Search Results (79)

Plastic waste accumulation is one of the most pressing environmental challenges of the 21st century, owing to the widespread use of synthetic polymers and the limitations of conventional recycling methods. Among available strategies, chemical upcycling via depolymerization has emerged as a promising circular approach that converts plastic waste back into valuable monomers and chemical feedstocks. This article provides an in-depth narrative review of recent progress in the upcycling of major plastic types such as PET, PU, PS, and engineering plastics through thermal, chemical, catalytic, biological, and mechanochemical depolymerization methods. Each method is critically assessed in terms of efficiency, scalability, energy input, and environmental impact. Special attention is given to innovative catalyst systems, such as microsized MgO/SiO₂ and Co/CaO composites, and emerging enzymatic systems like engineered PETases and whole-cell biocatalysts that enable low-temperature, selective depolymerization. Furthermore, the conversion pathways of depolymerized products into high-purity monomers such as BHET, TPA, vanillin, and bisphenols are discussed with supporting case studies. The review also examines life cycle assessment (LCA) data, techno-economic analyses, and policy frameworks supporting the adoption of depolymerization-based recycling systems. Collectively, this work outlines the technical viability and sustainability benefits of depolymerization as a core pillar of plastic circularity and monomer recovery, offering a path forward for high-value material recirculation and waste minimization. Full article

Vanillin photoinduced deprotonation was evaluated and analyzed. Vibronic states and transitions were computationally investigated. Optimizations and vertical electron transitions in the gas phase and with the continuum solvation model were computed using the time-dependent density functional theory. Static absorption and emission (photostatic optical) spectra were statistically averaged over the excited instantaneous molecular conformers fluctuating on quantum–classical molecular dynamic trajectories. Photostatic optical spectra were generated using the hybrid quantum–classical molecular dynamics for explicit solvent models. Conical intersection searching and nonadiabatic molecular dynamics simulations defined potential energy surface propagations, intersections, dissipations, and dissociations. The procedure included mixed-reference spin–flip excitations for both procedures and trajectory surface hopping for photodynamics. Insignificant structural deformations vs. hydroxyl bond cleavage followed by deprotonation were demonstrated starting from different initial structural conditions, which included optimized, transition state, and several other important fluctuating configurations in various environments. Vanillin electronic structure changes were illustrated and analyzed at the key points on conical intersection and nonadiabatic molecular dynamics trajectories by investigating molecular orbital symmetry and electron density difference. The hydroxyl group decomposed on transition to a σ-molecular orbital localized on the elongated O–H bond. Full article

Red beetroot (Beta vulgaris L.) is a nutritionally rich root vegetable. It is a potential alternative raw material for pestil, a traditional fruit-based snack. This study aimed to develop a healthy beetroot-based pestil using traditional boiling (95 °C) and novel pretreatment methods, including thermosonication and microwave processing, with and without additional concentration steps. The effects of these methods on heat treatment period, hydroxymethylfurfural (HMF) formation, and the physicochemical, sensorial, nutritional, and chemometric profiles of pestils were evaluated. The beetroot-based snack formulated in this study was hedonically acceptable (≥5/9) and rich in essential minerals (Ca, K, Na, P, Mg) and trace elements (Zn, Fe, Mn), as determined by inductively coupled plasma–mass spectrometry. Total antioxidant capacity (CUPRAC) ranged from 113.11 to 870.78 mg Trolox^® equivalent/100 g dry matter (DM). Total phenolic, flavonoid, and betalain contents varied between 220.6–313.8 mg gallic acid equivalent/100 g DM, 365.08–517.46 mg rutin equivalent/100 g DM, and 314.40–488.66 mg/kg, respectively. Major flavonoids identified and quantified included epicatechin, rutin, isoquercitrin, taxifolin, and quercetin, while major phenolic acids identified were chlorogenic acid, ferulic acid, caffeic acid, o-salicylic acid, p-coumaric acid, and vanillin, using liquid chromatography–electrospray tandem mass spectrometry. Reducing the soluble solids content of the pestil pulp from 40 to 20 Brix degrees, in combination with thermosonication and microwave treatments, significantly shortened the processing time by 10–67%. This approach also reduced the HMF content to the limit of quantification (LOQ). Pretreatment methods significantly (p < 0.05) affected the levels of minerals and bioactive compounds in the pestils. These findings highlight the importance of process optimization to improve overall safety and the nutritional quality of the pestil. Full article

