Plastic Wrap Research Articles

Development of smart packaging film incorporated with sodium alginate-chitosan quaternary ammonium salt nanocomplexes encapsulating anthocyanins for monitoring milk freshness

This study focused on the preparation, functionality, and application of smart food packaging films based on polyvinyl alcohol (PVA) and anthocyanins (ACNs) -loaded sodium alginate-chitosan quaternary ammonium salt (HACC-SA) nanocomplexes. The average encapsulation rate of anthocyanins-loaded nanocomplexes reached 62.51 %, which improved the hydrophobicity and water vapor barrier of the PVA film. FTIR confirmed that the nanocomplexes were immobilized in the PVA film matrix by hydrogen bonding, which improved the mechanical properties of the film. The SEM and XRD results demonstrated that the HACC-SA-ACNs nanocomplexes were uniformly distributed in the film matrix and the crystallinity of PVA was decreased. The P/HACC-SA-ACNs film showed a significant response to buffers of pH 2–13 and high color stability after 21 days of storage compared to the P/ACNs film. Furthermore, the color of the composite film changed from purple to red as the milk freshness decreased during 72 h of milk freshness monitoring, indicating that the P/HACC-SA-ACNs films were suitable and promising for application as smart packaging materials.

Testing the Biodegradability and Biodegradation Rate of Bio-based Film Products in Composting Environment

Bio-based film products have a considerable interest as a replacement for petroleum synthetic polymers of plastics. They are manufactured with a blend of corn starch such as Poly Lactic Acid (PLA) and Poly Butylene Adipate-co-Terephthalate (PBAT) based raw materials that have been specifically engineered to facilitate the process of biodegradation and compost ability. Hence, biodegradable polymers have been regarded as a promising solution to tackle the pollution caused by the wide use of conventional polymers. As the main responsible institute for integrating environmental considerations into the country‘s development process, the Central Environment Authority of Sri Lanka has taken an action to ban food wrappers (lunch sheets) made from conventional polymers in Sri Lanka. Thus, this study was to determine the biodegradability of bioplastic materials lunch sheets, available on the Sri Lankan market that are labeled as 100% biodegradable but not certified as compostable. The other specific objectives are to identify the biodegradability rate of each brand of lunch sheets, categorize those lunch sheets according to their biodegradability and finally get an idea to determine the optimum conditions for the biodegradation of a bio- based lunch sheet. In this study, the test was carried out in a controlled composting environment located in Gampaha–Dompe Green Park. Three different brands of biodegradable bio-based film products were tested together with cellulose paper as the positive control and nonbiodegradable lunch sheet (LDPE) as the negative control. The project length was 15 weeks. Samples were placed into frames which are made of wooden slats as width=280 mm, length=340 mm and height=50 mm and a 1x1 mm polyethylene mesh was fixed onto the frames. The methodology adopted was based on the study conducted in the Czech Republic in 2016. The emphasis was put on discovering whether bio-based film products are biodegradable or not. The biodegradability of each bio-based film product was tested using Visual inspection; the decomposed samples were inspected visually comparing with initial samples, Weight loss measurement; the initial weight and the weight after decomposition were measured using an analytical balance, FTIR and TGA analysis. Furthermore, the quality of the compost was analyzed using quality parameters such as pH, electrical conductivity, moisture, organic carbon%, nitrogen%, phosphorous%, potassium%, C/N ratio and S. The visual inspection of Sample C revealed large cracks and porous structure than Sample A and Sample B. Positive control was completely digested and the negative control stayed as it is. According to the weight loss measurement analysis, the positive control totally degraded and degradation order was Sample C>Sample A>Sample B. The TGA only suggested a partial degradation of samples. FTIR analysis indicated that the positive control was totally biodegradable, Sample B and sample C partially biodegradable and Sample A and negative control were not biodegradable. Based on the results it can be concluded that bio- based film products have not decomposed completely but their color, texture changed. Sample B exhibited the highest degradation rate and exhibited a high degree ofdecomposition. The degradation rate can be summarized as Positive control>Sample B>Sample C>Sample A> Negative Control respectively. The main conclusion from this study is that the biodegradation of bioplastics materials strongly depends on both the environment in which they are placed and the chemical nature of the material. 
 Keywords: Biodegradation, Biobased film products, Composting environment

Hemodynamic Renal Reserve Response in Conscious Normotensive and Hypertensive Mice

