Pulp concentration and particle size may be identified as the key structural parameters having a large
effect on the rheological properties of apple puree and then on their sensory properties. These parameters
can be modified by the processing operations, i.e. the size opening of the finisher screen.
Apple purees showed a shear thinning behaviour, presenting a yield stress. Increasing pulp content
increased shear thinning behaviour and consistency index. Apparent viscosity and yield stress decreased
with decreasing particle size and pulp content, which was in accordance with the results found in
literature [5,8]. The second heat treatment affected cell wall structure inducing a decrease of the viscosity
of the puree and the serum. Therefore controlling the heat treatment parameters is important as they can
affect the structural and rheological properties of the final product. Consistency and graininess are the
most important attributes to explain the texture of apple purees.