Ultrasound-Assisted Preparation of Brazil Nut Oil-in-Water Emulsions Stabilized by Arabic Gum

 The objective of this work is to evaluate the stability of Brazil nut oil emulsions with gum Arabic using ultrasound-assisted homogenization. The emulsions were prepared in a completely randomized design varying the time (2 and 4 min) and the ultrasound power (30 and 40%). The physicochemical properties of the emulsions (pH, conductivity, turbidity, zeta potential, surface tension, rheology and optical microscopy) were evaluated after the homogenization process and 4 hours later. The results showed that more energetic homogenization processes (longer duration and higher ultrasound power) favored the physicochemical properties, keeping the emulsions more stable. Thus, Brazil nut oil emulsions prepared with ultrasound-assisted showed good physic-chemical characteristics that can guarantee good emulsion stability during spray drying, guaranteeing efficiency and protection of the physical and chemical properties of the Brazil nut oil

Alternative Biodefensive based on the Essential Oil from Allium sativum Encapsulated in PCL/Gelatin Nanoparticles

The goal of this paper was to develop a biodegradable system containing the essential oil from Allium sativum bulbs encapsulated in PCL/gelatin-based nanoparticles, as well as evaluate its efficiency to control Aedes aegypti Linn. larvae and Cerataphis lataniae Bois. aphids. The essential oil was analyzed by GC-FID and GC-MS, and six compounds were identified, representing 93.1% of the total oil. The major compounds were diallyl trisulfide (51.8%), diallyl disulfide (23.2%) and allyl methyl trisulfide (13.6%). The PCL/gelatin-based nanoparticles containing this essential oil exhibited encapsulation efficiency higher than 94%, average particle diameter around 200 nm and zeta potential values about -36 mV. The essential oil presented no antioxidant nor enzymatic activities, so its effectiveness might be explained by the presence of sulfur compounds. The release kinetics of the encapsulated essential oil confirmed the release mechanism by the Fick's Law. About 50% of the encapsulated essential oil was released after 1 h, and about 90% was released after 50 h. This behavior is interesting from the technological point of view since the nanoparticles released as much oil as possible in a short period of time and then the lethal dosages were maintained along the time. Nanoparticles containing the encapsulated essential oil was submitted to in vitro bioassays against A. aegypti and C. lataniae and showed 100% of mortality against larvae and aphids up to 24 h. In conclusion, the essential oil from A. sativum presented effectiveness to be applied in sustainable management of pests in greenhouses, as well as for larvicidal control

Thermal Treatment and High-Intensity Ultrasound Processing to Evaluate the Chemical Profile and Antioxidant Activity of Amazon Fig Juices

The present paper evaluated the influence of heat treatment (HT) and high-intensity ultrasound (HIUS) on the chemical profile of the Amazon fig (Ficus subapiculata, Moraceae) juices. Antioxidant activity, quantification of carotenoids, total phenolic compounds (TPC), pH, titratable acidity, soluble solids, color and chemical profile (NMR) were evaluated. Treatments did not change the pH (3.4–3.5), titratable acidity (0.044–0.048%) and soluble solids (2.3–2.4 °Brix). The highest antioxidant activity (DPPH, ABTS) and TPC were presented by the HT-treated juice, which was equivalent to 1235 ± 11 µM TE, 1440 ± 13 µM TE and 312 ± 5 mg GAE mL−1, respectively. The treatments influenced the color luminosity according to the L* and a* parameters, while the b* parameter showed no significant change. The L* parameter was elevated in all treated samples compared to the control sample. Analyzing the parameter a* f, it was verified that the sample with thermal treatment (HT) was different from the control sample, but presented similarity with the samples of the HIUS processes. The 1H NMR spectra of the juices showed similar chemical profiles in all treatments. The compounds α-glucose, β-glucose, fructose, citric, malic, quinic, and p-hydroxybenzoic acids were identified. The HT treatment presented higher efficiency to extract the antioxidant compounds from fig juices. The HIUS treatments with constant energy density also improved the tolerance of the antioxidant compounds, especially in conditions of higher potency and reduced time. Future studies will be devoted to carry out microbiological analysis and evaluate the stability of treated juices

Species (most abundant)

Number of captures of velvet-ant species (most abundant) per tra

Species (monthly captures)

Number of captures of velvet-ant species per trap per mont

Species

Number of captures of velvet-ant species per tra

Maximum leaf photosynthetic light response for three species in a transitional tropical forest in Southern Amazonia

Measurements of CO2 and water vapor flux using eddy covariance are being made from a 40 m tower located in a transitional tropical forest near Sinop Mato Grosso. As complementary information to this study, the photosynthetic light response curves of three species located near the tower were measured at different heights in the forest canopy and light conditions with the objective of understanding seasonal and spatial (height in the forest canopy and gap or shade located plants) trends in the photosynthetic light response. The measurements were made in a canopy emergent tree (30 m tall) identified as Brosimum lactescens, and in two relatively short plants (0.6 to 1.6 m height) identified as Quiina pteridophylla and Diniszia excelsa located in different light condition. Measurements were made from the end of 2000 dry season to January 2002. These data suggest that species response to seasonal variations in rainfall are variable. In addition, shade plants have a higher quantum yield (A) and a lower estimated gross photosynthesis at saturating (photosynthetic active radiation - PAR) (Amax) than gap plants, presumably because shade plants are adapted to lower average light levels

Environment

Microclimatic variables recorded at each tra