Characterization of water mobility and ice crystallisation in plant tissue during freezing
Résumé
To improve the freezing process applied to vegetable and fruit, a better understanding of degradation mechanisms, strongly linked to the texture of the tissue during freezing is needed.Several studies described global texture modifications after freezing on vegetable and fruit(Marti and Aguilera,1991; Khan and Vincent, 1996; Delgado and Rubiolo, 2005), but none applied multi-scales qualitative and quantitative approach from macroscopic to microscopic level. In this work, different methodologies have been applied to the tissue as mechanical (rheometer), spectral (NMR), thermal (DSC), histological, cytological and chemical measurements, as well as the visualisation of micro-structural modification. As a complementary tool to quantify mechanisms, a mathematical model for the prediction of the water evolution during freezing of vegetable tissue has also been established.