Thermo-mechanical, structural characterization and antibacterial performance of solvent casted polylactide/cinnamon oil composite films

Active packaging film of poly(lactic acid) incorporated with plant-based essential oils of Trachyspermum ammi as an antimicrobial agent and vanilla as an aroma corrector for waffles

This study developed active packaging films of Polylactic acid incorporated with the plant-based essential oils of Trachyspermum ammi, T. ammi and Vanilla to package waffles, where the antimicrobial property was provided by T. ammi and its odor was masked by vanilla essential oil. Compared to conventional solvent-cast films of smaller sizes requiring a huge amount of solvents, bigger-size PLA-oil films with lower solvent demand were prepared by tape casting technique with 10, 30, and 50 wt% essential oil blends. Films were studied for their morphological, chemical, mechanical, barrier, and antimicrobial properties. The presence and time-bound release of volatile oils from the films was confirmed by infrared spectroscopy, with a continuous decrease of oils from the films till day 30. The plasticizing effect of oils in films was evidenced by decreased tensile strength and crystallinity. In contrast, an increase in elongation at break and water vapor permeability of oil films were also measured. Finally, when packed in PLA films containing 50 wt% blend of both oils, waffles shelf-life extended up to 30 days compared to 2 days for the neat PLA film, where Vanilla was found effective in masking the unpleasant odor of T.ammi as confirmed by sensory analysis.

Revisiting the ethnomedicinal, ethnopharmacological, phytoconstituents and phytoremediation of the plant Solanum viarum Dunal

Solanum viarum, a perennial shrub, belongs to the family Solanaceae known for its therapeutic value worldwide. As a beneficial remedial plant, it is used for treating several disorders like dysentery, diabetes, inflammation, and respiratory disorders. Phytochemistry studies of this plant have shown the presence of steroidal glycoside alkaloids, including solasonine, solasodine, and solamargine. It also has flavonoids, saponins, minerals, and other substances. S. viarum extracts and compounds possess a variety of pharmacological effects, including antipyretic, antioxidant, antibacterial, insecticidal, analgesic, and anticancer activity. Most of the heavy metals accumulate in the aerial sections of the plant which is considered a potential phytoremediation, a highly effective method for the treatment of metal-polluted soils. We emphasize the forgoing outline of S. viarum, as well as its ethnomedicinal and ethnopharmacological applications, the chemistry of its secondary metabolites, and heavy metal toxicity. In addition to describing the antitumor activity of compounds and their mechanisms of action isolated from S. viarum, liabilities are also explained and illustrated, including any significant chemical or metabolic stability and toxicity risks. A comprehensive list of information was compiled from Science Direct, PubMed, Google Scholar, and Web of Science using different key phrases (traditional use, ethnomedicinal plants, western Himalaya, Himachal Pradesh, S viarum, and biological activity). According to the findings of this study, we hope that this review will inspire further studies along the drug discovery pathway of the chemicals extracted from the plant of S. viarum. Further, this review shows that ethnopharmacological information from ethnomedicinal plants can be a promising approach to drug discovery for cancer and diabetes.

Development and characterization of active poly (3-hydroxybutyrate) based composites with grapeseed oil and MgO nanoparticles for shelf-life extension of white button mushrooms (Agaricus bisporus)

Poly (3-hydroxybutyrate) (PHB) is undoubtedly a potential substitute for petroleum-based non-biodegradable food packaging materials due to its renewability, high crystallinity, biocompatibility, and biodegradability. Nonetheless, PHB exhibits certain shortcomings, including low flexibility, moderate gas barrier properties, and negligible antimicrobial and antioxidant activities, which limit its direct application in food packaging. Loading essential oils can increase flexibility and induce antimicrobial and antioxidant activities in biopolymers but at the cost of reduced tensile strength. In contrast, nanofiller reinforcement can increase the tensile strength and barrier properties of such biopolymers. Therefore, to harness the synergistic effects of essential oil and nanofiller, PHB-based films incorporated with 5 wt% grapeseed oil (GS) and varying concentrations (0.1-1 wt%) of MgO nanoparticles (MgO NPs) were prepared in this study following simple sonication-assisted solution casting technique. Physicochemical, tensile, microstructural, optical, barrier, antimicrobial, and antioxidant properties were then evaluated for the prepared composite films. FESEM analysis of the PHB-based films with 5 wt% GS and 0.7 wt% MgO NPs (PHB/5GS/0.7MgO) confirmed its compact morphology without any aggregates, pores, or phase separation. In comparison with pristine PHB, the PHB/5GS/0.7MgO films demonstrated higher tensile strength (by 1.4-fold) and flexibility (by 30-fold), along with 79 and 90 % reduction in water vapor and oxygen transmission, respectively. In addition, PHB/5GS/0.7MgO showed good UV-blocking properties, 65.25 ± 0.98 % antioxidant activity, and completely inhibited the growth of Staphylococcus aureus and Escherichia coli. Moreover, PHB/5GS/0.7MgO films proved beneficial effects in terms of extending the shelf-life of white button mushrooms up to 6 days at ambient room conditions.

