2,007 research outputs found

    Physicochemical and sensorial properties of grapefruit jams as affected by processing

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    Jam is an effective and tasty way of preserving fruit. Jam processing procedures as well as storage conditions and duration are important factors for jam quality. Traditional jam processing involves the application of severe thermal treatments that imply undesirable changes in the product quality characteristics such as colour, texture, flavour and nutritional and functional value. In this work, osmotic dehydration (OD) and/or microwave energy (MW) was proven as adequate to obtain jam with the typical characteristics of water content, degree Brix, pH and water activity of jam obtained by conventional thermal heating. The sensory evaluation carried out to compare the product showed that samples submitted to more intense heating treatments (conventional or MW) had significantly higher scores in colour saturation, brightness, grapefruit taste and extensibility than OD or OD+MW ones. As deduced from the obtained results, OD treatment prevents grapefruit colour changes, and mild MW heating contributes to increase the consistency and decrease the extensibility of the obtained jam. In this way, OD+MW jam was preferred by assessors mainly due to its higher consistency. The sample obtained by this procedure was stable during storage.The authors would like to thank the Ministerio de Educacion y Ciencia for the financial support given throughout the Project AGL 2005-05994. The language revision of this paper was funded by the Universidad Politecnica de Valencia, Spain.Igual Ramo, M.; GarcĂ­a MartĂ­nez, EM.; Camacho Vidal, MM.; MartĂ­nez Navarrete, N. (2013). Physicochemical and sensorial properties of grapefruit jams as affected by processing. Food and Bioprocess Technology. 6(1):177-185. https://doi.org/10.1007/s11947-011-0696-2S17718561AENOR (2009). Sensory analysis. Methodology. Paired comparison test. UNE-EN-ISO 5495.AOAC. (2000). Official methods of analysis of AOAC International (17th ed.). Gaithersburg: AOAC International.Baker, R.-A., Berry, N., Hui, Y.-H., & Barrett, D.-M. (2005). Fruit preserves and jams. In Processing fruits: science and technology (2nd ed., pp. 113–125). Boca RatĂłn: CRC Press.Bodart, M., de Peñaranda, R., Deneyer, A., & Flamant, G. (2008). Photometry and colorimetry characterisation of materials in daylighting evaluation tools. Building and Environment, 43, 2046–2058.BOE (1990). Real Decreto 670/1990, de 25 de mayo, por el que se aprueba la norma de calidad para confituras, jaleas y marmalade de frutas, crema de castañas y mermelada de frutas. BOE NÂș 130 (31/5/1990), 15140–15144.Bourne, M. (1982). Food texture and viscosity—concept and measurement. New York: Academic.Cañumir, J.-A., Celis, J.-E., Brujin, J., & Vidal, L. (2002). Pasteurisation of apple juice by using microwaves. Lebensmittel-Wissenschaft und Technologie, 35, 389–392.Contreras, C., MartĂ­n-Esparza, M.-E., MartĂ­nez-Navarrete, N., & Chiralt, A. (2008). Influence of microwave application on convective drying: effects on drying kinetics, and optical and mechanical properties of apple and strawberry. Journal of Food Engineering, 88, 55–64.Dervisi, P., Lamb, J., & Zabetakis, I. (2001). High pressure processing in jam manufacture: effects on textural and color properties. Food Chemistry, 73, 85–91.Deyhim, F., Garica, K., Lopez, E., Gonzalez, J., Ino, S., Garcia, M., et al. (2006). Citrus juice modulates bone strength in male senescent rat model of osteoporosis. Nutrition, 22(5), 559–563.GarcĂ­a-MartĂ­nez, E., Ruiz-Diaz, G., MartĂ­nez-MonzĂł, J., Camacho, M.-M., MartĂ­nez-Navarrete, N., & Chiralt, A. (2002). Jam manufacture with osmodehydrated fruit. Food Research International, 35, 301–306.Igual, M., GarcĂ­a-MartĂ­nez, E., Camacho, M.-M., & MartĂ­nez-Navarrete, N. (2010a). Effect of thermal treatment and storage on the stability of organic acids and the functional value of grapefruit juice. Food Chemistry, 118, 291–299.Igual, M., Contreras, C., & MartĂ­nez-Navarrete, N. (2010b). Non-conventional techniques to obtain grapefruit jam. Innovative Food Science and Emerging Technologies, 11(2), 335–341.Meilgaard, M., Civille, G.-V., & Carr, B.-T. (1999). Attribute differences test. Pairwise ranking test: Friedman analysis. Sensory evaluation techniques (pp. 103–106). Boca RatĂłn: CRC Press.Moraga, M.-J., Moraga, G., Fito, P. J., & MartĂ­nez-Navarrete, N. (2009). Effect of vacuum impregnation with calcium lactate on the osmotic dehydration kinetics and quality of osmodehydrated grapefruit. Journal of Food Engineering, 90, 372–379.Nikdel, S., Chen, C., Parish, M., MacKellar, D., & Friedrich, L. (1993). Pasteurization of citrus juice with microwaves energy in a continuous-flow unit. 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Variation in the content of bioactive flavonoid in different brands of orange and grapefruit juices. Journal of Food Composition and Analysis, 19(2–3), 157–166.Wicklund, T., Rosenfeld, H.-J., Martinsen, B.-K., SundfĂžrb, M.-W., Lea, P., Bruun, T., et al. (2005). Antioxidant capacity and colour of strawberry jam as influenced by cultivar and storage conditions. LWT-Food Science and Technology, 38(4), 387–391.Yu, L.-L., Zhou, K.-K., & Parry, J. (2005). Antioxidant properties of cold-pressed black caraway, carrot, cranberry, and hemp seed oils. Food Chemistry, 91, 723–729