Introduction: Renal function may be compromised following recovery from kidney insults. Renal functional reserve (RFR) is a measure of the difference between the kidney’s maximum capacity and its baseline function, which helps identify any areas of the kidney with compromised function. Usually, RFR is evaluated using acute volume expansion (AVE), but this is typically done in anesthetized animals, which may not accurately represent the kidney’s complete functional capacity. In this study, we have introduced a novel method that enables AVE to be conducted in conscious mice. Methods: We have implemented this innovative approach in two animal models representing either intact or impaired renal function, specifically utilizing a lower nephron hypertensive model. Mice were implanted with radio-transmitters for mean artery blood pressure (MAP) monitoring during the experiment. After recovery, half of the mice were induced hypertension by right kidney nephrectomy combined with the ligation of the upper branch of the left kidney. For the AVE, a volume equivalent to 5% of the mouse’s body weight was administered via intravenous (IV) or intraperitoneal bolus injection. Subsequently, the mice were individually housed in cages covered with plastic wrap. Urine was collected every hour for a total of 3 h for the measurement of urine and sodium excretion. Results: The MAPs for all normotensive mice were consistent throughout the AVE, but it increased 5–16 mm Hg in the hypertensive mice upon AVE. Remarkably, conscious mice exhibited a significantly stronger response to IV-administered AVE when compared to anesthetized mice. This response was evident in the increase in urinary flow, which was approximately 170% and 145% higher in conscious normotensive and hypertensive mice, respectively, compared to their respective baselines. In contrast, anesthetized normotensive and hypertensive mice showed only around a 130% and 100% increase in urinary flow, respectively. Additionally, upon AVE, conscious normotensive mice excreted approximately 47% more sodium than conscious hypertensive mice. In contrast, anesthetized normotensive mice excreted only about 30% more sodium than their anesthetized hypertensive counterparts. Conclusion: Performing a kidney stress test with a significant solution load in conscious mice seems to be a superior method for evaluating RFR compared to conducting the test under anesthesia. Assessing kidney clearance while the mice are conscious has the potential to enhance the precision of diagnosing and predicting both acute and chronic kidney diseases.

Frequency of Neonatal Hypothermia in Preterm Infants Wrapped with and without Plastic Bag after delivery

Background: Preterm birth accompanies many complications including hypothermia that worsens neonatal health and may result in fatality if left untreated. Globally, plastic wraps are being used as a low-cost and effective method to maintain temperature. Aim: To compare frequency of neonatal hypothermia in preterm infants wrapped with and without plastic bag after delivery. Study design: This was randomized control trial. Methodology: This study was conducted using at Pediatrics department of SIMS hospital, Lahore, during 6 months. Data was collected using non-probability, consecutive sampling from a sample of 92 (46 newborns in each group). Infants randomized to group-B (no bag group) received standard hospital care based on WHO thermoregulation of the newborn protocol. The data was entered and analyzed in SPSS 23. Results: In plastic wrap group there were 32(69.57%) male and 14(30.43%) female cases while in no wrap group there were 27(58.70%) male and 19(41.30%) female cases, p-value >0.05. The median temperature after one hour was higher in plastic wrap and no wrap group was 37.6±0.7 and 36.85±1.80c respectively, p-value < 0.05. There were 3(6.5%) cases in plastic wrap group and 15(32.6%) of the cases in no wrap group who developed hypothermia, the frequency of hypothermia was statistically less in wrap group when compared with no wrap group, p-value <0.05. Practical Implication: However, there is limited literature in Pakistan that compares temperature maintenance among neonates wrapped and unwrapped with plastic bags. This investigation will help find better answers to this problem. Conclusion: It is concluded that the preterm infants wrapped with plastic bag after delivery had less frequency of neonatal hypothermia after 1 hour. Plastic wraps are effective, low cost and low resource friendly method that should be opted for temperature maintenance of preterm babies. Keywords: Hypothermia, Preterm Birth, Hyperthermia, plastic wraps, Neonates and Temperature.

