WOLFRAM|DEMONSTRATIONS PROJECT

Hysteresis in the Flow Curves of Pseudoplastic Semiliquid Foods

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erase plot and enable original shear rate slider
original shear rate
0.001
return shear rate
90.
flow characteristics
k
up
1.
n
up
0.5
n
down
0.8
plot axes maxima
shear rate
100.
shear stress
10.
k
down
= 0.259area under increasing curve = 569 (W/
3
m
)area under decreasing curve = 474 (W/
3
m
)hysteresis area = 95 (W/
3
m
)
Shearing a pseudoplastic semiliquid food, such as fruit juice concentrate or nectar, in a viscometer frequently disrupts its microstructure. Consequently, the flow curve recorded by first raising and then lowering the shear rate exhibits a hysteresis loop. The loop's area represents the energy dissipated in the shearing process in terms of power per unit volume. This Demonstration shows the phenomenon in simulated flow curves accompanied by the calculated hysteresis area.