The new study, published in Food Hydrocolloids, presents a new in-vitro model of oral processing. Researchers from the University of Birmingham, UK, succeeded in creating a model to reproduce key phenomena occurring during oral processing, such as diffusion through the sample and compression in a model food system.
The initial study tested salt release from a biopolymer gel as model food systems, demonstrating that the in vitro model has good repeatability, and “proving the method useful for gathering data on salt release from a variety of structures,” said the researchers.
“Trying to mimic the conditions experienced during the eating process would prove invaluable when attempting to reformulate products, as their behaviour could be tested in-vitro,” said the authors, led by Dr Tom Mills from the Department of Chemical Engineering at the University of Birmingham, UK.
“In the future this will be extended to include different structures which can be compared with the gel experiments carried out in this study,” they added.
Mouth modelling
Mills and colleagues noted that previous studies have suggested measuring volatile compound release in a static environment does not compare to actual perception – suggesting that more dynamic in-vitro systems or in-vivo modelling methods are needed.
The authors developed and tested a new in-vitro system for following release of salt from structures – which can be related to oral processing.
“In order to produce a working model, which can relate to the oral processing of products, the conditions that are experienced in the mouth need to be identified,” said the authors.
They noted that the process can be approximated by partitioning it into three main sections: Firstly, the oral processing stage, a second oral propulsion stage, and a final swallowing stage.
The experiments were carried out using two experimental setups to mimic oral the first two steps of processing. Firstly, a vessel was used to study release of salt from a system under application of low shear. Secondly, a vessel and diameter texture analyser probe was used to investigate the effect of cyclic compression during release.
As a way to test the new mouth model, the authors tested the release of salt from three model food systems.
Salt study
The initial experiments provide data on salt release from three common food grade gels into water, using commercially available food grade biopolymers: 250 bloom gelatin from porcine skin (Sigma); low acyl gellan (Kelcogel, CP Kelco); and sodium alginate (Sigma).
The release curves from the different hydrocolloids (gelatin, gellan and alginate) show no evidence of increased release rate with compressions that do not cause fracture of the structure.
When the compressions were significant enough to cause fractures within the samples, salt release increased dependent on the extent of fracture, related to an increase in surface area.
Source: Food Hydrocolloids
Volume 25, Issue 1, Pages 107-113, doi: 10.1016/j.foodhyd.2010.06.001
“Development of an in-vitro mouth model to quantify salt release from gels”
Authors: T. Mills, F. Spyropoulos, I.T. Norton, S. Bakalis