Feasibility study on thermo‐mechanical performance of 3D printed and annealed coir fiber powder/polylactic acid eco‐friendly biocomposites

AbstractThe enhancement of the mechanical and thermal characteristics of 3D printed polylactic acid (PLA) composites reinforced by coir fiber powder (CFP) has been investigated by varying the weight percentage (wt%) of the reinforcement and annealing process. CFP/PLA composite filaments with CFP compositions of 0.1, 0.3, and 0.5 wt% were fabricated. These filaments were used to print CFP/PLA test specimens. The specimens were annealed at 90°C for 120 min in a hot air oven followed by cooling at room temperature. Mechanical, morphological, crystalline, and thermal characterizations were conducted on these specimens. The tensile and flexural strength of neat PLA were observed as 49.7 and 82.4 MPa which decreased by 6.4% and 8.13% respectively for printed composite specimens with 0.5 wt% CFP as reinforcement material. On the other hand, the annealed CFP/PLA composite specimen, with 0.1 wt% CFP as a reinforcement material, demonstrated higher tensile and flexural strength. Specifically, it exhibited a maximum tensile strength of 56.4 MPa and a maximum flexural strength of 92.9 MPa, which are 13.5% and 12.7% higher, respectively, than neat PLA. These strengths are 15.5% and 16.7% higher, respectively, than those of the unannealed CFP/PLA composite specimen with the same wt% of CFP reinforcement. The annealing process increased the crystallinity of composites by enhancing the crystallinity index (63%) and crystalline size (6.7 nm). The high thermal stability of composites (with a glass transition temperature of 256°C) makes them suitable for applications in food and medical packaging.Highlights Enhancement of thermo‐mechanical characteristics of 3D printed bio‐composites. Annealing process improved mechanical features of 3D printed bio‐composites. Annealed composite with 0.1 wt% as reinforcement demonstrated better properties. SEM and XRD studies confirmed failure mechanisms and crystalline structure. Thermal and mechanical assets favor its utilization in food wrapping applications.

Valorization of waste paper sludge as a sustainable source for packaging applications

Paper sludge consists mainly of wet short cellulose fibers that are lost during papermaking and of residual chemicals used in the manufacturing process that remain dissolved in the water. Each ton of paper generates about 40–50 kg of dry sludge, of which 70% is primary sludge. Paper production, which exceeded 400 million tons globally in 2020, generates vast volumes of solid waste. Primary sludge is usually fiber-rich and hence suitable to be recycled back into the papermaking process. However, if the sludge is to be disposed of in landfills, sustainable practices must be developed in order to recover the fibers as they are valuable source for manufacturing high value-added products. This study investigates the valorization of paper sludge discarded by a filter paper manufacturer, with the purpose of producing cellulose acetate films for food packaging. The process involves recovering cellulose fibers from the sludge, purifying them and through acetylation reaction produce cellulose acetate films. FTIR spectra confirmed successful acetylation of fibers and also that acetyl groups reduced the hydrophilicity of cellulose—the contact angle was increased to over 80° from 50° in native cellulose. The films exhibited very good water barrier properties at both 50% and 90% relative humidity (RH).Graphical abstract

Protein‐based active films: Raw materials, functions, and food applications

AbstractBiopolymer packaging materials are an emerging trend in food packaging due to their degradability, nontoxicity, low cost, and low environmental stress; moreover, some properties of biopolymer packaging are better than those of traditional packaging. Proteins are a type of natural biopolymer packaging film matrix, and enhancing the packaging properties of proteins has been a focus of research. Preparing protein‐active packaging films by adding natural active substances with antimicrobial and antioxidant properties and nanoparticles to protein‐based films to provide more significant antimicrobial, antioxidant, and UV‐blocking effects is essential in food packaging and demonstrates the potential of using proteins in active food packaging applications. In recent years, the origin of natural actives, their mechanism of action, and their release from active packaging films have attracted much attention. In this review, we provide a comprehensive overview of protein film matrices for active packaging, natural antimicrobial agents, and natural antioxidants and discuss the potential of such active films in the packaging field. The sources of natural antimicrobial active substances and natural antioxidant active substances in packaging materials, their mechanisms of action, and their effects after being used to modify protein active films are summarized. The biorelease functions of protein active films with antimicrobial and antioxidant effects and their applications for various types of food are highlighted to understand the current effects of protein active films in food packaging.

Bio-nanocomposite active packaging films based on carboxymethyl cellulose, myrrh gum, TiO2 nanoparticles and dill essential oil for preserving fresh-fish (Cyprinus carpio) meat quality

