Abstract In the present work, a simple and high-throughput analytical procedure based on ultrasound-assisted extraction with diluted acid was proposed for the determination of Ca, Mg, K, P, S, Fe, Cu and Mn in guarana samples using inductively coupled plasma optical emission spectrometry. Two multivariate approaches were employed for optimization of the extraction procedure: mixture and Doehlert designs. The best experimental conditions were established by application of a multi-response function (overall desirability). An extractor medium composed of diluted nitric acid was selected for analytes extraction. Optimized conditions for ultrasound-assisted extraction followed the temperature of 60 °C, sonication time of 10 min and power of 100% applied to the ultrasonic bath. After the analytical validation step, the proposed procedure was successfully employed for determination of essential elements in thirty-three guarana samples from the state of Bahia, Brazil. Mass fractions higher than 0.42% (m m-1) were found for potassium in all analyzed samples. For the other macro-elements, the mass fraction ranged from 514 mg kg-1 (magnesium) to 0.19% m m-1 (calcium). The mass fraction of micro-elements ranged from 5.1 to 91.3 mg kg-1 for cooper and iron, respectively.

Abstract Isotonic repositories are specially designed to promote rehydration during or after physical exercise. These beverages are processed for commercialization from synthetic flavorings and dyes with sensorial characteristics similar to those of fruits, in order to attenuate their natural acidity. The aim of the present study was to develop two formulations of isotonic drinks without synthetic dyes and with functional attributes based on concentrated hydroethanolic extracts of peel and pulp of Myrciaria jaboticaba. Determination of chemical (sodium, potassium and calcium, total phenolics, total anthocyanins, total flavonoids, total condensed tannins), physical (objective color analysis), and physical-chemical characteristics (pH, acidity, total soluble solids), as well as sensory evaluation through preference testing was carried out. In addition, the drinks presented dark red coloration, according to the chromaticity diagram. The sensory evaluation results revealed that the beverage formulated with 12% pulp extract stood out as the preferred beverage among the judges.

Abstract In the present study, the physicochemical properties and mineral composition of commercially-frozen soursop pulps from the southern region of the state of Bahia, Brazil, were evaluated. The physicochemical parameters such as soluble solids (°Brix), acidity and pH were determined according to reference methodologies. For mineral composition evaluation, samples were digested in a closed microwave system and the elements K, P, S, Ca, Mg, Fe, Cu, Zn, and Mn were quantified through inductively coupled plasma optical emission spectrometry (ICP OES). Soluble solids content ranged from 4.77 to 15.37 °Brix among the different brands of analyzed frozen pulps. Titratable acidity (equivalent to citric acid) and pH ranged from 0.49 to 1.00 and 3.61 to 4.57, respectively. Some samples presented irregularities in regard to quality pattern established in the Brazilian legislation. The following range of concentration, in μg g-1, were found for essential elements: K (544-1761), P (44.3-139), S (71.8-174), Ca (24.3-77.0), Mg (47.2-132), Fe (1.40-4.05), Mn (0.32-1.22), Cu (0.30-0.88) and Zn (0.36-0.84). The use of principal component analysis (PCA) enabled a more in-depth data analysis, performing correlations between different variables and frozen pulp brands.

An understanding of feed ingredient digestibility for the pirarucu is a fundamental step in the development of feeds that promote proper growth of the specie while in captivity. A digestibility trial was conducted with four treatments in triplicate (corn starch, corn, rice bran and wheat bran) to evaluate the digestibility of dry matter, gross energy, crude protein and amino acids by the pirarucu. We used indirect methodology with the inclusion of chromium oxide at 0.1% in the feeds. In total, 18 juveniles were used, with an average live weight of 235 ± 36 g. The sampled juveniles were trained to consume the feeds prior to testing. The corn and cornstarch presented the best apparent digestibility coefficients (ADCs) of dry matter, with 76.37% and 70.66%, respectively, followed by rice bran (46.23%) and wheat bran (45.13%). The best ADCs of crude protein were observed in corn (93.44%) and cornstarch (90.94%) compared to rice bran (68.23%) and wheat bran (68.58%). There was no significant difference in the ADC of gross energy; the values ranged from 47.10% for corn starch to 40.10% for corn. The corn and corn starch presented the best ADCs for all the amino acids evaluated, followed by rice bran and wheat bran.

