Using underutilized residues of coffee to obtain valuable dietary and antioxidant bioactive compounds.

BACKGROUND: Coffee cultivation and agroindustry generate residues that are rich in several metabolites. These compounds, such as phenolic compounds and alkaloids, are known for their antioxidant activity and are usually consumed as nutraceuticals. The purpose of this study was to evaluate the occurrence of chemical and antioxidant components of low-pruned coffee stems under different fertilizer regimes. Extractives and lignin composition, histochemical, chromatographic, and antioxidant analyses were performed. RESULTS: Multiple compounds were found to accumulate in the stems of coffee trees. Furthermore, the presence of phenolic compounds such as chlorogenic acid, vanillin, resveratrol, and the alkaloids caffeine and trigonelline varied depending on the type of fertilization. In all samples examined, optimal performance was observed at the highest tested concentration (500 µg mL-1 ). All samples analyzed presented a great performance at the highest concentration tested (500 µg mL-1 ), with the dose 70% and the dose 100%, which is the recommended for the culture, showing the highest values for most of the concentrations and the best half-maximal inhibitory concentration (IC50 ) when compared with the other samples tested. CONCLUSION: As shown in the results, the reuse of stem residues as antioxidant material, with the potential to be profitable, and has the added benefit of providing a sustainable destination for material that until now has been underutilized. © 2023 Society of Chemical Industry.

Utilization of rice production residues as a reinforcing agent in bioadhesives based on polyphenols extracted from the bark of trees from the Brazilian Cerrado biome.

The scarcity of nonrenewable resources and the increase in environmental pollution have intensified the search for materials that exhibit specific characteristics and are nontoxic, renewable, and sustainable. Thus, the objective of this work was to produce natural polyphenol adhesives reinforced with rice husk and its ash to increase the mechanical resistance and moisture resistance of the glue line in wood bonded joints. Polyphenols were extracted from the bark of Stryphnodendron adstringens (Mart.) Coville (barbatimão). Adhesives were produced with a 50 % solid and 50 % liquid composition. Rice husk and husk ash underwent X-ray fluorescence analysis (XRF). Adhesives and reinforcement material were characterized by Fourier transform infrared (FTIR) and thermogravimetric analyses (TGA). The adhesives were glued in a mechanical press in specimens made of Pinus elliottii, which were subjected to shear testing of the wet and dry glue line. As a result, the chemical components present in rice husk and its ash positively influenced the properties of the adhesives. The mechanical glue line shear test showed that the adhesive reinforced with rice husk ash did not show a statistically significant difference. However, natural adhesives based on polyphenols from barbatimão strengthened with rice husk and ash showed improved properties, demonstrating how much it pays to use the residue of rice production to reinforce the matrix of tannin adhesives. Thus, it can be determined that reinforcement with rice husk and ash is efficient in improving some properties of natural adhesives based on polyphenols.

Substitution of petrochemical compounds for polyphenols of natural origin reinforced with cellulose nanofibrils to formulate adhesives for wood bonding.

