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21.
Ana Carolina Rodríguez-Negrette María José Rodríguez-Batiller Victor Alonso García-Londoño Virginia Borroni Roberto Jorge Candal María Lidia Herrera 《Journal of the American Oil Chemists' Society》2020,97(11):1215-1228
Physical chemical properties of cupuassu fat were modified by dry fractionation. Stearin and olein fractions were obtained at 29, 26, and 24 °C. Polymorphic behavior of unfractionated cupuassu fat (UCF) and its fractions were studied in situ by small-angle (SAXS) and wide-angle (WAXS) X-ray scattering using synchrotron light. Polymorphic transitions were followed in real time tempering samples with a thermal cycle. For UCF, the main polymorphic form crystallized under selected conditions was the β’2. α and β’1-forms appeared in trace amounts. β2-form was obtained after storage at 25 °C for 3 months. Stearins obtained at 26 (S-26) and 24 °C (S-24) showed a similar polymorphic behavior. However, S-26 with improved physical properties might be more suitable for chocolate production or as a trans-fat alternative than UCF. Stearin fraction obtained at 29 °C (S-29) had a complex polymorphic behavior. The α-form was the first polymorphic form detected followed by β’2-form. There was a polymorphic transition from α to β’1-form but no transition between β’-forms. They were independent to each other showing fractionation in two different solid solutions. Increased contents of the triacylglycerols (TAG) SOA and SOB together with lower contents of SOO compared to UCF led to co-crystallization because there was no complete compatibility among all TAG present in S-29. β1-form crystallized after storage forming crystals with a double-layer arrangement and a characteristic morphology. This form could be useful for accelerating crystallization process in melted liquid systems. 相似文献
22.
María del Pilar Monge Alejandra Paola Magnoli Maria Virginia Bergesio Nestor Tancredi Carina E. Magnoli 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2016,33(6):1043-1052
Aflatoxin B1 (AFB1) and fumonisin B1 (FB1) are mycotoxins that often co-occur in feedstuffs. The ingestion of AFB1 causes aflatoxicosis in humans and animals. Sodium bentonite (NaB), a cheap non-nutritive unselective sequestering agent incorporated in animal diets, can effectively prevent aflatoxicosis. Fumonisins are responsible for equine leukoencephalomalacia and porcine pulmonary oedema, and often have subclinical toxic effects in poultries. Fumonisin B1 and aflatoxin B1 are both strongly adsorbed in vitro on sodium bentonite. Co-adsorption studies, carried out with a weight ratio of FB1 to AFB1 that mimics the natural occurrence (200:1), showed that FB1 greatly decreases the in vitro ability of NaB to adsorb AFB1. The ability of two activated carbons to adsorb FB1 was also investigated. Both carbons showed high affinity for FB1. A complex behaviour of the FB1 adsorption isotherms with pH was observed. In vitro results suggest that under natural contamination levels of AFB1 and FB1, a mixture of activated carbon and sodium bentonite might be potentially useful for prevention of sub-acute aflatoxicosis. 相似文献
23.
Ester Rojo M. Virginia Alonso Beln Del Saz‐Orozco Mercedes Oliet Francisco Rodriguez 《应用聚合物科学杂志》2015,132(26)
Viscose cellulosic fibers from eucalyptus wood were treated with organosilanes to introduce specific functionalities on the fibers and enhance their wettability and adhesion with phenolic matrices in composites. Modeling procedures were employed to optimize the conditions of the treatments of the fibers with the silanes (3‐aminopropyl) trimethoxysilane (APS) and 3‐(2‐aminoethylamino) propyltrimethoxysilane (AAPS). The analyzed responses were relative intensities of the bands 1565/897 and 1120/897 cm−1, measured by Fourier transform infrared spectroscopy, and the silicon amount incorporated into the cellulosic fibers, which was determined by energy dispersive X‐ray analysis. In addition, surface morphology of the silane treated fibers was observed using scanning electron microscopy. The treatments of the cellulosic fibers with 2.2% APS for 120 min and 1.5% AAPS for 100 min were selected as optimums. According to contact angle measurements, both treatments enhanced the wettability between the fibers and a resol‐type phenolic resin, revealing the possible use of the silane treated fibers as reinforcement in phenolic composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42157. 相似文献
24.
Virginia R. Stovin Sarah L. Moore Matthew Wall Richard M. Ashley 《Water and Environment Journal》2013,27(2):216-228
Experience of retrofitting sustainable drainage systems (SuDS) in the United Kingdom is limited, and there are no well‐established procedures for evaluating the feasibility, value or cost‐effectiveness of doing this, particularly at the catchment scale. This paper demonstrates a two‐phase process for evaluating the potential to retrofit SuDS to address combined sewer discharges in three subcatchments within the Thames Tideway catchment of London. The first phase evaluates what might be achieved with various levels of disconnection (‘global’ disconnection scenarios) using hydraulic models, while the second phase considers how disconnection might practically be achieved. High levels of disconnection are technically possible but practicably difficult. In selected cases, and with aggressive implementation of SuDS, combined sewer overflow CSO discharges could potentially be eliminated or reduced to acceptable levels without the need for any modifications to underground assets. However, retrofit SuDS could not eliminate the requirement for some form of sewer modification in any subcatchments. 相似文献
25.
