has been revealed that essential oils can be successfully incorporated into nano emulsion delivery system with different biopolymers. These edible coatings and films help delay or prevent oxidation in various food products, enhancing their quality and safety during storage. They present a green, sustainable, and biodegradable solution for protecting fresh foods in the industry. Essential oil biopolymer nano emulsions not only extend shelf life but also offer protection against hazards, contributing to consumer trust in food safety and quality. This technology holds promise for delivering healthier food options in the marketplace. The current review thus provides an updated overview of the latest literature on EO nano emulsions as active agents in the advancement of edible coatings and films.

Effect of clove essential oil nanoemulsion on physicochemical and antioxidant properties of chitosan film

This study evaluated the physicochemical and antioxidant properties of clove essential oil (0, 0.2, 0.4, 0.6, 0.8, 1.0 % v/v) nanoemulsion (CEON) loaded chitosan-based films. With the increasing concentrations of the CEON, the thickness, b* and ΔE values of the films increased significantly (P < 0.05), while L* and light transmission dropped noticeably (P < 0.05). The hydrogen bonds formed between the CEON and chitosan could be demonstrated through Fourier-transform infrared spectra, indicating their good compatibility and intermolecular interactions. Furthermore, the added CEON considerably reduced the crystallinity and resulted in a porous structure of the films, as observed through X-ray diffraction plots and scanning electron microscopy images, respectively. This eventually led to a drop in both tensile strength and moisture content of the films. Moreover, the antioxidant properties were significantly enhanced (P < 0.05) with the increase in the amount of clove essential oil (CEO) due to the encapsulation of CEO by the nanoemulsion. Films containing 0.6 % CEO had higher elongation at break, higher water contact angle, lower water solubility, lower water vapor permeability, and lower oxygen permeability than the other films; therefore, such films are promising for application in meat preservation.

Pectin/sodium alginate films tailored with Acetyl-11-keto-beta-boswellic acid for active packaging

The present study aimed to develop food packaging films by using a combination of pectin (PE) and sodium alginate (SA) enriched with Acetyl-11-keto-beta-boswellic acid (AKBA) as a functional or active ingredient. The fabricated films underwent comprehensive evaluation of their morphological, chemical, mechanical, barrier, optical, thermal, antioxidant, and antimicrobial properties. SEM and FTIR analysis showed that AKBA had good compatibility with film-forming components. The AKBA-loaded film samples exhibited a decrease in their barrier properties and tensile strength, but enhancements in both elongation at break and thickness values was observed. With the addition of AKBA, a significant increase (p < 0.05) in the ultraviolet barrier properties of the films and total colour variation (ΔE) was observed. TGA analysis of the films unveiled an improvement in thermal resistance with the incorporation of AKBA. Moreover, the films loaded with AKBA exhibited potent antioxidant activity in the ABTS and DPPH assay methods. Disk diffusion analysis showed the antimicrobial activity of AKBA-loaded films against P. aeruginosa, highlighting the potential of AKBA as a natural antimicrobial agent for the safety of food products. The results demonstrate the practical application of PE and SA active films loaded with AKBA, particularly within the food packaging industry.

Development and Analysis of Silver Nitroprusside Nanoparticle-Incorporated Sodium Alginate Films for Banana Browning Prevention

