Search Results (55)

Recent studies have focused on the development of food packaging films based on biopolymers, with polysaccharides being at the forefront due to their abundant availability in food and agricultural by-products. Therefore, it was the aim of this work to prepare and characterize conjugated biopolymeric films using starch, galactomannans and buriti oil (BO), with the latter acting as a partial or integral replacement for glycerol as a plasticizer. The addition of BO to either the starch or the conjugated starch–galactomannan film formulations led to distinct interactions between the components and consequently to films with distinct properties. The addition of both BO and galactomannan to starch hindered retrogradation, characterized by a diminished degree of crystallinity in comparison to the film containing only starch, attesting the stabilization of the starch molecular structures in its interaction with galactomannan molecules and with the emulsified BO. The analyses of films’ mechanical properties demonstrated that the added BO did not act as a plasticizer, leading to increased tensile strength and elastic modulus and decreased elongation at break in all formulations. Overall, the films containing starch presented lower mechanical resistance than the ones based on galactomannan. All formulations led to biodegradable films, with those with BO taking longer to degrade. Full article

This study explores the production of composites based on polylactic acid (PLA) reinforced with microcrystalline cellulose (MCC), using Additive Manufacturing technology via LCD. Polylactic acid, being biodegradable and possessing good mechanical properties, was combined with microcrystalline cellulose, which has a high modulus of elasticity, aiming to further improve its performance. Composites with different microcrystalline cellulose contents (1, 3, 5, and 10%) were obtained and compared to pure PLA. Characterization involved thermal, mechanical, morphological, and structural tests. The results showed that the addition of microcrystalline cellulose increases hardness, tensile strength, and modulus of elasticity. Scanning electron microscopy revealed more heterogeneous fracture surfaces in the composites compared to pure polylactic acid. Thermal stability varies according to the microcrystalline cellulose content, with increased degradation observed in some samples, reaching 1%. Increased water absorption was also detected with increasing microcrystalline cellulose concentration, indicating potential limitations in humid environments. The incorporation of microcrystalline cellulose, especially at moderate concentrations such as 3%, proved to be an effective strategy for improving the mechanical properties of polylactic acid. Full article

K-jarosite (KFe₃(SO₄)₂(OH)₆), the most common jarosite-type mineral in natural and industrial settings, has been widely studied to understand its dissolution behavior in both environmental and industrial contexts. However, reported kinetic data remain inconsistent due to the combined influence of kinetic factors, despite the importance of such data for optimizing system conditions and improving process control and environmental management. The present work aims to help elucidate K-jarosite dissolution by carrying out new experiments in sulfuric acid medium (pH 1 and 2) at different temperatures (296, 323 and 343 K) and using two initial concentrations (0.4 and 1 g of K-jarosite/kg of solution). K-jarosite was synthesized and characterized by analytical techniques (XRD, SEM and BET), and the composition was determined by induction-coupled plasma optical emission spectroscopy (ICP-OES). Derivative (DVKM), Noyes–Whitney (NWKM) and Shrinking Core (SCKM) kinetic models previously used in the literature of jarosite-type compounds were adjusted to the data obtained here and compared. The results showed that higher temperatures and lower pH led to faster dissolution rates. Smaller initial concentrations decreased the rates slightly but had less impact than the other variables. Experiments at pH 1 led to the dissolution of all jarosite solids, while at pH 2 they led to incomplete dissolution. Remarkably, at pH 2 and at higher temperatures (mainly at 343 K), there was slight reprecipitation of the iron. XRD analysis identified no peak other than K-jarosite peaks after dissolution. DVKM and NWKM represented the effect of the studied parameters well. However, only using SCKM was a kinetic equation describing the dissolution process obtained. While the behavior of the kinetic curve is well established, the model fails to correctly describe the induction period. Under extreme conditions (>323 K, pH 1), dissolution is described by a chemical reaction controlling stage and it changes to mass transport in mild conditions. As theoretically expected, the results obtained in this work give important information about the prediction of the behavior of jarosite dissolution in terrestrial environments (acid mine and acid rock drainages) and hydrometallurgical process in mild acidic conditions and high temperatures. Full article

