Macromol, Volume 5, Issue 1 (March 2025) – 12 articles

Polyhydroxyurethanes (PHUs) synthesized from cyclic carbonates are promising alternatives to conventional polyurethanes due to their advantageous isocyanate-free synthesis and reprocessability characteristics. While many studies focus on PHUs derived from five-membered cyclic carbonates (5CCs) for more sustainable synthesis routes, PHUs from six-membered cyclic carbonates (6CCs) exhibit enhanced reactivity towards amines. Their reprocessability is facilitated by the presence of hydroxyl groups along the polymer chain, enabling transcarbamoylation reactions. However, since non-catalyzed transcarbamoylation is typically a sluggish reaction, catalysts are often required to enhance network reprocessability. This study presents a life cycle assessment (LCA) of PHU-5CC and PHU-6CC syntheses, with catalysts, for recycling applications targeting end-of-life scenarios. Environmental impact categories, including climate change, particulate matter, fossil resource depletion, mineral and metal resource use and freshwater eutrophication, were evaluated. Sensitivity analyses were also conducted to assess key variables. Our results indicate that PHUs from 6CCs show a higher environmental footprint due to their solvent-intensive synthesis process. Despite the increased reactivity and shorter reaction times associated with the 6CC monomer, these benefits do not fully offset the environmental impacts of the synthesis process. In conclusion, this study highlights potential improvements for future PHU synthesis, such as solvent-free processes, metal-free catalysts and optimized reaction monitoring. Full article

Biopolymers, such as polysaccharides, polyphenols, alkaloids, and terpenoids, found in marine algae exhibit antiviral and anticancer properties. These compounds can inhibit viral replication, induce apoptosis in cancer cells, and enhance the immune response. Their diverse bioactive properties make marine algae a promising source for the development of sustainable antiviral and anticancer therapies. A major advantage of marine algae is that they do not require freshwater or arable land and can be cultivated in seawater, thus making them sustainable substitutes for conventional resources. Additionally, their ability to sequester carbon and recycle nutrients enhances their environmental sustainability. Despite their promising biomedical potential, challenges, such as compound extraction, large-scale production, and clinical validation, must be addressed for effective drug development. The vast biological diversity of marine algae across different ocean ecosystems is a largely unexplored source of distinct chemical structures, which may be the basis for new therapeutic schemes. Despite their therapeutic potential, the translation of marine algae-derived compounds into clinical applications faces significant hurdles, including challenges in large-scale extraction, bioavailability enhancement, and regulatory approval. The need to extract particular compounds to make them available for large-scale production and to overcome issues such as bioavailability and regulatory policies are formidable challenges. Marine algae represent innovative advances in antiviral and anticancer drug development, but only when combined with ecologically sound cultivation methods, interdisciplinary approaches, and understanding. The integration of advanced biotechnological approaches, innovative gene editing techniques, and environmentally sustainable aquaculture practices is pivotal for harnessing the full potential of marine algae for the development of next-generation antiviral and anticancer therapeutics. Full article

There are few examples of covalent organic frameworks (COFs) based on phosphorus as the building element, probably because the structure of most phosphorus derivatives is pyramidal, which may prevent the stacking expected for classical 2-dimensional COFs. In addition, they are generally associated with linear difunctional derivatives. In this paper is reported the original association of a trifunctional 3-D compound with a trifunctional 2-D compound in an attempt to get a new COF. The condensation reaction between a thiophosphate derivative bearing three aldehydes and the trihydrazinotriazine has been carried out with the aim of obtaining either a COF or simply a porous organic polymer (POP), consisting in both cases of associated macrocycles, affording a new covalent triazine framework (CTF). The material resulting from this condensation has been characterized by multinuclear MAS NMR (³¹P, ¹H, and ¹³C), IR, and thermogravimetric analysis (TGA). All these data confirmed the condensation reactions. However, BET (Brunauer–Emmett–Teller) measurements indicated that the porosity of this material is low. Trapping dyes in solution, as a model of pollutants, by the insoluble porous material 3 has been attempted. Full article

