Preparation and properties of films loaded with cellulose nanocrystals stabilized Thymus vulgaris essential oil Pickering emulsion based on modified tapioca starch/polyvinyl alcohol

Active starch-based film using polyvinyl alcohol and chlorogenic acid for strawberry preservation: A comparative analysis of mechanical, barrier, and antibacterial properties

The broad application of starch films has been significantly limited by their insufficient hydrophobicity and antibacterial activity. To overcome these challenges, this study developed a new starch film by incorporating polyvinyl alcohol (PVA) and chlorogenic acid. The study explored the impact of PVA polymerization on the physical and functional characteristics of the resulting films, with particular emphasis on enhancing antimicrobial functionality by incorporating chlorogenic acid. Scanning electron microscopy (SEM) and rheological tests demonstrated the excellent compatibility and exceptional film-forming performance. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses validated the presence of intermolecular entanglements and hydrogen bonding within the films. Incorporating PVA with a polymerization degree of 2400 resulted in a contact angle (CA) of 79.81 ± 1.74°, a water absorption capacity (WAC) of 10.29 ± 0.71 %, and a water vapor permeability (WVP) of (0.44 ± 0.11) × 10-11 g × m-1 × s-1 × Pa-1. Notably, the SCP 2488 film exhibited superior mechanical properties, including the highest Young's modulus of 71.29 MPa, tensile strength of 11.77 MPa, and elongation at break of 106.75 %. Additionally, such a modified film displayed enhanced UV-blocking performance and antibacterial efficacy. Consequently, the SCP 2488 film showed great potential for maintaining the freshness and quality of strawberries.

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.

Utilization of potassium carbonate-olive oil solutions for wax removal from fruits: Investigation of mode of action using a model gelatin-based film system

This study evaluated a potassium carbonate-olive oil solution's efficacy in removing a wax from gelatin films (model surfaces). The solution (pH 12.15-12.40) was most effective with 1 % olive oil. Dipping treatment increased wax-free film thickness by 89 % and wax-containing films by 36 %, while reducing density by 50 % and 21 %, respectively. Optical analysis confirmed wax removal, showing a 20 % drop in whiteness and 144 % higher opacity in wax-containing films. Thermal analysis revealed a 35 % lower wax melting enthalpy and 28 % less mass loss in treated films. FTIR spectra showed reduced ester CO peak intensity (1735 cm-1), confirming hydrolysis. Post-treatment, the solution's particle size grew to 2138 nm, zeta potential fell to 20.4 mV, and surface tension dropped to 40.94 mN/m. Microscopy revealed increased particle aggregation with wax-containing films. These results demonstrate the potassium carbonate-olive oil solution's effectiveness in wax removal from gelatin film surfaces through hydrolysis, emulsification, and solubilization mechanisms.

Fabrication and characterization of Artemisia sphaerocephala Krasch. Gum-based active films containing coriander essential oil emulsion for meat preservation

Bio-based packaging holds substantial prospects due to the inherent non-toxic property and biodegradability. The potential for practical applications would be improved if the requirements of antimicrobial, antioxidant and mechanical properties could be met simultaneously. This work utilized Artemisia sphaerocephala Krasch. Gum (ASKG) (film-forming matrix) for forming the active film by adding coriander essential oil emulsion (COE) at different concentrations. The active films were systematically tested for their physicochemical properties and evaluated for their freshness preservation effect on refrigerated lamb and chicken. The results indicated that emulsion incorporation reduced the water sensitivity of the films while enhancing their barrier, mechanical, antioxidant, and antibacterial properties. Specifically, compared to the control ASKG film, the water solubility of the active film decreased from 42.55 % to 38.39 %, while the tensile strength (TS) and elongation at break (EAB) increased to 9.34 MPa and 62.38 %, respectively. Additionally, the active film demonstrated a high capacity for radical scavenging, with maximum 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azido-bis(3-ethylbenzothiazoline-6-sulphonate) diammonium salt (ABTS) radical scavenging rates of 49.87 % and 72.00 %, respectively. Combined with its antibacterial properties against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) the active film can extend the shelf life of lamb and chicken. In summary, the prepared ASKG active film exhibits excellent comprehensive properties and holds significant potential as a packaging material for fresh meat preservation.

