Influence of reaction variables on the surface chemistry of cellulose nanofibers derived from palm oil empty fruit bunches.

Nanocellulose, a versatile nanomaterial with a wide range of applications, is gaining significant attention for its sustainable and eco-friendly properties. In this study, we investigate the influence of reaction variables on the surface chemistry of TEMPO-oxidized cellulose nanofibers (TOCN) from palm oil empty fruit bunch (EFB) fibers, a high cellulose content biomass. Reaction time, primary oxidizing agent, and a pretreatment process affect, to various extents, the surface chemistry of EFB-TOCN. Conductometric titrations (CT), X-ray photoelectron spectroscopy (XPS), and statistical analysis indicate a positive and significant influence of reaction time and primary oxidizing agent on EBF-TOCN degree of oxidation and surface charge density. Partial EFB delignification increased EFB-TOCN oxidation and reaction yield compared to EFB without pretreatment. Interestingly, only reaction time has a significant effect on the EFB-TOCN hydrodynamic radii, with a reaction time of over 120 minutes required to obtain nanocellulose less than 100 nm in size. Utilizing palm oil residual biomass for nanocellulose extraction not only valorizes agricultural waste but also enhances the palm oil industry's economic prospects by reducing waste disposal costs and improving material circularity. This research contributes to the growing body of knowledge on nanocellulose production from renewable sources and highlights the potential of palm oil EFB fibers as a valuable raw material for sustainable nanomaterial development.

Exploring the chemical composition and coloring qualities of cacao fruit epicarp extracts.

Cacao pod husks (CHs), the most abundant by-product of cacao beans production, can potentially become a source of functional ingredients for the food, cosmetic, and pharmaceutical industries. Three pigment samples (yellow, red, and purple) from lyophilized and ground cacao pod husk epicarp (CHE), were isolated by ultrasound-assisted solvent extraction, with yields between 11 and 14 wt%. The pigments exhibited UV-Vis flavonoid-related absorption bands at 283 nm and 323 nm and, only for the purple extract, reflectance bands in the 400-700 nm range. As per the Folin-Ciocalteu method, the CHE extracts contain high yields of antioxidant phenolic compounds amounting to 161.6, 153.9, and 167.9 mg GAE per g extract for the yellow, red, and purple samples, respectively. Phloretin, quercetin, myricetin, jaceosidin, and procyanidin B1 were among the main flavonoids identified by MALDI-TOF MS. A biopolymeric bacterial-cellulose matrix can effectively retain up to 541.8 mg of CHE extract per g of cellulose in dry weight. Also, MTT assays revealed that CHE extracts are non-toxic and increase viability in cultured VERO cells.

Electron-transfer MALDI MS methodology for microalgae/phytoplankton pigments analysis.

The method describes pigment analysis from microalgae/phytoplankton extracts using electron-transfer Matrix-Assisted Laser Desorption Ionization Mass Spectrometry (ET MALDI MS). Current microalgae/phytoplankton pigment analysis requires resource- and time-intensive chromatographic methods due to the broad polarity range of the target analytes. On the other hand, traditional MALDI MS chlorophyll analysis, using proton-transfer matrices such as 2,5-dihydroxybenzoic acid (DHB) or α-cyano-4-hydroxycinnamic acid (CHCA), results in central metal loss and phytol-ester cleavage. ET MALDI MS is an alternative for the rapid screening and detection of pigments in microalgae extracts.•MALDI matrices with ionization energies above 8.0 eV guarantee electron-transfer processes from photosynthetic and photoprotective pigments whose ionization energies lay below 7.5 eV.•ET MALDI MS pigment analysis agrees with data gathered from conventional chromatographic techniques (HPLC) and optical microscopy for pigment extracts from C. vulgaris cultures and freshwater phytoplankton samples.•The ET MALDI MS method allows fast and reliable detection of pigments in microalgae cultures and freshwater phytoplankton samples.

Mass Balance and Compositional Analysis of Biomass Outputs from Cacao Fruits.