To expand the utilization of bio-based materials as flame retardants in epoxy resin (EP), a green Schiff base structural material (CSV) was synthesized via a one-pot approach employing chitosan and vanillin as the raw materials. Then, the CSV combined with 9,10-dihydro-9-oxa-10-phospha-phenanthrene-10-oxide (DOPO) (the mass ratio between CSV and DOPO was 1:2, written as CSV-DOPO) improved the flame retardancy of the EP. When the amount of CSV−DOPO in the EP was only 3 wt%, the thermogravimetric analysis (TGA) results indicated that the residue of the EP composites was 50.6% higher than that of the EP. The combustion class of the EP/3 wt% CSV−DOPO composites achieved a UL-94 V0 rating and the limit oxygen index (LOI) reached 34.0%. The cone calorimeter test (CCT) showed that the peak heat release rate (PHHR), total heat release (THR), total smoke release (TSP), and peak carbon dioxide production (PCO₂P) of the EP/3 wt% CSV−DOPO composites decreased by 32.3%, 22.0%, 4.6%, and 51.0%, respectively, compared to the EP. The flame-retardancy mechanism was studied by scanning electron microscopy (SEM) and Raman spectra. The quenching effect of phosphorus-containing radicals, the dilution effect of noncombustible gases, and the impeding effect of the carbon layer in the condensed phase contributed collectively to the excellent flame retardancy of the EP/CSV−DOPO composites. Considering the facile preparation method and small addition amount of the flame retardant, the present work provides a convenient solution for the preparation of modified EP with good flame retardancy and heat stability, which is expected to be widely used in industries. Full article

Spaghetti pasta is a popular food; different ingredients than wheat have been explored to increase their nutritional value, the use of mesquite flour with pea protein remains unexplored. This study aimed to evaluate the impact of substituting semolina with mesquite pod flour and pea protein isolate on the techno-functional properties of spaghetti. Spaghetti was prepared using semolina hydrated to 35–40%, (15 cm strands), dried at 50 or 60 °C until 7–8% moisture. Semolina was substituted (0–30%), with pea protein isolate (PPI) (0–20%) and mesquite flour (0–25%). Guar and xanthan gum were added (0–1%). Proximate analysis, trypsin inhibitors, culinary properties, water absorption, texture profile, color, soluble protein, protein, starch digestibility, Raman and confocal microscopy were performed. The legume incorporation increased the protein content and digestibility of the pasta. Although the culinary properties were affected by legume substitution, levels of 75–85% substitution yielded acceptable results. Spaghetti containing PPI and mesquite flour, dried at 60 °C, showed similar secondary protein structure compared to the control. However, mesquite flour notably altered the color of the pasta. The combination of PPI, mesquite flour, and hydrocolloids improved protein availability while reducing available starch and enhancing the nutritional quality of the spaghetti. Full article

The present study examines the effect of low-temperature thermal treatment before drying, through storage at −10 °C and 4 °C for 72 h, respectively, on the physicochemical and microbiological properties of spray-dried kefir powder. Furthermore, with the intention of improving the rheological behavior of the reconstituted product, texture modifiers were employed including milk proteins (milk proteins, sodium caseinates, and whey protein concentrates) and carrageenan. According to the results, the low-temperature thermal treatment of kefir, prior to drying, resulted to an increased moisture content and yellowness of the kefir powder samples, with a simultaneous drop to the whiteness index and an increase of the particle size in both the powder and the reconstituted samples. The sample with prior treatment at 4 °C for 72 h, exhibited decreased pH values and increased acidity for both kefir and reconstituted product, while it also improved post drying population survival of lactobacilli and yeasts. The reconstituted sample with prior treatment at −10 °C for 72 h, exhibited evident pseudoplastic behavior, which, at low shear rates, yielded viscosity values very close to those of the fresh control kefir. Addition of sodium caseinates, in the absence and/or simultaneous presence of carrageenan, resulted to the highest viscosity increase of the reconstituted products. Milk proteins with the combined presence of carrageenan exhibited similar apparent viscosity values to the control. Full article

Progress in the field of biodegradable materials has been significantly accelerated in recent years, driven by the search for sustainable substitutes for fossil-derived resources. This study investigates the formulation of biodegradable films composed of polyvinyl alcohol (PVA) and nanocellulose extracted from rice husk. The rice husk underwent alkaline treatment and bleaching for cellulose extraction, followed by sulfuric acid hydrolysis to obtain nanocellulose. The cellulose and nanocellulose were characterized through Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and Thermogravimetric Analysis (TGA). Films of pure PVA and those reinforced with 1 wt. % of nanocellulose were prepared using the solvent casting method. The evaluations showed that the modulus of elasticity and tensile strength of the PVA/nanocellulose films were increased by 295.45% and 29.6%, respectively, compared to the pure PVA film. The PVA/nanocellulose film exhibited the lowest solubility and water vapor permeability. Optical Microscopy confirmed a flawless surface for the nanocellulose-reinforced film, while the cellulose- and rice husk-reinforced films displayed irregularities. In the biodegradability assessment, the nanocellulose-reinforced film was the only one that withstood the experimental conditions. The results highlight the effectiveness of nanocellulose in enhancing PVA properties, making these films promising for sustainable packaging applications. Full article

The growing interest in renewable and natural antioxidants has positioned lignin as one of the most significant bioresources for sustainable applications. Lignin, a polyphenolic biomolecule and a major by-product of chemical pulping and biorefinery processes, is abundant and widely accessible. Recent advancements in lignin modification, fractionation, and innovative biorefinery techniques have expanded its potential applications, particularly as a natural antioxidant. This review explores the underlying chemistry of lignin’s antioxidant activities, from model compounds to technical lignin resources, and examines its current applications. Additionally, we highlight the influence of lignin’s chemical structure and functional groups on its antioxidant efficacy, emphasizing its promising role in the development of practical and sustainable solutions. Full article

