Paper described the method of measuring water content in food products, based on microwave heating and drying of the foodstuff samples. Power supplied to material is controlled as a function of sample mass and features, thus the sample is dried in a short time without overheating. Water content is automatically calculated from the mass losses during drying. The experiments conducted with yoghurt confirmed agreement of the results with a reference method

Pulsed-field gradient NMR (PFG -NMR) is widely applied to probe living tissues and biological cells structure for measuring thermodynamic binding constants, membrane permeability and rates of transmembrane exchange processes. Water movements in biological systems and food matrices are important in the engineering aspect such as quality manipulation in food processing. The measurement of diffusion properties of water molecules in food systems is now possible using PFG -NMR, and the hydration properties and hydrodynamic properties of food materials can be accurately evaluated by this method. In this paper, we measured the diffusion behavior of water in protein matrix, Tofu, and the membrane permeability in biological cell such as chlorella, yeast and human red blood cell non-invasively by PFG-NMR.

Une etude de faisabilite du tamisage humide par courant d'eau pour la mesure de la granulometrie de fibres alimentaires precise les conditions de son application tant au niveau de l'echantillon que de l'appareillage. La quantite necessaire d'echantillon a tamiser, la pression et la duree de pulverisation d'eau optimales sont determinees pour la fibre de betterave et les sons de ble et d'orge. L'echantillon entier et des fractions tamisees sont egalement analyses a l'aide d'un granulometre par diffraction de la lumiere laser. Les resultats montrent une certaine relation entre le diametre de maille dt et le diametre volumique dv, obtenu par diffraction de la lumiere laser, converti en diametre surface-volume, ds,v. Des modes d'expression synthetiques des resultats sont recherches pour caracteriser la distribution granulometrique. Les fibres de betterave sont proches du modele log-normal, le son d'orge du modele normal et le son de ble du modele Rosin-Rammler. En l'absence de loi generale pour caracteriser la granulometrie des fibres alimentaires, la representation graphique des classes de taille sous forme d'histogramme en frequence massique cumulee permet de determiner des diametres equivalents a des fractiles de la population totale