Nanocellulose bio-based composites for food packaging

The food industry is increasingly demanding advanced and eco-friendly sustainable packaging materials with improved physical, mechanical and barrier properties. The currently used materials are synthetic and non-degradable, therefore raising environmental concerns. Consequently, research efforts have been made in recent years towards the development of bio-based sustainable packaging materials. In this review, the potential of nanocelluloses as nanofillers or as coatings for the development of bio-based nanocomposites is discussed, namely: (i) the physico-chemical interaction of nanocellulose with the adjacent polymeric phase, (ii) the effect of nanocellulose modification/functionalization on the final properties of the composites, (iii) the production methods for such composites, and (iv) the effect of nanocellulose on the overall migration, toxicity, and the potential risk to human health. Lastly, the technology readiness level of nanocellulose and nanocellulose based composites for the market of food packaging is discussed.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte.” The authors also acknowledge the financial support of the FCT (ESF) through the grant given to Francisco A.G.S. Silva (SFRH/BD/146375/2019).info:eu-repo/semantics/publishedVersio

Performance of bacterial nanocellulose packaging film functionalised in situ with zinc oxide: Migration onto chicken skin and antimicrobial activity

Supplementary data associated with this article can be found in the online version at doi:10.1016/j.fpsl.2023.101140.Zinc oxide nanoparticles (ZnO) are cost-effective antimicrobial agents with great potential for the active packaging industry. Bacterial NanoCellulose (BNC) features a porous fibre network, with high absorption capacity, flexible and with good mechanical properties, suitable as a carrier of active agents. In this work, BNCZnO films were developed and optimized regarding the particle size and ZnO concentration. The NaOH dropwise addition to BNC membranes immersed in Zn(CH3COO)2-PVOH enabled the production of ZnO nanoparticles with an z-average of 144 nm and a low polydispersity index. High ZnO incorporation (27%mZn/mBNCZnO) was obtained, with uniform distribution all over the BNC membranes. These composites were then characterized and evaluated for Zn migration using food simulants (10%, 20%, and 50% ethanol) with results lower than the limit. Migration into chicken skin, as a real food model, was low at 4 °C but exceeded the migration limit at 10 and 22 °C. Zn migration was also found to be temperature and pH dependent. When applied to chicken skin, BNCZnO was effective against E. coli, Salmonella (0.51.0 log reduction), and Campylobacter spp. (2.0 log reduction), indicating its potential for active packaging applications.The authors appreciate the technical support from CINATE team, especially Susana Teixeira for the assistance in atomic absorption spectroscopy.info:eu-repo/semantics/publishedVersio

Synthesis of a novel series of Cu(I) complexes bearing alkylated 1,3,5-triaza-7-phosphaadamantane as homogeneous and carbon-supported catalysts for the synthesis of 1-and 2-substituted-1,2,3-triazoles

