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Selected AbstractsHydrothermal processing of rice husks: effects of severity on product distributionJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 7 2008Rodolfo Vegas Abstract BACKGROUND: Treatment in aqueous media (hydrothermal or autohydrolysis reactions) is an environmentally friendly technology for fractionating lignocellulosic materials. Rice husks were subjected to hydrothermal processing under a variety of operational conditions to cause the selective breakdown of xylan chains, in order to assess the effects of reaction severity on the distribution of reaction products. RESULTS: The effects of severity (measured by the severity factor, R0) on the concentrations of the major autohydrolysis products (monosaccharides, xylo- and glucooligosaccharides, xylooligosaccharide substituents, acetic acid, acid-soluble lignin and elemental nitrogen) were assessed. The interrelationship between the severity of treatment and molecular weight distribution was established by high-performance size-exclusion chromatography. Selected samples were subjected to refining treatments as ethyl acetate extraction and ion exchange for refining purposes, and the concentrates were assayed by high-performance anion-exchange chromatography and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. CONCLUSIONS The protein equivalent of the products present in liquors accounted for 43 to 51% of the protein present in the raw rice husks. The concentrations of glucose (derived from starchy material) and arabinose (split from the xylan backbone) were fairly constant with severity. Even in treatments at low severity, high molecular weight compounds derived from xylan accounted for a limited part of the stoichiometric amount. Operating under harsh conditions, about 50% of the total xylan-derived compounds corresponded to fractions with a degree of polymerization (DP) < 9. After refining, saccharides accounted for more than 90% of the non-volatile components of the sample. The refined products showed a series of xylose oligomers up to about DP 13, and a series of acetylated xylose oligomers up to about DP 15. Copyright © 2008 Society of Chemical Industry [source] INFLUENCE OF OSMOTIC DEHYDRATION ON THE VOLATILE PROFILE OF GUAVA FRUITSJOURNAL OF FOOD QUALITY, Issue 3 2008JORGE A. PINO ABSTRACT The effect of osmotic dehydration (OD) on the volatile compounds of guava fruits was studied. Osmotic treatments were carried out at atmospheric pressure, at continuous vacuum and by applying a vacuum pulse (5 min under vacuum and the remaining time at atmospheric pressure) at different temperatures (30, 40 and 50C) and times (1, 2 and 3 h). The volatile compounds of fresh and dehydrated samples were obtained by simultaneous distillation,extraction, and were analyzed by gas chromatography/mass spectrometry. In general, OD caused changes in the concentration of volatiles, depending on the process conditions. The use of lower temperatures and shorter treatment times can diminish the loss of volatiles with respect to the fresh samples. The greatest damage to volatiles loss is produced at 50C for up to 2 h under both pulsed and continuous vacuum. The lowest total volatiles loss occurred at 30 and 40C for up to 3 h under pulsed vacuum or atmospheric pressure. PRACTICAL APPLICATIONS Consumer demand for high-quality products with freshlike characteristics has promoted the development of a new category, minimally processed fruits and vegetables. Although these products present, as distinguishing features, simplicity in use and convenience, they generally perish more quickly than the original raw material because of tissue damage caused by mechanical operations. The use of osmotic dehydration process has been presented as a tool for the development of minimally processed fruits. The slight water activity reduction promoted by the process may provide stable products with good nutritional and sensorial quality and with characteristics similar to those of the fresh products. The application of minimal processing to tropical fruits can represent an interesting world market. Fruit flavor is an important quality factor that influences consumer acceptability, and for this reason, its study is relevant in the minimally processed food product. [source] The Lindisfarne Gospels and two other 8th century Anglo-Saxon/Insular manuscripts: pigment identification by Raman microscopyJOURNAL OF RAMAN SPECTROSCOPY, Issue 1 2004Katherine L. Brown Abstract The Lindisfarne Gospels (Cotton MS Nero D iv, ca. 715 AD) and two nearly contemporary manuscripts (Royal MS 1B vii and Add. MS 40618) held in the British Library have been analysed in detail by Raman microscopy in order to establish the palette of each. The blue pigment used on the Lindisfarne Gospels is shown not to be lazurite, as concluded in 1960 by visual examination of known pigments and those on the Gospels, but exclusively indigo. Of the Anglo-Saxon and Insular manuscripts studied so far by Raman microscopy, the earliest found to include lazurite in its palette is Add. MS 40618, not on its still extant original miniature of ca. 756 AD, but on later additions of ca. 920 AD. The Insular triumvirate palette, which had been assumed to consist of orpiment, red lead and verdigris, was found also to include red ochre and vergaut (indigo