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81.
82.
In Situ Rheo-NMR Measurements of Solid Fat Content 总被引:2,自引:0,他引:2
Gianfranco Mazzanti Elizabeth M. Mudge Emmanuel Y. Anom 《Journal of the American Oil Chemists' Society》2008,85(5):405-412
The properties of crystallized fats depend on their solid fat content (SFC) and their fractal structures. The SFC and the
structures are dramatically affected during crystallization under shear flow. A mini-Couette cell was developed to crystallize
fat samples under shear. The cell was tested with blends of canola stearin (CS) in canola oil (CO) in a 20-MHz NMR spectrometer.
The blends were placed in the cell, melted at 80 °C, and then crystallized under different shear rates (58–460 s−1) at 40 °C inside the spectrometer for 4 h. Time averaged NMR free induction decay (FID) curves were captured at 20 s intervals.
SFC values were calculated using parameters determined by a calibration procedure. The SFC values determined by the direct
method with and without the shaft of the Couette device were reasonably close. Similar results were observed with and without
shear in the Couette device. The FID curves did not show a significant difference either. Therefore this system is accurate
for in-situ time-resolved determination of SFC under shear flow. Furthermore, a combination of the direct and the indirect
methods was successfully used to estimate the temperature increase due to viscous heating. The system developed will help
in understanding the effects of shear flow on SFC of nanostructured lipid multicomponent systems. This will permit the optimization
of the manufacturing processes. 相似文献
83.
The cultivation of crops for biomass production on good soils allows to reduce surplus production of food crops and increase the sustainability of energy production from the environmental point of view. The short rotation forestry (SRF), is only at a preliminary study level in Italy but, is already a reality in North Europe where was already developed an high planting density (6000–8000 cuttings ha-1) technique and a whole mechanization of plantation and biomass harvest.On the basis of this cultivation technique, it was realized as an energetic and economic evaluation of a poplar SRF in Northern Italy. In detail, they were considered data of poplar growth in a plantation for the production of two-year whips in Western Po Valley considering SRF duration of 8 years and a biomass (20 t ha−1 D.M.) harvest every 2 years. Indeed it was assumed to operate on a plantation in production (12.5% of the surface replanted every year) with a spacing 3.00 × 0.4 m (6700 cutting per hectare) that allows the use of conventional tractors.In this computing system it was pointed out a ratio between output and input energy of 13 and a cost of 80 € t−1 of D.M. Nevertheless a positive energetic balance, the economic sustainability of poplar SRF depends, due to the present monopolistic energy management in the same countries, on political choices of chip price or public subventions to the producers. 相似文献
84.
One of the most investigated heat transfer fluid or heat storage medium in the field of thermal solar conversion is the “solar salt”, a mixture of nitrates NaNO3/KNO3, 60/40% by weight, respectively. The content of potassium in this fluid allows exploiting the self activity of the isotope 40K to perform measurements useful for control or diagnostics of a solar plant. Here an experimental test on the non-invasive measurement of the salt level in a tank by means of gamma-ray spectrometry is shown. 相似文献
85.
Gianfranco Mazzanti Alejandro G. Marangoni Stefan H.J. Idziak 《Food research international (Ottawa, Ont.)》2009,42(5-6):682-694
A detailed synchrotron X-ray diffraction study on the kinetics of crystallization of anhydrous milk fat (AMF) and milk fat triacylglycerols (MFT) was done in a Couette cell at 17 °C, 17.5 °C and 20 °C under shear rates between 0 and 2880 s?1. We observed shear-induced acceleration of the transition from phase α to β′ and the presence of crystalline orientation, but no effect of shear on the onset time of phase α was observed. A two stage regime was observed for the growth of phase β′. The first stage follows a series–parallel system of differential equations describing the conversion between liquid and crystalline phases. The second stage follows a diffusion-controlled regime. These mechanisms are consistent with the crystalline orientation, the growth of the crystalline domains and the observed displacement of the diffraction peak positions. The absence of the polar lipids explains the faster kinetics of MFT. 相似文献
86.
Norbornene (NB) has been polymerized with TiCl4-AlR2Cl (R = Et, Me, iBu) at various NB/TiCl4 molar ratio. The products obtained at low ratio (from ca. 5 to 12, depending on the mode of catalyst preparation) are a mixture of oligomers, from which it has been possible to isolate a crystalline heptamer having a 2,3-exo-disyndiotactic structure by single crystal X-ray analysis. The products obtained at higher NB/TiCl4 ratio have a higher molecular weight (up to ca. 5000 for the soluble products) and consist of amorphous and crystalline polymers. The crystalline polymers, characterized by X-ray and 13C NMR, are a new type of stereoregular polynorbornene (PNB), having a 2,3-exo-disyndiotactic structure. Mechanistic aspects are examined and a precise assignment of some resonances in the 13C NMR spectrum of vinyl-type PNBs is reported. 相似文献
87.
Giuseppe Cirillo Manuela Curcio Orazio Vittorio Francesca Iemma Donatella Restuccia Umile Gianfranco Spizzirri 《Critical reviews in food science and nutrition》2016,56(2):326-337
In recent years, antioxidants have gained great importance because of their potential use in food, pharmaceutical, and cosmetic industries. This interest is rooted in the cumulative evidence connecting active oxygen and free radicals with numerous human degenerative disorders, such as cardiovascular diseases, cancer, aging, and atherosclerosis. Polyphenols are the major class of antioxidant able to reduce the oxidative damages of lipids, proteins, enzymes, carbohydrates, and DNA in living cells and tissues. Among the realm of polyphenol compounds, polyphenol conjugates have been proposed as innovative materials which, by combining the advantageous properties of both the components, can increase the efficiency of antioxidants and their range of application in nutritional and biomedical fields. This work is an overview of the different class of polyphenol conjugates, which will be analyzed in terms of nutritional and biological properties, showing how these bio-conjugates will positively affect the human health. 相似文献
88.
89.
Guido Capotorti Pietro Cesti Antonella Lombardi Gianfranco Guglielmetti 《Polycyclic Aromatic Compounds》2013,33(3):197-213
Abstract The metabolism of four PAHs (phenanthrene, anthracene, pyrene and benzo(a)pyrene) by an Aspergillus terreus strain, isolated from a polluted soil, was investigated in liquid submerged culture. The main metabolites identified by the HPLC-MS technique, after solvent extraction of the fermentation broth and mycelium, were aryl-sulfates and hydroxyl-aryl-sulfates. A metabolic pathway was identified involving in sequence: the hydroxylation by a monooxygenase of the PAHs, the conjugation with a sulfate ion, followed by a further hydroxylation to hydroxyl-aryl-sulfates compounds. PAHs degradation by A. terreus yielded a different number of metabolite isomers depending on the type of the parent PAH. The environmental fate and ecotoxicity of the metabolite 9-phenanthrenesulfate was also investigated by a respirometric test of ready biodegradability and by a Vibrio fischeri acute toxicity test respectively. This compound was easily degradable by microbial consortia derived from polluted soil and capable of thriving on phenanthrene as its sole carbon source. Moreover the sulfate conjugate resulted in 2 orders of magnitude less toxic than its precursors phenanthrene. 相似文献
90.