The global chocolate value chain is based exclusively on cacao beans (CBs). With few exceptions, most CBs traded worldwide are produced under a linear economy model, where only 8 to 10% of the biomass ends up in chocolate-related products. This contribution reports the mass balance and composition dynamics of cacao fruit biomass outputs throughout one full year of the crop cycle. This information is relevant because future biorefinery developments and the efficient use of cacao fruits will depend on reliable, robust, and time-dependent compositional and mass balance data. Cacao husk (CH), beans (CBs), and placenta (CP) constitute, as dry weight, 8.92 ± 0.90 wt %, 8.87 ± 0.52 wt %, and 0.57 ± 0.05 wt % of the cacao fruit, respectively, while moisture makes up most of the biomass weight (71.6 ± 2.29 wt %). CH and CP are solid lignocellulosic outputs. Interestingly, the highest cellulose and lignin contents in CH coincide with cacao's primary harvest season (October to January). CB contains carbohydrates, fats, protein, ash, and phenolic compounds. The total polyphenol content in CBs is time-dependent, reaching maxima values during the harvest seasons. In addition, the fruit contains 4.13 ± 0.80 wt % of CME, a sugar- and nutrient-rich liquid output, with an average of 20 wt % of simple sugars (glucose, fructose, and sucrose), in addition to minerals (mainly K and Ca) and proteins. The total carbohydrate content in CME changes dramatically throughout the year, with a minimum of 10 wt % from August to January and a maximum of 29 wt % in March.

Cellulose biosynthesis using simple sugars available in residual cacao mucilage exudate.

Worldwide only 8% of the biomass from harvested cacao fruits is used, as cacao beans, in chocolate-based products. Cacao mucilage exudate (CME), a nutrient-rich fluid, is usually lost during cacao beans fermentation. CME's composition and availability suggest a potential carbon source for cellulose production. CME and the Hestrin and Schramm medium were used, and compared, as growth media for bacterial cellulose (BC) production with Gluconacetobacter xylinus. CME can be used to produce BC. However, the high sugar content, low pH, and limited nitrogen sources in CME hinder G. xylinus growth affecting cellulose yields. BC production increased from 0.55 ± 0.16 g L-1 up to 13.13 ± 1.09 g L-1 after CME dilution and addition of a nitrogen source. BC production was scaled up from 30 mL to 15 L, using lab-scale experiments conditions, with no significant changes in yields and production rates, suggesting a robust process with industrial possibilities.

Electron-Transfer Ionization of Nanoparticles, Polymers, Porphyrins, and Fullerenes Using Synthetically Tunable α-Cyanophenylenevinylenes as UV MALDI-MS Matrices.

Electron-transfer ionization in matrix-assisted laser desorption/ionization (ET-MALDI) is widely used for the analysis of functional materials that are labile, unstable, and reactive in nature. However, conventional ET matrices (e.g., trans-2-[3-(4- tert-butylphenyl)-2-methyl-2-propenylidene] malononitrile (DCTB)) still lack in performance due to cluster formation, reactivity with analytes, and vacuum instability. In this contribution, we report the use of α-cyanophenylenevinylene derivatives as UV MALDI matrices for the analysis, by ET ionization, of nanoparticles, polymers, porphyrins, and fullerenes. The synthetic versatility of the phenylenevinylene (PV) core allowed us to modulate physicochemical properties, fundamental for efficient formation of primary ions in the gas phase under MALDI conditions, such as planarity, ionization potentials, molar absorptivity, and laser thresholds. For instance, introduction of -CN groups in vinyl positions of the PV core induced structural disruption in planarity in the new α-CNPV derivatives, shifting their maximum molar absorptivity to UV wavelengths and increasing their ionization energy values above 8.0 eV. UV MALDI-relevant photophysical properties in solution and solid state are reported (λmax and ε355nm). LDI spectra of α-CNPVs exhibit predominant signals due to M+• and [M + H]+ species, whereas the standard matrix DCTB shows peaks associated with clusters and nondesirable products. The mass spectrometry (MS) performance of six α-CNPV derivatives was assessed for the ionization of a standard compound, with α-CNPV-CH3 and α-CNPV-OCH3 exhibiting better analytical figures of merit than those of a standard matrix (DCTB). These new matrices display high vacuum stability (79%) for up to 240 min of residence in the ionization source, in contrast with DCTB with 13%. Vacuum stability is vital, particularly for applications such as high-throughput analysis and imaging MS. In addition, when a mixture of 20 analytes (PAHs, porphyrins, and triphenylamine dyes) ranging from m/z 300 to 1700 was analyzed via ET-MALDI, we observed analyte coverage of 90% with the α-CNPV-CH3 derivative, whereas DCTB afforded only 70%. Finally, α-CNPV-CH3 was tested and compared with DCTB, as ET-MALDI matrix for petroporphyrins, conjugated polymers, gold nanoparticles, and fullerene derivatives analysis, outperforming in most cases the standard matrix.