Lemon co-products are valuable due to their high dietary fibre, making them significant for valorisation. This research aimed to characterise an innovative lemon dietary fibre (LDF) obtained through integrated extraction (of essential oil, phenolic compounds (PCs), and pectin) by evaluating its chemical, physicochemical, structural, techno-functional, total phenolic content, and antioxidant and antibacterial properties. The effects of incorporating LDF (3% and 6%) into mortadella, a bologna-type sausage, on chemical, physicochemical, technological, and sensory properties were analysed. LDF exhibited a total dietary fibre content of 85.79%, mainly insoluble (52.55%). Hesperidin (89.97–894.44 mg/100 g DW) and eriocitrin (68.75–146.35 mg/100 g DW) were the major free PCs. The major bound PCs were vanillin (5.90–9.16 mg/100 g DW) and apigenin-7-O-glucoside (8.82 mg/100 g DW). This functional ingredient demonstrated antioxidant and antibacterial activity. LDF significantly influenced mortadella’s colour, texture, and mineral composition. Higher levels of LDF result in a paler colour and increased hardness and contribute to reducing sodium levels of the final product. It also decreased residual nitrite levels, although this reduction was followed by a slight increase in lipid oxidation, which remained below the rancidity threshold (≥1.0), ensuring acceptable product quality. Sensory evaluation revealed positive feedback, favouring the 3% LDF formulation. Full article

The medicinal value of vanillin and its isomers has not been well developed, so it is necessary to prepare crystals of vanillin and its isomers as well as to investigate their crystallization rules in detail using advanced crystallization techniques in polymer gel. Based on molecular simulation, the maximum number of hydrogen bonds between CMCS with Van, IsoVan and oVan were reached at molar ratios of 1:9 and 1:4 and 1:5, respectively. The gel hardness and apparent viscosity of CMCS/Van isomers were proportional to the mole ratio, while elongation at break and tensile strength decreased with an increase in molar concentration depending on the position of the side chain group of the Van isomer, exposure of the benzene ring, steric resistance and the number of hydrogen bonds formed. The crystallization of Van, IsoVan and oVan in CMCS gel unexceptionally follow classical supersaturation theory in the case that nVan mainly exhibits a unique growth pattern from needle to strip, IsoVan’s growth style changes from plate to bulk and oVan adapts growth pattern from needle to branch bifurcating. It was also found that the Van crystal changed from II-type to I-type under long-term heating. Studies have further confirmed that the discrepancy of physicochemical characteristics of CMCS/Van blend gel can be attributed to differences in the number of hydrogen bonds compared to CMCS with given group positions of Van isomers. This study provides powerful technical support for the gel crystallization of van isomers. Full article

