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1.
Maurizio?ServiliEmail author Roberto?Selvaggini Agnese?Taticchi Sonia?Esposto Gianfrancesco?Montedoro 《Journal of the American Oil Chemists' Society》2003,80(7):685-695
The time of exposure of olive pastes to air contact (TEOPAC) during malaxation was studied as a processing parameter that
could be used to control endogenous oxidoreductases, such as polyphenoloxidase, peroxidase, and lipoxygenase, which affect
virgin olive oil quality. Phenolic and volatile compounds were analyzed in the oils obtained using progressive TEOPAC at three
ripening stages of olives. Multivariate statistical analysis was applied to the raw data. The phenolic concentration of virgin
olive oil progressively decreased with increasing IEOPAC. On the contrary, a positive relationship was found with the concentration
of several volatile compounds responsible for virgin olive oil aroma. The effect of TEOPAC, however, was strictly related
to fruit ripening. 相似文献
2.
Maurizio Servili Maura Baldioli Roberto Selvaggini Enrico Miniati Alceo Macchioni Gianfrancesco Montedoro 《Journal of the American Oil Chemists' Society》1999,76(7):873-882
Phenolic compounds are the most important antioxidants of virgin olive oil. This paper reports on the application of solid
phase extraction (SPE) in the separation of phenolic compounds from olive fruit, olive oil, and by-products of the mechanical
extraction of the oil and the complete spectroscopic characterization by nuclear magnetic resonance of demethyloleuropein
and verbascoside extracted from olive fruit. SPE led to a higher recovery of phenolic compounds from olives than did liquid/liquid
extraction. SPE also was used to separate phenolic compounds from pomaces and vegetation waters. Phenylacid and phenyl-alcohol
concentrations in extracts obtained from SPE and liquid/liquid extraction were not significantly different (P<0.05). The recovery of the dialdehydic form of elenolic acid linked to 3,4-(dihydroxyphenyl)ethanol and an isomer of oleuropein
aglycon, however, was low. 相似文献
3.
S. Caminada G. Cumino L. Cipolla A. Di Gianfrancesco 《International Journal of Pressure Vessels and Piping》2009
The metallurgical background of advanced ferritic steels must be considered during every stage of fabrication, including forming operations, such as cold bending, because they can negatively affect the high-temperature properties of the material when not performed properly. 相似文献
4.
C. Peri C. Pompei G. Montedoro C. Cantarelli 《Journal of the science of food and agriculture》1971,22(1):24-28
The oxidative browning of white wines (maderisation) obtained by fermenting musts derived from progressive pressing cycles, was studied in relation to the phenolic concentration. A picture of the distribution of the various phenolics was obtained by combining the total phenolics determination with selective precipitation of flavonoids with formaldehyde and tannins with cinchonine. Both enzymic and non-enzymic browning are directly related to the flavonoids concentration in the wines; a progressive insolubilisation of tannic flavonoids and a polymerisation of the non-tannic flavonoids accompanies the colour change. The concentration of non-flavonoid phenolics does not vary significantly during oxidative degradation and therefore they tend to become the most representative phenolic fraction in the maderised wines. 相似文献
5.
Several reports have indicated that platelet-activating factor (PAF) may play a role in the physiopathology of nervous tissue.
We previously have demonstrated the presence, in the microsomal fractions of rat brain, of a phosphocholinetransferase which
is able to synthesize PAF by thede novo pathway. The presence of dithiothreitol in the medium increases the rate of PAF biosynthesis, whereas it inhibits the synthesis
of long-chain alkylacyl- and diacyl-glycerophosphocholines (GPC), including dioctanoyl-GPC. This and other properties, such
as pH dependence and thermal stability, indicate that rat brain may have two distinct enzymes for the synthesis of PAF and
other choline phospholipids. The affinity of these enzymes for CDPcholine is similar to that reported for other tissues, the
Km being 42 μm and 55 μm with alkylacetylglycerol and dioctanoylglycerol as lipid substrates, respectively. The Vmax values were 3.0 and 2.2 nmol/mg prot/min for PAF and dioctanoyl-GPC, respectively. In addition, it was shown that the microsomal
fraction of rat brain contains an acetyltransferase which can convert lysoPAF to PAF. Since it has been reported previously
that brain tissue possesses phospholipase A2 activity that can hydrolyze alkylacyl-GPC to lysoPAF, we conclude that brain tissue has all enzymic activities for the synthesis
of PAF by the “remodeling pathway”. The role of the two routes of PAF biosynthesis in nervous tissue remains to be established.