Banana (Musa acuminate) has been popular among consumers worldwide due to its rich nutrients and minerals. However, bananas are highly susceptible to the physical and biological factors that lead to postharvest loss during transportation and storage. In this work, novel sodium alginate (SA) films incorporated with silver nitroprusside nanoparticles (AgNNPs) were prepared to extend the shelf life of bananas through antibacterial and antioxidant coating. The results exhibited that AgNNPs were cubical and that their size was <500 nm, with metal composition being Ag and Fe. Additionally, the incorporation of AgNNPs in the SA film was seen in FE-SEM and zeta analysis, with an average size of about 365.6 nm. Furthermore, the functional and crystalline properties of AgNNPs were assessed through FTIR and XRD. Transmittance testing of the SA-AgNNPs films confirmed they have good UV barrier properties. SA-AgNNPs films exhibited excellent high antibacterial activity against foodborne pathogens including L. monocytogenes, S. enterica, and E. coli at the concentration of 500 µg/mL. Moreover, during the storage of bananas, SA-AgNNPs nanocomposite coatings act as a barrier to microbial contamination and slow down the ripening of bananas. As a result, compared with SA-coated and uncoated bananas, SA-AgNNPs-coated bananas exhibited the lowest weight loss and lowest total bacterial colonies, thus greatly extending their shelf life. Particularly when coated with SA-AgNNPs films, total bacterial colonies (TBC) in the banana peel and pulp were as low as 1.13 × 103 and 51 CUF/g on the ninth day of storage, respectively. Our work offers an efficient strategy to improve the quality of bananas during the postharvest period, with extensive applications in fruit preservation and food packing.

Enhancement of Strawberry Shelf Life via a Multisystem Coating Based on Lippia graveolens Essential Oil Loaded in Polymeric Nanocapsules

Strawberries (Fragaria xannanasa) are susceptible to mechanical, physical, and physiological damage, which increases their incidence of rot during storage. Therefore, a method of protection is necessary in order to minimize quality losses. One way to achieve this is by applying polymer coatings. In this study, multisystem coatings were created based on polymer nanocapsules loaded with Lippia graveolens essential oil, and it was found to have excellent optical, mechanical, and water vapor barrier properties compared to the control (coating formed with alginate and with nanoparticles without the essential oil). As for the strawberries coated with the multisystem formed from the polymer nanocapsules loaded with the essential oil of Lippia graveolens, these did not present microbial growth and only had a loss of firmness of 17.02% after 10 days of storage compared to their initial value. This study demonstrated that the multisystem coating formed from the polymer nanocapsules loaded with the essential oil of Lippia graveolens could be a viable alternative to preserve horticultural products for longer storage periods.

Improving the performance of Ca-alginate films through incorporating zein-caseinate nanoparticles-loaded cinnamaldehyde

This study aimed to fabricate and characterize the Ca-alginate films functionalized by incorporating zein nanoparticles containing cinnamaldehyde (CA). The zein nanoparticles were coated with Na-caseinate (CN) to inhibit the precipitation of zein in the alginate solution. Afterward, the physical, mechanical, morphological, and barrier properties of the nanocomposite films were evaluated. The particle sizes of different zein nanoparticles (with/without CA and CN) ranged between 43.58 and 251.66 nm. The addition of free CA, zein, and CN nanoparticles significantly increased the thickness, opacity, thermal stability, and water contact angle and improved the mechanical properties of the films. The water vapor permeability was not affected but the antimicrobial activity was improved on fresh-cut apples. The lightness of nanocomposite films decreased and the yellowness and greenness increased. According to SEM and AFM images, a dense and organized interlayer arrangement with a rougher surface was detected in the nanocomposite films. FTIR analysis showed that no new interactions were formed between the Ca-alginate and zein/CN nanoparticles. An excellent sustained CA release into the water was observed for the CA/zein nanoparticles-loaded alginate films. Overall, the results showed that Ca-alginate nanocomposite films of zein nanoparticles have good potential to carry hydrophobic bioactive compounds for specific pharmaceutical and food applications.