This study developed a composite film for packaging refrigerated common carp fillets using carboxymethyl cellulose (CMC) (1.5 % w/v)/Myrrh gum (MG) (0.25 % w/v) base with the addition of titanium dioxide nanoparticles (TiO2 NPs) (0.25 %, 0.5 %, and 1 %) and Dill essential oil (DEO) (1.5 %, 2.25 %, and 3 %). The film was produced using a casting method and optimized for mechanical and barrier properties. The incorporation of DEO and TiO2 NPs into CMC/MG composite films significantly reduced moisture content (MC) and water vapor permeability (WVP), improved their tensile strength (TS), and increased their antimicrobial and antioxidant properties. Moreover, MG can improve the physicomechanical properties of the CMC/MG composite films. The film components had good compatibility without significant aggregation or cracks. In conclusion, the optimized CMC/MG (1.5 %/0.25 %) film containing TiO2 NPs (0.5 %), and DEO (2.25 %) has the best overall performance and can be a good source for making edible film. Functionally, this bioactive nanocomposite film significantly increased the shelf life of refrigerated fish fillet samples for 12 days by inhibiting microbial growth and reducing the oxidation rate compared to the control sample. The knowledge obtained from this study can guide the development of bio-nanocomposite and biodegradable food packaging films based on CMC/MG to increase the shelf life of food products and environmental protection.

Physicochemical Properties of Films from Semirefined Carrageenan/TiO2 Integrated with Cinnamaldehyde Pickering Emulsion for Active Food Packaging

Plastic waste has become a significant global environmental issue, particularly in the context of food packaging. In the present study, active packaging films were fabricated by integrating chitosan-stabilized cinnamaldehyde Pickering emulsion (PE) and titanium dioxide particles (TNPs) into the semirefined carrageenan (SRC) matrix. The impact of cinnamaldehyde PE and TNPs on the physical and mechanical attributes of the SRC films was explored. The integration of TNPs (3%, w/v) and 0.5% cinnamaldehyde PE revealed promising mechanical properties, with 21.86 MPa tensile strength and 34.21% of elongation at break value. The inclusion of TNPs and cinnamaldehyde PE led to enhancements in the moisture content and water solubility of the SRC films. The thermal stability of the film was marginally increased with 0.5% cinnamaldehyde PE. Scanning electron microscopy (SEM) revealed a uniform distribution of active compounds in the SRC matrix. The study findings highlight the potential of cinnamaldehyde PE and TNPs in active food packaging films as eco-friendly alternatives to conventional petrochemical-derived plastics in food packaging.

Keunggulan pati kulit singkong (Manihot esculenta) sebagai bahan pembuatan edible film ramah lingkungan

The use of plastic packaging is difficult to decompose by microbes, this raises the idea of making edible films in food packaging. Cassava peel starch can be the main component material in making this edible film, because its content can be used as an edible film making material and can reduce cassava peel waste. The aim is to understand and recognize the effectiveness of making edible film from cassava peel starch because the utilization of cassava peel as agroindustrial waste of cassava processing can be useful to reduce the amount of cassava peel waste and the use of plastic. The research method used is the literature study method. Cassava peel is the most effective material for making edible film. Researchers should conduct further research related to the use of natural materials that can make edible films more durable than before.

Robust design of starch composite nanofibrous films for active food packaging: Towards improved mechanical, antioxidant, and antibacterial properties

Developing efficient and biodegradable packaging films is of paramount significance owing to the scarcity of petroleum based resources. However, their applications in food packaging are limited due to their poor mechanical properties and inadequate biological activities. This study proposes a novel approach to develop the starch composite nanofibrous films (SNFs/TA/Fe3+) consisting of starch, tannic acid, and Fe3+ using the temperature-assisted electrospinning method. The addition of TA resulted in a decrease in the rate of thermal degradation, indicating an improvement in the thermal stability of SNFs. However, the incorporation of TA or TA/Fe3+ showed only a slight impact on the internal structure of SNFs. SNFs/TA/Fe3+ loaded with 0.1 wt% of Fe3+ demonstrated a significantly higher tensile strength compared to SNFs and those loaded with TA alone. The presence of TA enhances the antioxidant activity of SNFs, and the robust SNFs/TA/Fe3+ exhibited comparable antioxidant activity to SNFs/TA. However, the SNFs/TA/Fe3+ showed a reduction in antibacterial activity, possibly due to the high valence state of the metal ions. Overall, these findings highlighted that a simple electrospinning method was used to produce SNFs/TA/Fe3+ resulted in improved mechanical properties and antioxidant activity, offering a new strategy for the development of active food packaging using SNFs.