The aim of this study is to obtain poly(lactic acid) polymeric nanocomposites and carbon nanotubes for application in drone propellers produced through 3D printing. In this work, a filament based on poly(lactic acid)—PLA/functionalized carbon nanotube (CNT) composites was prepared for the fused deposition modeling (FDM) process. The effects of CNT content (0.2–1.0%), temperature variation, and extruder screw rotation variation were applied in the Design of Experiments (DOE) tool, where the main factors contributing to filament quality, focusing on mechanical strength, were identified. Through this tool, an optimum point for the material’s mechanical strength was reached, showing a value of 48.87 MPa, 43.17% above the initial value of 27.77 MPa. The response surface curve revealed a region where new filaments with similar mechanical strength values to those found in this work could be obtained. The results demonstrate that CNT content, extruder screw rotation, and extruder temperature directly influence filament quality. The data obtained from Thermogravimetry (TG) and Derivative Thermogravimetry (DTG) curves show that the addition of 0.6% CNT by weight does not significantly modify PLA degradation resistance, despite slight differences in temperatures. The main reason for these alterations is the dispersion of CNTs in the PLA matrix and CNT agglomeration. Through the demonstrated simulation, it is possible to confirm the application of the developed material in drone propeller manufacturing, facilitating access and providing new opportunities for users. Full article

Given the growing consumer demand for improved quality of life and health-promoting foods, replacing conventional fats in widely consumed products such as bread with oils derived from native Brazilian fruits represents a promising strategy. This study aimed to evaluate the bioactive and technological potential of buriti (Mauritia flexuosa) and acuri (Attalea phalerata) oils, extracted from palm fruits native to the Cerrado and Amazon biomes. Both oils proved to be rich sources of lipophilic bioactives, particularly carotenoids, tocopherols, and phenolic compounds, and exhibited excellent carotenoid bioaccessibility under in vitro digestion, with recovery rates of 74% for acuri oil and 54% for buriti oil. Notably, buriti oil showed a high β-carotene content (1476.5 µg/g). When incorporated into sandwich bread formulations, these oils enhanced antioxidant activity, improved texture, volume, and color, and maintained high sensory acceptance compared to bread made with soybean oil. Sensory evaluation scores averaged above 7 for all tested attributes. These findings underscore the industrial applicability of buriti and acuri oils as functional lipids aligned with sustainable development and nutritional innovation. Full article

Background/Objectives: A great biodiversity of compounds from Brazilian medicinal plants are considered to be a promising source for biological activities in the cosmetics and pharmaceuticals sectors. Lipids and mainly fatty acids from Brazilian medicinal plants and their bioactive components are promising ingredients with proven diverse biological activities. To undertake a review of some rare oils of Brazilian medicinal plants with corroborated biological activities, we selected data from the scientific literature reporting the efficacy of plants used in folk medicine as antioxidant, anti-inflammatory or other types of activity of their oil phases extracts and isolated fatty acids. Methods: A search of the literature was undertaken by using the following web tools: Web of Science, SciFinder, Pub-Med and ScienceDirect. The terms “biological activity”, “anti-inflammatory”, “açai oil, andiroba oil, bacuri butter, buriti oil, cupuaçu butter and pracaxi oil”, and “free fatty acids” and “Amazonian plant oils” were used as keywords in the search engines. The Tropicos and Reflora websites were used to verify the origin of the plants, and only native plants from Brazil were included in this review. Only the publications reporting the use of well-accepted scientific protocols to corroborate the potential biological activities of rare oils of Amazonian plants were considered. Results: We selected 6 Brazilian medicinal plant oils extracts (acai, andiroba, bacuri, buriti, cupuaçu, pracaxi) with multiple biological activities. The observations were presented as a function of the oil origin and the most important biological activities were detailed. Conclusions: The collected data on the rare oils from Amazonian plants, in the form of crude extract and/or isolated compounds, showed significant biological activities involving different mechanisms of action, indicating that these oils could be an important source of lipids with biological activity. Full article

