Rheological study of different mashed potato preparations using large amplitude oscillatory shear and confocal microscopy

Texture is a major driver for mashed potato products. Measuring food texture via descriptive sensory analysis can be expensive and timeconsuming, so rheometry is often used as a method of estimating food texture. The objective of this study was to determine small- and largestrain rheological behavior of different mashed potato formulations. Rheological data, including large amplitude oscillatory shear data, and confocal microscopy images were collected. Comparison of rheological data and confocal images showed relationships between sample rheological behavior and sample structural damage were found. With the exception of freeze-dried samples, samples exhibiting greater starch damage exhibited more linear, fluid-like rheological behavior. Freeze-dried samples showed microfractures on the surface of the starch granules. It was hypothesized that these microfractures allowed amylose strands to leach from the granules without destroying structural integrity. Based on these results, mashed potato rheological behavior, and therefore texture, can be controlled by controlling extent of starch damage. (C) 2015 Elsevier Ltd. All rights reserved.