Vegetable tannins are excellent options to produce adhesives for the panel industry since they have the capacity to reduce formaldehyde emissions and are derived from renewable sources. They also allow for the possibility of increasing the resistance of the glue line through the use of natural reinforcements such as cellulose nanofibrils. Condensed tannins, polyphenols isolated from tree bark, are widely studied for the production of natural adhesives as an alternative to commercial synthetic adhesives. So, the purpose of our research is to show a natural adhesive alternative for wood bonding. Therefore, the objective of the study was to evaluate the quality of tannin adhesives of different species reinforced with different nanofibrils and thus predict which adhesive is the most promising at different concentrations of reinforcement and with different types of polyphenols. To meet this objective, polyphenols were extracted from the bark, nanofibrils were obtained, and both processes followed the current standards. Then, the adhesives were produced, their properties were characterized, and they were chemically analyzed via Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). A mechanical shear analysis of the glue line was also performed. According to the results, the addition of cellulose nanofibrils affected the physical properties of the adhesives, mostly the content of solids and the gel time. In the FTIR spectra, the OH band of the 5% Pinus and 5% Eucalyptus (EUC) TEMPO in the barbatimao adhesive and the 5% EUC of the cumate red adhesive were reduced, possibly due to their higher moisture resistance. Mechanical tests of the glue line showed that barbatimao with 5% Pinus and cumate red with 5% EUC performed best in the dry and wet shear tests. The control was the best-performing sample in the test of the commercial adhesives. The cellulose nanofibrils used as reinforcement did not change the thermal resistance of the adhesives. Therefore, the addition of cellulose nanofibrils to these tannins is an interesting means of increasing the mechanical strength, as occurred in commercial adhesive with 5% EUC. Thus, the physical and mechanical properties of tannin adhesives were better with reinforcement, making it possible to expand the use of these adhesives in the panel industry. At the industrial level, it is important to replace synthetic products with natural ones. Besides environmental and health issues, there is the question of the value of petroleum-based products, which have been widely studied so that they can be replaced.

Mandacaru cactus as a source of nanofibrillated cellulose for nanopaper production.

In this work, nanofibrillated cellulose (NFC) was extracted from cactus Cereus jamacaru DC. (mandacaru) for nanopaper production. The technique adopted includes alkaline treatment, bleaching, and grinding treatment. The NFC was characterized according to its properties and scored based on a quality index. Particle homogeneity, turbidity, and microstructure of the suspensions were evaluated. Correspondingly, the optical and physical-mechanical properties of the nanopapers were investigated. The chemical constituents of the material were analyzed. The sedimentation test and the zeta potential analyzed the stability of the NFC suspension. The morphological investigation was performed using environmental scanning electron microscopy (ESEM) and transmission electron microscopy (TEM). X-ray diffraction (XRD) analysis revealed that Mandacaru NFC has high crystallinity. Thermogravimetric analysis (TGA) and mechanical analysis were also used and revealed good thermal stability and good mechanical properties of the material. Therefore, the application of mandacaru is interesting in sectors such as packaging and electronic device development, as well as in composite materials. Given its score of 72 points on a quality index, this material was presented as an attractive, facile, and innovative source for obtaining NFC.

Bark anatomy, chemical composition and ethanol-water extract composition of Anadenanthera peregrina and Anadenanthera colubrina.

The bark of Anadenanthera peregrina (L.) Speg and Anadenanthera colubrina (Vell.) Brenan were characterized in relation to anatomical and chemical features. The barks were similar and included a thin conducting phloem, a largely dilated and sclerified non-conducting phloem, and a rhyridome with periderms with thin phellem interspersed by cortical tissues. Only small differences between species were observed that cannot be used alone for taxonomic purposes. The summative chemical composition of A. peregrina and A. colubrina was respectively: 8.2% and 7.7% ash; 28.8% and 29.3% extractives; 2.4% and 2.6% suberin; and 18.9% lignin. The monosaccharide composition showed the predominance of glucose (on average 82% of total neutral sugars) and of xylose (9%). The ethanol-water extracts of A. peregrina and A. colubrina barks included a high content of phenolics, respectively: total phenolics 583 and 682 mg GAE/g extract; 148 and 445 mg CE/g extract; tannins 587 and 98 mg CE/g extract. The antioxidant activity was 238 and 269 mg Trolox/g extract. The barks of the Anadenanthera species are a potential source of polar extractives that will represent an important valorization and therefore contribute to improve the overall economic potential and sustainability of A. peregrina and A. colubrina.