Development and characterization of corn starch-based films enhanced with Chlorella vulgaris nanocellulose-stabilized Pickering emulsion of Zanthoxylum bungeanum essential oil for cherry tomato preservation

To reduce plastic usage in food packaging, this study developed an active composite film, named CNZC, by incorporating Chlorella vulgaris derived-cellulose nanocrystals-stabilized ZBEO Pickering emulsions into a corn starch (CS) matrix for cherry tomatoes preservation. Microalgae are a sustainable source of cellulose nanocrystals (CNC) due to their rapid growth and low resource demands, offering potential for sustainable packaging. Zanthoxylum bungeanum essential oil (ZBEO) was chosen as an active component. The overall properties of 1.0-CNZC and 2.0-CNZC films were enhanced compared to CS films. CNC-stabilized Pickering emulsions facilitated the uniform dispersion of ZBEO, enhancing continuity of films. Besides, CNZC films were found to exhibit enhanced antioxidant and antimicrobial properties, attributed to the presence of monoterpenes, alcohols, and ketones in ZBEO, which terminate free radical chain reactions and increase cell permeability. To evaluate preservation performance, the 2.0-CNZC film was selected for cherry tomato preservation experiments, showing its ability to reduce weight loss, retaining acidity, and stabilizing total soluble solids levels. These results presented CNZC films as promising candidates for active composite packaging materials.

Preparation, characterization, and antibacterial properties of a soybean protein isolate/gelatin composite film containing rosemary-modified bentonite and application of fresh lemon slices

To address the rapid deterioration of fruit slices, soy protein isolate (SPI) and gelatin (GEL) composite films were optimized for food packaging using rosemary-modified bentonite (RB) as an active ingredient and glycerol as a plasticizer to enhance flexibility. Composite films with RB demonstrated superior ultraviolet-visible (UV-Vis) light barrier properties, increased opacity, and enhanced mechanical performance, achieving a tensile strength of 2.27 MPa. Barrier properties were significantly improved, with reduced water vapor transmission rate (1.85 × 10-3 g·m-2·s-1) and oxygen permeability (6.69 × 10-3 g·m-2·s-1), alongside elevated hydrophobicity, antibacterial activity, and antioxidant capacity (DPPH scavenging activity: 54.74 %; ABTS scavenging activity: 53.89 %). In preservation trials with fresh lemon slices, RB/SPI/GEL-2 films reduced weight loss to 37.89 %, maintained firmness at 0.99 N, stabilized pH at 3.14, and extended freshness lifetime by delaying mold formation. These results confirm that RB/SPI/GEL films effectively preserve freshness and minimize nutritional loss in lemon slices, demonstrating their feasibility for fruit preservation applications.

Enhancement of konjac glucomannan/carrageenan blend films by incorporating cellulose nanocrystals/tannic acid stabilized Litsea cubeba essential oil Pickering emulsion and their application to pork preservation

With increasing demands for environmental protection and food safety, biodegradable active food packaging is gaining attention. Hereby, konjac glucomannan/carrageenan blend films (KCNTO) incorporating Litsea cubeba essential oil (LCEO) Pickering emulsion stabilized by cellulose nanocrystals/tannic acid were developed and evaluated for their preservation effect on pork. The formation, structure, physical properties, antioxidant and antimicrobial activities of KCNTO, as well as the release of LCEO were investigated. The results showed that the viscosity and pseudoplasticity of KCNTO film-forming solutions decreased due to LCEO Pickering emulsion interfering with the molecular entanglement network of konjac glucomannan/carrageenan. LCEO droplets were homogeneously distributed in KCNTO to make its structure loose. Hydrogen bonding interactions occurred between LCEO Pickering emulsion and the film matrix. The addition of LCEO Pickering emulsion improved KCNTO's elongation at break, water contact angle, water vapor barrier and UV shielding, while giving it excellent antioxidant and antimicrobial activities. LCEO was slowly and sustainably released from KCNTO at 25 °C in air. KCNTO-8 maintained the quality of pork by slowing down the increase in pH, aerobic plate count and thiobarbituric acid reactive substances during storage at 4 °C. The findings suggested that KCNTO was a promising active packaging material for pork preservation.