This research presents the results of different periods of T6 heat treatment (homogenization and artificial aging) for A356 aluminum alloy used in the fabrication of motorcycles. The samples were cast using gravity die casting, and industrial furnaces for T6 were used in the experiment. Two heat treatment conditions were used, with a total time of 7 h and 12 h, and the results were compared with the alloy without heat treatment. The effects of the reduction of treatment time on mechanical behavior were evaluated in terms of hardness, Charpy and tensile tests, as well as morphological analysis of fractures and microstructural behavior via optical microscopy, SEM-EDS, measurement of eutectic Si evolution, and XRD. Excellent mechanical properties were achieved with a treatment period of 7 h, which achieved a yield strength of 226.58 (±3.76) MPa, tensile strength limit of 264.78 (±4.27) MPa and elongation of 3.41 (±0.47) %. This is competitive with other cast alloys subjected to T6 heat treatment in longer treatment cycles. The peak of hardness and highest impact resistance was recorded for the sample treated for 12 h; however, in the impact test, there was no significant difference between the two experiments. Full article

Amazonian fruits are a source of bioactive compounds, among which phenolic compounds, flavonoids, and carotenes stand out. These compounds play a crucial role in restoring oxidative balance, consequently reducing the proliferation of cancer cells. However, the content of these metabolites and their biological properties may vary significantly depending on the geographical location and the environmental conditions where plants grow. This research assessed the content of metabolites, free radical scavenging capacity, and hemolytic and antiproliferative effects of the hydro-methanolic extracts of the Amazonian fruits Theobroma grandiflorum and Mauritia flexuosa. The results revealed that the extracts derived from the seeds of Theobroma grandiflorum sourced from the Balcanes experimental farm and the pulp of Mauritia flexuosa harvested in Florencia exhibited higher contents compared to other analyzed sites: Total phenolic content (TPC) (619.41 ± 12.05 and 285.75 ± 10.06 mg GAE/100 g FW), Total flavonoid content (TFC) (569.09 ± 4.51 and 223.21 ± 3.92 mg CAT/100 g FW), and Total carotenoid content (TCC) (25.12 ± 0.16 and 48.00 ± 0.28 mg eq β-carotene/100 g FW), respectively. Also, these samples demonstrated superior scavenging capacities for the ABTS and DPPH radicals, while the peel of Mauritia flexuosa exhibited the highest scavenging capacity for the oxygen radical (526.23 ± 2.08 µmol Trolox.g⁻¹). The hemolytic effect shows dose-dependent responses with IC50 values of 27.73 μg/mL for the Balcanes seeds and 1.27 μg/mL for the Florencia pulp. Furthermore, it was observed that treatment with the fruit-derived extracts effectively reduced the number of viable human colorectal cancer cells, using SW480 ATCC cell line, demonstrating a non-dose-dependent behavior compared to the control cells. Full article

In the Amazon region, the impact of fire on the region’s biogeochemical processes remains poorly understood. In this study, we examined the relationship of seasonal fire on greenhouse gas (GHG) emissions over the study region during the last two decades of the 21st century by integrating calibrated and validated satellite-derived products of estimations of burned biomass area, land cover, vegetation greenness, rainfall, carbon monoxide (CO), and nitrogen dioxide (NO₂) through geospatial techniques. Results revealed a strong impact of fire activity on GHG emissions, with abrupt changes in CO and NO₂ emission factors between early- and middle-dry-season fires (July–September). We found a strong positive correlation (r² = 0.71) between NO₂ and burned biomass when a small percentage of burned biomass (around ≤ 0.5%) is released during a fire. However, in the event of a large percentage of burned biomass (>0.8%), the correlation coefficient between NO₂ and burned biomass was weak (r² = 0.41). New models need to be developed that incorporate the substantial existing knowledge on the seasonal dynamics of fire-derived GHG emissions. This information should be utilized to make effective decisions about how to manage fire in the Amazon ecosystems and to drive further data collection campaigns and modelling initiatives. Full article