Fabrication of antimicrobial and high-toughness poly (lactic acid) composite films using tung oil derivatives

Tung oil derivatives are promising alternatives to traditional toxic plasticizers for improving the toughness of poly (lactic acid) (PLA) films. In this study, a tung oil-based quaternary ammonium salt (Q-ETO) was synthesized using a multi-step process involving epoxidation, ring opening, and substitution reactions. PLA based composite films with various amounts of Q-ETO were prepared by solvent casting. The impact of various amount of Q-ETO on PLA/Q-ETO composite films were evaluated with regard to their mechanical properties, hydrophilicity, water vapor permeability, optical properties, thermal stability, antibacterial properties, and leaching properties. The PLA/5%Q-ETO composite film yielded the highest elongation at break (82.52 ± 9.53 %), which was 153.67 % higher than that of pure PLA. All PLA composite films showed an antibacterial efficiency exceeding 90 % against both S. aureus and E. coli. Moreover, the PLA/Q-ETO composite film blocked the transmission of both ultraviolet and visible light while preventing the permeation of water vapor. The addition of Q-ETO only weakly affected the color and thermal stability of the PLA/Q-ETO composite film. Given the numerous advantages of the PLA composite film, it has significant potential for application as a food packaging material.

Green Synthesis and Characterization of Silver Nanoparticles Using Azadirachta indica Seeds Extract: In Vitro and In Vivo Evaluation of Anti-Diabetic Activity

BACKGROUND

Diabetes mellitus (DM) is a non-communicable, life-threatening syndrome that is present all over the world. The use of eco-friendly, cost-effective, and green-synthesised nanoparticles as a medicinal therapy in the treatment of DM is an attractive option.

OBJECTIVE

In the present study, silver nanoparticles (AI-AgNPs) were biosynthesized through the green synthesis method using Azadirachta indica seed extract to evaluate their anti-diabetic potentials.

METHODS

These nanoparticles were characterized by using UV-visible spectroscopy, Fourier transform infrared spectrophotometers (FTIR), scanning electron microscopy (SEM), DLS, and X-ray diffraction (XRD). The biosynthesized AI-AgNPs and crude extracts of Azadirachta indica seeds were evaluated for anti-diabetic potentials using glucose adsorption assays, glucose uptake by yeast cells assays, and alpha-amylase inhibitory assays.

RESULTS

Al-AgNPs showed the highest activity (75 ± 1.528%), while crude extract showed (63 ± 2.5%) glucose uptake by yeast at 80 µg/mL. In the glucose adsorption assay, the highest activity of Al-AgNPs was 10.65 ± 1.58%, while crude extract showed 8.32 ± 0.258% at 30 mM, whereas in the alpha-amylase assay, Al-AgNPs exhibited the maximum activity of 73.85 ± 1.114% and crude extract 65.85 ± 2.101% at 100 µg/mL. The assay results of AI-AgNPs and crude showed substantial dose-dependent activities. Further, anti-diabetic potentials were also investigated in streptozotocin-induced diabetic mice. Mice were administered with AI-AgNPs (10 to 40 mg/kg b.w) for 30 days.

CONCLUSIONS

The results showed a considerable drop in blood sugar levels, including pancreatic and liver cell regeneration, demonstrating that AI-AgNPs have strong anti-diabetic potential.

Facile fabrication and characterization of novel antimicrobial and antioxidant poly (3-hydroxybutyrate)/essential oil composites for potential use in active food packaging applications

Poly (3-hydroxybutyrate) (PHB) is a bio-based biodegradable biopolymer with excellent potential to substitute petrochemical-based food packaging materials. Nevertheless, low elongation at break is one of the limiting factors for its commercial-scale application in the packaging field. Microbial contamination and lipid oxidation are the two main causes of food spoilage and pose huge challenges to the food industry. In this regard, essential oils are bioactive compounds that, in addition to providing antimicrobial and antioxidant properties, can improve the flexibility of biopolymers. Therefore, to overcome the aforementioned challenges, the current study aimed to fabricate novel PHB composite films loaded with essential oils, viz. grapeseed oil (GS), bergamot oil (BG), and ginger oil (GG), by a simple solution casting technique. To evaluate the potential of prepared PHB/essential oil composites for food packaging applications, extensive characterizations of their mechanical, structural, barrier, optical, and thermal properties were carried out. Interestingly, PHB/essential oil composites demonstrated good UV-blocking properties without affecting its transparency. PHB films loaded with 5 wt% GS showed a 30-fold enhancement in flexibility compared to pristine PHB. The DPPH radical scavenging activities of PHB/5GS, PHB/5BG, and PHB/5GG films are 53.17 ± 4.76, 50.70 ± 3.92 and 86.38 ± 2.73 %, respectively. The antibacterial activities of PHB/5GS, PHB/5BG, and PHB/5GG films against the model bacterium E. coli are 19.72 ± 0.97, 12.62 ± 2.23 and 29.98 ± 2.15 %, respectively, whereas, for S. aureus, the values are 61.56 ± 3.39, 30.28 ± 0.92 and 70.97 ± 0.26 %, respectively. Moreover, the overall migration values of the composite films in simulants representing hydrophilic, acidic, and lipophilic foods did not exceed the prescribed overall migration limit (10 mg/dm2).