A Novel Source of Lignin from Date Palm Leaves as a Reinforcing Agent for Fabrication of Carboxymethyl Cellulose-Based Active Food Packaging Film

A Novel Source of Lignin from Date Palm Leaves as a Reinforcing Agent for Fabrication of Carboxymethyl Cellulose-Based Active Food Packaging Film

Berry wax improves the physico-mechanical, thermal, water barrier properties and biodegradable potential of chitosan food packaging film

Chitosan (CT) is extensively applied in developing food packaging films due to its non-toxic, biodegradable, and good film-forming properties. But CT-based single polymer film has issues with poor physico-mechanical, thermal, and light barrier properties. Therefore, this study aimed to incorporate natural berry wax (BYW) at various concentrations (5 %, 10 %, 15 %, 20 %, and 25 %, wt%) into CT to improve the quality characteristics of CT film. The microstructure of the film matrix was effectively proven to be compatible with BYW through the utilization of SEM, XRD, and FTIR spectroscopy. The results demonstrated that the quality parameters of CT/BYW composite film were significantly affected by the increasing concentration of BYW. The integration of BYW with a concentration of 5 % to 20 % to CT substantially improved the film characteristics by reducing moisture content, swelling power, solubility, and water vapor permeability, increasing the film’s opacity, thermal stability, and tensile strength as well as enhancing the biodegradable potential. Furthermore, CT/BYW films showed higher thermal stability and UV and visible light resistance compared to pure CT film. Taken together, the CT film with 20 % berry wax showed the best film characteristics and biodegradable potential, which could be promising for enhancing the shelf-life of various food products.

An antibacterial packaging film based on amylose starch with quaternary ammonium salt chitosan and its application for meat preservation

A new generation of food packaging films is gradually replacing traditional plastic packaging films because of their biodegradability, safety, and some functional properties such as anti-bacterial and oxidant resistance. In the present work, an antibacterial packing film based on amylose starch and 2-hydroxypropyl-trimethylammonium chloride chitosan (HTCC) was prepared for meat preservation. The interfacial bonding mechanism between amylose, HTCC, and glutaraldehyde (GA) was determined experimentally and through molecular dynamics (MD) simulation. The macromolecular chains of amylose starch and HTCC became entangled via inter-molecular H-bonds and then cross-linked with GA via the Schiff base reaction. The interaction of amylose starch and HTCC improved the mechanical properties of the amylose films. Compared with the amylose films, the tensile strength and elongation at break of the optimal HTCC/amylose films reached to 16.13 MPa (an increase of 206.65 %) and 53.86 % (an increase of 109.49 %). The HTCC/amylose films were found to provide obvious bacteriostatic performance, a relatively low cytotoxicity, the lower transmittance in the UV region, and thus the ability to enhance the preservation of fresh meat. These excellent characteristics therefore suggest that HTCC/amylose films might be promising candidates for application in antibacterial food packaging films.

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.

Assessment of phthalate knowledge, plastic use practices and cheese handling among adults in Jeddah city (Saudi Arabia)

Background: Phthalates are chemical compounds that have the tendency to migrate into food and beverages, thereby leading to negative health consequences. Aims: was to assess the knowledge of phthalates and practices relating to plastic use among adults residing in Jeddah, Saudi Arabia, with an emphasis on cheese wrapped in plastic materials. Material and Methods: A total of 435 adult participants completed an online questionnaire consisting of three sections 1) socio-demographic characteristics, 2) knowledge-related phthalates, and 3) practices related to plastic use. All collected data were verified and analyzed using the Statistical Package for Social Sciences (SPSS). Results: Our findings revealed that 64.1% of the respondents had poor knowledge regarding plastics and phthalates with gender being a significant factor (p=0.0003). The usage rate of plastic material was found to be remarkably high with 38.2% keeping the purchased cheese either in its original plastic wrapping or placed inside plastic boxes. Moreover, 53.6% never viewed the safe plastic number before purchasing the food products. However Interestingly enough, the type of plastics did not influence participant’s decision-making process when it came down to purchasing or consuming cheese (45.1% &amp; 46.2%, respectively). Respondents who had poor practice represented up to 85 %, while those with poor knowledge and practice constituted 65.1%. However, no significant link between these two factors could be established. Conclusions: Poor awareness levels concerning phthalates along with imprudent usage rates for plastics were observed among adults living within Jeddah city's boundaries; thus, appropriate interventions aimed at raising awareness need implementation so as minimize exposure risks associated with this issue. Keywords: Phthalate, Plastic use, Cheese, Knowledge, Practice, Saudi Arabia.