Bioactive interpenetrating hybrids of poly(hydroxyethyl methacrylate-co-glycidyl methacrylate): Effect of polysaccharide types on structural peculiarities and multifunctionality

Crosslinked poly(hydroxyethyl methacrylate-co-glycidyl methacrylate) hybrids prepared in the same experimental condition by adding various polysaccharides of different chemical types; inulin, Na-alginate, starch and κ-Carrageenan were qualitatively compared. The results are presented to extract relevant physicochemical properties for qualitative comparison of structures within the same synthesis batch. Elastic properties and swelling degree of hybrids can be tightly regulated using different types of polysaccharides and by controlling effective cross-linking density. Addition of κ-Carrageenan to copolymer network increased elastic modulus by 6.2-fold in as-prepared state, but greatest increase in effective cross-link density through swelling was observed in alginate-doped gels. An overshooting effect was observed for alginate-doped hybrids; swelling first to a maximum, followed by a gradual deswelling until equilibrium was reached. Compressive elasticity of hybrids is mainly controlled by type of polysaccharides and cross-linking density but also depends on polymerization temperature. The obtained hybrid gels displayed excellent adsorption performance for methyl orange (MO). The highest adsorption capacity was reached with inulin-doped hybrids. The rate of adsorption was very fast and reached equilibrium with 98.9 % efficiency at about 90 min. This approach to modify the properties of hybrid gels with various types of polysaccharides may find wide use in biomaterials and water purification applications.

Animal derived biopolymers for food packaging applications: A review

It is essential to use environment-friendly, non-toxic, biodegradable and sustainable materials for various applications. Biopolymers are derived from renewable sources like plants, microorganisms, and agricultural wastes. Unlike conventional polymers, biopolymer has a lower carbon footprint and contributes less to greenhouse gas emission. All biopolymers are biodegradable, meaning natural processes can break them down into harmless products such as water and biomass. This property is of utmost importance for various sustainable applications. This review discusses different classifications of biopolymers based on origin, including plant-based, animal-based and micro-organism-based biopolymers. The review also discusses the desirable properties that are required in materials for their use as packaging material. It also discusses the different processes used in modifying the biopolymer to improve its properties. Finally, this review shows the recent developments taking place in using specifically animal origin-based biopolymer and its use in packaging material. It was observed that animal-origin-based biopolymers, although they possess unique properties however, are less explored than plant-origin biopolymers. The animal-origin-based biopolymers covered in this review are chitosan, gelatin, collagen, keratin, casein, whey, hyaluronic acid and silk fibroin. This review will help in renewing research interest in animal-origin biopolymers. In summary, biopolymer offers a sustainable and environment-friendly alternative to conventional polymers. Their versatility, biocompatibility will help create a more sustainable future.

Novel applications of black pepper essential oil as an antioxidant agent in sodium caseinate and chitosan based active edible films

In the current study, sodium caseinate and chitosan-based composite edible films were developed with the incorporation of black pepper (Piper nigrum) essential oil (BPO) in various concentrations (0.05, 0.1 and 0.15 %) for potential food packaging applications. The chemical composition of BPO was determined using GCMS and the major compound detected were β-caryophyllene, limonene, β-phellandren, pinene, copaene and α-humulene. The addition of BPO resulted in an increase in the thickness, EAB, WVP, moisture content and swelling index values of the films; however, the TS and water solubility decreased. The inclusion of BPO led to a substantial enhancement in the DPPH and ABTS radical scavenging capabilities of the edible films. SEM micrographs demonstrated intermolecular interaction between BPO, sodium caseinate, and chitosan. FTIR spectra confirmed the interaction of the functional groups of the polymers and BPO. The incorporation of the BPO increased the crystallinity of the films. Moreover, the thermal analysis including TGA, DSC and DTG demonstrated an increase in the thermal stability of the edible films with the addition of the BPO. These findings demonstrated that sodium caseinate and chitosan composite based edible films loaded with BPO can be used as sustainable active food packaging material.

