Squeeze flow of potato starch gel: effect of loading history on visco-elastic properties

TL;DR

This study demonstrates that gelatinized potato starch retains a memory of past loading, affecting its visco-elastic response, which can be modeled using a fractional calculus approach to capture non-linear and history-dependent behaviors.

Contribution

The paper introduces a visco-elastic model incorporating fractional calculus to accurately describe the memory effects in potato starch gel under squeeze flow.

Findings

Memory effect observed in strain response

Model reproduces initial oscillations and long-term behavior

Dynamic visco-elastic properties characterized

Abstract

In this work gelatinized potato starch is shown to retain the memory of past loading history. It exhibits a visco-elastic response which does not depend solely on instantaneous conditions. A simple squeeze flow experiment is performed, where loading is done in two steps with a time lag $\tau \sim$ seconds between the steps. The effect on the strain, of varying $\tau$ is reproduced by a three element visco-elastic solid model. Non-linearity is introduced through a generalized calculus approach by incorporating a non-integer order time derivative in the viscosity equation. A strain hardening proportional to the time lag between the two loading steps is also incorporated. This model reproduces the three salient features observed in the experiment, namely - the memory effect, slight initial oscillations in the strain as well as the long-time solid-like response. Dynamic visco-elasticity of the sample is also reported.