Many problems of dry solid food and intermediate products are related to water
uptake or its redistribution during storage since they lead e.g. to unwanted
changes in sensory properties for products like bread and fried snacks or to
caking in the case of powders.
A previous study within TIFN/WCFS resulted in (1) a much better understanding
of crispness and its retention in terms of relations between sensory attributes
and physical parameters, (2) mechanisms responsible for perceived crispness and
loss of crispness during storage, (3) role of morphology for crispness and (4)
the formulation of hypotheses related to the determination of water holding in
crispy products during manufacturing.
The importance of the behaviour of water in dry cellular systems with a moist
interior was shown, but a basic understanding on how the migration of water
determines crispness retention is still lacking. The main remaining problem is
the relation between the rate of water transport in the product and its
morphology. Such understanding is required to make another step in the further
improvement of the manufacturing of crispy products in such a way that it will
lead to an extended crispness retention. In addition it has been realised that
basics of water transport through cellular solid foods also apply to certain
powders where spatial heterogeneity in water content is a major source for loss
of functional properties.
To obtain the basic understanding this project is focussing on the migration of
water in solids.
Time frame January 2007 - December 2010