Modification of banana starch (Musa paradisiaca L.) with polyethylene terephthalate: Virgin and bottle waste

Quaternization of cassava starch and determination of antimicrobial activity against bacteria and coronavirus

This study describes the novel development of quaternized cassava starch (Q-CS) with antimicrobial and antiviral properties, particularly effective against the MHV-3 coronavirus. The preparation of Q-CS involved the reaction of cassava starch (CS) with glycidyltrimethylammonium chloride (GTMAC) in an alkaline solution. Q-CS physicochemical properties were determined by FTIR, NMR, elemental analysis, zeta potential, TGA, and moisture sorption. FTIR and NMR spectra confirmed the introduction of cationic groups in the CS structure. The elemental analysis revealed a degree of substitution (DS) of 0.552 of the cationic reagent on the hydroxyl groups of CS. Furthermore, Q-CS exhibited a positive zeta potential value (+28.6 ± 0.60 mV) attributed to the high positive charge density shown by the quaternary ammonium groups. Q-CS demonstrated lower thermal stability and higher moisture sorption compared to CS. The antimicrobial activity of Q-CS was confirmed against Escherichia coli (MIC = 0.156 mg mL-1) and Staphylococcus aureus (MIC = 0.312 mg mL-1), along with a remarkable ability to inactivate 99% of MHV-3 coronavirus after only 1 min of direct contact. Additionally, Q-CS showed high cell viability (close to 100%) and minimal cytotoxicity effects, guaranteeing its safe use. Therefore, these findings indicate the potential use of Q-CS as a raw material for antiseptic biomaterials.

Mechanical, chemical, and bio-recycling of biodegradable plastics: A review

The extensive use of petroleum-based non-biodegradable plastics for various applications has led to global concerns regarding the severe environmental issues associated with them. However, biodegradable plastics are emerging as green alternatives to petroleum-based non-biodegradable plastics. Biodegradable plastics, which include bio-based and petroleum-based biodegradable polymers, exhibit advantageous properties such as renewability, biocompatibility, and non-toxicity. Furthermore, certain biodegradable plastics are compatible with existing recycling streams intended for conventional plastics and are biodegradable in controlled and/or predicted environments. Recycling biodegradable plastics before their end-of-life (EOL) degradation further enhances their sustainability and reduces their carbon footprint. Since the production of biodegradable plastic is increasing and these materials will coexist with conventional plastics for many years to come, it is essential to identify the optimal recycling options for each of the most prevalent biodegradable plastics. The substitution of virgin biodegradable plastics by their recyclates leads to higher savings in the primary energy demand and reduces global warming impact. This review covers the current state of the mechanical, chemical, and bio-recycling of post-industrial and post-consumer waste of biodegradable plastics and their related composites. The effects of recycling on the chemical structure and thermomechanical properties of biodegradable plastics are also reported. Additionally, the improvement of biodegradable plastics by blending them with other polymers and nanoparticles is comprehensively discussed. Finally, the status of bioplastic usage, life cycle assessment, EOL management, bioplastic market, and the challenges associated with the recyclability of biodegradable plastics are addressed. This review gives comprehensive insights into the recycling processes that may be employed for the recycling of biodegradable plastics.

Biopolymers as green-based food packaging materials: A focus on modified and unmodified starch-based films

The ideal food packaging materials are recyclable, biodegradable, and compostable. Starch from plant sources, such as tubers, legumes, cereals, and agro-industrial plant residues, is considered one of the most suitable biopolymers for producing biodegradable films due to its natural abundance and low cost. The chemical modification of starch makes it possible to produce films with better technological properties by changing the functional groups into starch. Using biopolymers extracted from agro-industrial waste can add value to a raw material that would otherwise be discarded. The recent COVID-19 pandemic has driven a rise in demand for single-use plastics, intensifying pressure on this already out-of-control issue. This review provides an overview of biopolymers, with a particular focus on starch, to develop sustainable materials for food packaging. This study summarizes the methods and provides a potential approach to starch modification for improving the mechanical and barrier properties of starch-based films. This review also updates some trends pointed out by the food packaging sector in the last years, considering the impacts of the COVID-19 pandemic. Perspectives to achieve more sustainable food packaging toward a more circular economy are drawn.