Effect of Edible Coating Made from Arrowroot Flour and Kaffir Lime Leaf Essential Oil on the Quality Changes of Pork Sausage under Prolonged Refrigerated Storage

Edible coatings are pivotal in enhancing the quality of processed meat products, acting as barriers to environmental and microbial influences by adhering directly to the food surface. Arrowroot flour, a widely produced edible tuber in Thailand, is uncharted in terms of its capability and effectiveness as an edible coating on food materials. This study aims to elucidate the composition and spectral properties of arrowroot tuber flour (ATF) to discern its viability as an edible coating for pork sausages. ATF exhibited a composition predominantly featuring carbohydrates (74.78%), moisture (9.59%), and protein (8.89%), underlining its appropriateness as an edible coating. Rapid visco amylograph revealed ATF's significant pasting capability. This study incorporated kaffir lime leaves essential oil (KEO) into the ATF coating in diverse concentrations (0-3%). Fourier-transform Infrared spectroscopy illuminated characteristic peaks and bands, showing observable shifts with the integration of KEO, yet the majority of peak placements remained essentially unchanged. The microstructure of the coatings maintained its homogeneity at heightened KEO concentrations, reflecting compatibility with ATF. The efficacy of the ATF-KEO coatings was evaluated on pork sausages, using uncoated samples as controls. While color modifications were evident, coated sausages maintained consistent moisture content, water activity, and pH levels throughout the storage duration. The coated samples also manifested enhanced textural attributes and a decline in lipid oxidation, as evidenced by reduced TBARS levels compared to controls. A subsequent microbial examination corroborated the inhibitory capacity of the ATF-KEO coatings on the microbial proliferation in pork sausages, encapsulating Total Viable Count (TVC), psychrotrophic bacteria, and lactic acid bacteria. In conclusion, the findings substantiate the promising application of ATF, especially in synergy with KEO, as a proficient edible coating for meat products. This combination aids in preserving color and texture, impeding microbial advancement, and moderating lipid oxidation, thereby contributing to the overall quality and safety of the products.

Green, Eco-Friendly, Highly Biocompatible and Bioactive Nanocomposite-Based Biopolymers Loaded with ZnO@Fe3O4 Nanoparticles

Biocompatibility is a major concern for promising multifunctional bioactive materials. Unfortunately, bioactive materials lack biocompatibility in some respects, so active ingredient formulations are urgently needed. Bimetallic nanoparticles have demonstrated drawbacks in stabilized biocompatible formulations. This study examined the preparation of biomaterial-based multifunctional biopolymers via an eco-friendly formulation method using ultrasound. Bimetallic zinc oxide/iron oxide (magnetic form) nanoparticles (ZnO@Fe3O4NPs) were formulated using casein and starch as capping agents and stabilizers. The formulated nanocomposite was characterized using ultraviolet-visible spectroscopy (UV-vis), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HR-TEM). Herein, the formulated nanocomposite was shown to have a thermally stable nanostructure, and the bimetallic ZnO@Fe3O4 NPs were measured as 85 nm length and 13 nm width. Additionally, the biocompatibility test showed its excellent cytocompatibility with Wi 38 and Vero normal cell lines, with IC50 550 and 650 mg/mL, respectively. Moreover, the antimicrobial activity was noted against six pathogens that are represent to the most common pathogenic microbes, with the time required for killing of bacteria and unicellular fungi being 19 h and 61 h for filamentous fungi with remarket an excellent antioxidant activity.

Modulation of physicochemical properties and antimicrobial activity of sodium alginate films through the use of chestnut extract and plasticizers

Due to the growing demand for robust and environmentally friendly antimicrobial packaging materials, biopolymers have recently become extensively investigated. Although biodegradable biopolymers usually lack mechanical properties, which makes it inevitable to blend them with plasticizers. The purpose of this study was to investigate plasticization efficiency of bio-based plasticizers introduced into sodium alginate compositions containing chestnut extract and their effect on selected film properties, including primarily mechanical and antibacterial properties. The films were prepared by the casting method and sodium alginate was cross-linked with calcium chloride. Six different plasticizers, including three commercially available ones (glycerol, epoxidized soybean oil and palm oil) and three synthesized plasticizers that are mixtures of bio-based plasticizers, were used to compare their influence on the film properties. Interactions between the polymer matrix and the plasticizers were investigated using Fourier transform infrared spectroscopy. The morphological characteristics of the films were characterized by scanning electron microscopy. Thermal properties, tensile strength, elongation at break, hydrophilic, and barrier properties of the obtained films were also determined. To confirm the obtaining of active films through the use of chestnut extract and to study the effect of the proposed plasticizers on the antibacterial activity of the extract, the obtained films were tested against bacteria cultures. The final results showed that all of the obtained films exhibit a hydrophilic character and high barrier effect to oxygen, carbon dioxide and water vapor. In addition, sodium alginate films prepared with chestnut extract and the plasticizer proposed by us, showed better mechanical and antimicrobial properties than the films obtained with chestnut extract and the commercially available plasticizers.

