Variação dos teores de proteínas e lipidios totais em genótipos de açaí.

O objetivo do presente trabalho foi avaliar possíveis variações na composição química da polpa do fruto, neste trabalho especificamente, proteínas e lipídio

Influência da integridade dos frutos de taperebá (Spondias mombin L.) in natura na qualidade da polpa congelada.

Encontrado na região Amazônica o taperebá é um fruto amplamente consumido, em função do sabor agradável, boa composição nutricional e presença de carotenoides. A comercialização como polpa congelada é a forma de beneficiamento mais usual no Brasil. A polpa do fruto é revestida por uma casca fina, facilmente rompida por choque mecânico, o tornando muito perecível. A coleta dos frutos na Amazônica é feita de forma manual, quando maduros se desprendem das árvores (altura de 20 a 30 metros), sendo então coletados no solo ou em telas de proteção. Tal prática resulta na perda de integridade da maioria dos frutos, o que torna mais rápida a deterioração dos mesmos. Entretanto, não há registros científicos relacionando a qualidade da polpa com a integridade dos frutos. Desta forma, o objetivo do trabalho foi avaliar esta influência, realizando a caracterização físico-química, estudos de compostos bioativos e análise microbiológica. Resultados mostraram que a polpa obtida através de frutos mais íntegros apresentou maiores teores de compostos fenólicos, vitamina C, sólidos solúveis e açúcares totais, podendo indicar que os frutos batidos possivelmente sofreram ligeiro processo fermentativo. Análises microbiológicas apresentaram contagens de bactérias e bolores e leveduras superiores, além da detecção de coliformes, inclusive fecais. Tais resultados reforçam a necessidade de técnicas mais apropriadas de coleta e da prática de pasteurização para polpa, visando a qualidade do produto final

Avaliação de perdas de antocianinas totais ao longo da linha de processamento de polpa de açaí pasteurizada e congelada.

O objetivo deste trabalho foi avaliar como o processamento em escala industrial afeta os teores de antocianinas presentes na polpa de aça

A strategy for cross-calibrating U–Pb chronology and astrochronology of sedimentary sequences: An example from the Green River Formation, Wyoming, USA

Astronomical calibration of the geological timescale has been limited until recently by the precision and accuracy of radioisotopic dates, especially for pre-Neogene records. Uncertainties for radioisotopic dates of older strata were typically much larger than a single precessional cycle, and dates were often sparse, leading to the practice of orbital tuning of cyclic strata in order to astronomically calibrate the desired interval. Ideally, in order to test the assumptions of astronomical calibration with geochronology, it is necessary that the precision of radioisotopic dates be comparable to the period of the cycle being tested. The new U–Pb CA-TIMS (chemical abrasion–thermal ionization mass spectrometry) zircon dates reported here conform to this precision requirement, with 2σ analytical uncertainties from ±11000 to ±52 000 years for seven volcanic ashes from the Wilkins Peak Member of the Green River Formation. The zircon dates have simple distributions with few outliers and allow accurate estimations of the eruption ages with potential inaccuracies of less than precessional cycle. The Eocene Green River Formation (Wyoming, USA) has long been recognized as a record of cyclicly- deposited lacustrine sediments, and the abundant intercalated volcanic ashes make it a suitable place to test new approaches to astronomical calibration of cyclic strata. The abundance of different types of marker beds, including tuffs that are intercalated with the sedimentary cycles, guarantee an unambiguous correlation between sampling locations of dated tuffs on the margins of the basin and the basin center where the cyclicity is best developed, thus reducing any stratigraphic uncertainties to a fraction of (hypothesized) precession cycle. Tuning-based orbital age models, accepted by the previous geochronology, significantly deviate from the new geochronology, whereas a previously rejected model that assumes a short eccentricity period of 125 ky is now allowed. In order to test possible explanations for the apparent 125 ky period, such as changes in orbital periods, or gaps in the sedimentary record, we present an iterative strategy to select future ashes for dating such that the astronomical calibration/testing is optimized. We iteratively contrast two ad-hoc age models that bracket the linear interpolation between the dated ashes. The optimal intervals for further dating are located where the deviations between the models exceed our reported uncertainties. We propose that the iterative approach described here should become the standard for establishing a rigorous orbital calibration of the stratigraphic record where sufficient ashes exist

Bighorn Basin Coring Project (BBCP): a continental perspective on early Paleogene hyperthermals

During the summer of 2011, the Bighorn Basin Coring Project (BBCP) recovered over 900m of overlapping core from 3 different sites in late Paleocene to early Eocene fluvial deposits of northwestern Wyoming. BBCP cores are being used to develop high-resolution proxy records of the Paleocene–Eocene Thermal Maximum (PETM) and Eocene Thermal Maximum 2 (ETM2) hyperthermal events. These events are short-term, large magnitude global warming events associated with extreme perturbations to the earth’s carbon cycle. Although the PETM and ETM2 occurred ~55–52 million years ago, they are analogous in many ways to modern anthropogenic changes to the carbon cycle. By applying various sedimentological, geochemical, and palynological methods to the cores, we hope to better understand what caused these events, study the biogeochemical and ecological feedbacks that operated during them, and reveal precisely how they impacted continental environments. Core recovery was > 98% in all holes and most drilling was carried out without fluid additives, showing that continuous coring of continental smectitic deposits like these can be achieved with minimal risk of contamination to molecular biomarkers. Cores were processed in the Bremen Core Repository where the science team convened for 17 days to carry out data collection and sampling protocols similar to IODP projects. Initial results show that the weathered horizon extends to as much as ~30m below the surface and variations in magnetic susceptibility within the cores record an interplay between grain size and pedogenesis. Previous investigations of outcrops near the BBCP drill sites allow detailed evaluation of the effects of weathering on common proxy methods. Studies of lithofacies, organic geochemistry, stable isotope geochemistry, calibrated XRF core scanning, paleomagnetics, and palynology are underway and will represent the highest resolution and most integrated proxy records of the PETM from a continental setting yet known. An extensive outreach program is in place to capitalize on the educational value associated with the Bighorn Basin’s unusually complete record of Phanerozoic earth history