Based on a paper presented at the Third International Conference on Platelet-Activating Factor and Structurally Related Alkyl
Ether Lipids, Tokyo, Japan, May 1989. 相似文献
6.
Maurizio Servili Alberto L Begliomini Gianfrancesco Montedoro Maurizio Petruccioli Federico Federici 《Journal of the science of food and agriculture》1992,58(2):253-260
The possibility of using an endo-polygalacturonase produced by the yeast Cryptococcus albidus var albidus (yeast pectinase) in the mechanical olive oil extraction process and in the production of red wine was investigated. Compared with the control and olive pastes treated with a commercial enzyme preparation, an increase in oil yield was achieved by treatment with the yeast pectic preparation. Also, the finished oil quality (turbidity, oxidation induction time, chlorophyll, and the content of polyphenols and aromatic compounds) was generally better. Treatment of red musts with yeast pectinase resulted in an improved aromatic profile in the wines, even in the absence of an increase in colour intensity. Moreover, the use of the yeast pectinase did not cause any particular increase in the methanol content of the finished wines. 相似文献
7.
Y. Nikolova J. Petit A. Gianfrancesco C. F. W. Sanders J. Scher 《Drying Technology》2015,33(13):1654-1661
To design dairy powder properties according to their future use, it is necessary to know how to identify the main process parameters that influence the drying mechanisms and to optimize them on the basis of the desired powder properties. The impacts of atomization process parameters on powder physicochemical properties and surface composition were investigated and correlated. The analytical results permitted us to sort the produced powders into groups according to their dependency to process parameters. This study shows the feasibility of developing a model for the prediction of the physicochemical properties of dairy powders via a reverse engineering approach. 相似文献
8.
Anna Porowska Maksym Dosta Stefan Heinrich Lennart Fries Alessandro Gianfrancesco Stefan Palzer 《Drying Technology》2015,33(15-16):1911-1919
Surface properties of multicomponent particles produced in spray drying can be controlled by selective accumulation of specific components, which are present in the liquid feed, on the particle surface. Such modification of the surface composition can take place only before a solid shell forms on the particle surface. In this contribution, the influence of the concentration of surface active component on modifications of the surface composition is discussed. Based on results of single-droplet drying simulations, changes in the concentration of the surface active component at the solution-air interface are related to the composition of spray-dried particles. 相似文献
9.
CFD Modeling and Simulation of Maltodextrin Solutions Spray Drying to Control Stickiness 总被引:2,自引:0,他引:2
Alessandro Gianfrancesco Christelle Turchiuli Denis Flick Elisabeth Dumoulin 《Food and Bioprocess Technology》2010,3(6):946-955
Particle stickiness during spray drying can lead to operational problems or be used to perform agglomeration inside the chamber.
A simplified computational fluid dynamics approach is proposed to simulate the spray drying of 40% w/w aqueous solutions of maltodextrin DE12 and DE21 in a pilot cocurrent spray dryer equipped with rotary atomizer. Drying was
simulated at steady state considering the geometry of the equipment (drying chamber, air inlet, atomizer) and the close relation
between drying air and product properties. To take into account the lower drying rate of liquid solutions compared to pure
water, the water vapor pressure of the drying particles was decreased with a coefficient determined from experimental data
on air temperatures and humidities measured in the chamber. The evolution of particle temperature and water content was simulated.
From these values and glass transition temperatures of the considered materials, it was possible to determine zones and operating
conditions for which particles could be sticky inside the chamber. Maltodextrin DE12 was quickly dried close to the atomizer
reaching a stable nonsticky state below glass transition temperatures Tg, while maltodextrin DE21 with lower Tg could exhibit
a sticky behavior in a wider part of the chamber, depending on the liquid flow rate. This approach provides a methodology
to evaluate possible stickiness to avoid fouling of the plant or to optimize powder insertion position for agglomeration. 相似文献
10.