Biobased Food Packaging Systems Functionalized with Essential Oil via Pickering Emulsion: Advantages, Challenges, and Current Applications

The development of innovative active food packaging is a promising strategy to mitigate food loss and waste while enhancing food safety, extending shelf life, and maintaining overall quality. In this review, Pickering emulsions with essential oils are critically evaluated as active additives for sustainable food packaging films, focusing on their antimicrobial and antioxidant properties, stabilization mechanisms, and physicochemical performances. A bibliometric approach was used to contextualize the current research landscape and new trends. Data were collected from the Web of Science and Scopus databases to find studies published between 2020 and 2024. The analysis of 51 articles shows that cinnamon, clove, and oregano are the most used essential oils, while cellulose and chitosan are the predominant polymer matrices. Pickering emulsions as stabilizers in food science represent a step forward in sustainable emulsion technology. The incorporation of essential oils into biobased films via Pickering emulsions can improve the mechanical and barrier properties, antimicrobial and antioxidant activities, and shelf life of foods. This approach offers a natural, environmentally friendly alternative to conventional materials and is in line with the 2030 Agenda goals for sustainability and responsible consumption. Recent advances show that composite particles combining polysaccharides and proteins have higher stability and functionality compared to single particles due to their optimized interactions at the interfaces. Future research should focus on developing scalable, cost-effective production methods and conducting comprehensive environmental testing and regulatory compliance, particularly for nanotechnology-based packaging. These efforts will be crucial to drive the development of safe and effective biobased active food packaging.

Chitosan decoration enhanced the thermal and ultraviolet resistance of vitamin A-vitamin D coencapsulated in OSA starch-stabilized emulsion by regulating viscoelasticity, interfacial thickness and structure

In this study, octenyl succinic acid sodium starch (OSAS) decorated with chitosan (CS) of different molecular weights (50-150 kDa) and concentrations (10-30 mg/mL) was used to stabilize an emulsion coencapsulating with vitamin A (VA) and vitamin D (VD). The effect of CS decoration on the thermal and UV stability of the emulsion, as well as the underlying mechanism, was elucidated. The incorporation of CS increased the retention rates of VA and VD by 11.36-25.52 % and 3.65-20.54 %, respectively, when exposed to 100 °C for 30 min, and by 13.35-33.05 % and 15.97-37.49 %, respectively, under ultraviolet (UV) exposure for 12 h, respectively. The OSAS/CS complexes were absorbed at the oil-water interface through electrostatic interactions and hydrogen bonding, forming thick interfacial film barriers, and regulating emulsion viscoelasticity to achieve protection against thermal and UV damage. CS decoration increased the thickness, relative crystallinity, and thermal degradation resistance of the interfacial films to mitigate thermal interference with the emulsion. The OSAS/CS complex barriers shielded UV by forming longer molecular chains or ring structures at the interface, enhancing amide functionality, and promoting intermolecular hydrogen bonding. This research could provide a reference for designing practical delivery systems for heat-sensitive and UV-sensitive nutrients like VA and VD.

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.

