In this explorative work we show how the breakdown processes of the internal structure of diluted fruit purees can vary, depending on the laminar or the turbulent motion conditions. This experimental investigation shows that transition to turbulence, if it occurs, causes an increase in mechanical stresses due to the turbulent velocity components and this reflects on the entity of the breakdown processes. The damage to the structure induced by the laminar or the turbulent motion depends on the kind of fruit and on its internal structure and strongly influences the rheological properties of the degradated product. This work leads to the need for future investigation into the transition to turbulence as a function of such 'industrial parameters as dilution degree or temperature level of the transport processes, (C) 2002 Elsevier Science Ltd. All rights reserved.