1,654 research outputs found

    Effect of crop rotations soil quality, production, and economic returns of barley grown under zero till in Parana (Brazil)

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    Non-Peer ReviewedThe cereal growing area of southern Brazil is characterized by high intensity rainstorms, warm temperatures, hilly topography, and acid soils low in natural fertility. Traditionally, cereals are grown in winter in a double cropping system with soybeans grown in summer. These factors combined with excessive use of disc-type implements causes severe soil loss by water erosion, low grain yields due to disease and insects, and general soil degradation. The combined use of zero or minimum tillage with crop rotations which include other crop types is one solution being examined with assistance from CIDA and involving scientists from Canada and Brazil. This paper reports on the agronomic and economic performance of four zero-till barley rotations. After four years of study, the results show the beneficial effects of extending rotation lengths to break disease cycles as shown by improved barley yields. The choice of cropping sequence, however, significantly influences subsequent grain yields. While barley yields were highest for the 2-year and 4-year rotations and lowest for the barley-soybean rotation, net returns were generally highest for the 4-year and continuous barley systems. Soil properties such as organic matter, pH, and Al concentration did not change significantly with the use of extended rotations, however, the potential for soil erosion was reduced by use of zero-tillage management

    Preservation of a highly perishable food, watermelon juice, at and above room temperature under mild pressure (hyperbaric storage) as an alternative to refrigeration

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    The feasibility of food preservation under pressure (hyperbaric storage) at and above room temperatures, as an alternative to refrigeration was evaluated. Preservation of a highly perishable food, watermelon juice, was studied at pressures of 25e150 MPa and temperatures ranging 20e37 C, being compared to refrigeration and storage at atmospheric pressure at the same temperatures. Hyperbaric storage at 75 MPa (20e37 C) revealed an inhibitory effect on microbial growth, with at least an equal performance compared to refrigeration. An additional inactivation effect was verified for storage at 100 and 150 MPa, with reduction of the initial microbial counts to 1.00 Log CFU/mL for enterobacteriaceae and yeasts and moulds, and from 4.43 ± 0.04 to 3.31 ± 0.04 and 2.99 ± 0.07 Log CFU/ mL, respectively, for total aerobic mesophiles (25 C). In general, pH, titratable acidity and total soluble solids did not show a clear variation trend with pressure and no considerable differences among storage conditions were verified. Cloudiness decreased for samples stored under pressure and browning degree was in general lower in samples stored under pressure compared to refrigeration. This work demonstrates the potentiality of hyperbaric storage as a new preservation methodology, at variable (uncontrolled) room temperature without energetic costs during storage, as an alternative to refrigeration

    Brayton technology for Concentrated Solar Power plants: Comparative analysis of central tower plants and parabolic dish farms

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    [EN]Concentrated solar power plants intend to be key in the pool of renewable energy production technologies in the next future because of their versatility and high efficiency. In this work a comparative study between two promising technologies is developed. A central tower receiver surrounded by a heliostat field and a farm of parabolic dishes, both coupled to a hybrid Brayton cycle, are considered. Two power scales are surveyed (between 5 and 20 MW) at three different locations with quite different latitudes (between Sahara desert and medium European latitudes) and meteorological conditions. A modelling scheme developed by our group that allows to obtain the expected thermodynamic and thermo-economic plant records is applied. Key indicators like efficiency, net generated energy, levelized cost of electricity, and specific plant investment are calculated and analysed. Variability of natural gas prices and also land cost uncertainty are reflected on levelized cost of electricity range. Among the plants compared, minimum values are found within the interval [135–163] USD/MWh for central towers at the highest power considered and southern latitudes. In addition, the area needed for the installation of the plants and the influence of CO taxes is also analysed. Displayed cashflows show larger investment costs for central tower than for dish farms. Finally, those systems are put into the context of other concentrated solar power, other renewable, like wind or photovoltaic, and other conventional power plants.PC_TCUE18-20P_010. Universidad de Salamanca and Banco de Santande

    High pressure and thermal pasteurization effects on sweet cherry juice microbiological stability and physicochemical properties

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    This study evaluated high pressure processing (P1 – 400 MPa/5 min; P2 – 550 MPa/2 min) and thermal pasteurization (TP – 70°C/30 s) effects on sweet cherry juice’s microbiological and physicochemical parameters, during four weeks of refrigerated storage. All treatments reduced the microbiological load to undetectable levels not affecting total soluble solids and titratable acidity. The pH increased with all treatments, however, it decreased during storage. Phenols were differently affected: TP increased them by 6%, P1 had no effect while P2 decreased them by 11%. During storage, phenols in control and TP samples decreased by 26% and 20%, P1 samples decreased them by 11% whereas P2 showed no variation. TP had no effect on anthocyanins, while pressure treatments increased them by 8%. Anthocyanins decreased during storage, particularly in the control and P1 (decreasing 41%). All treatments had no effect on antioxidant activity until the 14th day, thereafter high pressure processing samples showed the highest antioxidant activity

    Preservation under pressure (hyperbaric storage) at 25ºC, 30ºC and 37ºC of a highly perishable dairy food and comparison with refrigeration