Arundo donax L. is a plant with great potential as lignocellulosic biomass, being a promising source for the development of biodegradable materials. This study evaluated the effects of different chemical pretreatments (H₂SO₄, NaOH, and NaClO) combined with dry milling on the physicochemical properties of biomass. Pretreatment with NaClO was the most effective in removing lignin, reducing its content to 0.2%, while increasing the cellulose content to 67%. Pretreatment with H₂SO₄, although retaining a higher lignin content (24%), resulted in the greatest reduction in particle size, reaching a mean diameter (Dm) of 44.31 µm after 20 h of milling. Density analysis revealed that the raw samples reached a maximum density of 0.218 g/cm³ after 20 h of milling, with the pretreated samples showing lower densities due to the removal of structural components. Thermal analysis showed mass losses of up to 66.4% for samples pretreated with NaClO after 10 h of milling, indicating significant structural changes and improved thermal stability. Morphological analysis via SEM demonstrated elongated and fine particles, with acid pretreatment resulting in the most pronounced structural changes. These findings highlight the efficiency of combining chemical and physical pretreatments to modify the structure of A. donax L., optimizing its properties for the production of high-performance biodegradable materials. Full article

The study of the techno-functional properties of novel plant-based proteins has gained importance due to their as alternatives to conventional proteins in food systems. This work evaluated the techno-functional and structural properties of white bean protein concentrate (WBPC) in comparison with commercial soy and pea proteins. The WBPC exhibited a higher foaming capacity (FC) at neutral pH and excellent foam stability (FS) at both tested pH levels, outperforming the commercial proteins. Although the WBPC’s gelation occurred only at concentrations above 16% and its water-holding capacity (WHC) was lower than that of the soy and pea proteins, the WBPC showed a high binding capacity for nonpolar molecules, excelling in its oil-holding capacity (OHC) and forming stable emulsions, which are relevant for stabilization in food products. Additionally, WBPC can form more rigid gel networks, suitable for systems requiring greater mechanical strength. These techno-functional properties indicate that WBPC is a promising alternative source for the plant-based food industry, helping to meet the demand for innovative, sustainable products and contributing to the diversification of protein sources. Full article

Isothermal titration calorimetry (ITC) is a widely used and valuable technique for studying the binding interactions and the formation and dissociation of molecular complexes. ITC directly measures the energetics associated with the interactions and allows for a precise and complete thermodynamic description of association and binding processes, thereby providing an understanding of the interaction mechanisms. In this review, the role, practical aspects related to the experimental design and setup, advantages, and challenges of using ITC to evaluate polyphenol–macromolecule binding are discussed in detail. The focus is on the possibilities offered by ITC, but at the same time, its limitations are taken into account, especially in the study of complex biological processes and in the subsequent reliable determination of thermodynamic parameters. Polyphenols and proteins typically exhibit exothermic interactions, producing strong signals and distinctive titration curves that can be fitted by one- or two-site binding models; of course, there are exceptions to this. Tannins and tannin fractions usually have a high binding stoichiometry and stronger interactions with proteins than the smaller polyphenols. The driving forces behind these interactions vary, but in many cases, both hydrogen bonding and hydrophobic interactions have been reported. The interactions between polyphenols and polysaccharides or lipid bilayers have been far less studied by ITC in comparison to polyphenol–protein interactions. ITC could be utilized more extensively to study polyphenol–macromolecule interactions, as it is an excellent tool for evaluating the thermodynamic parameters of these interactions, and when used together with other techniques, ITC can also help understand how these interactions affect bioavailability, food applications, and other uses of polyphenols. Full article

The objective of this study was to examine the changes in starch processed under various ohmic heating (OH) conditions in relation to the characteristics of nixtamalized maize. Ground and dehydrated nixtamalized doughs (masas) were analyzed. Samples were prepared using both OH and traditional nixtamalization methods for comparison. The OH process variables included cooking temperature (85 and 90 °C), heating time (0, 5, and 10 min), and voltage (120 and 130 V). Starch modifications were assessed through viscosity measurements, differential scanning calorimetry (DSC), X-ray diffraction, and scanning electron microscopy (SEM). The results showed that viscosity in OH-treated samples was influenced by both thermal conditions (time and temperature) and the electric field (at 130 V), due to gelatinization and electroporation, evidenced by starch granule damage in SEM. DSC and X-ray diffraction revealed gelatinization and a loss of crystalline structures, along with new interactions between starch components that stabilized the system and reduced peak viscosity in the OH masa flours. Full article