Abstract: Low field nuclear magnetic resonance (LF-NMR), magnetic resonance imaging (MRI), a rapid viscosity analyzer (RVA) and an optical microscope were used to study the moisture migration, water status, pasting properties and microstructure of noodles during steaming. The correlation among moisture content, transverse relaxation time (T2), proton density (M2) and pasting properties was also analyzed. The results showed that less tightly bound water was the major component of the total moisture in steamed noodle. During steaming, moisture migrated from the surface to the interior until reaching the core. Moisture content and the proportions of less tightly bound water and tightly bound water increased until reaching a plateau; the proportion of tightly bound water showed a slower increase and the mobility of less tightly bound water gradually rose. Both peak viscosity and breakdown decreased with the increase of steaming time. The microscopic investigation showed that starch granules swelled, and became greater in size. Moreover, starch granules in the central region of steamed noodles had a lower degree of gelatinization than in the external region. Correlation analysis showed that moisture content was highly significantly correlated with T22, M22 and Mtotal (P < 0.01), and each of these was significantly (P < 0.05) or extremely significantly (P < 0.01) with peak viscosity, breakdown and final viscosity.

Key words: noodle, steaming, low ?eld nuclear magnetic resonance (LF-NMR), magnetic resonance imaging (MRI), moisture migration, pasting properties