Development of probiotic loaded multilayer microcapsules incorporated into dissolving microneedles for potential improvement treatment of vulvovaginal candidiasis: A proof of concept study

Vulvovaginal candidiasis (VVC) is a vaginal infection caused by abnormal growth of Candida sp., especially Candida albicans, in the vaginal mucosa. A shift in vaginal microbiota is prominent in VVC. The presence of Lactobacillus plays a vital role in maintaining vaginal health. However, several studies have reported resistance of Candida sp. against azoles drugs, which is recommended as VVC treatment. The use of L. plantarum as a probiotic would be an alternative to treat VVC. In order to exert their therapeutic activity, the probiotics needed to remain viable. Multilayer double emulsion was formulated to obtain L. plantarum loaded microcapsules (MCs), thus improving its viability. Furthermore, a vaginal drug delivery system using dissolving microneedles (DMNs) for VVC treatment was developed for the first time. These DMNs showed sufficient mechanical and insertion properties, dissolved rapidly upon insertion, facilitating probiotic release. All formulations proved non-irritating, non-toxic, and safe to apply on the vaginal mucosa. Essentially, the DMNs could inhibit the growth of Candida albicans up to 3-fold than hydrogel and patch dosage forms in ex vivo infection model. Therefore, this study successfully developed the formulation of L. plantarum-loaded MCs with multilayer double emulsion and its combination in DMNs for vaginal delivery to treat VVC.

Fabrication, Characterization, and Antioxidant Potential of Sodium Alginate/Acacia Gum Hydrogel-Based Films Loaded with Cinnamon Essential Oil

Several studies have reported the advantages of incorporating essential oils in hydrogel-based films for improving their physiochemical and antioxidant attributes. Cinnamon essential oil (CEO) has great potential in industrial and medicinal applications as an antimicrobial and antioxidant agent. The present study aimed to develop sodium alginate (SA) and acacia gum (AG) hydrogel-based films loaded with CEO. Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), and texture analysis (TA) were performed to analyze the structural, crystalline, chemical, thermal, and mechanical behaviour of the edible films that were loaded with CEO. Moreover, the transparency, thickness, barrier, thermal, and color parameters of the prepared hydrogel-based films loaded with CEO were also assessed. The study revealed that as the concentration of oil in the films was raised, the thickness and elongation at break (EAB) increased, while transparency, tensile strength (TS), water vapor permeability (WVP), and moisture content (MC) decreased. As the concentration of CEO increased, the hydrogel-based films demonstrated a significant improvement in their antioxidant properties. Incorporating CEO into the SA-AG composite edible films presents a promising strategy for producing hydrogel-based films with the potential to serve as food packaging materials.