Advances in enteropathogen control throughout the meat chicken production chain

Enteropathogens, namely Salmonella and Campylobacter, are a concern in global public health and have been attributed in numerous risk assessments to a poultry source. During the last decade, a large body of research addressing this problem has been published. The literature reviewed contains review articles on certain aspects of poultry production chain; however, in the past decade there has not been a review on the entire chain-farm to fork-of poultry production. For this review, a pool of 514 articles were selected for relevance via a systematic screening process (from >7500 original search articles). These studies identified a diversity of management and intervention strategies for the elimination or reduction of enteropathogens in poultry production. Many studies were laboratory or limited field trials with implementation in true commercial operations being problematic. Entities considering using commercial antienteropathogen products and interventions are advised to perform an internal validation and fit-for-purpose trial as Salmonella and Campylobacter serovars and biovars may have regional diversity. Future research should focus on nonchemical application within the processing plant and how a combination of synergisticinterventions through the production chain may contribute to reducing the overall carcass burden of enteropathogens, coupled with increased consumer education on safe handling and cooking of poultry.

Effects of ginger essential oil on physicochemical and structural properties of agar‑sodium alginate bilayer film and its application to beef refrigeration

To maintain the freshness of meat products, an agar‑sodium alginate (AS) bilayer antibacterial film incorporated with ginger essential oil (GEO) was developed. The effect of GEO at different concentrations (1%, 2%, 3% and 4% v/v) on the physical properties, micro-structure and antibacterial activity closely related to AS film's application to beef refrigeration was extensively studied. In addition, the effects of AS bilayer active film on refrigeration quality and shelf life of beef were systematically evaluated. The porous structure and number of oil droplets became more obvious with the increase of GEO amount in AS film. The incorporation and increase of GEO could delay the lipid oxidation and protein decomposition of beef, reduce the total counts of the tested microorganisms (total viable bacteria, psychrotrophic bacteria, Escherichia coli, Staphylococcus aureus, yeast, and mold) in meat samples. Compared with commercial polyethylene (PE) packaging, the accumulation of basic compounds from the degradation of beef protein as well as the microbial contamination was obviously improved, which could extend the comprehensive shelf life of beef by 4-6 days. Consequently, AS bilayer films incorporated with GEO, especially GEO at 4.0% (v/v) GEO concentration can be developed to be an antibacterial active packaging material for beef refrigeration.

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.

Birch Tar Introduced into Polylactide and Its Influence on the Barrier, Thermal, Functional and Biological Properties of the Film Obtained by Industrial Extrusion

The aim of the study was to evaluate possibility of producing a polylactide film with birch tar by the industrial extrusion method and whether the addition of 10% birch tar can ensure adequate biocidal properties of PLA against pathogenic microorganisms (E. coli, S. aureus, P. aeruginosa, A. tumefaciens, X. campestris, P. brassicacearum, P. corrugate and P. syringae) and fungi (A. niger, A. flavus and A. versicolor) while ensuring beneficial functional properties, such as water vapor, nitrogen, oxygen and carbon dioxide permeability, which are of considerable importance in the packaging industry. The main test methods used were ISO 22196, ISO 846, ISO 2556, ASTM F 1927 and ASTM F 2476-20. The obtained results prove the possibility of extruding polymer films with a biocidal additive, i.e., birch tar, and obtaining favorable properties that qualify the produced film for applications in the packaging industry.

An Asymmetric Microfluidic/Chitosan Device for Sustained Drug Release in Guided Bone Regeneration Applications

One of the major challenges of guided bone regeneration (GBR) is infections caused by pathogen colonization at wound sites. In this paper, an asymmetric microfluidic/chitosan device was developed to release drugs to inhibit infections and to ensure that guided bone regeneration can be realized. The microfluidic technique was introduced into the GBR membrane for the first time, which demonstrated more controllable drug release, more flexible clinical use and had a lower cost compared with surface treatments and embedded nanoparticles. Based on the theory of diffusion and Fick’s first law, the contact area and concentration gradient were adjusted to realize sustained drug release. The standard deviation of minocycline release over 5 days was only 12.7%, which was lower than the joint effect of porous chitosan discs and nanospheres. The in vitro experiments against E. coli and Streptococcus mutans showed the excellent antibacterial performance of the device (>95%). The in vitro experiments for fibroblasts at the microfluidic side and osteoblasts at the chitosan side showed the satisfactory biocompatibility and the ability of the device to enhance bone regeneration. Therefore, this microfluidic/chitosan device is a promising therapeutic approach to prevent infection and guide bone regeneration.

