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61.
62.
Electrotechnologies,microwaves, and ultrasounds combined with binary mixtures of ethanol and water to extract steviol glycosides and antioxidant compounds from Stevia rebaudiana leaves
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63.
Asphaltenes which differ in their abilities to form water/oil emulsions were analysed by acidimetry, infrared and nuclear magnetic resonance spectroscopies. Asphaltenes which easily form such emulsions are loosely packed molecules and exhibit a marked acid/base imbalance. 相似文献
64.
Bitumen was treated with elemental sulphur at 140 °C and changes in the surface properties of the bitumen and the corresponding asphaltenes were studied. The bitumen-sulphur interfacial tension is low, a fact which accounts for the ease of formation of a sulphur-bitumen emulsion. The sulphur-treated bitumen shows increased adsorption characteristics, especially for a basic surface, such as magnesium oxide. The change in the polar character of the asphaltenes, as revealed by the contact-angle method, is responsible for this behaviour. 相似文献
65.
Ana I. Manzano Isabel Matía Fernando González-Camacho Eugénie Carnero-Díaz Jack J. W. A. van Loon Camelia Dijkstra Oliver Larkin Paul Anthony Michael R. Davey Roberto Marco F. Javier Medina 《Microgravity science and technology》2009,21(4):293-297
Changes have been reported in the pattern of gene expression in Arabidopsis on exposure to microgravity. Plant cell growth and proliferation are functions that are potentially affected by such changes in gene expression. In the present investigation, the cell proliferation rate, the regulation of cell cycle progression and the rate of ribosome biogenesis (this latter taken to estimate cell growth) have been studied using morphometric markers or parameters evaluated by light and electron microscopy in real microgravity on the International Space Station (ISS) and in ground-based simulated microgravity, using the Random Positioning Machine and the Magnetic Levitation Instrument. Results showed enhanced cell proliferation but depleted cell growth in both real and simulated microgravity, indicating that the two processes are uncoupled, unlike the situation under normal gravity on Earth in which they are strictly co-ordinated events. It is concluded that microgravity is an important stress condition for plant cells compared to normal ground gravity conditions. 相似文献
66.
Houcine Mhemdi Olivier Bals Nabil Grimi Eugène Vorobiev 《Food and Bioprocess Technology》2014,7(3):795-805
Alternative process of sugar beet transformation is investigated by tuning experimental conditions. A three-step process has been set-up: (1) sugar beet cossettes pretreatment by pulsed electric field (PEF) and (or) short preheating to different temperatures; (2) extraction of juice from pre-treated cossettes by pressing; and (3) purification of the expressed juice by ultrafiltration. The PEF treatment was applied to cold (10 °C) and preheated (to 20, 50, 60, 70, and 80 °C) sugar beet cossettes with intensity of E?=?600 V cm?1 using rectangular monopolar pulses of 100 μs during t PEF?=?5–20 ms. Experiments were performed with cossettes of three sizes. Control experiments were done without PEF treatment using cold (10 °C) and preheated (to 20–80 °C) cossettes. PEF-treated and (or) preheated cossettes were pressed at 5 bars during 15 min. Afterward, expressed juices obtained from the PEF-treated cossettes at 20 °C and from the untreated ones at 80 °C were purified by dead-end ultrafiltration with stirring (500 rpm) at the temperature of 20 °C by using polyethersulfone membrane with MWCO of 30 kDa. Application of PEF (E?=?600 V cm?1, t PEF?=?10 ms, T?=?20 °C) with following pressing of cossettes at 5 bars during 15 min permits to obtain the juice yield Y?=?66,5 %, which is equivalent to that obtained from cossettes preheated to 80 °C and untreated electrically (Y?=?64 %). The energy consumption of cold PEF treatment (≈2–3 Wh/kg) is very attractive as compared to preheating at high temperatures (≈138–194 Wh/kg). Combination of thermal and electrical pretreatments leads to additional softening of sugar beet tissue and to a slightly higher (on 5–10 %) juice yield, but the electroporation of preheated cossettes is more energetically costly. The raw juice expressed from PEF-treated cossettes at 20 °C has higher purity (93.5 %) than juices expressed at 50 °C (92.9 %) and at 80 °C (92.3 %). The temperature increasing from 20 to 80 °C results in a higher juice coloration (5680 IU at 20 °C and 7820 IU at 80 °C) and leads to a higher (on about 35 %) colloids concentration in the expressed juice. The filtrate obtained from the juice expressed at 20 °C with PEF treatment has a higher purity (96 %) than the filtrate obtained from the juice expressed at 80 °C (95.3 %) and its coloration is considerably lower (330 IU versus 1930 IU). In addition, the quantity of proteins and colloids in the filtrate of juice expressed at 20 °C is lower than that in the filtrate of juice expressed at 80 °C 相似文献
67.