The Amazon region is becoming more vulnerable to wildfires occurring in the dry season, a crisis amplified by climate change, which affects biomass burning across a wide range of forest environments. In this study, we examined the impact of seasonal fire on greenhouse (GHG) emissions over the study region during the last two decades of the 21st century by integrating calibrated and validated satellite-derived products of estimations of burned biomass area, land cover, vegetation greenness, rainfall, land surface temperature (LST), carbon monoxide (CO), and nitrogen dioxide (NO₂) through geospatial techniques. The results revealed a strong impact of fire activity on GHG emissions, with abrupt changes in CO and NO₂ emission factors between early and middle dry season fires (July–September). Among these seven variables analyzed, we found a positive relationship between the total biomass burned area and fire-derived GHG emission factors (r² = 0.30) due to the complex dynamics of plant moisture and associated CO and NO₂ emissions generated by fire. Nevertheless, other land surface drivers showed the weakest relationships (r²~0.1) with fire-derived GHG emissions due to other factors that drive their regional distribution. Our analysis suggests the importance of continued research on the response of fire season to other land surface characteristics that represent the processes driving fire over the study region such as fuel load, composition, and structure, as well as prevailing weather conditions. These determinants drive fire-related GHG emissions and fire-related carbon cycling relationships and can, therefore, appropriately inform policy fire-abatement guidelines. Full article

This experiment evaluated the effects of including buriti oil (BO) in the diet of broilers on growth performance, nutrient digestibility, carcass yield, meat quality, blood parameters, intestinal morphometry, the proliferation of collagen fibers in the skin and collagen concentration in the breast muscle. A total of 180 one-day-old Ross male chicks were distributed in a completely randomized experimental design with three treatments (0%, 1% and 2% BO) and six replications of 10 birds each. Nutrient digestibility was evaluated from 8 to 21 days, while the performance, carcass yield, meat cut yields, abdominal fat, meat quality, blood parameters, intestinal morphometry and skin histology of the birds were evaluated after 21 days. The inclusion of BO significantly affected (p ≤ 0.05) performance, digestibility, meat color, lymphocyte count, duodenal morphometry and collagen concentration. In addition, it increased the metabolizable energy of the diet and reduced the birds’ performance, indicating that the nutraceutical effect of BO improved nutrient use. However, it caused an excess of energy that had to be metabolized by the birds, consequently affecting their performance. BO increased the pigmentation of the breast meat and reduced the lymphocyte count, probably due to its antimicrobial action, consequently decreasing the recruitment of defense cells. An increase in the height of the crypt of the duodenum was observed as the inclusion of BO increased, with the opposite being observed in the jejunum. The inclusion of BO increased the histological proliferation of collagen from minimal (0%) to medium (1%) and moderate (2%), as well as the collagen concentration (CC = 35.933 + 4.677BO; R² = 0.80). Thus, due to functional/nutraceutical effects, adding BO in the diet of broilers can be a promising alternative to antibiotic growth promoters to improve poultry production. Full article

This study investigated the abundance of zooplankton copepods and ostracods taxonomic groups in fish farms in Rondônia’s Vale do Jamari and Centro-Leste microregions during the rainy and dry seasons. It also analyzed the correlation between zooplanktons abundance and the presence of acanthocephalan parasites. Conducted in 41 fish farms between November 2021 and September 2023, the study included water, zooplankton, and fish samples from 196 Colossoma macropomum. The results showed that 95% of the farms had fish infected with Neoechinorhynchus buttnerae, with varying parasitism levels. Georeferencing revealed higher parasite densities in the municipalities of Ariquemes, Monte Negro, Machadinho do Oeste, and Buritis (Vale do Jamari), as well as Urupá, Ji-Paraná, Ouro Preto do Oeste, and Teixeirópolis (Centro-Leste), with clusters of heat islands in the latter group. Water quality parameters were suitable for raising C. macropomum. The presence of ostracods and copepods could serve as indicators of parasitic infestations, highlighting the importance of monitoring zooplankton and parasite communities. This approach is valuable for detecting changes in artificial ecosystems, such as fish farms, which could lead to significant long-term effects. Full article