Background: The consumption of unpasteurized fruit juices poses a food safety risk due to the survival of pathogens such as Salmonella Enteritidis and Escherichia coli O157:H7. Methods: This study evaluated natural antimicrobials (nisin, coumaric acid, citral, sinapic acid, and vanillin) in orange juice as a strategy to ensure the control of these pathogens during the preservation of the non-thermally treated juices. Results: The addition of nisin, coumaric, or citral did not alter the juice’s physicochemical characteristics, ensuring product quality. Nisin (1–2 mL/L), coumaric acid (0.25–0.5 g/L), and citral (0.25–0.5 mL/L) were the most effective in reducing bacterial populations. The antimicrobial activity of the most effective compounds was then tested against both acid-adapted and non-acid-adapted bacteria in refrigerated juice, applying Weibull and linear decay models to assess bacterial inactivation. Non-acid-adapted S. Enteritidis showed a rapid 5 log reduction after 30 h of refrigeration with the highest nisin dose, while the acid-adapted strain exhibited a smaller reduction (2 and 1.5 log units for 1 and 2 mL/L, respectively). Citral was effective but excluded due to solubility and aroma concerns. Non-acid-adapted E. coli O157:H7 showed a 5 log reduction with coumaric acid at 0.5 g/L, whereas acid-adapted strains exhibited a lower reduction (around 1.5 log units). Nisin and coumaric acid also reduced bacterial survival in gastrointestinal tract simulations. However, acid-adapted bacteria were more resistant. Conclusions: These findings highlight the potential of these antimicrobials for food safety applications, though further studies should explore their mechanisms and combinations for enhanced efficacy. Full article

In parallel with the worldwide issues of malnutrition and food waste, society at large focuses on the advantages of ‘recycling’ food waste. Brewer’s spent grain (BSG), a primary byproduct of the brewing industry, is produced in large quantities in many regions of the world, leading to environmental issues. The present study aimed at valorizing BSG through bioactive compound extraction using more traditional approaches, including Soxhlet extraction, recrystallization, and salting-out adsorption for proteins and lactic purification. The extraction rate of total dietary fiber (TDF) was 93.3%. FTIR analysis showed specific structural vibrations of fiber with C-O and C-O-C attachments in hemicellulose, C-H bends in lignin, and various bending patterns in tannins and fatty acid esters. Hemicellulose (8245.2 mg/L), lignin (10,432.4 mg/L), and cellulose (13,245.4 mg/L) were extracted with rates of 54.9%, 69.5%, and 88.3%, respectively. These bioactive compounds extracted from BSG could be utilized in food and nutraceutical products based on their purity. The analysis of extracted bioactive components confirmed the presence of arachidic acid (C20:0), oleic acid (C18:1), linoleic acid (C18:2), myristic acid (C14:0), pentacyclic acid (C30:0), palmitic acid (C16:0), margaric acid (C17:0), gallic acid, catechol, ellagic acid, acetyl sialic acid, benzoic acid, and vanillin. These findings highlight the valorization potential of BSG, a previously regarded waste material, as a source of active biocomponents. This is consistent with the principles of the circular economy by reducing waste in the environment and supporting tangible sustainability in food systems. The efforts made in the current study in utilizing BSG are part of the fast-growing area of food waste recycling and provide a way to avoid waste and create added value. Full article

Two new 2p–3d complexes, (Et₃NH)[ML(hfac)₂], have been obtained using the nitronyl-nitroxide radical (HL) derived from 2-hydroxy-3-methoxy-5-nitrobenzaldehyde (M = Mn 1; Co 2). The two compounds are isomorphous and their structures consist of anionic mononuclear species, [M(hfac)₂L]⁻, M = Mn 1; Co 2, and triethylammonium cations, Et₃NH⁺. The metal ions adopt an octahedral geometry, being coordinated by phenoxido and aminoxyl oxygen atoms from the ligand and four oxygen atoms from the hexafluoroacetylacetonato (hfac⁻) ligand. The cryomagnetic behaviors of the two compounds reveal relatively strong antiferromagnetic M(II)-Rad interactions (J_MnRad = −191 cm⁻¹, J_CoRad = −166 cm⁻¹ with H = −JS_MS_Rad). The EPR spectra (X- and Q-band) of compound 1 below 70 K show the characteristical features of a S = 2 spin system with zero field splitting terms of D = 0.26 cm⁻¹ and E = 0.031 cm⁻¹. Full article