The Properties, Modification, and Application of Banana Starch

Banana is a tropical fruit crop that is consumed at large, not only because of the quantity produced but also because it serves the calorific needs of millions of people. Banana is a potential source of high starch content (more than 60%). The application of starch for various purposes is dependent upon its structural, physicochemical, and functional properties. A native starch does not possess all required properties for specific use in the food product. To improve its application, starch can be modified physically, chemically, and enzymatically. Each of these modification methods provides different characteristics to the modified starch. This review aims to examine the chemical composition, granule morphology, crystallinity, pasting, thermal properties, and digestibility of banana starch, and discusses the various modifications and potential applications of banana starch in the food industry.

Post COVID-19 pandemic: Disposable face masks as a potential vector of antibiotics in freshwater and seawater

With the outbreak and widespread of the COVID-19 pandemic, large numbers of disposable face masks (DFMs) were abandoned in the environment. This study first investigated the sorption and desorption behaviors of four antibiotics (tetracycline (TC), ciprofloxacin (CIP), sulfamethoxazole (SMX), and triclosan (TCS)) on DFMs in the freshwater and seawater. It was found that the antibiotics in the freshwater exhibited relatively higher sorption and desorption capacities on the DFMs than those in the seawater. Here the antibiotics sorption processes were greatly related to their zwitterion species while the effect of salinity on the sorption processes was negligible. However, the desorption processes were jointly dominated by solution pH and salinity, with greater desorption capacities at lower pH values and salinity. Interestingly, we found that the distribution coefficient (K_d) of TCS (0.3947 L/g) and SMX (0.0399 L/g) on DFMs was higher than those on some microplastics in freshwater systems. The sorption affinity of the antibiotics onto the DFMs followed the order of TCS > SMX > CIP > TC, which was positively correlated with octanol-water partition coefficient (log K_ow) of the antibiotics. Besides, the sorption processes of the antibiotics onto the DFMs were mainly predominated by film diffusion and partitioning mechanism. Overall, hydrophobic interaction regulated the antibiotics sorption processes. These findings would help to evaluate the environmental behavior of DFMs and to provide the analytical framework of their role in the transport of other pollutants.

Sulfur functionality-modified starches: Review of synthesis strategies, properties, and applications

Starch is the second most abundant naturally-occurring polymer after cellulose that possess superior physicochemical and biological features with numerous practical applications ranging from industrial to biomedical. Despite, native starch suffer from some drawbacks, including difficult processability, low shear and thermal stability, weak mechanical properties, and tendency to easily retrograde and undergo syneresis. Therefore, modification of native starch is necessary for circumvent the above-mentioned problems and expanding application ranges. This natural polymer can be modified using chemical, physical, enzymatic, and genetic engineering strategies. Amongst, chemical approaches have received more attention owing to enhancing physicochemical and biological features that lead to higher performance than those of the other strategies. In this context, incorporation of sulfur functionality-containing groups (sulfonation and sulfation) can be considered as an efficient approach due to significant enhancement in physiochemical properties, including zeta potential (move to negative values), molecular weight, processiability (e.g., solubility and meltability), and rheology. Furthermore, this strategy can modified some biological features, such as hemocompatibility, protein sorption, biostability, adhesion and proliferation of numerous cells, antithrombogenicity, antiinflammatory, antiviral, antimicrobial, antioxidant, antifungal, anticoagulant and antifouling properties. Accordingly, this review highlight's the synthesis strategies, physiochemical and biological properties, as well as applications of sulfur functionality-modified starches in numerous practical fields.