Renato Guardini Jucinei José Comin Djalma Eugênio Schmitt Tales Tiecher Marcos Ant?nio Bender Danilo Rheinheimer dos Santos Célito Pescador Mezzari Bruno Salvador Oliveira Luciano Colpo Gatiboni Gustavo Brunetto 《Nutrient Cycling in Agroecosystems》2012,93(2):215-225
In this paper we explore the accumulation of different phosphorus (P) fractions in soil submitted to successive applications of pig slurry (PS) and deep pig litter (DL). After 88?months of no-till crop cycles, soil samples were collected in the following treatments: control (C), PS applications equivalent to 90 and 180?kg?N?ha?1 (PS90 and PS180), and DL applications equivalent to 90 and 180?kg?N?ha?1 (DL90 and DL180). The cumulative application of P of the C, PS90, PS180, DL90 and DL180 treatment was 0, 303, 606, 825 and 1650?kg P ha?1, respectively. The soil samples were then submitted to P chemical fractionation. Successive applications of 303 and 606?kg P ha?1 in PS form and 825 and 1.650?kg P ha?1 in DL form increased P levels down to 20?cm depth, especially in the labile inorganic fraction extracted by anion exchange resin and 0.5?M NaHCO3 and to a lesser extent extracted by 0.1?M NaOH. Successive additions of PS180 and DL180 increased the levels of organic P extracted by 0.5?M NaHCO3, 0.1?M NaOH and 0.5?M NaOH, and successive applications of PS and DL caused P accumulation in the soil profile, especially in labile fractions. This increased the availability to plants, but also increases the potential for environmental contamination. 相似文献
68.
Absalome A Monde Françoise Michel Marie‐Annette Carbonneau Georges Tiahou Marie‐Hélène Vernet Sabrina Eymard‐Duvernay Stephanie Badiou Benjamin Adon Eugène Konan Daniel Sess Jean Paul Cristol 《Journal of the science of food and agriculture》2009,89(15):2535-2540
BACKGROUND: Fatty acid, tocopherol, tocotrienol and carotene contents were assessed in four oil palm species from the National Centre of Agronomical Research of Côte d'Ivoire, two of which were the basal Lamé (HP1) and Deli (HP2) collections and two of which resulted from crossings between HP1 and HP2 varieties of Eleais guineensis, HP3 and HP4 being identified as the first and second cycle selection, respectively. RESULTS: Palm oil species were characterized by the richness in polyunsaturated fatty acids composition (48–60%) compared to saturated fatty acids (40–52%), especially the first variety, which was from the base collection, and the two hybrids ensuing from crossing. Total carotene content of those varieties was higher and accounted for 832–3575 µg g?1, and the β‐carotene level (580–2390 µg g?1) was predominant. Total vitamin E content was 864–1124 µg g?1, with a notable higher content of tocotrienols, especially γ‐and α‐tocotrienol, ranging from 400 to 515 µg g?1 and from 238 to 350 µg g?1, respectively. CONCLUSION: Crossing seemed to be useful in improving the performance and analytical characteristics of the base collection materials. Copyright © 2009 Society of Chemical Industry 相似文献
69.
E Baril L Coroller O Couvert M El Jabri I Leguerinel F Postollec C Boulais F Carlin P Mafart 《Food microbiology》2012,32(1):79-86
Sporulation niches in the food chain are considered as a source of hazard and are not clearly identified. Determining the sporulation environmental boundaries could contribute to identify potential sporulation niches. Spore formation was determined in a Sporulation Mineral Buffer. The effect of incubation temperature, pH and water activity on time to one spore per mL, maximum sporulation rate and final spore concentration was investigated for a Bacillus weihenstephanensis and a Bacillus licheniformis strain. 相似文献
70.
Xavier Solimando Clément Lherbier Jérôme Babin Carole Arnal‐Herault Eugénie Romero Samir Acherar Brigitte Jamart‐Gregoire Danielle Barth Denis Roizard Anne Jonquieres 《Polymer International》2016,65(12):1464-1473
1:1[α/α‐Nα‐Bn‐hydrazino] pseudopeptide?polymer bioconjugates were synthesized and investigated as additives in a reference gas separation membrane (Pebax®) for CO2 capture. Pebax® is a polyether block amide thermoplastic elastomer provided by Arkema and is already well known for its good performance for CO2 separations. First, dimer and tetramer pseudopeptides were synthesized and their terminal amine was modified into a ‘clickable’ alkyne group in view of coupling. Second, an α‐azido acrylic poly(ethylene glycol)‐based oligomer was obtained by single‐electron transfer living radical polymerization and the two partners were coupled using copper(I) catalyzed alkyne‐azide cycloaddition (CuAAC) ‘click’ chemistry. The pseudopeptides and their bioconjugates were then assessed as original additives in Pebax® membranes for CO2/CH4 and CO2/N2 separations. The permeation data were analyzed according to the solution‐diffusion model. Compared to pseudopeptides, the pseudopeptide?polymer bioconjugates enabled the membrane properties to be greatly improved with better permeability (×1.5) and a good constant selectivity for CO2 capture. The best membrane properties were obtained with 3 eq. wt% of the tetramer‐based bioconjugate with a CO2 permeability of 194 Barrer (+46% compared to that of Pebax®) and constant selectivity (αCO2/N2 = 44 and αCO2/CH4 = 13). © 2016 Society of Chemical Industry 相似文献