Abstract: Abstract: Dough mixing is the key step in noodle production, which has a great influence on noodle quality and performance in subsequent processing. During the noodle dough mixing, there is a limited development of gluten due to low water addition (only 30%-37% moisture content), resulting in crumbly dough pieces. Studying the state and distribution of water in noodle dough has important implications for better understanding physical and chemical changes during dough mixing, illuminating the effect of water on noodle processing and providing the guidance for mixing technology optimization. In this study, 3 kinds of wheat flour with different qualities were used as test materials, and the noodle doughs (with the moisture content of 35%) were made by vacuum mixing at different vacuum degrees and mixing time. The state and distribution of water in sheeted noodle dough were determined by low-field nuclear magnetic resonance (LF-NMR) and differential scanning calorimetric (DSC). The correlation between the results of water state detected by the 2 techniques was also analyzed. The results showed that 3 spin-spin relaxation time constants, namely T21, T22 and T23, were identified by the LF-NMR experiments using the Carr-Purcell-Meiboom-Gill (CPMG) pulse sequences. The second category of water (T22, 0.49-21.54 ms) represented the less tightly bound water, and made up almost 80% of the total moisture in noodle dough. The gluten content and quality of wheat flour had influence on the state and distribution of water in noodle dough, and the mobility of water in dough from strong gluten wheat (Jimai 20) was lower than that from other 2 weak gluten wheats. According to the effects of vacuum degree on T2 and its corresponding peak area, the vacuum mixing at 0.06 MPa may promote the interaction of water and gluten protein, and result in a decrease in the molecular mobility of water in noodle dough. And non-vacuum condition or excessive vacuum (0.09 MPa) could also increase the molecular mobility of water in dough. For Jimai 20 and Jimai 22, the mobility of water was low in noodle dough after being mixed for 8 min, and the mixing time of deficiency (4 min) or excess (12 min) could lead to significantly higher water mobility as evidenced by LF-NMR and DSC. While for the flour of Ningchun 4 with low protein and gluten content, the water mobility was low in dough after mixed for 4 min; with mixing time prolonging, the fraction of less mobile water decreased and the more mobile fraction increased. The results of water state in noodle dough measured by LF-NMR and DSC were consistent. The change tendency for the less tightly bound water (T22) detected by LF-NMR was the same to that for freezable water detected by DSC, and the change tendency for the tightly bound water (T21) was the same to that for non-freezable water. LF-NMR technique is accurate, sensitive, convenient and non-destructive, which is the preferred technique to analyze the state and distribution of moisture in food.