Influence of uniaxial compression rate on rheological parameters and sensory texture prediction of cooked potatoes

The effect of uniaxial compression rare (20-1000 mm/min) on the parameters: Stress (sigma(ftrue)), strain (epsilon(fHencky)) and work to fracture (W-f ), modulus of deformability (E-d), maximum slope before fracture (E-max) an d work during 75% compression (W-total) was investigated for ten potato var ieties. Multivariate data analysis was used to study the correlation betwee n and within the sensory and nonsensory measurements by Principal Component Analysis (PCA) which showed sigma(ftrue), E-max, W-f, and W-total to expla in the same type of information in the data, and epsilon(fHencky) versus E- d another type of information in the data. The deformation rate had a large effect on epsilon(fHencky). Nine sensory texture attributes covering the m echanical, geometrical and moistness attributes were evaluated. Relationshi ps between uniaxial compression data at various deformation rates and the s ensory texture attributes were studied by Partial Least Squares Regression (PLSR). A minor effect of deformation rate on the correlation with the sens ory texture properties was obtained. Mechanical properties were predicted t o a higher extent than the geometrical attributes and moistness. The predic tion of the mechanical, geometrical and moistness attributes increased larg ely by using uniaxial compression supplemented by chemical measures such as dry matter and pectin methylesterase, but here no relevant effect of defor mation rate was obtained.