Resumo em Português:

The volatile composition of coffee exerts a substantial influence on its quality, as it defines the characteristics of the beverage. However, these compounds are influenced by factors within the coffee production chain, such as botanical origin, geography, processing methods, and roasting. Consequently, the identification of such compounds becomes a vital tool for characterizing coffees to these factors. In this context, gas chromatography with headspace extraction is widely used for aroma analysis, providing a composition closer to consumer perception. Headspace extraction offers speed, simplicity, minimal sample preparation, and no need for solvents. In this study, static headspace extraction (SHS) coupled with gas chromatography-mass spectrometry (SHS-GC-MS) was employed to establish the chemical profile of volatile compounds in Coffea arabica and Coffea canephora var. conilon and determine discriminants between the species. A total of 97 compounds, belonging to 17 chemical classes, were identified. The chemometric analysis highlighted furans, phenols, and carboxylic acids as key differentiating classes. Notably, furfuryl alcohol, acetic acid, 4-vinylguaiacol, N-acetyl-4(H)-pyridine, and N-furfurylpyrrole emerged as crucial volatile compounds. The variable selection using Fisher weight applied directly in the chromatograms, produced models consistent with relative area data, with furfuryl alcohol and 4-vinylguaiacol regions being particularly influential in differentiation.

Resumo em Inglês:

The synthesis of 1-(bromomethyl)-3,5-dimethoxybenzene, a crucial intermediate in the formation of various natural products, was carried out through a straightforward three-step procedure starting from 3,5-dihydroxybenzoic acid. The structure of the synthesized derivative was fully characterized using a combination of spectroscopic techniques and single crystal X-ray diffraction. The crystalline sample was found to possess monoclinic symmetry with dimensions a = 8.4054(10) Å, b = 4.4245(6) Å, c = 25.016(3) Å, volume V = 928.9(2) Å3 and Z = 4.0. In order to assess the inhibitory potential of the synthesized crystal, a comprehensive in-silico investigation was conducted which involved molecular docking, density function theory (DFT) analysis, and molecular dynamics (MD) simulation studies. The docking analysis was utilized to determine the binding orientation of the compound with respect to the target proteins, while DFT analysis was utilized to evaluate the molecule’s reactivity profile. The MD simulation approach was used to evaluate the structural rearrangements and chemical interactions that occurred during the simulation period. The results of these studies suggest that the synthesized crystal could potentially serve as a dual inhibitor of RNR and tyrosinase and could be a suitable candidate for the synthesis of noval anti-cancer agent for the treatment of associated malignancies.

Resumo em Inglês:

In this work, the support, cashew apple bagasse (CAB), was chemically modified with divinyl sulfone (DVS), and it was evaluated to immobilize Candida antarctica lipase A (CAL-A). The best activation conditions of CAB support were defined by an advanced experimental design using the Taguchi method, assessing five factors at four levels (concentration of DVS, ionic strength, pH, temperature, and time). The support and biocatalyst (CAB-DVS-CAL-A) were characterized by Fourier transform infrared spectroscopy (FTIR), elemental analysis, thermogravimetry (TGA), scanning microscopy (SEM), fluorescence spectroscopy (XRF) and electrophoresis. The optimal conditions to activate the support were DVS concentration of 1.4 mol L-1 (3 mL of DVS in 20 mL of reaction volume), a concentration of sodium bicarbonate buffer at 5 mmol L-1, pH 3.0 at 30 °C for 12 h. The immobilization on CAB-DVS promoted increased thermal stability at 70 °C and different pHs of CAL-A. Therefore, the selected conditions allowed for a catalyst with a catalytic activity of 6.8 U g-1 and more stable than the free enzyme (CAL-A). This demonstrates that pretreated and DVS-activated CAB is a promising support for enzyme immobilization.

Resumo em Inglês:

A charge-assisted hydrogen-bonded organic framework (HOF) FJU-201 is constructed by N,N’-bis(5-isophthalic acid)naphthalimide divalent anion (H2L2-), p-xylene and dimethylammonium. FJU-201 can only crystallize in solutions containing p-xylene, and cannot crystallize in both o-xylene and m-xylene. FJU-201 can also crystallize in xylene mixtures with the content of p-xylene is not less than 50%, which can be used for separating and purifying p-xylene, and it has good recyclability.