Adsorption Properties of Essential Oils on Polylactic Acid Microparticles of Different Sizes

The interaction between the polymer and the materials in contact with it affects its applicability. This can be particularly important in applications such as packaging or controlled drug delivery systems. Because of these interactions, the adsorption and diffusion properties of polylactic acid (PLA) are important. The absorption capacity of different polylactic acid particles for different additives like essential oils (Thymus vulgaris, Melissa officinalis, and Foeniculum vulgare essential oils) was investigated depending on the concentration of the essential oil. The PLA microparticles were prepared by the solvent evaporation emulsification method. The prepared particles had a degree of crystallinity of 0.1% and 16.1%, respectively, according to the granules used. This affects the particles' adsorption properties. The specific essential oil uptake of the more crystalline microparticles was on average 15% higher than that of the amorphous particles. The specific amount of essential oil adsorbed decreases with the decreasing concentration of essential oil in the solutions. We also investigated whether the amount of essential oil taken up was correlated with the solubility parameter of the essential oils. We concluded that the difference between the adsorption of the essential oils on the polymer was related to the essential oils' Hansen solubility parameter.

Preparation and characterization of chitosan/pullulan film loading carvacrol for targeted antibacterial packaging of chilled meat

In this research, the common microorganisms in chilled meat were used as the targeted antibacterial objects. Chitosan, pullulan, and carvacrol were chosen to prepare the edible antibacterial film. The effects of different concentrations of carvacrol on the microstructure, physical properties and antibacterial properties of the films were investigated. The results showed that the antibacterial activity of chitosan/pullulan film (CS/PU) was unsatisfactory, when carvacrol was added, the antibacterial activity of the chitosan/pullulan/carvacrol film (CS/PU/CAR) improved significantly (p < 0.05), and the water vapor permeability (WVP) of the CS/PU/CAR decreased significantly (p < 0.05). When the carvacrol concentration was higher than 1.25% (w/v), the tensile strength and percentage elongation at break of the CS/PU/CAR increased significantly (p < 0.05), and the CS/PU/CAR exhibited satisfying antibacterial activity against the common bacteria in chilled meat such as Pseudomonas fluorescens, Listeria monocytogenes, Escherichia coli, Pseudomonas putida, Enterobacter cloacae, and Staphylococcus aureus. Finally, the CS/PU/CAR film was applied to the preservation of chilled goat meat and extended the shelf life of goat meat to more than 15 days. These results suggested that the targeted CS/PU/CAR film can be used as biodegradable films for the active packaging of chilled meat.

Poly (lactic acid)-based pH responsive membrane combined with chitosan and alizarin for food packaging

A poly (lactic acid) (PLA) -based functional partition composite membrane (PLA/CA) containing chitosan (CS) and alizarin (AL) was designed by solution casting method. The PLA/CA membrane contains the antibacterial zone of the edge part (PLA/CS) and the pH response detection zone of the central part (PLA/AL). At the same time, the environmentally friendly plasticizer tributyl citrate (TBC) was added to make the prepared PLA/CA composite membrane have good flexibility and high transparency. The results of FE-SEM and FTIR showed that CS and AL were uniformly dispersed in PLA matrix and had good compatibility with PLA. The antioxidant activities of PLA/CS and PLA/AL composite films were 43.3 % and 72.8 %, respectively. At the same time, the inhibitory rates of PLA/CS membrane against Escherichia coli and Staphylococcus aureus were as high as 87.91 % and 75.17 %, respectively. PLA/AL films exhibit excellent UV barrier properties. When the environmental pH (ammonia and acetic acid vapor) changed repeatedly, the PLA/AL membrane showed reversible color change of yellow under acidic condition and purple under alkaline condition. During the packaging and storage of chicken breast meat, the freshness of chicken breast meat can be detected by the color change of functional PLA/CA composite membrane.

Preparation, Characterization and Evaluation of Antibacterial Properties of Polylactide-Polyethylene Glycol-Chitosan Active Composite Films

Chitin is a natural biopolymer obtained from the exoskeleton of crustaceans. Chitosan is a derivative of chitin, which has antimicrobial properties and potential applications in several industries. Moreover, the composites of chitosan with other biodegradable polymers, such as polylactide (PLA) as packaging film, have shown promising results. In this study, chitosan was obtained and characterized from shrimp shells. Then, polylactide-chitosan composite films were prepared by a solvent casting technique using various amounts of chitosan (0.5–2% w/w) and polyethylene glycol as plasticizer (10% w/w). Thermal, mechanical properties, Fourier-transform infrared, scanning electron microscopy, as well as antibacterial properties of composite films were determined. It was found that adding chitosan (CH) into PLA films has a significant effect on tensile strength and no effect on thermal properties. The results showed a reduction on average of 1 log of colony-forming units against Staphylococcus aureus, while there is no antibacterial effect against Salmonella typhimurium. The study proved the antibacterial effect of CH in films of PLA against Gram-positive bacteria and appropriate mechanical properties. These films could be used for the development of biodegradable/eco-friendly food packaging prototypes, as a potential solution to replace conventional non-degradable packaging materials.

