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Cesare Oliviero Rossi, Fitim Destani, Alfredo Cassano
Rheological behavior of blood orange juice concentrated by osmotic distillation and thermal evaporation

Appl. Rheol. 24:6 (2014) 63776 (6 pages)

Fruit juices concentrated by osmotic distillation are characterized by higher organoleptic and sensorial properties than those of juices concentrated by thermal evaporation as confirmed by several research studies. On the other hand, no literature is readily available about the rheological characterization of juices concentrated by osmotic distillation. This work aimed at investigate the rheological behavior of the concentrated blood orange juice prepared from the clarified juice by using thermal evaporation and osmotic distillation processes as a function of solids concentration in the range 115 - 614 g/kg of total soluble solids (TSS) within a range of 20 - 70 C. The effect of the temperature and concentration on the juice viscosity was studied. Arrhenius-type correlation equations for viscosity were used to represent the temperature dependence of viscosity. Values of the Arrhenius equation parameters (flow activation energy) were calculated for the measured viscosities of juices as a function of concentration. Results indicated no significant differences in the rheological behavior for orange juices concentrated with both methods. The juices exhibited a Newtonian behavior regardless of the concentration method.

Cite this publication as follows:
OlivieroRossi C, Destani F, Cassano A: Rheological behavior of blood orange juice concentrated by osmotic distillation and thermal evaporation, Appl. Rheol. 24 (2014) 63776.

Luigi Gentile, Giuseppina De Luca, Filipe E. Antunes, Cesare Oliviero Rossi, Giuseppe Antonio Ranieri
Thermogelation Analysis Of F127-Water Mixtures By Physical Chemistry Techniques

Appl. Rheol. 20:5 (2010) 52081 (9 pages)

Aqueous solutions of F127 pluronic systems exhibit an interesting thermal gelation above a certain concentration. This phenomenon concerns the transition from a liquid-like behavior at low temperatures to a solid-like behavior at high temperatures, and it is due to different temperature responses from the different polymer segments, polypropylene oxide (PPO) and polyethylene oxide (PEO). Such property leads to a structural change in the self assembled macromolecule upon heating, from an isotropic micellar structure to an ordered cubic structure. These two types of assembly are clearly distinct with respect to their rheological behavior.This contribution emphasizes the rheological properties of the pluronic system in micellar and cubic phase, in combination with NMR, Dynamic Light Scattering and DSC information. The results emphasize the gelation process upon heating and a cubic phase characterized by higher storage modulus and higher A and z Weak Gel Model exponents than the micellar phase. Micellar growth upon heating was found within micellar phase. The presented data support the hypothesis that each polymer segment actively participates in the formation of the different phases: while PPO is responsible for micelle formation, PEO plays a dominating role in cubic phase formation. Finally, different stiffness between the core and the corona of the aggregates in the two phases is observed.

Cite this publication as follows:
Gentile L, DeLuca G, Antunes FE, OlivieroRossi C, Ranieri GA: Thermogelation Analysis Of F127-Water Mixtures By Physical Chemistry Techniques, Appl. Rheol. 20 (2010) 52081.

Filipe E. Antunes, Luigi Gentile, Lorena Tavano, Cesare Oliviero Rossi
Rheological characterization of the thermal gelation of poly(N-isopropylacrylamide) and poly(N-isopropylacrylamide)co-Acrylic Acid

Appl. Rheol. 19:4 (2009) 42064 (9 pages)

The combined effect of charged addition and molecular weight, Mw, on the thermal gelation and gel dissolution of poly(Nisopropylacrylamide) chains was explored by using Rheological techniques. The synthesized charged derivative is poly(N-isopropylacrylamide co-Acrylic acid). The rheological behavior of the two macromolecules is clearly different: the thermal gelation of the high Mw and charged macromolecule is much more accentuated. This suggests that the gelation at high temperatures only occurs when the inter polymer aggregate distance is sufficiently short to allow polymer bridging; this situation can be achieved by different approaches, such as increasing polymer concentration and increasing polymer persistence length and polymer Mw.

Cite this publication as follows:
Antunes FE, Gentile L, Tavano L, OlivieroRossi C: Rheological characterization of the thermal gelation of poly(N-isopropylacrylamide) and poly(N-isopropylacrylamide)co-Acrylic Acid, Appl. Rheol. 19 (2009) 42064.