Resumo em Português:

Pineapple, important in Brazilian fruit growing and highly consumed worldwide, can be affected by fusariosis, a disease caused by Fusarium guttiforme, which compromises the quality of the fruit and produces a mycotoxin called beauvericin (BEA), which is harmful to the health of consumers. The importance of detecting BEA and establishing maximum permitted limits is urgent, as there are few studies on this mycotoxin and there is still no regulation in world legislation. In this work, methodologies were used to detect BEA using HPLC-DAD and MALDI-FT-ICR MS. The results of HPLC-DAD allowed the detection of BEA in the tissues of the samples with F. guttiforme, evidenced by chromatographic peaks in the retention time, 6.1 min, similar to the standard, however, in the samples of visibly healthy tissue the mycotoxin was not detected. With MALDI-FT-ICR MS, BEA was detected with mass errors of less than 1 ppm in all samples (tissues infected with F. guttiforme and in healthy tissues), showing that, in addition to the greater sensitivity of the method, there is the possibility of mycotoxin diffusion in the healthy tissues of fruits inoculated with F. guttiforme, when these tissues are also contaminated.

Resumo em Português:

Nanoparticles of zein (NPZ) stabilized with surfactant polyvinyl alcohol (PVA), and nanoparticles of zein/PVA loaded with eugenol (NPZ-Eug) and the essential oil extracted from the clove (Syzygium aromaticum) (NPZ-OC) were produced by nanoprecipitation method. The extraction method of essential oil of the clove was carried out by the hydrodistillation technique, obtaining a content of 81.5% (m/m) of eugenol. The nanoparticle preparation method was optimized using a one-factor-at-a-time design of experiments, where different levels of variables (zein concentration, PVA concentration, and eugenol concentration) were explored. The best condition of synthesis was obtained with 0.3% (m/v) zein, 0.6% (m/v) PVA and 1.5 mg L-1 eugenol or essential oil of the clove, reaching NPs with acceptable propriety for stable nanoparticulate systems: size particles (NPZ = 113, NPZ-Eug = 229 and NPZ-OC = 279 nm), polydispersity index (PDI < 0.26), and zeta potential (≈ -30 mV). Loaded NPs showed encapsulation efficiency and drug-loading of 52 and 20% (NPZ-Eug), and 62, 27% (NPZ-OC), respectively. The quantification method of eugenol was validated by analytical parameters. Finally, all NPs produced exhibited good colloidal stability, confirming the effectiveness of PVA as a stabilizing agent, which had not been previously reported for these systems. The results obtained provide promising prospects for further investigations into its potential application as a bioinsecticide agent.

Resumo em Português:

Steelmaking is an important industrial branch, but it is also associated with large emissions of pollutants into the environment, especially nickel, which is used in the manufacturing process of metallic alloys and steel. Nickel is generally associated with particulate matter and, in industrial regions, its concentration can be 14 times higher than those observed in non-industrialized regions. This study was carried out in a residential area located in the city of Volta Redonda, in the state of Rio de Janeiro, which is impacted by industrial steel activity and by a deposit of steel slag tailings. The goal of this study was to measure air contamination and its impact on the health of the population by determining Ni in the total particulate matter and in the urine of 211 residents. The results obtained showed that the average values of Ni in the atmospheric air varied in the range of 1.3-13.2 ng m-3, with a maximum value of 20 ng m-3, which is comparable to other industrialized regions. In turn, Ni concentration in the urine of the residents presented an average concentration of 3.61 μg L-1, which is higher than the values normally found in the urine of occupationally exposed persons.