Optimization of Platinum Nanoparticles (PtNPs) Synthesis by Acid Phosphatase Mediated Eco-Benign Combined with Photocatalytic and Bioactivity Assessments

Noble metal nanoparticles (NMNPs) are viable alternative green sources compared to the chemical available methods in several approach like Food, medical, biotechnology, and textile industries. The biological synthesis of platinum nanoparticles (PtNPs), as a strong photocatalytic agent, has proved as more effective and safer method. In this study, PtNPs were synthesized at four different temperatures (25 °C, 50 °C, 70 °C, and 100 °C). PtNPs synthesized at 100 °C were smaller and exhibited spherical morphology with a high degree of dispersion. A series of physicochemical characterizations were applied to investigate the synthesis, particle size, crystalline nature, and surface morphology of PtNPs. The biosynthesized PtNPs were tested for the photodegradation of methylene blue (MB) under visible light irradiations. The results showed that PtNPs exhibited remarkable photocatalytic activity by degrading 98% of MB only in 40 min. The acid phosphatase mediated PtNPs showed strong bacterial inhibition efficiency against S. aureus and E. coli. Furthermore, it showed high antioxidant activity (88%) against 1,1-diphenyl-2-picryl-hydrazil (DPPH). In conclusion, this study provided an overview of the applications of PtNPs in food chemistry, biotechnology, and textile industries for the deterioration of the natural and synthetic dyes and its potential application in the suppression of pathogenic microbes of the biological systems. Thus, it could be used as a novel approach in the food microbiology, biomedical and environmental applications.

High-pressure treatment of water-filled co-extruded polylactide films: Effect on microstructure, barrier, thermal, and rheological properties

The impact of high-pressure treatments (450 and 600 MPa) on the morphological, thermal, structural, and barrier properties of commercial coextruded polylactide (PLA) packaging films has been explored to evaluate their applicability in food processing. Pouches filled with water as a food simulant were subjected to high-pressure treatment for 15 min at ambient temperature. Results indicated no significant changes in the visual appearance, color, integrity, or water barrier properties of the post-process pouches. However, high-pressure treatment affected mechanical property results. Thermal analysis of the film showed endothermic double melting peaks (165.12 and 170.55°C), which did not change with the pressurization; however, the exothermic crystallization peak (118.08°C) varied significantly. Both SEM and AFM micrographs demonstrated that the surface morphology and roughness parameters (arithmetic mean [S_a ] and root mean square height [S_q ]) of the films were significantly affected by the HP treatment, which is further complemented by the FTIR spectra and XRD diffractogram. Melt rheology (175-205°C) of the pressure-treated films showed a significant drop (20-30%) in mechanical rigidity (G') when compared to the untreated sample. Changes in the microstructure/crystallinity in the PLA films were indicated by van Gurp and Palmen plot. PRACTICAL APPLICATION: The results reported here can help to improve the design of the coextruded packaging materials so that it can be successfully implemented to high-pressure processing and high pressure-assisted thermal processing of food.

Formation and Investigation of Mechanical, Thermal, Optical and Wetting Properties of Melt-Spun Multifilament Poly(lactic acid) Yarns with Added Rosins

One method for adding enhancing properties to textile materials is the insertion of natural ingredients into the textile products during the manufacturing or finishing process. The aim of this research is to investigate the formation of biodegradable melt-spun multifilament Poly(lactic acid) (PLA) yarns with different contents (i.e., 5%, 10%, and 15%) of natural material–rosin, also known as colophony. In this study, multifilament yarns were successfully formed from PLA and a natural substance–pine rosin by melt-spinning them at two different draw ratios (i.e., 1.75 and 2.75). The results indicated that a 1.75 draw ratio caused the formation of PLA and PLA/rosin yarns that were brittle. The presence of rosin (i.e., 5% and 10%) in multifilament yarns decreased the mechanical properties of the PLA/rosin melt-spun multifilament yarns’ tenacity (cN/tex), breaking tenacity (cN/tex), and tensile strain (%) and elongation at break (%) and increased absorbance in the entire UV region spectra. In addition, the melting point and degree of crystallinity decreased and there was an increase in the wetting angle compared with pure PLA multifilament. The investigation of melt-spun yarns with Raman spectroscopy proved the presence of rosin in PLA melt-spun yarns.

