Determination of Chocolate Viscosity

Abstract

A critical appraisal of the Casson model for measuring chocolate versus a new proposed method is performed. The new method is validated with both research grade rheometers and factory grade viscometers. This includes elements of measurement uncertainty. In this way, a new reference method is validated for the viscosity of chocolate and related cocoa products using factory grade viscometers. It involves recording: (1) the value of the stress at a shear rate of 5 s‐1 to represent the yield stress of chocolate, (2) the value of the viscosity at a shear rate of 40 s‐1 to represent the high shear viscosity, and (3) the difference between the viscosity measured at a shear rate of 40 s‐1 during the ramp up and down in shear rate to represent thixotropy. Results relate to the solid to liquid glass transition of dispersions under applied stress, and it is shown that they reflect existing theories of stress induced formation and rupture of fractal aggregates, for particle crowded colloidal suspensions with low interaction energy.

Current trend and future prospective of functional probiotic milk chocolates and related products - a review

“…Rheological properties of chocolate are important in the manufacturing process for obtaining high-quality products with a well-defined texture (Servais et al 2004). Chocolates with a high viscosity have a pasty mouth feel, persisting in the mouth (Beckett 2000).…”

The Effect of Milk Replacer Incorporation on the Physicochemical Properties of Milk Chocolate

“…According to Servais et al (2003) [22], an increase in the shear rate disrupts the aggregates of particles in molten chocolate causing a diminished size and decreasing the viscosity to an equilibrium value. If the shear rate is reduced, the aggregates will reform and the viscosity will get back to a higher equilibrium value [23].…”

Rheological properties of sugarfree milk chocolate: Comparative study and optimisation

“…These properties can be characterized by several mathematical models including Bingham, Herschel-Bulkley, and Casson models (Chevalley 1994;Servais et al 2004). Replacement of sucrose with sugar alcohols would affect rheological properties and therefore the processing conditions and quality of chocolates.…”

“…Flow index could be related to the strength of the aggregated particle to the particle network system of chocolate blend during manufacture (Beckett 2000;Servais et al 2004) with the distribution and arrangement of particle sizes, fat and emulsifier contents as the effective factors dictating the rheological flow behaviour of chocolate (Afoakwa et al 2007). The rate index of prebiotic milk chocolates produced by Konar (2013) comprised similar values for samples with isomalt and maltitol.…”