Citrus oil gland and cuticular wax inspired multifunctional gelatin film of OSA-starch nanoparticles-based nanoemulsions for preserving perishable fruit

Inspired by the citrus oil gland and cuticular wax, a multifunctional material that stably and continuously released the carvacrol and provided physical defenses was developed to address issues of fresh-cut fruits to microbial infestation and moisture loss. The results confirmed that low molecular weight and loose structure of starch nanoparticles prepared by the ultrasound-assisted Fenton system were preferable for octenyl succinic anhydride modification compared to native starch, achieving a higher degree of substitution (increased by 18.59 %), utilizing in preparing nanoemulsions (NEs) for encapsulating carvacrol (at 5 % level: 81.58 %). Furthermore, the NEs-based gelatin (G) film improved with surface hydrophobic modification by myristic acid (MA) successfully replicated the citrus oil gland and cuticular wax, providing superior antioxidant (enhanced by 3-4 times) and antimicrobial properties (95.99 % and 84.97 % against Staphylococcus aureus and Escherichia coli respectively), as well as the exceptional UV shielding (nearly 0 transmittance in the UV region), mechanical (72 % increase in tensile strength), and hydrophobic (WCA 133.63°). Moreover, the 5%NE-G@MA film inhibited foodborne microbial growth (reduced by 50 %) and water loss (controlled below 15 %), extending the shelf life of fresh-cut navel orange and kiwi. Thus, the multifunctional film was a potential shield for preserving perishable fresh-cut products.

High-performance carboxymethyl starch/PVA based intelligent packaging films engineered with Cu-Trp nanocrystal as functional compatibilizer

A spindle-like Cu-based framework (Cu-Trp, Trp = L-Tryptophan) nanocrystal with ammonia-responsiveness was fabricated via simple aqueous solution approach, and it was subsequently explored as a functional compatibilizer of carboxymethyl starch/polyvinyl alcohol (CMS/PVA) blend toward constructing high-performance intelligent packaging films. The results showed that incorporation of Cu-Trp nanocrystal into CMS/PVA blend resulted in significant promotions regarding to the compatibility, mechanical strength (42.92 MPa), UV-blocking (with UV transmittance of only 2.4%), and water vapor barrier effectiveness of the blend film. Besides, the constructed CMS/PVA/Cu-Trp nanocomposite film exhibited superb long-term color stability, favorable antibacterial capacity (over 98.0%) toward both E. coli and S. aureus bacteria, as well as color change ability under ammonia environment. Importantly, the application trial confirmed that the CMS/PVA/Cu-Trp nanocomposite film is capable of visually monitoring shrimp spoilage during storage. These results implied that the CMS/PVA/Cu-Trp nanocomposite film holds tremendous potential as an intelligent active packaging material.

Recent progress on Pickering emulsion stabilized essential oil added biopolymer-based film for food packaging applications: A review

Nowadays food safety and protection are a growing concern for food producers and food industry. The stability of food-grade materials is key in food processing and shelf life. Pickering emulsions (PEs) have gained significant attention in food regimes owing to their stability enhancement of food specimens. PE can be developed by high and low-energy methods. The use of PE in the food sector is completely safe as it uses solid biodegradable particles to stabilize the oil in water and it also acts as an excellent carrier of essential oils (EOs). EOs are useful functional ingredients, the inclusion of EOs in the packaging film or coating formulation significantly helps in the improvement of the shelf life of the packed food item. The highly volatile nature, limited solubility and ease of oxidation in light of EOs restricts their direct use in packaging. In this context, the use of PEs of EOs is suitable to overcome most of the challenges, Therefore, recently there have been many papers published on PEs of EOs including active packaging film and coatings and the obtained results are promising. The current review amalgamates these studies to inform about the chemistry of PEs followed by types of stabilizers, factors affecting the stability and different high and low-energy manufacturing methods. Finally, the review summarizes the recent advancement in PEs-added packaging film and their application in the enhancement of shelf life of food.