Efeito da incorporação de casca de café nas propriedades físico-mecânicas de painéis aglomerados de Eucalyptus urophylla S. T. Blake / Effect of the incorporation of coffee husks on the physico-mechanical properties of Eucalyptus urophylla S. T. Blake particleboards

Neste trabalho objetivou-se avaliar a influência da incorporação de casca de café nas propriedades físico-mecânicas de painéis aglomerados produzidos com Eucalyptus urophylla S.T. Blake. Os painéis foram produzidos com incorporação de 25, 50 e 75 por cento de casca de café, em três teores da resina fenol-formaldeído (6, 9 e 12 por cento) e 1 por cento de parafina. A densidade nominal dos painéis foi de 0,7 g/cm³ e o ciclo de prensagem compreendeu uma pressão de 3,92 MPa e temperatura de 180ºC por 8 minutos. Pelos resultados obtidos foi possível observar que: as propriedades físicas dos painéis aglomerados apresentam relação linear decrescente com o aumento do teor de resina, e crescente com a porcentagem de casca de café, apresentando maiores valores de absorção de água e inchamento em espessura. As propriedades mecânicas apresentam relação linear crescente com o aumento do teor de resina, e decrescente com a porcentagem de associação de casca de café. Do modo que a pesquisa foi conduzida, a incorporação da casca de café prejudica a qualidade dos painéis produzidos.

The objective of this study was to evaluate the influence of the incorporation of Coffee husks in the production of particleboard with Eucalyptus urophylla S.T. Blake. The panels were produced incorporating 25 percent, 50 percent, and 75 percent of Coffee husks at three levels of resin phenol-formaldehyde (6, 9 and 12 percent) and 1 percent of paraffin. The nominal density of the panels was 0.7 g/cm³ and the cycle of pressing consisted in a pressure of 3.92 MPa under a temperature of 180°C for 8 minutes. By the results it was possible to observe that the physical properties of the particleboard have a linear relationship decreasing with the increase in the level of resin, and increasing with the increase in the percentage of coffee husks, showing higher values of water absorption and thickness swelling. The mechanical properties show a linear relationship growing with the increase of resin level, and decreasing with a reduction the percentage of coffee husk association. The way that the search was conducted, the incorporation of the Coffee husks harms the quality of the panels produced.

Avaliação de resíduos de painéis de madeira gerados por indústrias moveleiras para aproveitamento na confecção de pequenos objetos: estudo de caso / Evaluation of residues of wood boards generated by furniture industries for their utilization in the production of small objects: study of case

A indústria moveleira produz uma quantidade de resíduos que, normalmente, é descartada no meio ambiente ou utilizada como combustível em caldeiras e similares, ou apenas queimada. Alternativas para utilização desses resíduos têm sido alvo de pesquisas, destacando-se a confecção de pequenos objetos, na forma de artesanato. Neste trabalho, objetivou-se avaliar os resíduos de indústrias do pólo moveleiro de Ubá/MG. No levantamento quantitativo, constatou-se que as empresas geraram resíduos dos mesmos tipos de painéis de madeira. Os resíduos mais comuns foram de aglomerado e MDF (Medium Density Fiber). Observou-se grande variabilidade das dimensões desses resíduos, principalmente em sua largura. Concluiu-se que alguns resíduos não apresentaram dimensões adequadas para a confecção de determinados objetos e que se torna necessária uma seleção prévia desses resíduos para direcioná-los a trabalhos mais minuciosos, de forma a viabilizar a sua utilização.

The furniture industry generates an amount of residues, which, normally, is discarded in the environment or destined to steam production in boilers. The handmade production of small wood board objects is an outstanding alternative to take advantage of these residues. The general aim of this study was to evaluate residues in furniture industries located at the pole of Ubá/MG. Through the survey and the analysis of the data, one established that the industries generate residues from the same kind of wood board. The most common residues were of particleboard and MDF (Medium Density Fiber). One observed a great diversity of residue dimensions, mainly in width. One concluded that some residues did not present adequate dimensions for the manufacturing of some objects and that there is a necessity of previous residues selection, in order to destine them to more detailed works and make possible their use.