Vanillin (4-hydroxy-3-methoxybenzaldehyde) is the main component of natural vanilla and a relevant substance in the flavoring and aromatic industries. This study presents a kinetic model to explain both vanillin and vanillic acid concentrations achieved in the alkaline oxidation of pine kraft lignin. Considering that they come from the same precursors, this approach allows an understanding of vanillin production with reaction conditions that minimize the vanillic acid pathway directly from the lignin oligomers, thus maximizing vanillin production. This study involves the effects of oxygen partial pressure, temperature, and the presence or absence of a catalyst (CuSO₄ and Fe₂(SO₄)₃ mixture) on the vanillin and vanillic acid yields. An adapted reactor (M/K Systems Inc., Williamstown, MA, USA) with a recirculation and spray liquids system was used in the experiments. The experiments were performed using one liter of a solution of NaOH 2 M and 60 g of lignin. During the lignin oxidation reaction, liquid samples were analyzed at different times (from 0 to 200 min). The oxidation products were quantified by liquid chromatography (HPLC). The catalyzed experiments presented higher maximum vanillin yields than the non-catalyzed ones (39.2–39.6% on nitrobenzene oxidation) achieved at 150 °C. A kinetic model is proposed where the kinetic parameters were estimated using Monte Carlo methods, fitting satisfactorily to the experimental results. The statistical analysis of the kinetic parameters showed that all the studied variables significantly affect the vanillin yield. Full article

The quality of life of patients affected by Parkinson’s disease is improved by medications containing levodopa and carbidopa, restoring the dopamine concentration in the brain. Accordingly, the affordable quality control of such pharmaceuticals is very important. Here is reported the simple and inexpensive colorimetric quantification of carbidopa in anti-Parkinson drugs by the selective condensation reaction between the hydrazine group from carbidopa and the formyl functional group of selected aldehydes in acidified hydroalcoholic solution. An optical assay was developed by using indole-3-carbaldehyde (I3A) giving a yellow aldazine in EtOH:H₂O 1:1 (λ_max~415 nm) at 70 °C for 4 h, as confirmed by LC-MS analysis. A filter-based plate reader was used for colorimetric data acquisition, providing superior results in terms of analytical performances for I3A, with a sensitivity ~50 L g⁻¹ and LOD ~0.1 mg L⁻¹ in comparison to a previous study based on vanillin, giving, for the same figures of merit values, about 13 L g⁻¹ and 0.2–0.3 mg L⁻¹, respectively. The calibration curves for the standard solution and drugs were almost superimposable, therefore excluding interference from the excipients and additives, with very good reproducibility (_avRSD% 2–4%) within the linear dynamic range (10 mg L⁻¹–50 mg L⁻¹). Full article

Voltammetric sensors based on CeO₂, SnO_2, CeO₂·Fe₂O₃ nanoparticles (NPs) and MnO₂ nanorods (NRs) were developed for the quantification of various organic substances. Surfactant media were applied as dispersive agents for metal oxide nanomaterials, providing a high stability of the dispersions after sonication and a decrease in the NPs’ size, as well as the preconcentration of the target analytes at the sensor surface due to the hydrophobic interactions between the surfactant and the analyte molecules. Natural phenolics (quercetin, rutin, gallic acid, taxifolin, eugenol, vanillin, and hesperidin), propyl gallate, α-lipoic acid, and synthetic food colorants (tartrazine, brilliant blue FCF, and sudan I) were studied as analytes. The effect of the nature and concentration of the surfactant on the target analyte response was evaluated. Cationic surfactants (cetylpyridinium (CPB) or cetyltriphenylphosphonium bromides (CTPPB)) showed the best effect for the majority of the analytes. Wide linear dynamic ranges and low detection limits were obtained and were improved vs. reported to date. The simultaneous quantification of tartrazine and brilliant blue FCF was achieved with a high selectivity. The practical applicability of the sensors was shown on the real samples and was validated by comparison to independent methods. Full article