The Effect of Sage (Salvia sclarea) Essential Oil on the Physiochemical and Antioxidant Properties of Sodium Alginate and Casein-Based Composite Edible Films

The aim of this study was to examine the effect of Sage (Salvia sclarea) essential oil (SEO) on the physiochemical and antioxidant properties of sodium alginate (SA) and casein (CA) based films. Thermal, mechanical, optical, structural, chemical, crystalline, and barrier properties were examined using TGA, texture analyzer, colorimeter, SEM, FTIR, and XRD. Chemical compounds of the SEO were identified via GC–MS, the most important of which were linalyl acetate (43.32%) and linalool (28.51%). The results showed that incorporating SEO caused a significant decrease in tensile strength (1.022–0.140 Mpa), elongation at break (28.2–14.6%), moisture content (25.04–14.7%) and transparency (86.1–56.2%); however, WVP (0.427–0.667 × 10−12 g·cm/cm2·s·Pa) increased. SEM analysis showed that the incorporation of SEO increased the homogeneousness of films. TGA analysis showed that SEO-loaded films showed better thermal stability than others. FTIR analysis revealed the compatibility between the components of the films. Furthermore, increasing the concentration of SEO increased the antioxidant activity of the films. Thus, the present film shows a potential application in the food packaging industry.

Effects of grape seed oil nanoemulsion on physicochemical and antibacterial properties of gelatin‑sodium alginate film blends

The present study aimed to evaluate the impact of incorporating grape seed oil (GSO) nanoemulsion (NE) at varying concentrations into the film matrix on the physicochemical and antimicrobial properties of the resulting films. In this study, ultrasonic treatment was used to prepare GSO-NE, and different levels (2, 4, and 6 %) of nanoemulsioned GSO were incorporated into gelatin (Ge)/sodium alginate (SA)-based films to produce films with improved physical and antibacterial properties. The results revealed that incorporation of GSO-NE at 6 % concentration decreased the tensile strength (TS) and puncture force (PF) significantly (p < 0.05). The whiteness index (WI) of the films decreased from 63.4 to 47.79, while the total color change (ΔE) increased significantly (p < 0.05) with the increase in GSO-NE concentration. Thermogravimetric analysis (TGA) results showed that GSO-NE at different concentrations had improved the thermal stability of Ge/SA-based films. The incorporation of GSO-NE into the films led to the formation of a slightly porous structure. The incorporation of GSO-NE at 4 and 6 % concentrations decreased the water vapor permeability (WVP), moisture content (MC) %, and water solubility (WS) % significantly (p < 0.05). All composite films exhibited hydrophobic surfaces with contact angles θ > 90°. Ge/SA/GSO-NE films were found to be effective against both Gram-positive and Gram-negative bacteria. The prepared active films containing GSO-NE had a high potential for preventing food spoilage in food packaging.

Physicochemical Characterization and Antioxidant Properties of Chitosan and Sodium Alginate Based Films Incorporated with Ficus Extract

Aqueous extract of fruit obtained from Ficus racemosa enriched with phenolic components was used for the first time to fabricate chitosan (CS) and sodium alginate (SA)-based edible films. The edible films supplemented with Ficus fruit aqueous extract (FFE) were characterized physiochemically (using Fourier transform infrared spectroscopy (FT-IR), Texture analyser (TA), Thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD), and colourimeter) and biologically (using antioxidant assays). CS-SA-FFA films showed high thermal stability and high antioxidant properties. The addition of FFA into CS-SA film decreased transparency, crystallinity, tensile strength (TS), and water vapour permeability (WVP) but ameliorate moisture content (MC), elongation at break (EAB) and film thickness. The overall increase in thermal stability and antioxidant property of CS-SA-FFA films demonstrated that FFA could be alternatively used as a potent natural plant-based extract for the development of food packaging material with improved physicochemical and antioxidant properties.

