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Influence of high-temperature drying on pasta rehydration studied by nuclear magnetic resonance
microimaging (MRI). C. ZWEIFEL (1), D. Gross (2), S. Handschin (1), B. Conde-Petit (1), and F.
Escher (1). (1) Swiss Federal Institute of Technology (ETH), Institute of Food Science, CH-8092 Zurich,
Switzerland; (2) Bruker Analytik GmbH, D-7512 Rheinstetten4/Karlsruhe, Germany.
Most dried foods are rehydrated by the consumer prior consumption. In
the case of dried pasta, rehydration occurs upon cooking and determines quality factors such as stickiness
and firmness. Nuclear magnetic resonance microimaging (MRI) was used to investigate the influence of
drying conditions on the moisture profile of pasta during rehydration. High-temperature (HT) drying at
100°C was applied at high (early HT phase), intermediate (intermediate HT phase), and low (late HT phase)
product moisture. Spaghetti dried at 55°C served as reference. Water penetration after different cooking
times in boiling deionized water was studied by MRI with a multi slice multi echo sequence. The water
content in transverse slices through the spaghettis was determined by calculating water intensity maps under
consideration of the local transverse (T(2)) and longitudinal (T(1)) relaxation times. For calibration,
deionized water was used as reference. Additionally, structural changes during cooking were investigated
by light and confocal laser scanning microscopy (CLSM). The results suggest that the changes of the
rehydration kinetics are dependent on the drying conditions.
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