El conocimiento de la digestibilidad de los ingredientes en la alimentación del pirarucu es primordial para la elaboración de pienso específico, que promueva un crecimiento óptimo. Se realizó un ensayo de digestibilidad con cuatro ingredientes energéticos, almidón de maíz, harina de maíz, salvado de arroz y salvado de trigo para la evaluación de las digestibilidades de materia seca, energía bruta, proteína bruta y aminoácidos. Se utilizaron 18 juveniles con peso de 235 ± 36 g. La harina de maíz y el almidón de maíz presentan los mejores coeficientes de digestibilidad aparente (CDA) de la materia seca, 76,37% y 70,66% respectivamente, seguidos por el salvado de arroz (46,23%) y salvado de trigo (45,13%). Los mejores CDA de la proteína bruta se determinaron para harina de maíz (93,44%) y almidón de maíz (90,94%), en relación al salvado de arroz (68,23%) y salvado de trigo (68,58%). Para el CDA de la energía bruta no fue registrada diferencia estadística, variando entre 47,10% para el almidón de maíz y a 40,10%, para la harina de maíz. La harina de maíz y el almidón de maíz presentaron los mejores CDA de todos los aminoácidos evaluados, seguidos por el salvado de arroz y salvado de trigo.

A contaminação de plantas medicinais com Pb e Cd pode afetar o crescimento e a produção de óleo essencial das plantas e representa um risco para quem as consome como medicamento. Este estudo teve como objetivo avaliar os efeitos da absorção e localização de Pb e Cd sobre o crescimento das plantas, aspectos ultraestruturais de folhas e sobre o rendimento e composição química do óleo essencial de M. arvensis, os quais foram aplicados ao solo em concentrações crescentes (8, 16, 32, 64 and 128mg kg-1). Houve absorção diferencial de Pb e Cd por M. arvensis, que se concentraram principalmente nas raízes. O Pb foi encontrado em baixas concentrações nas folhas, enquanto o Cd excedeu largamente o limite de segurança sem demonstrar sintomas de toxicidade. As análises ultraestruturais revelaram o acúmulo de metais em vesículas ao redor de mitocôndrias e a presença de depósitos eletrodensos ao redor de mitocôndrias, núcleo e cloroplastos. As pequenas mudanças causadas pela aplicação de Pb e Cd não foram suficientes para afetar o crescimento das plantas e o rendimento e composição química do óleo essencial de M. arvensis

Contamination of medicinal plants with heavy metals as Pb and Cd can affect the growth and the essential oil production of the plants and represent a risk to those who consume as medicine. This study aimed to evaluate the effects of absorption and localization of Pb and Cd on growth, ultrastructural aspects of leaves and essential oil yield and composition of Mentha arvensis, applied on the soil with increasing concentrations (8, 16, 32, 64 and 128mg kg-1). There was a differential absorption of Pb and Cd by M. arvensis mainly concentrated in the roots. Pb was found in small amounts in the leaves while Cd largely exceeded the safety limit without symptoms of toxicity. The ultrastructural analysis revealed the metal accumulation on vesicles surrounding the mitochondria and the presence of electron dense deposits surrounding the mitochondria, nucleus and chloroplasts. Little changes caused by Pb and Cd application were not enough to affect the growth and essential oil yield and composition of M. arvensis

The present work aims at presenting a methodological approach for the electrochemistry content that connects the three levels of representation of chemical knowledge through the classic experiment of the Saline Drop. From this activity it tries to integrate the different levels of representation in order to help the student organize his ideas in a vision of totality, presenting and discussing the possible connections that are established among the different levels of representation.

Este trabajo pretende presentar un enfoque metodológico para abordar el contenido electroquímico que conecta los tres niveles de representación del conocimiento químico, a través del experimento clásico de la gota salina. A partir de esta actividad se procura integrar los diferentes niveles de representación para auxiliar al estudiante a organizar sus ideas en una visión de totalidad, al presentar y discutir las conexiones posibles entre los diversos tipos de representación.

In this work, we describe a pedagogical experiment using work projects in chemistry undergraduate programs in general chemistry and inorganic chemistry courses making learning more dynamic and consolidating the link between students and the external community. We highlight as fundamental outcomes the improvement in the learning process and, above all, the active participation of the students in investigation and problem-solving activities.