Authors:N. Nedić Tiban, V. Piližota, D. Šubarić, D. Miličević, and M. Kopjar
Influence of adding six hydrocolloids, guar gum, carrageenan, carboxymethylcellulose and three types of pectin, and of sweeteners, aspartame and fructose, as replacement of sucrose, on flow behaviour of peach nectar was studied. A series of peach nectar samples (with approximately 65% fruit) was prepared using commercially processed peach purée with sucrose and substituting sugar with low-calorie sweetener aspartame and fructose (alone and in combination in a sweetness ratio of 1:1) taking into account their sweetness. To prevent reduction of viscosity and mouthfeel/body of low-calorie peach nectars, different concentrations of hydrocolloids were added. A control sample was prepared by mixing fruit purée with a sucrose solution (7% mass fraction) to provide a 14% (in total solids) nectar. Rheological measurements were carried out on a rotational viscosimeter Rheotest 3 at 20 C and 5°C. The flow of all peach nectars was characterized as pseudoplastic. Among all used hydrocolloids, addition of only 0.03% of carrageenan to the peach nectar was enough to obtain viscosity similar to the viscosity of the control sample.
Authors:Vinod Dhaygude, Anita Soós, Réka Juhász, and László Somogyi
Blending is widely used for modification of the physicochemical properties of fats to enhance their commercial applications. This paper studied the flow behavior of coconut oil (NHCO) under variation in the temperature and proportion of fully hydrogenated coconut oil (FHCO). The oscillatory results showed that there is a change in the linear viscoelastic region, storage (G') and loss (G'') moduli with increasing proportion of FHCO in NHCO. In rotational tests, the blends showed shearthinning behavior. The viscosity of oils and their blends were investigated at different temperatures. The Herschel-Bulkley model was fitted to flow curves (shear stress in function of shear rate) of the samples. During heating, NHCO approached Newtonian behavior earlier than FHCO, because of their loosely-packed structure. Thus it indicated that the fatty acid composition affects these behaviors of the oil. The blending of fully hydrogenated coconut fat improved the elastic and textural character of the coconut oil.
This study measured the flow behaviour of whey protein isolate mixtures with cinnamic or ferulic acids. Samples were heated in a vacuum (80 °C, –0.9 atm, 280 r.p.m., 0.5 h). The flow curves of all samples showed a non- Newtonian shear thinning flow and the viscoelastic properties were typical for weak gel systems. At pH 6.0, 6.7, and 8.0, the highest shear stress values were obtained with 20, 40, and 40 mg of cinnamic acid g–1 protein, respectively. At pH 6.0, the use of ferulic acid (20 mg g–1 protein) resulted in the elevation of shear stress values, but at pH 8.0, ferulic acid caused a decrease in shear stress values in comparison to cinnamic acid. The thixotropic area (AT) was increased in mixtures containing 20–40 mg cinnamic acid g–1 protein (at pH 6.7) and 20 mg of cinnamic acid g–1 protein (at pH 6.0). Similarly, the addition of ferulic acid (40 and 20 mg g–1 protein at pH 6.7 and 6.0, respectively) caused a significant increase in AT. At pH 8.0, no significant differences in AT values were observed between samples. Such systems can be applied with reference to health promoting foods such as WPI-based desserts.
reservoir. The main goal of this study is to find a method which can reduce the huge number of realizations for hydrocarbon reservoirs in a way that the remaining ones retain the information of spatial uncertainty for the reservoir’s flowbehavior as
Authors:Tamás Csurka, Klára Pásztor-Huszár, Adrienn Tóth, Richárd Pintér, and László Ferenc Friedrich
.2, 24 w/w%. The prepared samples were stored in test tubes for one day under refrigerated condition before the measurements. Three parallel samples were prepared for the investigation. Flowbehavior An Anton-Paar Physica MCR 91 (Anton-Paar GmbH, Germany
Authors:S. Filipe, B. Knogler, K. Buchmann, and M. Obadal
The article addresses the relevance of shear and uniaxial extensional flow behaviour on the crystallisation of isotactic polypropylenes
differing in terms of molar mass distribution (MMD). The importance of combining several experimental techniques, namely rheological,
thermal and microscopic, to follow the response of the material arising from the application of given processing conditions,
is here demonstrated. Systems with a broader MMD possessing even residual amounts of high molar mass (MM) tails were shown to be more prone to develop β-phase crystallites. The latter effect was seen to be a consequence of the
application of a step shear at a temperature for which the formation of β-phase is known to be preferential.
Authors:A.K. Siroha, S. Punía, K.S. Sandhu, and B.L. Karwasra
Physicochemical, pasting, and rheological properties of pearl millet starches were studied and correlations among these properties were calculated. Amylose content, swelling power, and solubility of starches varied from 11.57 to 21.93%, 11.11 to 17.91 g g−1 and 12.20 to 15.20%, respectively. Volume% of starch granule size less than 10 µm varied from 36.23 to 48.34%, and 12.16 to 18.75% for above 20 µm size of granule. Peak viscosity of starches varied from 1291 to 1853 mPa·s, cv. RHB-173 had the highest value. Frequency sweep measurement of starch pastes revealed higher magnitude of G′ as compared to G″ with increase in to, indicating visco-elastic behaviour. Yield stress (σo), consistency index (K), and flow behaviour index (n) were observed as 40.73 to 115.72 Pa, 0.729 to 3.998 Pa·s, and 0.604 to 0.964, respectively. Starch pastes from cultivars studied showed shear thinning behaviour.
Shell eggs have been irradiated with increasing radiation doses in the 0.5-3.0 kGy dose range and various non-microbiological changes, important from the point of view of consumer quality, have been estimated. Dose-dependent changes in the flow behaviour of egg white and brittleness of the yolk membrane in broken eggs, sensorial parameters of the raw and soft-boiled eggs, whippability and foam stability of the egg white were observed. Considering that a minimal dose of 1.5 kGy would be required for radiation inactivation of salmonellae and other, non-pathogenic bacteria, the quality of irradiated eggs upon such gamma radiation dose would not be equal in all parameters to those of the fresh shell eggs, however, changes in sensorial and functional properties at this dose level may be still acceptable, mainly for risk population and some industrial use.