Cold brew is a method of coffee extraction that uses low temperature, preserving the volatile compounds of coffee. Freeze-drying allows the preservation of coffee features and nutritional value. The aim of this study was to evaluate the effects of different cryoprotectants in cold brew extracts as a basis for freeze-dried coffee production. Thus, the Coffea arabica extracts and the soluble coffee were characterized concerning caffeine content, antioxidant capacity, total phenolic compounds, and antimicrobial activity to verify the potential of this method. The extracts did not show antimicrobial activity with a high soluble solid content. It was observed that the cold extraction methods were efficient regarding the caffeine content, antioxidant capacity, and total phenolic compounds. Freeze-dried coffees also did not show antimicrobial activity, and they maintained the water and humidity activity standards. In general, cryoprotectants displayed an unfavorable influence on the extract and freeze-dried coffee in the analyses performed. The coffee extract without cryoprotectants had a higher antioxidant capacity (88.12%) and content of phenolic compounds (7.74 mg AG/mL of the coffee extract). Only for the analyses of soluble solids, the cryoprotectants mannitol and fructose showed promising results (14.03 °Brix, 14.40 °Brix, 11.33 °Brix, respectively). Thus, for the analyses conducted, the cryoprotectants did not lead to significant advantages for this process.

Carboxymethyl cellulose (CMC) is considered a non-toxic, biodegradable and biocompatible polymer. CMC-based films are rated as flexible, clear, odorless, moderately tear resistant, resistant to oil and grease migration, and water soluble. Due to its hydrophilicity, CMC can serve as matrix to encapsulate hydrophobic substances, like essential oils, by emulsion dispersions. The essential oil of rue (Ruta graveolens) has antifungal, antimicrobial, insecticide and therapeutic properties already reported in the literature. For the incorporation of rue essential oil in the CMC films, the ultrasound-assisted emulsion technique was used. The films were produced by casting evaporation. The rue essential oil emulsion and CMC polymeric films with the incorporation of emulsified essential oil were evaluated according to the emulsion droplet size, chemical composition, morphology and thermogravimetric profile. The droplet size obtained for the emulsion was 229.1 nm. The films showed good transparency, regularity and chemical characteristics similar to those of the pure polymer.

The objective of this work was to evaluate the mechanical performance of Z350 resin composite modified with Bombyx mori cocoons silk nanoparticles for dental applications. Four experimental groups were analyzed G0% = Filtek Z350 resin composite (control); G1% = Filtek Z350 with 1% of silk nanoparticles; G3% = Filtek Z350 with 3% of silk nanoparticles; G5% = Filtek Z350 with 5% of silk nanoparticles. It was employed scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, 3-point flexural strength test, Knoop hardness test, and surface roughness. From 3-point flexural strength tests the control group presented the best results G_0% = 113.33 MPa (±23.73). The higher flexural modulus was shown by groups G_3% = 29.150 GPa (±5.191) and G_5% = 34.101 GPa (±7.940), which are statistically similar. The Knoop microhardness test has shown statistical difference only among the G_3% group between the top 80.78 (± 3.00) and bottom 68.80 (±3.62) and no difference between the groups. The roughness test presented no statistical difference between the groups. The incorporation of silk nanoparticles reduced the flexural strength of Z350 resin composite. The surface roughness and microhardness tests showed no changes in any of the groups studied.

From the rupture of the Fundão dam in Mariana–MG, there are tailings still present at the bottom of the plant that must be recovered. The flocculation followed by sedimentation operation can be applied as a unit operation in this recovering process. Instead of using conventional inorganic coagulants, bio-based coagulants offer some advantages, due to their low toxicity and biodegradability. Nonetheless, the use of bio-based coagulants in the mining industry is not established yet, due to the complex parameters that must be taken in consideration. This study analyzes the influence of the pH and flocculant concentration, which are the variables of the 2² full factorial design. The pH value for the batch sedimentation process was defined ranging from 5 to 9. Tanfloc, a tannin-based coagulant, was used as a coagulant agent. The results indicate a strong dependence on the coagulant concentration, and a recommended 15 g/L dosage with pH varying from 6 to 8. From batch sedimentation, it was possible to determine an exponential model for the sedimentation with an excellent fitting (R² = 0.997). The sedimentation efficiency calculated is 65.6%. These results confirm the potential use of bio-based materials in mining tailing treatments. In addition, they can be used in equipment sizing and simulations of the sedimentation operation.

The processing of tamarind pulp (Tamarindus indica L.) produces residues such as seeds, bark and fibers, which remain underused. Therefore, taking advantage of fruit residues in the development of new products is a technological alternative that can bring economic benefits to producers and positively impact the environment, leading to more diversified products. A byproduct that is less known and explored is the tamarind mucilage, a neutral polysaccharide biopolymer derived from the endosperm of tamarind seeds, in which it has functions of stabilization, emulsification, thickening, coagulation, water retention and film formation. For mucilage extraction, different temperatures (50, 60 and 70 ºC), pH (4, 7 and 10) and mass ratio (0.015; 0.020 and 0.025 g·g−1) were used for a 23 full factorial design. The resulting mucilage was dried in a circulation at 50 °C for 24 h, obtaining an average yield of 0.019 g mucilage·g−1 seed. The extraction yield is dependent on the pH extraction media and the ratio between seeds and solvent. Also, the polysaccharide chemical structure of the mucilage is confirmed by spectroscopic analysis.