β-Glucan content, viscosity, and solubility of Canadian grown oat as influenced by cultivar and growing location

2016 ◽  
Vol 96 (2) ◽  
pp. 183-196 ◽  
Author(s):  
Mariana Perez Herrera ◽  
Jun Gao ◽  
Thava Vasanthan ◽  
Feral Temelli ◽  
Kelly Henderson

The composition and physicochemical properties of oat flour with respect to β-glucan content and its solubility and viscosity were investigated. Eight oat cultivars grown in 20 prairie locations for three consecutive years were examined in this study to establish how cultivar, growing location, and their interaction influence the abovementioned attributes. It was found that the β-glucan content was primarily influenced by oat cultivar, while growing location and the interaction between cultivar and location had minimal effect. Among the eight cultivars, HiFi had the highest β-glucan content (5.82% w/w), while Derby had the lowest (4.37% w/w). Growing location, oat cultivar, and their interaction had a significant effect on β-glucan solubility and viscosity. The β-glucan solubility differed among oat cultivars, where 28.44–34.28% of the β-glucan present in the oat flour could be solubilized at 37°C. Viscosity was evaluated by consecutive fixed speed tests at shear rates of 1.29–129 s−1. Results showed that shear rate, growing location, and cultivar affected viscosity. The flow behavior index (n) for all β-glucan dispersions indicated shear-thinning behavior. HiFi had the highest β-glucan solubility and viscosity among all the cultivars analyzed. The findings provide insight into raw material selection and variations in raw material characteristics when targeting specific oat product applications.

2008 ◽  
Vol 18 (3) ◽  
pp. 34482-1-34482-11 ◽  
Author(s):  
Vassilios C. Kelessidis ◽  
Roberto Maglione

AbstractA methodology is presented to invert the flow equation of a Herschel-Bulkley fluid in Couette concentric cylinder geometry, thus enabling simultaneous computation of the true shear rates, γ̇HB, and of the three Herschel-Bulkley rheological parameters. The errors made when these rheological parameters are computed using Newtonian shear rates, γ̇N, as it is normal practice by research and industry personnel, can then be estimated. Quantification of these errors has been performed using narrow gap viscometer data from literature, with most of them taken with oil-field rheometers. The results indicate that significant differences exist between the yield stress and the flow behavior index computed using γ̇HB versus the parameters obtained using γ̇N and this is an outcome of the higher γ̇HB values. Predicted true shear rates and rheological parameters are in very good agreement with results reported by other investigators, who have followed different approaches to invert the flow equation, both for yield-pseudoplastic and power-law fluids.


2002 ◽  
Vol 25 (2) ◽  
pp. 169-179 ◽  
Author(s):  
Umesh Kumar

Copper (Cu) based pastes have emerged as the termination materials of choice for ceramic capacitors with base metal internal electrodes. To prevent oxidation of nickel (Ni) internal electrode and the copper terminations, it is necessary to fire the terminations in a nitrogen atmosphere. This requirement places significant restrictions on raw material selection for the termination pastes. For example, acrylic-based resins are used as organic binder for their clean burning characteristics over the traditional ethyl cellulose based binder system. As the viscoelastic behavior of acrylic resin systems are different to those of cellulose systems, differences are observed in the flow behavior of the paste. In this paper, the influence of paste rheology on the green cosmetic defects such as mooning, peaking, etc. is discussed. Additionally, the influence of process condition such as dipping parameters, drying conditions etc., on the green cosmetic defects are discussed. Finally, properties of a copper termination, which can be processed between 800–825°C, are discussed.


2019 ◽  
Vol 15 (4) ◽  
pp. 437-441 ◽  
Author(s):  
Vasiliki Lagouri ◽  
Georgia Dimitreli ◽  
Aikatarini Kouvatsi

Background: Oxidation reactions are known to shorten the shelf life and cause damage to foods rich in fat, such as dairy products. One way to limit oxidation and increase the shelf life of fermented dairy products is to use natural antioxidants. The aim of this study was to examine the effect of adding pomegranate extracts in the antioxidant properties, rheological characteristics and the storage stability of the fermented product of kefir. Methods: The Pomegranate Juice (PGJ) and Peel Extracts (PGPE) (5%, 10% w/v) were added to kefir and the antioxidant properties were evaluated by using the methods of radical scavenging activity (DPPH) and Ferric Reducing Antioxidant Power Activity (FRAP). Spectrophotometric and instrumental methods were used to determine the Total Phenols (TPs), pH values, viscosity and flow behavioral index values of enriched with pomegranate kefir samples. The same properties were tested when kefir samples stored at 4°C for 7, 14, 21 and 28 days. Results: The addition of PGJ and PGPE results in an increase in the antioxidant activity (DPPH, FRAP) and total phenol content (TPs) of kefir samples. Increasing the concentration of the added PGJ and PGPE, results in an increase in the TP content and the DPPH activity of kefir. As far as the storage time is concerned, the results showed an increase in the amount of TP at 7th day and a reduction in the DPPH activity in the 14th day of storage. In contrary to the DPPH method, the increase in storage time has resulted in a reduction in antioxidant activity by the FRAP method. The addition of PGJ and PGPE in kefir results in a decrease in pH values while the pH of kefir samples increased during storage at 4°C for 28 days. The addition of PGJ and PGPE to kefir samples results to a decrease in viscosity and an increase in the flow behavior index. Increasing storage time results in increased flow behavior index of kefir samples. Conclusion: The addition of PGJ and PGPE increased the antioxidant activity and total phenols of the kefir product and preserved its properties during the total storage time of 28 days at 4°C.


Author(s):  
Cunlu Zhao ◽  
Chun Yang

Electroosmotic flow of power-law fluids in a slit channel is analyzed. The governing equations including the linearized Poisson–Boltzmann equation, the Cauchy momentum equation and the continuity equation are solved to seek analytical expressions for the shear stress, dynamic viscosity and velocity distributions. Specifically, exact solutions of the velocity distributions are explicitly found for several special values of the flow behavior index. Furthermore, with the implementation of an approximate scheme for the hyperbolic cosine function, approximate solutions of the velocity distributions are obtained. In addition, a mathematical expression for the average electroosmotic velocity is derived for large values of the dimensionless electrokinetic parameter, κH, in a fashion similar to the Smoluchowski equation. Hence, a generalized Smoluchowski velocity is introduced by taking into account contributions due to the finite thickness of the electric double layer and the flow behavior index of power-law fluids. Finally, calculations are performed to examine the effects of κH, flow behavior index, double layer thickness, and applied electric field on the shear stress, dynamic viscosity, velocity distribution, and average velocity/flow rate of the electroosmotic flow of power-law fluids.


Antiquity ◽  
2000 ◽  
Vol 74 (284) ◽  
pp. 372-379 ◽  
Author(s):  
S. Miller-Antonio ◽  
L. A. Schepartz ◽  
D. Bakken

Research in Dadong Cave, southern China, has revealed evidence suggesting that nonlithic materials were used in the tool kits of the Chinese Lower Palaeolithic.


1995 ◽  
Vol 33 (12) ◽  
pp. 3301-3310
Author(s):  
R. CHEN ◽  
O. HAWALESHKA ◽  
D. STRONG

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