Preparation and Characterization of Novel Food Packaging Materials Based on Biodegradable PCL/Ag-Kaolinite Nanocomposites with Controlled Release Properties

Effect of Kaolin clay and Ficus carica mediated silver nanoparticles on chitosan food packaging film for fresh apple slice preservation

In this work, a novel antioxidant, antibacterial, and biodegradable food packaging film was elaborated, by incorporating natural kaolin clay (KC) and Ficus carica mediated silver nanoparticles (AgNPs) into Chitosan (Cht). A comparison of the physico-chemical and functional characteristics of the Cht/KC/AgNPs film was performed with those of Cht, Cht/KC, and Cht/AgNPs. SEM analysis showed a rough surface in the composite films containing KC particles because of their large diameter (50-120 μm) compared to AgNPs (20-80 nm). The FTIR analysis suggested that the interactions between Cht and AgNPs were stronger than those between Cht and KC. The tensile strength of Cht film increased from 16 MPa to ∼24 MPa in Cht/KC/AgNPs film. The introduction of KC and/or AgNPs considerably improved the light and moisture barrier capacity of the Cht film. The UV light transmittance decreased by 50 % for Cht film when incorporated by KC and AgNPs. Moreover, Cht/AgNPs was better in terms of antioxidant, antibacterial, and mechanical compared to Cht/KC, which was superior in biodegradability and water vapor barrier capacity. In particular, the Cht/KC/AgNPs film presented good barrier, antioxidants, antibacterial, mechanical, and biodegradable properties, owing to the synergistic effect between KC and AgNPs. For the packaging properties, all the films were tested for their ability to keep the freshness of apple slices as wrapping material. The films exhibited good results, and the Cht/KC/AgNPs showed promising performance regarding the moisture loss, browning index, total phenolic compound, and antioxidant activity of the apple slices. Moreover, the Cht/KC/AgNPs film exhibited a migration of silver meeting the standards set by EFSA and ECHA, which makes this film safe for food packaging.

Scalable and Room-Temperature Ring-Opening Polymerization of ε-Caprolactone Catalyzed by Active Lithium Tetramethylene-Tethered Bis[N-(N'-butylimidazol-2-ylidene)] N-Heterocyclic Carbene as a Lewis Acid Organocatalyst

The Lewis acid organocatalytic system of lithium tetramethylene-tethered bis[N-(N'-butylimidazol-2-ylidene)] N-heterocyclic carbene (1,4-bisNHC) including lithium benzyloxide and benzyl alcohol has been successfully utilized in the ring-opening polymerization (ROP) of ε-caprolactone (CL) for the first time. The catalytic performance of this organic catalyst in the synthesis of high-molecular-weight polymers was investigated via bulk polymerization using different combinations of tetramethylene-tethered bis[N-(N'-butylimidazolium)] hexafluorophosphate (1,4-bis[Bim][PF₆]), benzyl alcohol (BnOH), and n-butyl lithium (nBuLi) ([1,4-bis[Bim][PF₆]]/[BnOH]/[nBuLi]) with the molar ratios of 0:2:2, 1:1:3, 1:2:3, and 1:2:4. The results showed that the molar ratio of 1:2:3 efficiently and rapidly initiated the bulk ROP of CL at room temperature with a high molar ratio of CL to 1,4-bis[Bim][PF₆] of 3000/1 and produced the highest number of average-molecular-weight (M_n) poly(ε-caprolactone) (103,057 g mol^-1) with the dispersity (D̵) and %conversion of 1.73 and 98% in a short period of time (152 s). From comparative studies, the relative polymerization rates of the bulk ROP of CL with different [1,4-bis[Bim][PF₆]]/[BnOH]/[nBuLi] molar ratios was determined in the following order: 1:2:4 > 1:1:3 > 1:2:3 > 0:2:2. For mechanistic investigation, the bulk ROP mechanism of CL with our organic catalyst was proposed through the intramolecular bis-lithium-carbene interaction pathway for 1,4-bisNHC_1,1,3, 1,4-bisNHC_1,2,3, and 1,4-bisNHC_1,2,4 systems.

A Review of Nonbiodegradable and Biodegradable Composites for Food Packaging Application

The dependency on nonbiodegradable-based food packaging, increase in population growth, and persistent environmental problems are some of the driving forces in considering the development of biodegradable food packaging. This effort of green packaging has the potential to solve issues on plastic wastes through the combination of biodegradable composite-based food packaging with plant extracts, nanomaterials, or other types of polymer. Modified biodegradable materials have provided numerous alternatives for producing green packaging with mechanical strength, thermal stability, and barrier performance that are comparable to the conventional food packaging. To the best of our knowledge, the performance of nonbiodegradable and biodegradable composites as food packaging in terms of the above properties has not yet been reviewed. In this context, the capability of biodegradable polymers to substitute the nonbiodegradable polymers was emphasized to enhance the packaging biodegradation while retaining the mechanical strength, thermal stability, barrier properties, and antioxidant and antimicrobial or antibacterial activity. These are the ultimate goal in the food industry. This review will impart useful information on the properties of food packaging developed from different polymers and future outlook toward the development of green food packaging.