Preparation and characterization of polylactic acid/fenugreek essential oil/curcumin composite films for food packaging applications

Curcumin and Fenugreek essential oil (FEO) were blended into the PLA matrix by solution casting technique to improve the functional properties of the composite film. Both fillers (curcumin and FEO) were properly combined and uniformly distributed in the polymer matrix to create a PLA-compatible composite evidenced by Scanning electron microscope (SEM) and Fourier Transform Infrared (FT-IR) results. The addition of FEO and curcumin to the composite film improved UV-blocking, surface color, tensile strength, flexibility, thickness, and Water contact angle (WCA). However, the inclusion of curcumin and FEO slightly diminish the Water vapor permeability (WVP) while maintaining its thermal stability. The PLA-based composite film exhibited good antibacterial and anti-oxidant properties. In addition, a food quality test was performed on strawberry, and the results were compared to the commercial (polyethylene) film.

The Role of Birch Tar in Changing the Physicochemical and Biocidal Properties of Polylactide-Based Films

The objective of this study was to produce bactericidal polymer films containing birch tar (BT). The produced polymer films contain PLA, plasticiser PEG (5% wt.) and birch tar (1, 5 and 10% wt.). Compared to plasticised PLA, films with BT were characterised by reduced elongation at break and reduced water vapour permeability, which was the lowest in the case of film with 10% wt. BT content. Changes in the morphology of the produced materials were observed by performing scanning electron microscopy (SEM) and atomic force microscopy (AFM) analysis; the addition of BT caused the surface of the film to be non-uniform and to contain recesses. FTIR analysis of plasticised PLA/BT films showed that the addition of birch tar did not change the crystallinity of the obtained materials. According to ISO 22196: 2011, the PLA film with 10% wt. BT content showed the highest antibacterial effect against the plant pathogens A. tumefaciens, X. campestris, P. brassicacearum, P. corrugata, P. syringae. It was found that the introduction of birch tar to plasticised PLA leads to a material with biocidal effect and favourable physicochemical and structural properties, which classifies this material for agricultural and horticultural applications.

Microfibrillated cellulose reinforced starch/polyvinyl alcohol antimicrobial active films with controlled release behavior of cinnamaldehyde

The starch/polyvinyl alcohol (ST/PVA) films incorporated with cinnamaldehyde (CIN) and microfibrillated cellulose (MFC) were developed. The effect of MFC content on the films' properties was studied. The SEM results showed that MFC promoted compatibility among starch, PVA and CIN. With increased content of MFC, the strength of the films was improved and their flexibility reduced, the films' crystallinity degree and hydrophobicity were improved. The oxygen and water vapor permeability of the films both reduced first and then increased as a whole. The release of CIN from films into the food stimulant (10% ethanol) could be controlled by MFC. When MFC content was between 1% and 7.5%, it decelerated the release of CIN but high MFC content exceeded 10% promoted the release of CIN. It revealed that films containing CIN could inhibit growth of S. putrefaciens. It showed a good prospect of using MFC to develop controlled release active ST/PVA films.

Efficacy of Biopolymer/Starch Based Antimicrobial Packaging for Chicken Breast Fillets

Food contamination leading to the spoilage and growth of undesirable bacteria, which can occur at any stage along the food chain, is a significant problem in the food industry. In the present work, biopolymer polybutylene succinate (PBS) and polybutylene succinate/tapioca starch (PBS/TPS) films incorporating Biomaster-silver (BM) and SANAFOR^® (SAN) were prepared and tested as food packaging to improve the lifespan of fresh chicken breast fillets when kept in a chiller for seven days. The incorporation of BM and SAN into both films demonstrated antimicrobial activity and could prolong the storability of chicken breast fillets until day 7. However, PBS + SAN 2%, PBS/TPS + SAN 1%, and PBS/TPS + SAN 2% films showed the lowest microbial log growth. In quality assessment, incorporation of BM and SAN into both film types enhanced the quality of the chicken breast fillets. However, PBS + SAN 1% film showed the most notable enhancement of chicken breast fillet quality, as it minimized color variation, slowed pH increment, decreased weight loss, and decelerated the hardening process of the chicken breast fillets. Therefore, we suggest that the PBS + SAN and PBS/TPS + SAN films produced in this work have potential use as antimicrobial packaging in the future.

Elaboration and Characterization of Bioactive Films Obtained from the Incorporation of Cashew Nut Shell Liquid into a Matrix of Sodium Alginate

The objective of this work was to obtain and characterize sodium alginate-based biopolymer films with the addition of cashew nut shell liquid (CNSL). The study employed a completely randomized design, including 0%, 0.5%, 1%, and 1.5% inclusion of CNSL. Uniform formation of the films was observed, and the addition of CNSL provided better thermal resistance than did the treatment without inclusion, while the addition of CNSL reduced the homogeneity of the microstructure, especially for the 1.5% inclusion level. The permeability of the film increased as the level of CNSL increased, especially in response to the concentrations of 1% and 1.5%, and no significant difference in permeability was observed between these treatments. The tensile strength decreased proportionally as a function of the addition of CNSL, as its inclusion increased the elasticity and elongation of the films. In addition, the films with CNSL demonstrated strong antioxidant activity and discrete antimicrobial activity, and ecotoxicity analysis showed that the levels of CNSL tested and the films produced were nontoxic. Thus, these films are promising and self-sustainable alternatives for the agrifood industry.