Funding Information: This research was funded by the Funda??o para a Ci?ncia e a Tecnologia (FCT), Portugal, project UIDB/00100/2020 of the Centro de Qu?mica Estrutural, FCT/MCTES (UIDB/50006/2020 and UIDP/50006/2020) from Associate Laboratory for Green Chemistry?LAQV, Scientific Employment Stimulus?Institutional Call (CEECINST/00102/2018) and by the RUDN University Strategic Academic Leadership Program. I.L.L. acknowledges the FCT through the CATSUS PhD Program (PD/BD 135555/2018). A.G.M. was funded by Instituto Superior T?cnico, Portugal through the project CO2usE-1801P.00867.1.01 (contract no. IST-ID/263/2019). Funding Information: Funding: This research was funded by the Fundação para a Ciência e a Tecnologia (FCT), Portugal, project UIDB/00100/2020 of the Centro de Química Estrutural, FCT/MCTES (UIDB/50006/2020 and UIDP/50006/2020) from Associate Laboratory for Green Chemistry—LAQV, Scientific Employment Stimulus—Institutional Call (CEECINST/00102/2018) and by the RUDN University Strategic Academic Leadership Program. I.L.L. acknowledges the FCT through the CATSUS PhD Program (PD/BD 135555/2018). A.G.M. was funded by Instituto Superior Técnico, Portugal through the project CO2usE-1801P.00867.1.01 (contract no. IST-ID/263/2019). Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.The N-alkylation of 1,3,5-triaza-7-phosphaadamantane (PTA) with ortho-, meta-and para-substituted nitrobenzyl bromide under mild conditions afforded three hydrophilic PTA ammonium salts, which were used to obtain a new set of seven water-soluble copper(I) complexes. The new compounds were fully characterized and their catalytic activity was investigated for the low power microwave assisted one-pot azide–alkyne cycloaddition reaction in homogeneous aqueous medium to obtain disubstituted 1,2,3-triazoles. The most active catalysts were immobilized on activated carbon (AC), multi-walled carbon nanotubes (CNT), as well as surface functionalized AC and CNT, with the most efficient support being the CNT treated with nitric acid and NaOH. In the presence of the immobilized catalyst, several 1,4-disubstituted-1,2,3-triazoles were obtained from the reaction of terminal alkynes, organic halides and sodium azide in moderate yields up to 80%. Furthermore, the catalyzed reaction of terminal alkynes, formaldehyde and sodium azide afforded 2-hydroxymethyl-2H-1,2,3-triazoles in high yields up to 99%. The immobilized catalyst can be recovered and recycled through simple workup steps and reused up to five consecutive cycles without a marked loss in activity. The described catalytic systems proceed with a broad substrate scope, under microwave irradiation in aqueous medium and according to “click rules”.publishersversionpublishe

The catalytic activity of carbon-supported Cu(I)-phosphine complexes for the microwave-assisted synthesis of 1,2,3-triazoles

This research was funded by Fundação para a Ciência e a Tecnologia (FCT), Portugal, through project UIDB/00100/2020 of the Centro de Química Estrutural. It was also funded by national funds though FCT, under the Scientific Employment Stimulus-Institutional Call (CEECINST/ 00102/2018). We also acknowledge the Associate Laboratory for Green Chemistry—LAQV financed by national funds from FCT/MCTES (UIDB/50006/2020 and UIDP/50006/2020). I.L.L. is grateful to the CATSUS Ph.D. Program for her grant (PD/BD 135555/2018). AGM is grateful to Instituto Superior Técnico, Portugal for his post-doctoral fellowship through the project CO2usE-1801P.00867.1.01 (Contract No. IST-ID/263/2019). It was also supported by the RUDN University Strategic Academic Leadership Program.A set of Cu(I) complexes with 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo-[3.3.1]nonane (DAPTA) phosphine ligands viz. [CuX(κP-DAPTA)3] (1: X = Br; 2: X = I) and [Cu(µ-X)((κP-DAPTA)2]2 (3: X = Br; 4: X = I) were immobilized on activated carbon (AC) and multi-walled carbon nanotubes (CNT), as well as on these materials after surface functionalization. The immobilized copper(I) complexes have shown favorable catalytic activity for the one-pot, microwave-assisted synthesis of 1,2,3-triazoles via the azide-alkyne cycloaddition reaction (CuAAC). The heterogenized systems with a copper loading of only 1.5-1.6% (w/w relative to carbon), established quantitative conversions after 15 min, at 80 °C, using 0.5 mol% of catalyst loading (relative to benzyl bromide). The most efficient supports concerning heterogenization were CNT treated with nitric acid and NaOH, and involving complexes 2 and 4 (in the same order, 2_CNT-ox-Na and 4_CNT-ox-Na). The immobilized catalysts can be recovered and recycled by simple workup and reused up to four consecutive cycles although with loss of activity.publishersversionpublishe

Heterogeneous gold nanoparticle-based catalysts for the synthesis of click-derived triazoles via the azide-alkyne cycloaddition reaction

