Rheological properties of plant-tissue suspensions: aqueous suspensions of potato and carrot parenchyma powders
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Date
2016-11
Authors
Younessinaki, Nasibeh
Journal Title
Journal ISSN
Volume Title
Publisher
Springer
Abstract
Comprehending the rheological behavior of food-based plant-tissue suspensions, e.g., soups and purees, is critical in terms of production efficiency and final product quality. The rheological behavior of suspensions is governed mainly by the continuous phase properties, the dispersed phase properties, e.g., particle size, solid volume fraction of suspensions, and by processing conditions such as temperature. Therefore, an understanding of how these parameters influence the rheological properties of food-based plant-tissue suspensions is helpful for development of novel foods and process design. In this study, the rheological properties of suspensions of potato and carrot powder were investigated at six solid volume fractions (Φ), three temperatures and two particle sizes. Corn and potato starch granule suspensions were used as model systems due to an anticipated minimal level of interactions among their components. A concentrated sucrose solution was used as the continuous phase to prevent sedimentation of particles. Rheological measurements were carried out using a rotational rheometer with a concentric cylinder geometry via shear flow and oscillatory shear tests. Starch granule suspensions exhibited essentially Newtonian behavior at all Φ. The potato and carrot powder suspensions showed shear-thinning behavior at similar Φ, obeying either a power-law equation or the Herschel-Bulkley equation. Differences in the rheological properties of the potato and carrot powder suspensions compared to starch granule suspensions are due to intra- and inter-cellular components in potato and carrot parenchyma that migrate from the dispersed to the continuous phase. The viscosity or consistency factor data of all the suspensions conformed well to the Krieger-Dougherty equation. Oscillatory shear testing indicated the presence of viscoelastic properties in the potato and carrot powder suspensions. Higher consistency factor and yield stress, more shear-thinning behavior, and lower loss factor were observed in the carrot powder suspensions compared to potato powder suspensions. The greater amount of soluble solids content in carrot compared to potato is postulated to be the cause of the differences observed in the rheological properties of carrot and potato suspensions. Comparing the rheological behavior of carrot and potato powder suspensions revealed the dominant role of the continuous phase in the rheological properties of carrot powder suspensions.
Description
Keywords
Potato parenchyma powder, Carrot parenchyma powder, Starch granule, Suspension, Rheological properties, Viscosity, Solid volume fraction, Temperature
Citation
Sinaki, Nasibeh Y., and Martin G. Scanlon. "Flow Behavior of Native Corn and Potato Starch Granules in Aqueous Suspensions." Food biophysics 11.4 (2016): 345-353.