Resumo em Português:

We present to users unfamiliar with the programming language a user-friendly interface for the multivariate design of experiments (DoE) in Matlab®. The interface of the GAMMA app - Grupo de Análise Multivariada em Matrizes Alimentares, in Portuguese-BR, is available for free download on GitHub https://github.com/appGAMMA, and has a YouTube channel https://www.youtube.com/@appGAMMA with a series of tutorial videos. In this tutorial, some practical demonstrations are made using the DoE interface with real applications: (i) screening design for variable selection; (ii) optimization by Box-Behnken design; (iii) optimization by central composite design; (iv) factorial design for variable selection following by optimization with Doehlert design; (v) optimization by mixture design; (vi) optimization by mixture design with pseudocomponents; (vii) optimization by mixture design with process variable; and (viii) multiple-response optimization; also reproduced in the software Statistica v.13, StatSoft® for comparison. The GAMMA-GUI is constantly developing; suggestions for improvements or new ideas are welcome and can be directed to the developers.

Resumo em Inglês:

The aim of this work was to construct and characterize dye-sensitized solar cells (DSSC) using alternative materials and low-cost equipment. Instead of using the TiO2 semiconductor, a water-based white paint pigment was employed as a substitute. This pigment, when combined with natural dyes, absorbs visible light and acts as the photoelectrode. Pencil graphite was utilized to create the conductive layer, serving as the positive electrode. Lugol’s solution was employed as the electrolyte to establish electrical contact between the two electrodes. These materials were assembled between two glasses with a conductive surface made of tin oxide doped with fluorine (FTO glass). Subsequently, the assembled devices were exposed to three types of lamps: daylight (45 W), LED (15 W), and halogen (105 W), all positioned at the same height as the solar cell. Voltage and current measurements were taken using a simple multimeter. These results enabled the correlation of theoretical concepts related to absorption (dye) and light emission (lamp) ranges, different types of anchoring groups, and the dye-semiconductor anchoring mode. The voltage and current production were found to depend on the type of lighting source. However, it became evident that several factors beyond those mentioned strongly influenced the energy production mode of the solar cell.

Resumo em Português:

The article aims to address the use of the theoretical-methodological teaching strategy, Problematized Experimental Activity (PEA), to introduce a method employed in chemometrics, called Principal Component Analysis, through digital images linked to a smartphone app (REDGIM®). The application of a didactic workshop occurred in the pandemic context of SARS-CoV2, in remote teaching, with students of the undergraduate course in Chemistry of a public University of Espírito Santo. The students were divided into two groups and developed solutions to a proposed problem, working with the themes: differentiation of false and true banknotes, and recognition of patterns in vegetable oils. The groups presented promising results in terms of learning in the development of their experimental methodologies and were able to have contact with analysis of chemical problems that are still little explored in the undergraduate course.

Resumo em Português:

The discussions on human rights, gender and race are global and urgent. Using elements of participatory research, this study aimed to analyze, understand and characterize the formative process of postgraduate student’s knowledge and reflections mobilized on the gender and sexuality in the teaching of Science/Chemistry. The results show that the students started from a counter-hegemonic intentionality regarding the way in which the issue of hormones is traditionally treated in Science/Chemistry teaching. Furthermore, they recognized scientific knowledge as active in the production and reproduction of systems of oppression teacher on diversity education transgressive way of teaching the subject, beyond the binary conception of gender. The results revealed the possibility of rationalizing sexual and gender dissidences as a form of innovation, as well as the importance of formative processes to rethink dominant epistemologies for the advancement of educational and practices in and for education, to break with the cisheteromonormative perspective that erases the production and existence of people who flee from this logic in Science/Chemistry.

Resumo em Português:

The article presents the importance of practice in teaching Organic Chemistry in higher education, in addition to doing it following the methods of Green Chemistry, in view of how chemistry is seen as a “villain” due to dangerous reactions and incorrect waste disposal toxic. In this work, three chalcones with different substituents were synthesized: an electron donor (OCH3), an electron withdrawer (NO2) and the unsubstituted one, through 4 different methodologies, the first being the traditional methodology (methodology A) and the following methodologies ecofriendly alternatives. Methods B and C through maceration (without solvent), modifying only the support (BaO and Al2O3, respectively) and finally (methodology D) through microwave irradiation. Method C proved to be as efficient as the traditional one, with the advantage of being carried out without solvent and in a shorter reaction time and could be a replacement for the traditional method.