Chitosan-Coated Poly(lactic acid) Nanofibres Loaded with Essential Oils for Wound Healing

Chronic skin wounds are characterised by a non-healing process that makes necessary the application of wound dressings on the damaged area to promote and facilitate the recovery of skin’s physiological integrity. The aim of the present work is to develop a bioactive dressing that, once applied on the injured tissue, would exert antibacterial activity and promote adhesion and proliferation of fibroblasts. Nanofibres consisting of poly(lactic acid) (PLA) and essential oils (EOs) were electrospun and coated with a medium molecular weight chitosan (CS). Black pepper essential oil (BP-EO) or limonene (L), well-known for their antibacterial properties, were added to the PLA/acetone solution before electrospinning; phase separation phenomena occurred due to the poor solubility of the EOs in the PLA solution and led to fibres having surface nano-pores. The porous electrospun fibres were coated with CS to produce hydrophilic membranes that were easy to handle, biocompatible, and suited to promote cellular proliferation. The fibrous scaffolds were tested in terms of mechanical resistance, wettability, antibacterial activity, in-vitro cytotoxicity, and ability to promote fibroblasts’ adhesion and proliferation. The results obtained proved that the CS coating improved the hydrophilicity of the fibrous mats, enhanced EO’s antibacterial potential, and promoted cell adhesion and proliferation.

Development of a Sodium Alginate-Based Active Package with Controlled Release of Cinnamaldehyde Loaded on Halloysite Nanotubes

The worsening environment and the demand for safer food have accelerated the development of new food packaging materials. The objective of this research is to prepare antimicrobial food packaging film with controlled release by loading cinnamaldehyde (CIN) on etched halloysite nanotubes (T-HNTs) and adding it to sodium alginate (SA) matrix. The effects of T-HNTs-CIN on the physical functional properties and antibacterial activity of the film were systematically evaluated, and the release of CIN in the film was also quantified. Transmission electron microscopy and nitrogen adsorption experiments showed that the halloysite nanotubes had been etched and CIN was successfully loaded into the T-HNTs. The addition of T-HNTs-CIN significantly improved the water vapor barrier properties and tensile strength of the film. Similarly, the presence of T-HNTs-CIN in the film greatly reduced the negative effects of ultraviolet rays. The release experiment showed that the diffusion time of CIN in SA/T-HNTs-CIN film to fatty food simulation solution was delayed 144 h compared with that of SA/CIN film. Herein, the antibacterial experiment also confirmed the controlled release effect of T-HNTs on CIN. In conclusion, SA/T-HNTs-CIN film might have broad application prospects in fatty food packaging.

Antimicrobial, antioxidant and physical properties of chitosan film containing Akebia trifoliata (Thunb.) Koidz. peel extract/montmorillonite and its application

A novel active packaging film was prepared in this study that incorporated Akebia trifoliata (Thunb.) Koidz. peel extracts (APE) and montmorillonite (MMT) into chitosan (CH) films. Compared with the pure CH film, the CH/APE film showed significantly higher tensile strength, elongation at break, UV light resistance, and antibacterial activity; the CH/MMT film displayed significant increases in contact angle, antioxidant activity, oxygen permeability, and thermal stability. SEM and AFM analyses showed that the additions were well-distributed into the CH matrix, but MMT induced a more compact and rougher structure. The CH-based film formula was optimized using the single-factor test and Box-Behnken design and was 0.15% MMT, 0.15% APE, and 1.50% CH. Besides, the optimized coating was applied in the postharvest preservation of A. trifoliata fruits, which yielded a significant effect on the delaying crack and mature of the fruits during 35 days of storage at 5 °C.

Influence of Tea Tree Essential Oil and Poly(ethylene glycol) on Antibacterial and Physicochemical Properties of Polylactide-Based Films

The aim of the study was to establish the influence of poly(ethylene glycol) (PEG) on the properties of potential biodegradable packaging materials with antibacterial properties, based on polylactide (PLA) and tea tree essential oil (TTO). The obtained polymeric films consisted of PLA, a natural biocide, and tea tree essential oil (5–20 wt. %) was prepared with or without an addition of 5 wt. % PEG. The PLA-based materials have been tested, taking into account their morphology, and their thermal, mechanical and antibacterial properties against Staphylococcus aureus and Escherichia coli. It was established that the introduction of a plasticizer into the PLA–TTO systems leads to an increase in tensile strength, resistance to deformation, as well an increased thermal stability, in comparison to films modified using only TTO. The incorporation of 5 wt. % PEG in the PLA solution containing 5 wt. % TTO allowed us to obtain a material exhibiting a satisfactory antibacterial effect on both groups of representative bacteria. The presented results indicated a beneficial effect of PEG on the antibacterial and functional properties of materials with the addition of TTO.