admixed with orpiment) but not necessarily verdigris. The palettes of the manuscripts studied, as specified in existing literary sources, are not reliable, and careful in situ scientific analysis of the pigments present is essential to establish the identity of the latter and of any decomposition products present. Copyright © 2004 John Wiley & Sons, Ltd. [source] Drying Stages during the Heating of High-Alumina, Ultra-Low-Cement Refractory CastablesJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 7 2003Murilo D. M. Innocentini The purpose of this work was to investigate the drying kinetics of high-alumina, ultra-low-cement refractory castables under continuous heating conditions. Three main drying stages were identified during the castable heat-up and were related to the phase change of free water and to the decomposition of hydrated products present in the body. A clear correlation was found between the actual heating profile inside the castable and the dewatering stages under various heating schedules. Thermal analysis was used to assess the drying temperature that represents the highest risk of steam pressure buildup and, thus, of explosive spalling. [source] Geology and geochemistry of shallow drill cores from the Bosumtwi impact structure, GhanaMETEORITICS & PLANETARY SCIENCE, Issue 8 2003Daniel Boamah The interior of the structure is largely filled by the 8 km diameter Lake Bosumtwi, and the crater rim and region in the environs of the crater is covered by tropical rainforest, making geological studies rather difficult and restricted to road cuts and streams. In early 1999, we undertook a shallow drilling program to the north of the crater rim to determine the extent of the ejecta blanket around the crater and to obtain subsurface core samples for mineralogical, petrological, and geochemical studies of ejecta of the Bosumtwi impact structure. A variety of impactite lithologies are present, consisting of impact glassrich suevite and several types of breccia: lithic breccia of single rock type, often grading into unbrecciated rock, with the rocks being shattered more or less in situ without much relative displacement (autochthonous?), and lithic polymict breccia that apparently do not contain any glassy material (allochtonous?). The suevite cores show that melt inclusions are present throughout the whole length of the cores in the form of vesicular glasses with no significant change of abundance with depth. Twenty samples from the 7 drill cores and 4 samples from recent road cuts in the structure were studied for their geochemical characteristics to accumulate a database for impact lithologies and their erosion products present at the Bosumtwi crater. Major and trace element analyses yielded compositions similar to those of the target rocks in the area (graywacke-phyllite, shale, and granite). Graywacke-phyllite and granite dikes seem to be important contributors to the compositions of the suevite and the road cut samples (fragmentary matrix), with a minor contribution of Pepiakese granite. The results also provide information about the thickness of the fallout suevite in the northern part of the Bosumtwi structure, which was determined to be ,15 m and to occupy an area of ,1.5 km2. Present suevite distribution is likely to be caused by differential erosion and does not reflect the initial areal extent of the continuous Bosumtwi ejecta deposits. Our studies allow a comparison with the extent of the suevite at the Ries, another well-preserved impact structure. [source] Cover Picture , Mol.MOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue S1 2008Nutr. Cancer chemoprevention has been defined as the use of drugs, vitamins, or other agents to try to reduce the risk of, or delay the development or recurrence of, cancer. Phytochemicals from food as well as medicinal plants are recognized as agents that play a role in cancer prevention. In this Special Issue of "Natural Products and Dietary Prevention of Cancer" recent reviews on selected natural products present in food, beverages and condiments, and their putative role in the prevention of various types of cancer are provided. [source] SAAG-4 is a novel mosquito salivary protein that programmes host CD4+ T cells to express IL-4PARASITE IMMUNOLOGY, Issue 6 2009V.D. BOPPANA Summary Mosquitoes represent the most important vector for transmitting pathogens that cause human disease. Central to pathogen transmission is the ability to divert the host immune system away from Th1 and towards Th2 responsiveness. Identification of the mosquito factor(s) critical for programming Th2 responsiveness should therefore lead to strategies to neutralize their function and thus prevent disease transmission. In the current study, we used a TCR transgenic adoptive transfer system to screen gene products present in the saliva of the mosquito Aedes aegypti for their ability to programme CD4 T cells to express the signature Th2 cytokine IL-4. The clone SAAG-4 encodes a secreted protein with a predicted size of 20 kDa whose function has previously been uncharacterized. Notably, SAAG-4 reduced host CD4 T cell expression of the signature Th1 cytokine IFN-, while simultaneously increasing expression of IL-4. SAAG-4 is therefore the first identified mosquito factor that can programme Th2 effector CD4 T cell differentiation. [source] | ||||||||||