A Critical Review of the Performance and Soil Biodegradability Profiles of Biobased Natural and Chemically Synthesized Polymers in Industrial Applications

This review explores biobased polymers for industrial applications, their end fate, and most importantly, origin and key aspects enabling soil biodegradation. The physicochemical properties of biobased synthetic and natural polymers and the primary factors governing degradation are explored. Current and future biobased systems and factors allowing for equivalent comparisons of degradation and possible sources for engineering improved biodegradation are reviewed. Factors impacting ultraviolet (UV) stability of biopolymers have been described including methods to enhance photoresistance and impact on biodegradation. It discusses end-fate of biopolymers in soil and impact of residues on soil health. A limited number of studies examine side effects (e.g., microbial toxicity) from soil biodegradation of composites and biopolymers. Currently available standards for biodegradation and composting have been described with limitations and scope for improvements. Finally, design considerations and implications for sustainable polymers used, under consideration, and to be considered within the context of a rational biodegradable strategy are elaborated.

Overview of Bioplastic Introduction and Its Applications in Product Packaging

Each year, more than 330 million tons of plastic are produced worldwide. The main consumers of plastics are the packaging (40%), building (20%) and automotive (8%) industries, as well as for the manufacture of household appliances. The vast majority of industrial plastics are not biodegradable and, therefore, create environmental problems due to the increase in the amount of solid waste. Studies have been conducted to produce biodegradable materials such as bioplastics to overcome this environmental problem. Bioplastics are defined as materials that are bio-based, biodegradable, or both; they can provide excellent biodegradability and can be used to help alleviate environmental problems. Therefore, this article presents an overview of the introduction of bioplastic materials and classifications, and a comprehensive review of their drawbacks and areas of importance, including basic and applied research, as well as biopolymer mixtures and biocomposites developed in the last decade. At the same time, this article provides insights into the development of bioplastics research to meet the needs of many industries, especially in the packaging industry in Malaysia. This review paper also focuses generally on bioplastic packaging applications such as food and beverage, healthcare, cosmetics, etc.

Biotechnological methods to improve the quality and safety of milk

The foremost task of milk producers and processors is to prolong the shelf life of dairy products. One of the high-tech and innovative ways to address this issue is to suppress the growth of undesirable microorganisms. EMR milk treatment is proposed as one of such promising methods of product exposure in order to reduce the total microbial count, improve the milk’s chemical composition, and, ultimately, improve the quality and safety of milk and dairy products. The requirements of regulatory documents for the safety of milk and dairy products prohibit the direct introduction of preservatives into milk. In this regard, it is advisable to look for ways to use preservatives in packaging materials’ composition while observing the safety of the packaging itself. The purpose of our study was to identify the effect of electromagnetic treatment and preservatives, both direct application and in the composition of polyethylene packaging, on the physicochemical and microbiological parameters of milk at various storage temperatures. It was established that preservative’s introduction into the packaging film did not affect the chemical parameters of milk; the content of lactic acid bacteria in the product after a day of storage in modified polyethylene amounted to 1.4x106 CFU/cm3, while their number amounted 8.1x106 CFU/cm3 when stored in glass packaging.

Behaviours of poly(ε-caprolactone)/silver-montmorillonite nanocomposite in membrane ultrafiltration for wastewater treatment

The scope of this work consists in studying the possibility of using the long-lasting antimicrobial poly(ε-caprolactone)/silver-montmorillonite (PCL/Ag-MMT) materials which we have developed in our previous research, as new class of nanocomposite membranes, finding their application in the wastewater treatment. The surface properties of these hybrid membranes were investigated by scanning electron microscopy (SEM) analysis and contact angle measurements. The SEM results showed that the synthesized membranes exhibited homogeneous sponge microstructures. It was found that the gradual inclusion of nanoparticles (2, 3 and 5 wt. %) into PCL matrix induced a remarkable increase of the membrane thickness. Moreover, these hybrid materials exhibited an enhancement of the surface hydrophilicity attributed to the hydrophilic nature of clay incorporated. The water contact angle of the PCL membrane surface noticeably decreased after the Ag-MMT addition: dropping from 82.60° for PCL 0%Ag-MMT to 64.28° for PCL 5%Ag-MMT membrane. The antimicrobial properties of the membranes were confirmed using Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) as the model bacteria. Quality parameters including total suspended solids (TSS), electric conductivity (EC), nitrates, chlorides, bicarbonates, heavy metals and other trace elements, were determined before and after treatment of real wastewater. A decrease of nitrates by 15.12%, a diminution of sulphates by 45.61% and a removal of 41.38%, 53.57% and61.11% for heavy metals Pb, Zn and Cd respectively indicating clearly that the ultrafiltration process using PCL/AgMMT nanocomposite membranes is an effective way to eliminate the wastewater effluents.

Biodegradable Poly(ε-Caprolactone) Active Films Loaded with MSU-X Mesoporous Silica for the Release of α-Tocopherol

In this study, new active PCL (poly(ε-caprolactone)) films containing α-tocopherol (TOC) and MSU-X mesoporous silica were prepared by melt blending. The studied additives were directly incorporated into the polymer matrix or by impregnating TOC into MSU-X silica (PCL-IMP). Thermal, optical, oxygen and water barrier properties as well as oxidation onset parameters, were studied. Films containing MSU-X and/or TOC showed a significant increase in oxidative onset temperature (OOT) and oxidative induction time (OIT), improving thermal stability against materials oxidation by the addition of mesoporous silica and TOC into the polymer matrix. In addition, the effect of MSU-X addition on the migration behaviour of α-tocopherol from active films was investigated at 40 °C using 50% (v/v) ethanol as fatty food simulant, showing PCL-IMP films the lower release content and diffusion coefficient (3.5 × 10⁻¹⁵ cm² s⁻¹). Moreover, radical scavenging (DPPH and ABTS) and antibacterial activity against E. coli and S. aureus were favoured by the release of α-tocopherol in the developed films. The obtained results have demonstrated the potential of the new PCL-based active formulations for TOC controlled release in antioxidant and antibacterial food packaging applications.