Fabrication of coconut dregs residue derived nano-cellulose film for food packaging

To replace conventional plastic as food packaging, several studies related to the preparation of cellulose films from various types of biomass have been reported. However, there have been no reports regarding the use of coconut dregs residue as source of cellulose for the fabrication of cellulose films. This is the first report on the fabrication of cellulose film from coconut dregs under various conditions. The purpose of this work was to investigate the effect of hydrochloric acid, and ultrasonication during the isolation process of cellulose from coconut dregs on the characteristic of cellulose film produced. Hydrochloric acid was used in the hydrolysis process and the concentrations used were 3 M, 5 M, and 7 M. The ultrasonication process was performed after the bleaching process of cellulose isolation. Cellulose films were prepared from ultrasonicated isolated cellulose particles prepared with different hydrochloric acid concentrations and compared with cellulose films obtained from isolated cellulose without the ultrasonication process. Results showed the higher hydrochloric acid concentration the lower particle size of cellulose produced. The cellulose particle size decreased after ultrasonication treatment and cellulose obtained using hydrochloric acid 7 M became nano-size cellulose particles after the ultrasonication process. These results influence the film properties obtained from these cellulose particles, where the lower the particle size the more transparent the film produced. The most transparent film was produced from cellulose particles isolated using hydrochloric acid 7 M in combination with the ultrasonication process. Furthermore, hydrochloric acid concentration and ultrasonication also influenced the tensile strength, crystallinity, and thermal stability of the films.

Effect of electrostatic repulsion on barrier properties and thermal performance of gelatin films by carboxymethyl starch, and application in food cooking

Carboxymethyl starch (CST) was introduced to improve gelatin films and its practical application as edible high-performance films for food packaging and cooking was also investigated. The gelatin films modified by carboxymethyl starch exhibited the transparent appearance, tensile strength, barrier properties (oxygen, water vapor and UV light), and thermal performance (TGA, thermal shrinkage and heat-sealing strength). Resulting from the effect of electrostatic interaction modes on the properties of films, electrostatic repulsion could surpass electrostatic attraction in improving the tensile strength, oxygen barrier property and thermal stability of the films probably due to extensive physical entanglement without aggregation. Analysis of FTIR, zeta potential, interfacial dilatational rheology, shear rheological properties, XRD, Raman, SEM and AFM suggested that hydrogen bonding and electrostatic repulsion contributed to the excellent performance. The packaged food could also be cooked with the prepared film for porridge; and the film slightly influenced the shear rheological properties of porridge and imposed little effect on the odors (Electronic-Nose) of porridge. Hence, the gelatin films modified by carboxymethyl starch could potentially work as the edible inner packaging or the edible quantitative packaging for food, offer convenience for consumers, reduce the packaging waste and avoid an extra burden on environment.

Functionalized pectin/alginate food packaging films based on metal-phenol networks

It was focused on development a film with excellent properties. The pectin/sodium alginate (PS) composite films were developed by a casting technology, incorporating with tannic acid and Fe3+ for double cross-linking, and the effects of the film thickness, optical, mechanical, barrier, and antioxidant properties were investigated. This results displayed the inclusion of tannic acid (TA) and Fe3+ considerably increased the physical aspects, and they were very compatible with the matrix of the PS, exhibiting higher UV barrier capacity and lower gas permeability. On the other hand, the more compact structure observed by SEM as well as the hydrogen bonding interactions between the film components revealed by FTIR spectroscopy and XRD diffraction analyses further confirmed the significant enhancement of the properties. The functionalized coating of TA-Fe3+ demonstrated an improved adhesion and barrier properties, thereby effectively retarding the ageing process of golden passion fruit and this encompassed a decrease in the weight loss and a significant enhancement in water retention capability.

Transparent biodegradable composite plastic packaging film from TEMPO-oxidized cellulose nanofibers

In this research, we develop a method to create biodegradable food packaging films. Initially, TEMPO-oxidized cellulose nanofiber (TOCNF) undergoes sonication to produce well-dispersed single-strain nanofibers. These nanofibers are then blended with waterborne polyurethane (WPU) to enhance their extensibility. To further enhance compatibility between these two components, a non-ionic surfactant, Tween 80, is introduced into the TOCNF/WPU mixture to improve the dispersion of the WPU within the blend. The addition of Tween 80 significantly increases the transparency of the resulting film (Transmittance: 89.4 %, Haze: 2.2 %). Furthermore, the incorporation of the surfactant effectively reduces the formation of wrinkles and cracks during the film drying process, preventing adverse impacts on the film's barrier properties. The thin film further undergoes esterification crosslinking with citric acid to remove its hydrophilic groups for better water vapor barrier properties. The resulting bio-based packaging film exhibits remarkable transparency, strong biodegradability, and superior gas-barrier properties (water vapor and oxygen) compared to commonly used food packaging.