PD/BD 135555/2018 IST-ID/263/2019A supported gold nanoparticle-catalyzed strategy has been utilized to promote a click chemistry reaction for the synthesis of 1,2,3-triazoles via the azide-alkyne cycloaddition (AAC) reaction. While the advent of effective non-copper catalysts (i.e., Ru, Ag, Ir) has demonstrated the catalysis of the AAC reaction, additional robust catalytic systems complementary to the copper catalyzed AAC remain in high demand. Herein, Au nanoparticles supported on Al2 O3, Fe2 O3, TiO2 and ZnO, along with gold reference catalysts (gold on carbon and gold on titania supplied by the World Gold Council) were used as catalysts for the AAC reaction. The supported Au nanoparticles with metal loadings of 0.7–1.6% (w/w relative to support) were able to selectively obtain 1,4-disubstituted-1,2,3-triazoles in moderate yields up to 79% after 15 min, under microwave irradiation at 150◦ C using a 0.5–1.0 mol% catalyst loading through a one-pot three-component (terminal alkyne, organohalide and sodium azide) procedure according to the “click” rules. Among the supported Au catalysts, Au/TiO2 gave the best results.publishersversionpublishe

cyclohexane oxidation in homogeneous and carbon-supported catalysis

The authors are grateful for the Financial support from Fundação para a Ciência e a Tecnologia (FCT), Portugal, through project UIDB/00100/2020 of Centro de Quίmica Estrutural. The work was also funded by national funds through FCT, under the Scientific Employment Stimulus-Institutional Call (CEEC-INST/00102/2018). We also acknowledge the Associate Laboratory for Green Chemistry – LAQV financed by national funds from FCT/MCTES (UIDB/50006/2020 and UIDP/5006/2020) and Base-UIDB/50020/ 2020 and Programmatic-UIDP/50020/2020 funding of the Associate Laboratory LSRE-LCM. I. L. L. acknowledges the CATSUS Ph.D. Program from FCT for her grant PD/BD/135555/2018. A. P. is grateful to FCT and Instituto Superior Técnico (IST), Portugal through DL/57/2017 (Contract no. IST-ID/197/2019). AGM is grateful to Associação do Instituto Superior Técnico para Investigação e Desenvolvimento for his post-doctoral fellowship through grant no. BL133/2021-IST-ID. This publication is also supported by the RUDN University Strategic Academic Leadership Program (recipient AJLP, preparation). A. V. G. thanks FCT, Instituto Superior Técnico (DL 57/2016, L 57/2017 and CEEC Institutional 2018 Programs, Contract no: IST-ID/110/2018) and Baku State University for financial support. The authors also acknowledge the Portuguese NMR Network (IST-UL Centre) for access to the NMR facility. CFGCG thanks the FCT for funding the Coimbra Chemistry Centre through the programmes UIDB/00313/2020 and UIDP/00313/2020, also co-founded by FEDER/ COMPETE 2020-EU. The authors are also thankful to Benjoe Rey B. Visayas (University of Massachusetts Dartmouth) for the help with the graphics.In accordance with UN's Sustainable Development Goal (UN's SDG) 12 which encompasses the sustainable use of chemical products and a sound circular economy, this work is focused on the synthesis of Co(II), Ni(II) and Mn(II) complexes bearing combined 1,3,5-triaza-7-phosphaadamantane and benzyl terpyridine core moieties (PTA–Bztpy) as ligand, followed by their evaluation as catalysts for the microwave-assisted cyclohexane oxidation using tert-butyl hydroperoxide (TBHP) as oxidant. The most active catalyst, with a manganese metal center, was heterogenized on six different carbon materials. The results disclosed the influence of several reaction parameters, such as catalyst loading, temperature, reaction time and solvent, on the catalytic activity and selectivity of the homogeneous and carbon-supported catalysts. Recyclability of the carbon-supported catalyst allowed facile separations, recovery and reuse for five consecutive cycles.publishersversionpublishe

Enzymatic inhibition studies of selected flavonoids and chemosystematic significance of polymethoxylated flavonoids and quinoline alkaloids in Neoraputia (Rutaceae)