Effectiveness assessment of TiO2-Al2O3 nano-mixture as a filler material for improvement of packaging performance of PLA nanocomposite films

The main objective of this study was to assess the effectiveness of TiO2-Al2O3 nano-mixture used as filler in improving packaging films performance. Polylactic acid/titanium dioxide (PLA/TiO2), polylactic acid/alumina (PLA/Al2O3) and polylactic acid/TiO2-Al2O3 (PLA/TiO2-Al2O3) nanocomposite films were successfully prepared via melt mixing process and thoroughly characterized by FTIR spectroscopy, X-ray diffraction (XRD), UV–vis spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The properties such as heat resistant, barrier, mechanical and antimicrobial properties, required for food packaging have also been investigated. As compared to the neat PLA film, the developed PLA nanocomposites have displayed superior properties particularly the PLA/ TiO2-Al2O3 nanocomposite film. This resulted material has showed a 22 °C increase in its thermal stability versus 14 and 2 °C in the cases of PLA/TiO2 and PLA/Al2O3 respectively, and a 54% reduction of its water vapor permeability in comparison with 47% for PLA/TiO2 and 39% for PLA/Al2O3. In addition, the PLA/TiO2-Al2O3 had a significant enhancement of its mechanical properties. Its Young modulus increased by 102% unlike 23.60% for the PLA/TiO2 and 44.66% for the PLA/Al2O3. It was also noticed that this nanocomposite film demonstrated stronger antibacterial activity than the two others. The bacterial growth inhibition effect of TiO2-Al2O3 nano-mixture against Pseudomonas aeruginosa and Escherichia coli bacteria was more effective than that of its two constituents.

Influence of Myrrh Extracts on the Properties of PLA Films and Melt-Spun Multifilament Yarns

A possible approach for providing new properties for textiles is the insertion of natural ingredients into the textile product during the process of its manufacture. Myrrh has long been used in medicine as an antibacterial and antifungal material. Polylactide (PLA) is a thermoplastic synthetic biopolymer obtained from renewable resources-and due its biodegradability, is also widely used in medicine. In this study, films and multifilament yarns from modified biodegradable PLA granules with ethanolic and aqueous myrrh extracts were developed and characterized. Optical microscopy was used to determine the surface morphology of PLA/myrrh multifilament yarns. Tensile tests, ultraviolet-visible (UV-vis), differential scanning calorimetry (DSC) were applied to determine, consequently, mechanical, optical properties and degree of crystallinity of PLA/myrrh films and multifilament yarns. The chemical composition of PLA/myrrh multifilament yarns was estimated by Fourier-transform infrared (FTIR) spectroscopy method. The results showed that it is possible to form PLA melt-spun multifilament yarns with myrrh extract. The type of myrrh extract (ethanolic or aqueous) has a significant influence on the mechanical and optical properties of the PLA films and melt-spun yarns. The mechanical properties of PLA films and melt-spun multifilament yarns formed from PLA granules with aqueous myrrh extract decreased 19% and 21% more than PLA with ethanolic extract, respectively. Analysis of UV-vis spectra showed that, due to the yellow hue, the reflectance of PLA films and melt-spun PLA multifilament yarns modified with myrrh extracts decreased exponentially. The DSC test showed that multifilament yarns from PLA modified with aqueous extract had the highest degree of crystallization.

Zein/MCM-41 Nanocomposite Film Incorporated with Cinnamon Essential Oil Loaded by Modified Supercritical CO2 Impregnation for Long-Term Antibacterial Packaging

Antimicrobial medicine and food packages based on bio-based film containing essential oils have attracted great attention worldwide. However, the controlled release of essential oils from these film nanocomposites is still a big challenge. In this study, a long-term antibacterial film nanocomposite composed of zein film and cinnamon essential oil (CEO) loaded MCM-41 silica nanoparticles was prepared. The CEO was loaded into MCM-41 particles via modified supercritical impregnation efficiently with a high drug load (>40 wt%). The morphologies of the prepared nanoparticles and film nanocomposite were characterized by a scanning electron microscope. The release behaviors of CEO under different temperatures, high humidity, continuous illumination and in phosphate buffer solution (PBS) solution were investigated. The results showed that the film nanocomposite had an outstanding release-control effect. The addition of MCM-41 nanoparticles also improved the mechanical properties of zein films. The antibacterial effect of CEO was significantly prolonged by the film nanocomposite; indicating the CEO film nanocomposite fabricated via modified supercritical CO₂ impregnation was a potential long-term antibacterial medicine or food package material.