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    Hyperbaric storage (HS) under mild pressure of requeijão, a traditional Portuguese whey cheese, as a case study of a highly perishable dairy food, was evaluated as a possible energy costless alternative to refrigeration. Whey cheese was stored for 4 and 8 hours, at different pressure levels (0.1, 100 and 150 MPa) and temperatures (25°C, 30°C and 37°C), and the results were compared with refrigeration (4°C). Microbial analyses showed that storage for 4 hours at 100 MPa was able to maintain microbial counts similar to refrigeration and initial load, ≈3 Log10 CFU/g, at all tested temperatures. By increasing the pressure to 150 MPa and the storage time to 8 hours, microbial loads were reduced to undetectable counts, with the exception for total aerobic mesophiles that were reduced to about ≈1 Log unit. HS in general maintained pH, water activity and lipid oxidation values, at levels similar to that in refrigeration

    Preservation of sliced cooked ham at 25, 30 and 37°C under moderated pressure (hyperbaric storage) and comparison with refrigerated storage

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    The feasibility of hyperbaric storage (HS) to substitute refrigeration as a lower energetic cost alternative to refrigeration, for sliced cooked ham preservation was assessed by using temperatures and pressures ranging 25–37◦C and 25–150 MPa for 4 and 8 h. At microbiological level, storage at 25 ◦C, 30 ◦C, and 37 ◦C, showed no effect on microbial growth at 25 MPa reaching levels similar to atmospheric pressure storage, around 5 log CFU/g for both total aerobic mesophiles (TAM) and lactic acid bacteria (LAB). Nevertheless, the storage at 50 MPa and 30 ◦C resulted in microbial growth inhibition, resulting in TAM and LAB counts similar to refrigeration, of about 3.8 log CFU/g for both the microorganisms. Additionally, the increase of the storage pressure to 100–150 MPa resulted in microbial inacti-vation, leading to microbial loads of almost 1 log CFU/g lower than refrigeration. In general, hyperbaric stored sliced cooked ham showed physicochemical parameters similar to the refrigerated samples. In conclusion, these results show that HS at uncontrolled (naturally variable room tem-perature conditions at 25–37 ◦C) is a promising alternative to refrigeration for cooked ham preservation. To this new preservation technology, no energetic costs are associated throughout storage, compared to refrigeration, needing only energy to generate the pressure and decompress, since no energy is required to maintain the pressure

    Food preservation under pressure (hyperbaric storage) as a possible improvement/alternative to refrigeration

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    Food preservation is highly dependent on refrigeration, which is limited by its high energy costs. Among alternatives being developed, this review focused on hyperbaric storage (food preservation under pressure). This new preservation methodology has as main objective microbial growth inhibition similarly to freezing and refrigeration, showing a great potential to lower energy costs since refrigerated/room temperatures (RT) can be used. This, even at variable (uncontrolled) RT (up to 37 C), has been shown to preserve foods and thus achieving significant energy savings. Covering the earliest up to the more recent studies, this review aimed to gather information about the state of art of hyperbaric storage at refrigerated and RTs, with the primary objective of showing it potential and possible future applications of this new preservation method based on microbial growth inhibition under pressure, using pressure as the main variable to slow down microbial growth

    Relationship between the occurrence of filamentous bacteria on Bathymodiolus azoricus shell and the physiological and toxicological status of the vent mussel

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    En libre-accès sur Archimer : http://archimer.ifremer.fr/doc/2009/publication-6821.pdfInternational audienceThe edifice walls of the Eiffel Tower hydrothermal vent site (Mid-Atlantic Ridge, Lucky Strike vent field) are populated with dense communities of dual symbioses harboring vent mussel Bathymodiolus azoricus, some of which are covered by white filamentous mats belonging to sulfur-oxidizing bacteria. Mussels were collected in both the presence and absence of the filamentous bacteria. A sample of the filamentous bacteria was collected and water measurements of temperature, CH4 and H2S were recorded at the collection area. The whole soft tissues were analyzed for total lipid, carbohydrate and total protein. Metallothioneins and metals (Cu, Fe and Zn) levels were determined in the major organs. The results showed no significant physiological and toxicological evidence that emphasizes the influence of associated sulfur-oxidizing filamentous bacteria on B. azoricus mussel shells. However, B. azoricus mussel seems to be well adapted to the assorted physico-chemical characteristics from the surrounding environment since it is able to manage the constant fluctuation of physico-chemical compounds

    Analysis of phenolic, polysaccharidic and lipidic fractions of mushrooms from northeast Portugal

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    Mushrooms consumption continues to increase due to their functional benefits and presence of bioactive compounds. Herein, phenolic, polysaccharidic and lipidic fractions of wild mushrooms from Northeast Portugal (Coprinopsis atramentaria, Lactarius bertillonii, Lactarius vellereus, Rhodotus palmatus and Xerocomus chrysenteron) were analysed. Protocatechuic, phydroxybenzoic, p-coumaric and cinnamic acids were found in the phenolic fraction; ramnose, xylose, fucose, arabinose, fructose, glucose, manose, mannitol, sucrose, maltose and trehalose were quantified in polysaccharidic fraction; linoleic and stearic (only in Lactarius sp.) acids, and β- and γ-tocopherols were the main compounds in the lipidic fraction
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