Influence of processing on the rheological properties of tomato paste

This paper deals with the influence that some processing variables (sieve pore size and breaking temperature) and tomato variety exert on the linear viscoelastic properties of tomato paste. With this aim, 16 tomato paste samples from four different varieties (with different contents of the pectolytic enzymes polygalacturonase and pectin methylesterase) have been manufactured at different breaking temperatures (65–85 °C) and screen sizes (0.8–2.2 mm). From the experimental results obtained, we conclude that tomato paste behaves as a weak gel, showing a wide plateau region in its linear relaxation spectrum. The linear viscoelastic properties of tomato paste depend dramatically on water‐insoluble solids content and particle size, which may be greatly influenced by processing variables. Nevertheless, the specific action of the above‐mentioned pectolytic enzymes must also be taken into account. © 2002 Society of Chemical Industry