Empar Llorca Isabel Hernando Isabel Pérez-Munuera Amparo Quiles Virginia Larrea M. Ángeles Lluch 《European Food Research and Technology》2007,225(5-6):807-813
The objective of this paper was to study the main chemical and microstructural changes in squid proteins during processing
as a frozen batter-coated product using different coatings. Protein bands of the squid and of the batters used for coating
were studied using SDS-PAGE. It is concluded that it is not only the proteins of the layer of batter, which are directly exposed
both to the frying oil and to freezing temperatures, that deteriorate during the preparation process, the protein fraction
of the squid substrate, mainly the myofibrillar proteins, is also degraded. At a microstructural level, big voids are generated
during freezing as a consequence of the packing of the fibres, although the size of these voids decreases after final frying.
After this step of the process, the central sarcoplasm is still visible but has been altered by coagulation of the sarcoplasmic
proteins and the sarcolemma is observed to be separate from the myofibrillar package. 相似文献
26.
Virginia León-Ruiz Soledad Vera Amelia V. González-Porto María Paz San Andrés 《Food Analytical Methods》2013,6(2):488-496
An isocratic RP-HPLC method has been developed for the identification and quantification of water-soluble vitamins in honey. The mobile phase tested was an aqueous solution of sulphuric acid and the detection was carried out simultaneously by UV and fluorescence. The separation of vitamins C (l-ascorbic acid), B1 (thiamine), B3N (nicotinamide), B3H (nicotinic acid), B5 (d-pantothenic acid) and B6 (pyridoxine) is achieved in these conditions in 15 min. The addition to the mobile phase of methanol 2 %?v/v reduced significantly the analysis time in the separation of these vitamins up to 10 min. Moreover, in presence of a cationic surfactant hexadecyltrimethylammonium bromide (CTAB) in the mobile phase, the separation of vitamin C, B1, B3N, B3H, B2 (riboflavin) and B6 is possible in 6 min. The combination of both mobile phases, H2SO4/methanol and H2SO4/methanol/CTAB, has been applied to the analysis, in isocratic mode, of several monofloral honeys (rosemary, thyme, lavender, chestnut, echium) and a honeydew honey in a short time analysis. 相似文献
27.
Pappier U Fernández Pinto V Larumbe G Vaamonde G 《International journal of food microbiology》2008,125(2):153-157
Incidence of fungal contamination of quinoa seeds from three locations (Salar de Uyuni, Bolivia; Salta and Tucumán provinces, Argentina) was analyzed in samples with and without treatment to remove saponins (wet method). In processed samples, the percentage of infection was reduced. Distribution of the different fungal genera was not homogeneous in the three locations (p<0.05), although Penicillium and Aspergillus were the most prevalent contaminants, regardless the geographic origin of the samples. Other genera, such as Eurotium, Fusarium, Phoma, Ulocladium, Mucor and Rhizopus were less frequently isolated. Absidia, Alternaria, Cladosporium, Dreschlera, Epicoccum and Monascus were sporadically encountered. Significant differences (p<0.05) in the distribution of fungal genera in samples with and without saponins from each location were observed. In all cases, processing caused a decrease of Aspergillus incidence, while increased the proportion of Penicillium, Eurotium, Mucor and Rhizopus indicating that these genera were part of the internal mycota. A. flavus and A. niger were the dominating species of genus Aspergillus. A similar pattern of prevalent Penicillium species was observed in samples with and without saponins, since P. aurantiogriseum, P.chrysogenum, P. citrinum and P. crustosum were always present in high number, although their relative density was variable according to the geographic origin of samples. Mycotoxin-producing ability of most representative species was also determined. Toxigenic strains of A. flavus (aflatoxins and cyclopiazonic acid), A. parasiticus (aflatoxins), P. citrinum (citrinin) and P. griseofulvum (cyclopiazonic acid) were found. None of the A. niger isolates was ochratoxin A producer. The above mentioned mycotoxins were not detected in the samples analyzed. 相似文献
28.
Evanthia Vorria Virginia Giannou Constantina Tzia 《European Journal of Lipid Science and Technology》2004,106(11):759-765
Deep frying can pose hazards due to oil deterioration (oxidation, polymerization, hydrolysis) and harmful components formation such as trans fatty acids, highly oxidized or polymerized constituents of fatty acids and acrylamide. An analysis of safety hazards of the production of the potato chips and french fries, was carried out from potato harvesting until final products packaging according to hazard analysis and critical control point approach focusing mainly on the first three principles. Since frying is considered a critical control point, the critical limits for the frying temperature and for the potential hazards must be controlled in order to ensure fried products safety. 相似文献
29.
30.
Trewartha Kevin M.; Endo Alejandro; Li Karen Z. H.; Penhune Virginia B. 《Canadian Metallurgical Quarterly》2009,24(2):450
Two experiments were designed to explore how age differences in conflict detection may contribute to poorer motor performance. In each experiment, 12 young adults (YAs) and 12 older adults (OAs) performed a finger sequencing task in which the frequency of specific critical transitions was varied. These critical transitions were contrasted with violation transitions to assess the ability to detect a conflict in response requirements. In addition to accuracy and reaction time, the authors used kinematic data to parse movements into planning and motor execution phases. OAs were differentially slower to respond to violations than YAs, in line with other research on executive control, prepotent response suppression, and aging. Kinematic analyses revealed that YAs executed movements more rapidly on violation than critical transitions, whereas OAs executed movements at the same speed regardless of response predictability and increased planning time. The authors argue that OAs are unable to reprogram prepotent movement plans to overcome slowed movement planning in cognitively challenging situations. The results are discussed in terms of the influence of age-related cognitive inefficiency on motor control. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献