Luigi Coppola, Domenico Gabriele, Isabella Nicotera, Cesare Oliviero
MRI Experiments as a Tool to Study Asymptotic-Shear Flow Behaviour of a Worm-Like Reverse Micellar Phase

Appl. Rheol. 16:4 (2006) 190-197

This paper deals with a Magnetic Resonance micro-Imaging (MRI) analysis of asymptotic kinematics which is a condition adopted in some rheological characterisations. Asymptotic kinematics (for example the slow shearing ) aim is to evaluate material properties at ''equilibrium'', avoiding structural changes induced by external stimuli. Measured material functions in these mechanical conditions deal with the structure/morphology of materials and can be used to investigate the structure as a function of the state variables only, as temperature, pressure and composition. In this paper MRI experiments were performed to study some shear flow behaviours of surfactant wormy micelles made by lecithin/water and diluted in cyclohexane (reverse micellar phase L2). MRI was used as a non-invasive tool in order to follow the structural responses both during slow shearing and when the sample is stirred outside the linear behaviour range. Relations can be found between the typical NMR parameters, strictly related to the microstructure, and the rheological macroscopic parameters as zero-shear viscosity.

Cite this publication as follows:
Coppola L, Gabriele D, Nicotera I, Oliviero C: MRI Experiments as a Tool to Study Asymptotic-Shear Flow Behaviour of a Worm-Like Reverse Micellar Phase, Appl. Rheol. 16 (2006) 190.

Luigi Coppola, Isabella Nicotera, Cesare Oliviero
Dynamic Rheological Analysis of MLVs and Lamellar Phases in the System C_12 E_4/D_2O

Appl. Rheol. 15:4 (2005) 230-237

The mechanical properties of the lamellar phase, La, of the system C_12 E_4/D_2O were studied along an isoplethal path (30 wt% C_12 E_4) in the temperature range 10 - 60 C. A dynamic analysis was determined by small strain oscillatory rheometry. The multilamellar vesicles (MLVs) (onions) were transformed by shearing the lamellar phase. The micellar phase was investigated by steady and dynamic rheological experiments. The micellar aggregate size increases slightly upon heating and the transition from micelles to lamellae appears to be a first order transition. The mechanical spectra of the lamellar phase show a strong dependence of the moduli on the frequency. This is typical of defective lamellar phases. They are different from MLVs mechanical spectra. The MLVs viscous and storage moduli are almost independent from the frequency and they exhibit the characteristics of a strong gel. The temperature of formation of the MLVs phase influences the mechanical properties of the MLVs. Three different packing states of the MLVs phase were observed in the temperature range 25 - 55 C.

Cite this publication as follows:
Coppola L, Nicotera I, Oliviero C: Dynamic Rheological Analysis of MLVs and Lamellar Phases in the System C_12 E_4/D_2O, Appl. Rheol. 15 (2005) 230.

Luigi Coppola, Domenico Gabriele, Isabella Nicotera, Cesare Oliviero
Rheological Properties of the Reverse Mesophases of the Pluronic L64/P-Xylene/Water System

Appl. Rheol. 14:6 (2004) 315-323

The behaviour of reverse micellar solution and reverse hexagonal and lamellar liquid crystal phases in pluronic L64/water/p-xylene ternary system was investigated by rheological techniques. Samples with an increasing water content along the amphiphilic copolymer-lean side of the ternary phase diagram were analysed at different temperatures and a different behaviour was evidenced by both dynamic and steady tests for each considered phase, depending on the morphology of structure (micellar, lamellar, hexagonal phases). It was observed that the reverse micelles size increases with increasing water concentration and decreases with increasing temperature, without any phase transition. On the contrary the normal micelles become anisometric on temperature, showing a transition to a liquid crystalline phase. The observed mechanical spectra of the liquid crystalline phases are typical of hexagonal and lamellar phases according to the literature. A phase transition with temperature was found for both liquid crystalline phase (lamellar and hexagonal) by rheological tests and was confirmed by ocular inspection.

Cite this publication as follows:
Coppola L, Gabriele D, Nicotera I, Oliviero C: Rheological Properties of the Reverse Mesophases of the Pluronic L64/P-Xylene/Water System, Appl. Rheol. 14 (2004) 315.


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