A New Method to Determine Antioxidant Activities of Biofilms Using a pH Indicator (Resazurin) Model System

Biopolymeric films were prepared with gelatin, plasticizer, and three different types of antioxidants (ascorbic acid, phytic acid, and BHA) corresponding to different mechanisms in activity. The antioxidant activity of films was monitored for 14 storage days upon color changes using a pH indicator (resazurin). The instant antioxidant activity of films was measured by a DPPH free radical test. The system using resazurin was composed of an agar, an emulsifier, and soybean oil to simulate a highly oxidative oil-based food system (AES-R). Gelatin-based films (GBF) containing phytic acid showed higher tensile strength and energy to break than all other samples due to the increased intermolecular interactions between phytic acid and gelatin molecules. The oxygen barrier properties of GBF films containing ascorbic acid and phytic acid increased due to the increased polarity, while GBF films containing BHA showed increased oxygen permeability compared to the control. According to "a-value" (redness) of the AES-R system tested with films, films incorporating BHA showed the most retardation of lipid oxidation in the system. This retardation corresponds to 59.8% antioxidation activity at 14 days, compared with the control. Phytic acid-based films did not show antioxidant activity, whereas ascorbic acid-based GBFs accelerated the oxidation process due to its prooxidant activity. The comparison between the DPPH free radical test and the control showed that the ascorbic acid and BHA-based GBFs showed highly effective free radical scavenging behavior (71.7% and 41.7%, respectively). This novel method using a pH indicator system can potentially determine the antioxidation activity of biopolymer films and film-based samples in a food system.

Physicochemical and Antimicrobial Characterization of Chitosan and Native Glutinous Rice Starch-Based Composite Edible Films: Influence of Different Essential Oils Incorporation

Biopolymer-based edible packaging is an effective way of preserving food while protecting the environment. This study developed an edible composite film using chitosan and native glutinous rice starch (NGRS) and incorporated essential oils (EOs) such as garlic, galangal, turmeric, and kaffir lime at fixed concentrations (0.312 mg/mL) to test its physicochemical and antimicrobial properties. The EO-added films were found to significantly improve the overall color characteristics (lightness, redness, and yellowness) as compared to the control film. The control films had higher opacity, while the EO-added films had slightly reduced levels of opacity and produced clearer films. The tensile strength and elongation at break values of the films varied among the samples. The control samples had the highest tensile strength, followed by the turmeric EO-added samples. However, the highest elongation at break value was found in the galangal and garlic EO-added films. The Young's modulus results showed that garlic EO and kaffir lime EO had the lowest stiffness values. The total moisture content and water vapor permeability were very low in the garlic EO-added films. Despite the differences in EOs, the Fourier-transform infrared spectroscopy (FTIR) patterns of the tested films were similar among each other. Microstructural observation of the surface and cross-section of the tested edible film exhibited smooth and fissureless patterns, especially in the EO-added films, particularly in the galangal and kaffir lime EO-added films. The antimicrobial activity of the EO-added films was highly efficient against various gram-positive and gram-negative pathogens. Among the EO-added films, the garlic and galangal EO-added films exhibited superior inhibitory activity against Escherichia coli, Salmonella Typhimurium, Listeria monocytogenes, Staphylococcus aureus, and Pseudomonas fluorescence, and turmeric and kaffir lime EO-added films showed potential antimicrobial activity against Lactobacillus plantarum and L. monocytogenes. Overall, this study concludes that the addition of EOs significantly improved the physicochemical and antimicrobial properties of the CH-NGRS-based edible films, making them highly suitable for food applications.

Nano-Encapsulation of Citrus Essential Oils: Methods and Applications of Interest for the Food Sector

Citrus essential oils possess many health-promoting benefits and properties of high interest in the food and agri-food sector. However, their large-scale application is limited by their sensitivity to environmental factors. Nanostructures containing citrus essential oils have been developed to overcome the high volatility and instability of essential oils with respect to temperature, pH, UV light, etc. Nanostructures could provide protection for essential oils and enhancement of their bioavailability and biocompatibility, as well as their biological properties. Nano-encapsulation is a promising method. The present review is mainly focused on methods developed so far for the nano-encapsulation of citrus essential oils, with emphasis on lipid-based (including liposomes, solid lipid nanoparticles, nanostructured lipid particles, and nano- and micro-emulsions) and polymer-based nanostructures. The physico-chemical characteristics of the obtained structures, as well as promising properties reported, with relevance for the food sector are also discussed.