In this case study, exploratory techniques were applied for the selection of potential targets for rare-earth elements (REEs) in the Fazenda Buriti Mafic–Ultramafic Complex, part of the Goiás Alkaline Province. The results of the processing and interpretation of aeromagnetic and radiometric data associated with the direct measurements of magnetic susceptibility and radiometry in rock samples collected in the study area allowed for the characterization and delimitation of the geological units. The application of Boolean logic in the radiometric data of uranium (U), thorium (Th), and the U/Th ratio allowed for the generation of a prospective map with the delimitation of two exploration targets. A 100 m deep exploratory drill hole was drilled at the main target, intercepting REE mineralization and validating the developed prospective technique. The results contributed to the detailing of a 1:25,000 scale geological map and the interpretation of shallow and deep magnetic structures. Petrophysical data allowed for the estimation of the magnetite content in the main units of the study area. The delimitation of targets with the applied method proved to be efficient after positive geochemical results for REE from the drilled rocks. The total sum of ∑REEs reached 19,629 ppm in the superficial part of the hole and 3,560 ppm in the fresh rock. Mineralogical results in two follow-up drill core samples indicated that monazite was the main REE mineral. Total REE ranged from 34,746 ppm in HG1 to 30,017 ppm in HG2, with LREEs in its majority. The bulk and clay XRD analyses indicated that monazite consisted of 5.7% (HG1) and 5.1% (HG2). The mineral abundance from the TIMA-X analysis indicated 4.2% (HG1) and 4.4% (HG2) in monazite content. Full article

Recent advancements highlight the utilization of vegetable oils as additives in polymeric materials, particularly for replacing conventional plasticizers. Buriti oil (BO), extracted from the Amazon’s Mauritia flexuosa palm tree fruit, boasts an impressive profile of vitamins, minerals, proteins, carotenoids, and tocopherol. This study investigates the impact of incorporating buriti oil as a plasticizer in linear low-density polyethylene (LLDPE) matrices. The aim of this research was to evaluate how buriti oil, a bioactive compound, influences the thermal and rheological properties of LLDPE. Buriti oil/LLDPE compositions were prepared via melt intercalation techniques, and the resulting materials were characterized through thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), mechanical property testing, and contact angle measurement. The addition of buriti oil was found to act as a processing aid and plasticizer, enhancing the fluidity of LLDPE polymer chains. TGA revealed distinct thermal stabilities for buriti oil/LLDPE under different degradation conditions. Notably, buriti oil exhibited an initial weight loss temperature of 402 °C, whereas that of LLDPE was 466.4 °C. This indicated a minor reduction in the thermal stability of buriti oil/LLDPE compositions. The thermal stability, as observed through DSC, displayed a nuanced response to the oil’s incorporation, suggesting a complex interaction between the oil and polymer matrix. Detailed mechanical testing indicated a marked increase in tensile strength and elongation at break, especially at optimal concentrations of buriti oil. SEM analysis showcased a more uniform and less brittle microstructure, correlating with the enhanced mechanical properties. Contact angle measurements revealed a notable shift in surface hydrophobicity, indicating a change in the surface chemistry. This study demonstrates that buriti oil can positively influence the processability and thermal properties of LLDPE, thus expanding its potential applications as an effective plasticizer. Full article

The microbiological and biochemical properties of a goat cheese produced using Helianthus annuus (sunflower) seed extract as a coagulant and the potentially probiotic autochthonous culture Limosilactobacillus mucosae CNPC007 were examined in comparison to a control cheese devoid of the autochthonous culture. Throughout a 60-day storage period at 6 ± 1 °C, lactobacilli maintained a count of above 8 log CFU/g. Additionally, its viability in cheeses subjected to the in vitro gastrointestinal conditions demonstrated improvement over this period. Specifically, the recovery of lactobacilli above 6 log CFU/g was observed in 16.66% of the samples in the first day, increasing to 66.66% at both 30 and 60 days. While total coliforms were detected in both cheese trials, this sanitary parameter exhibited a decline in L. mucosae cheeses during storage, falling below the method threshold (<3 MPN/g) at 60 days. This observation suggests a potential biopreservative effect exerted by this microorganism, likely attributed to the higher acidity of L. mucosae cheeses at that point (1.80 g/100 g), which was twice that of the control trial (0.97 g/100 g). Furthermore, distinct relative proportions of >30 kDa, 30–20 kDa, and <20 kDa proteins during storage was verified for L. mucosae and control cheeses. Consequently, either the H. annuus seed extract or the L. mucosae CNPC007 autochthonous culture influenced the biochemical properties of the cheese, particularly in terms of proteolysis. Moreover, L. mucosae CNPC007 acidification property resulted in a biopreservative effect throughout the storage period, indicating the potential as a promising source of probiotics for this product. Full article