Clinical Study

Viscosity development during aqueous dispersion and dissolution: a comparison of PGX® with other dietary supplements and individual polysaccharides


Dissolution of a supplemental Fibre that allows a high and sustainable viscosity to develop over several hours from a low gramme quantity makes for useful supplementation to help the consumer increase their dietary fibre intake, which in turn helps with appetite control, blood sugar normalisation, lowering cholesterol etc. Of the 19 samples tested (that included Lipozene®, Metamucil®, Konjac etc) PGX® granules, PGX® powder and a blend of the materials that make up PGX® attained some of the highest ultimate viscosities. These PGX® samples achieved this target of several hours for maximum viscosity development whilst other dietary supplements at the same dosage (0.5% w/w) failed to achieve high viscosity or if they did, did so too slowly to be useful in the transit time though a human digestive system.


Viscosity is an important quality in fibres, as it is an indication of the measure of potential fullness. The lower the gramme quantity required to do this as well as the time the viscosity takes to achieve its full potential are also important. The aim of this study was to evaluate a range of commercially available Fibre supplements on the market with a rheometer using a vane and cup system.


A wide range of supplements were obtained and then tested using a rheometer for over 14 hrs to determine how the viscosity developed over this time using a fixed amount of product to water. Typically a stomach will empty in about 4 hrs, so data after this time point is somewhat mute.


The viscosity–time curves up to 1 h for all the samples tested fall into two groups, one displaying high and the other displaying low final viscosities. The easiest way to view these is graphically as shown below (3PB is the blend of the three materials used to make up PGX, PGXf is the powdered material).

PGX Viscosity Comparison Chart

Ian H. Smith, Christopher J. Lawson, Stephen E. Harding, Roland J. Gahler, Michael R. Lyon, Simon Wood. Food Hydrocolloids (2014), doi: 10.1016/ j.foodhyd.2013.12.004.

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