Development and characterization of starch/PVA antimicrobial active films with controlled release property by utilizing electrostatic interactions between nanocellulose and lauroyl arginate ethyl ester

The two nanocellulose (nanofibrillated cellulose (NFC) and carboxylated nanofibrillated cellulose (C-NFC)) could interact with lauryl arginine ethyl ester hydrochloride (LAE) through electrostatic bonding. The zeta potential (absolute value) of C-NFC (-27.80 mV) was higher than that of NFC (-10.07 mV). The starch/polyvinyl alcohol active films with controlled release property by utilizing electrostatic interactions between nanocellulose and LAE were prepared and their properties were investigated. For incorporation of the NFC or C-NFC, the cross-section of the films became slightly uneven and some fibrils were observed, the films exhibited an increase in strength, while the film water vapor and oxygen barrier properties decreased. The release of LAE from the films to food simulants (10 % ethanol) decelerated with increasing of NFC or C-NFC. These might be mainly attributed to the enhanced electrostatic interaction between NFC or C-NFC and LAE. It demonstrated that nanocellulose with higher negative charges would exhibit stronger electrostatic interaction with LAE, thus slowing the release of LAE. The film with highest C-NFC content exhibited smallest inhibition zone among LAE-containing films, which was related with its slowest release rate of LAE. It showed a great prospect to develop controlled release active packaging films by utilizing electrostatic interactions between substances.

Improving water resistance and mechanical properties of starch-based films by incorporating microcrystalline cellulose in a dynamic network structure

The widespread use of starch-based films is hindered by inadequate tensile strength and high water sensitivity. To address these limitations, a novel starch film with a dynamic network structure was produced via the dehydration-condensation reaction of N, N'-methylene diacrylamide (MBA) and microcrystalline cellulose (MCC). The improvement in mechanical properties was enhanced by the incorporation of MCC, which was achieved through intermolecular hydrogen bonding and chemical crosslinking. To verify the interactions among MCC, MBA, and starch, x-ray photoelectron spectroscopy (XPS), fourier transform infrared spectroscopy (FTIR), and x-ray diffraction (XRD) were conducted. The results established the predicted interactions. The dynamic network structure of the film reduced the water absorption capacity (WAC) of starch and MCC hydroxyl groups, as confirmed by differential scanning calorimeter (DSC) and dynamic mechanical thermal analysis (DMTA). These analyses showed a restriction in the mobility of starch chains, resulting in a higher glass transition temperature (Tg) of 69.26 °C. The modified starch films exhibited excellent potential for packaging applications, demonstrating a higher contact angle (CA) of 89.63°, the lowest WAC of 4.73 g/g, and the lowest water vapor transmission rate (WVTR) of 13.13 g/m2/d, along with improved mechanical properties and identical light transmittance compared to pure starch films.

Cellulose Nanocrystal-Based Emulsion of Thyme Essential Oil: Preparation and Characterisation as Sustainable Crop Protection Tool

Essential oil-based pesticides, which contain antimicrobial and antioxidant molecules, have potential for use in sustainable agriculture. However, these compounds have limitations such as volatility, poor water solubility, and phytotoxicity. Nanoencapsulation, through processes like micro- and nanoemulsions, can enhance the stability and bioactivity of essential oils. In this study, thyme essential oil from supercritical carbon dioxide extraction was selected as a sustainable antimicrobial tool and nanoencapsulated in an oil-in-water emulsion system. The investigated protocol provided high-speed homogenisation in the presence of cellulose nanocrystals as stabilisers and calcium chloride as an ionic crosslinking agent. Thyme essential oil was characterised via GC-MS and UV-vis analysis, indicating rich content in phenols. The cellulose nanocrystal/essential oil ratio and calcium chloride concentration were varied to tune the nanoemulsions' physical-chemical stability, which was investigated via UV-vis, direct observation, dynamic light scattering, and Turbiscan analysis. Transmission electron microscopy confirmed the nanosized droplet formation. The nanoemulsion resulting from the addition of crosslinked nanocrystals was very stable over time at room temperature. It was evaluated for the first time on Pseudomonas savastanoi pv. savastanoi, the causal agent of olive knot disease. In vitro tests showed a synergistic effect of the formulation components, and in vivo tests on olive seedlings demonstrated reduced bacterial colonies without any phytotoxic effect. These findings suggest that crosslinked cellulose nanocrystal emulsions can enhance the stability and bioactivity of thyme essential oil, providing a new tool for crop protection.