Developing highly efficient and multifunctional epoxy resins (EPs) that overcome the shortcomings of flammability and brittleness is crucial for pursuing sustainable and safe application but remains a huge challenge. In this paper, a novel biomass-containing intumescent flame retardant containing a rigid–flexible and multi-siloxane bridge structure (DPB) was synthesized using siloxane; 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO); and biomass vanillin. DPB could facilitate the formation of a carbon residual with an intumescent structure, which effectively blocked the propagation of heat and oxygen. As a result, the peak heat release rate (pHRR) and total heat release (THR) of DPB/EP-7.5 decreased by 38.8% and 45.0%, respectively. In terms of mechanical properties, the tensile and flexural elongations at break of DPB/EP-7.5 increased by 77.2% and 105.3%, respectively. Impressively, DPB/EP-7.5 had excellent dielectric properties, with a dielectric constant of 2.5–2.9. This was due to the Si-O bonds (multi-siloxane bridges) contained in DPB/EP, which can quench the polarization behavior of the hydroxyl group. This paper provides a facile strategy for the preparation of multifunctional EP, which will pave the way for the promotion and application of EP in the high-end field. Full article

Background: Low back pain is a global health problem directly related to intervertebral disc (IVD) degeneration. Senolytic drugs (RG-7112 and o-Vanillin) target and remove senescent cells from IVDs in vitro, improving tissue homeostasis. One drawback of using a single senolytic agent is the failure to target multiple senescent antiapoptotic pathways. This study aimed to determine if combining the two senolytic drugs, o-Vanillin and RG-7112, could more efficiently remove senescent cells and reduce the release of inflammatory factors and pain mediators in cells from degenerating human IVDs than either drug alone. Methods: Preliminary data evaluating multiple concentrations of o-Vanillin and RG-7112 led to the selection of four treatment groups. Monolayer and pellet cultures of cells from painful degenerate IVDs were exposed to TLR-2/6 agonist. They were then treated with the senolytics o-Vanillin and RG7112 alone or combined. p16^ink4a, Ki-67, caspase-3, inflammatory mediators, and neuronal sprouting were assessed. Results: Compared to the single treatments, the combination of o-Vanillin and RG-7112 significantly reduced the amount of senescent IVD cells, proinflammatory cytokines, and neurotrophic factors. Moreover, both single and combination treatments significantly reduced neuronal sprouting in rat adrenal pheochromocytoma (PC-12 cells). Conclusions: Combining o-Vanillin and RG-7112 greatly enhanced the effect of either senolytic alone. Together, these results support the potential of senolytics as a promising treatment for IVD-related low back pain. Full article

Plant secondary metabolites are key components for new, safe and effective drugs. Ethanolic extract of Maesa indica Roxb. Sweet (ME) aerial parts were used for biosynthesis of sustainable green zinc oxide nanoparticles (ZnO NPs) with an average particle size 6.80 ± 1.47 nm and zeta potential −19.7 mV. Both transmission electron microscopy and X-ray diffraction assay confirmed the hexagonal shape of ZnO NPs. Phenolic ingredients in ME were identified using LC-ESI-MS/MS-MRM revealing the identification of chlorogenic acid, gallic acid, caffeic acid, rutin, coumaric acid, vanillin, naringenin, quercetin, ellagic acid, 3.4-dihydroxybenzoic acid, methyl gallate, kaempferol, ferulic acid, syringic acid, and luteolin. The major compound was chlorogenic acid at concentration of 1803.84 μg/g. The antiviral activity of ME, ZnO NPs, and combination of ME with ZnO NPs against coronavirus 229E were investigated. ZnO NPs had superior antiviral effect against coronavirus 229E than ME while their combination showed the highest anti-coronavirus 229E effect, with 50% inhibition concentration (IC₅₀) of 5.23 ± 0.18 µg/mL and 50% cytotoxic concentration (CC₅₀) of 138.49 ± 0.26 µg/mL while the selectivity index (SI) was 26.47. The current study highlighted the possible novel anti-coronavirus 229E activity of green ZnO NPs synthesized from Maesa indica. More studies are needed to further investigate this antiviral activity to be utilized in future biomedical and environmental applications. Full article