Oligo p-Phenylenevinylene Derivatives as Electron Transfer Matrices for UV-MALDI.

Phenylenevinylene oligomers (PVs) have outstanding photophysical characteristics for applications in the growing field of organic electronics. Yet, PVs are also versatile molecules, the optical and physicochemical properties of which can be tuned by manipulation of their structure. We report the synthesis, photophysical, and MS characterization of eight PV derivatives with potential value as electron transfer (ET) matrices for UV-MALDI. UV-vis analysis show the presence of strong characteristic absorption bands in the UV region and molar absorptivities at 355 nm similar or higher than those of traditional proton (CHCA) and ET (DCTB) MALDI matrices. Most of the PVs exhibit non-radiative quantum yields (φ) above 0.5, indicating favorable thermal decay. Ionization potential values (IP) for PVs, calculated by the Electron Propagator Theory (EPT), range from 6.88 to 7.96 eV, making these oligomers good candidates as matrices for ET ionization. LDI analysis of PVs shows only the presence of radical cations (M+.) in positive ion mode and absence of clusters, adducts, or protonated species; in addition, M+. threshold energies for PVs are lower than for DCTB. We also tested the performance of four selected PVs as ET MALDI matrices for analytes ranging from porphyrins and phthalocyanines to polyaromatic compounds. Two of the four PVs show S/N enhancement of 1961% to 304% in comparison to LDI, and laser energy thresholds from 0.17 µJ to 0.47 µJ compared to 0.58 µJ for DCTB. The use of PV matrices also results in lower LODs (low fmol range) whereas LDI LODs range from pmol to nmol. Graphical Abstract ᅟ.

Síntesis in situ de nanopartículas de plata sobre fibras de fique / In situ synthesis of silver nanoparticles on fique fibers / Síntese in situ de nanopartículas de prata em fibras de fique

Se realizó la síntesis de un material nanocompuesto mediante la deposiciónin situ de nanopartículas (NPs) de plata sobre fibras de Fique. La influencia de parámetros experimentales, como concentración del precursor, concentración del agente reductor y tiempos de inmersión de las fibras en la solución del precursor y del agente reductor, se evaluó en términos de recubrimiento, tamaño y dispersión del nanomaterial sobre la superficie. Los nanocompositos fueron caracterizados mediante espectroscopia de reflectancia difusa UV-Vis (RD), microscopía electrónica (FESEM) y difracción de rayos X (DRX). El control de los parámetros experimentales mencionados permitió obtener un material que exhibe recubrimiento uniforme y completo de NPs sobre la superficie y tamaños promedio de NPs de 40 nm.

A nanocomposite material was synthesized by silver nanoparticles (NPs) in situ deposition on Fique fibers. The influence of experimental conditions such as precursor concentration, reducing agent concentration and immersion times of fibers in precursor and reducing agent solutions was evaluated in terms of nanomaterial coating, size and dispersion on the fibers surface. The nanocomposites were characterized by UV-Vis diffuse reflectance spectroscopy (DR), electron microscopy (FESEM) and X-ray diffraction (XRD). By carefully controlling experimental conditions we were able to produce a material with uniforme and complete coating of NPs on the surface of the fiber, and average sizes of 40 nm.

Nanocompósito foi sintetizado através de deposição in situ de nanopartículas (NPs) de prata sobre as fibras de Fique. A influência dos parâmetrosexperimentais, tais como a concentração do sal metálico, a concentração do agente de redução e os tempos de imersão das fibras na solução do sal metálico e o agente de redução, foram avaliadas em termos do revestimento, tamanho e a dispersãona superfície do nanomaterial. Os nanocompósitosforam caracterizados por espectroscopia de refletância difusa no UV-Vis (RD), microscopia eletrônica (FESEM) e difração de raios X (XRD). O controle dos parâmetrosexperimentais mecionados originaram um material que exibe um revestimento uniforme e completo das NPs sobre a superfície das fibras e tamanhos médios de 40 nm.