Rheology of liquid foods under shear flow conditions: Recently used models

Abstract

Proper modeling of flow or viscosity curves as a function of shear rate is a useful tool in any engineering activity. The rheology of foods depends on the composition, processing to which they have been subjected and the state of dispersion in which they are found. Liquid foods are complex biosystems, that show non‐Newtonian behavior under flow conditions. This review presents models used in recent decades to describe the experimental rheological behavior of various liquid foods, ranging from Newtonian fluids to the most complex. Some non‐Newtonian parameters such as those of the Ostwald‐de Waele, Bingham, Herschel–Bulkley, Casson, Cross, and Carreau models are summarized. Examples of thixotropic behavior described by the Weltman and Abu‐Jdayil models are also presented. In each model, explanations based on the composition and dispersion state of the food are made. This is useful in innovative processing technologies and for scientists new to the field of food rheology. An attempt is made to exemplify and group the expected behavior for most fluid foods, including some for a dysphagia diet, depending on their composition or the dispersed system formed, which will be useful for professionals who wish to compare reported rheological parameters with those obtained experimentally.

Rheology and physical properties of sonicated chickpea concentrate with fructans in aqueous media and stable emulsions

“…The parameter p = (1-n) /2, which is related to the flow behavior index n of the Oswald-de Waele model [15], varied slightly from 0.18 to 0.20 for the samples with fructans, except for CHF 6%; however, this parameter was close to that obtained in the CMC solution, which implies a similar viscosity dependence of the shear rate.…”

“…This characteristic was also observed in samples where a standard commercial CPC (non-gelling) was used, confirming that the rheology of the emulsions depends completely on the formulation and the processing applied [14]. Furthermore, when the aqueous phase exhibits non-Newtonian behavior due to the thickener used, the emulsion may show the same rheological behavior or be more complicated, depending on the interactions that occur between the oil droplets and the macromolecules present in the emulsion [15]. For example, emulsions containing polysaccharides such as galactomannans, xanthan gum or mixtures of polysaccharides showed weak gel-like rheological behavior (viscoelastic properties), and non-Newtonian shear-thinning behavior and yield stress were observed in sonicated emulsions under flow conditions [16,17].…”

“…CPC/AGF aqueous mixtures, such as liquid materials with low molecular weight soluble compounds or low particle concentrations that do not exceed colloidal size (< 10 μm), also exhibit Newtonian behavior (Eq. 1) [15]. Statistically significant differences in shear viscosity were found for the CHF, CPC and CPC/AGF aqueous mixtures (p < 0.05) (Table 1).…”

Stability in Aqueous Solution of a New Spray-Dried Hydrocolloid of High Andean Algae Nostoc sphaericum

“…The activation energy serves as a metric for quantifying the energy required to overcome resistance in the flow of a viscous fluid [ 30 , 63 ]. It can be calculated using the consistency index, an indirect measure of viscosity.…”

“…The influence of temperature on the rheological behavior was examined by assessing the activation energy ( E a ), providing insights into the behavior of colloidal solutions, interpenetrating networks, and nanofluid flow. This parameter is linked to the energy necessary for the interchain displacement of polymers, with higher E a values indicating elevated crosslinking [ 29 , 30 ]. The calculation of E a was carried out using the Arrhenius equation (Equation (8)) based on the consistency index values.…”