    Characterization of the VVV Survey RR Lyrae Population across the Southern Galactic Plane

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    This is an author created, un-copyedited version of an article published in The Astronomical Journal. Under embargo. Embargo end date: 27 March 2018. IOP Publishing is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at doi: https://doi.org/10.3847/1538-3881/aa5be4.Deep near-IR images from the VISTA Variables in the VĂ­a LĂĄctea (VVV) Survey were used to search for RR Lyrae stars in the Southern Galactic plane. A sizable sample of 404 RR Lyrae of type ab stars was identified across a thin slice of the fourth Galactic quadrant (295° < ℓ < 350°, −2°.24 < b < −1°.05). The sample’s distance distribution exhibits a maximum density that occurs at the bulge tangent point, which implies that this primarily Oosterhoff type I population of RRab stars does not trace the bar delineated by their red clump counterparts. The bulge RR Lyrae population does not extend beyond ℓ ∌ 340°, and the sample’s spatial distribution presents evidence of density enhancements and substructure that warrants further investigation. Indeed, the sample may be employed to evaluate Galactic evolution models, and is particularly lucrative since half of the discovered RR Lyrae are within reach of Gaia astrometric observations.Peer reviewedFinal Accepted Versio

    First bounds on the high-energy emission from isolated Wolf-Rayet binary systems

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    High-energy gamma-ray emission is theoretically expected to arise in tight binary star systems (with high mass loss and high velocity winds), although the evidence of this relationship has proven to be elusive so far. Here we present the first bounds on this putative emission from isolated Wolf-Rayet (WR) star binaries, WR 147 and WR 146, obtained from observations with the MAGIC telescope.Comment: (Authors are the MAGIC Collaboration.) Manuscript in press at The Astrophysical Journal Letter

    The Pierre Auger Observatory III: Other Astrophysical Observations

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    Astrophysical observations of ultra-high-energy cosmic rays with the Pierre Auger ObservatoryComment: Contributions to the 32nd International Cosmic Ray Conference, Beijing, China, August 201

    Measurement of the Depth of Maximum of Extensive Air Showers above 10^18 eV

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    We describe the measurement of the depth of maximum, Xmax, of the longitudinal development of air showers induced by cosmic rays. Almost four thousand events above 10^18 eV observed by the fluorescence detector of the Pierre Auger Observatory in coincidence with at least one surface detector station are selected for the analysis. The average shower maximum was found to evolve with energy at a rate of (106 +35/-21) g/cm^2/decade below 10^(18.24 +/- 0.05) eV and (24 +/- 3) g/cm^2/decade above this energy. The measured shower-to-shower fluctuations decrease from about 55 to 26 g/cm^2. The interpretation of these results in terms of the cosmic ray mass composition is briefly discussed.Comment: Accepted for publication by PR

    Operations of and Future Plans for the Pierre Auger Observatory

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    Technical reports on operations and features of the Pierre Auger Observatory, including ongoing and planned enhancements and the status of the future northern hemisphere portion of the Observatory. Contributions to the 31st International Cosmic Ray Conference, Lodz, Poland, July 2009.Comment: Contributions to the 31st ICRC, Lodz, Poland, July 200

    Azimuthal asymmetry in the risetime of the surface detector signals of the Pierre Auger Observatory

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    The azimuthal asymmetry in the risetime of signals in Auger surface detector stations is a source of information on shower development. The azimuthal asymmetry is due to a combination of the longitudinal evolution of the shower and geometrical effects related to the angles of incidence of the particles into the detectors. The magnitude of the effect depends upon the zenith angle and state of development of the shower and thus provides a novel observable, (sec⁡ξ)max(\sec \theta)_\mathrm{max}, sensitive to the mass composition of cosmic rays above 3×10183 \times 10^{18} eV. By comparing measurements with predictions from shower simulations, we find for both of our adopted models of hadronic physics (QGSJETII-04 and EPOS-LHC) an indication that the mean cosmic-ray mass increases slowly with energy, as has been inferred from other studies. However, the mass estimates are dependent on the shower model and on the range of distance from the shower core selected. Thus the method has uncovered further deficiencies in our understanding of shower modelling that must be resolved before the mass composition can be inferred from (sec⁡ξ)max(\sec \theta)_\mathrm{max}.Comment: Replaced with published version. Added journal reference and DO

    A search for point sources of EeV photons

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    Measurements of air showers made using the hybrid technique developed with the fluorescence and surface detectors of the Pierre Auger Observatory allow a sensitive search for point sources of EeV photons anywhere in the exposed sky. A multivariate analysis reduces the background of hadronic cosmic rays. The search is sensitive to a declination band from -85{\deg} to +20{\deg}, in an energy range from 10^17.3 eV to 10^18.5 eV. No photon point source has been detected. An upper limit on the photon flux has been derived for every direction. The mean value of the energy flux limit that results from this, assuming a photon spectral index of -2, is 0.06 eV cm^-2 s^-1, and no celestial direction exceeds 0.25 eV cm^-2 s^-1. These upper limits constrain scenarios in which EeV cosmic ray protons are emitted by non-transient sources in the Galaxy.Comment: 28 pages, 10 figures, accepted for publication in The Astrophysical Journa
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