[3Ba01-10] Physical property of food

9:30 AM - 9:45 AM JST(12:30 AM - 12:45 AM UTC)

[3Ba03] Microscopic fracture behavior of whipped cream under shear

*Shuji Fujii¹ (1. Toyo University)

Keywords:

Whipped cream,Fracture,shear deformation

Whipped cream is formed by the aggregation of partially coalesced fat globules that entrap air bubbles. Its fracture behavior is considered to be influenced by the state of fat globule aggregation. In this study, fluorescent colloidal particles were dispersed in whipped cream to clarify how fracture initiates and propagates under shear deformation by tracking the motion of these particles. Colloidal particles with a diameter of 0.5 μm were dispersed in Megmilk Snow Brand Whip (40% vegetable fat), and whipped using a hand mixer to obtain the whipped cream. The whipped cream was placed on a microscope-mounted rheometer, and its response to oscillatory shear deformation was observed under a microscope. The motion of the colloidal particles was recorded as a movie, and the positions of the particles at the zero strain point were tracked to investigate the fracture behavior of whipped cream under oscillatory shear. As the strain amplitude increased, the displacement of the colloidal particles gradually became larger, and nonlinear behavior in the complex modulus was observed simultaneously. This indicated that the motion of the colloidal particles reflects the fracture behavior of the whipped cream. The motion of the colloidal particles exhibited anisotropy, showing larger displacements in the direction perpendicular to the shear direction during the fracture. This suggests that the fracture of whipped cream is anisotropic. Subsequently, with increasing shear strain, fracture propagated in the shear direction.