Measuring the consistency of vegetable purées

Purées are very thick and viscous slurries made from processed vegetables that are often concentrated and include fibrous material or fruit pieces that adds structure. 

They are commonly used in fillings for pies, ketchup or baby food. Additional ingredients are usually added to manipulate consistency and processing properties.

For the measurement of consistency, a Back Extrusion test can be carried out by fixing a suitable diameter disc to the TA.XTplusC Texture Analyser: the disc moves down into the vessel with good clearance between the vessel and disc so as not to produce erroneous increase force readings due to ‘side effects’.

Testing within the sample container (e.g. jar) is often the only means of assessing the product reliably where depositing the sample into an alternative vessel for testing may cause disruption of the structure of a ‘gelled’ product. The disc moves down into the product to a chosen distance (up to 75% of the depth of the product depending upon vessel height) and the area under the positive region of the resulting curve is taken as an indication of product consistency/overall firmness.