Our taxonomic interest in the Neoraputia stimulated an investigation of N. paraensis searching for alkaloids. Fractions were monitored by ¹H NMR and ESI-MS/MS and only those which showed features of anthranilate alkaloids and flavonoids absent in the previous investigations were examined. Stems afforded the alkaloids flindersine, skimmianine, 8-methoxyflindersine and dictamnine; leaves yielded 3',4',7,8-tetramethoxy-5,6-(2,2-dimethylpyrano)-flavone, 3',4',5,7,8-pentamethoxyflavone, 5-hydroxy-3',4',6,7-tetramethoxyflavone, 3',4'-methylenedioxy-5,6,7-trimethoxyflavone and 5-hydroxy-3',4'-methylenedioxy-6,7-dimethoxyflavone. The alkaloids have remained undiscovered for 10 years. A number of flavonoids isolated from N. paraensis, N. magnifica, Murraya paniculata, Citrus sinensis graft (Rutaceae), Lonchocarpus montanus (Leguminosae) were evaluated for their ability to inhibit the enzymatic activity of the protein glyceraldehyde-3-phosphate dehydrogenase from Trypanosoma cruzi. Highly oxygenated flavones and isoflavone were the most actives.Nosso interesse quimiotaxonômico sobre Neoraputia nos estimulou a examinar N. paraensis, visando a busca de alcalóides. As frações foram monitoradas via RMN ¹H e ESI-EM/EM e foram analisadas somente aquelas cujos espectros apresentavam características de alcalóides do ácido antranílico e flavonóides não isolados anteriormente. Foram isolados do caule os alcalóides flindersina, skimmianina, 8-metoxiflindersina e dictamnina; das folhas os flavonóides 3',4',7,8-tetrametoxi-5,6-(2,2-dimetilpirano)-flavona, 3',4',5,7,8-pentametoxiflavona, 5-hidroxi-3',4',6,7-tetrametoxiflavona, 3',4'-metilenodioxi-5,6,7-trimetoxiflavona e 5-hidroxi-3',4'-metilenodioxi-6,7-dimetoxiflavona,. Os alcalóides do ácido antranílico não foram encontrados em dez anos. Vários flavonóides isolados de N. paraensis, N. magnifica, Murraya paniculata, enxerto de Citrus sinensis (Rutaceae) e Lonchocarpus montanus (Leguminosae) foram testados frente a gliceraldeído-3-fosfato desidrogenase de Trypanosoma cruzi, visando verificar seus potenciais em inibir a atividade da enzima. Os flavonóides polimetoxilados e um isoflavonóide foram os mais ativos.380387Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Novel organotin-PTA complexes supported on mesoporous carbon materials as recyclable catalysts for solvent-free cyanosilylation of aldehydes

The work was also funded by national funds through FCT, under the Scientific Employment Stimulus-Institutional Call (CEEC-INST/00102/2018). AGM is grateful to Associação do Instituto Superior Técnico para a Investigação e Desenvolvimento ( IST-ID ) for his post-doctoral fellowship through grant no. BL133/2021-IST-ID . AP and AMF are grateful to FCT and Instituto Superior Técnico (IST), Portugal through DL/57/2017 (Contract no. IST-ID/197/2019 and IST-ID/131/2018). This publication is also supported by the RUDN University Strategic Academic Leadership Program (recipient AJLP, preparation). The authors also acknowledge the Portuguese NMR Network (IST-UL Centre) for access to the NMR facility. Publisher Copyright: © 2023 Elsevier B.V.New organotin compounds with general formula [(PTA-CH2-C6H4-p-COO)SnR3]Br (where R is Me for 3 and Ph for 4; PTA = 1,3,5-triaza-7-phosphaadamantane), bearing the methylene benzoate PTA derivative, were synthesized through a mild two-step process. The compounds were characterized by Fourier transform infrared spectroscopy, electrospray ionization mass spectrometry, elemental analysis and nuclear magnetic resonance spectroscopy (NMR). They were heterogenized on commercially available activated carbon (AC) and multi-walled carbon nanotubes (CNT), as well as on their chemically modified analogues. The obtained materials were characterized by scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectroscopy. Complex 3 supported on activated carbon (3-AC) was found to be an active and recyclable catalyst for the cyanosilylation of several aromatic and aliphatic aldehydes. Using 3-AC with a low loading of 0.1 mol% several substrates were quantitatively converted, within just 5 min at 50 °C and under microwave irradiation in solvent-free conditions. Multinuclear NMR analysis suggested a mechanism that potentially involves a double activation process, where the nucleophilic phosphorus at the PTA derivative acts as a Lewis base and the Sn(IV) metal centre as a Lewis acid.publishersversionpublishe