A new method,a magnetic resonance imaging (MRI) technique characterized by T2 relaxation time,was developed to study the water migration mechanism between arabinoxylan (AX) gels and gluten matrix in a whole wheat dough (WWD) system prepared from whole wheat flour (WWF) of different particle sizes.The water sequestration of AX gels in wheat bran was verified by the bran fortification test.The evaluations of baking quality of whole wheat bread (WWB) made from WWF with different particle sizes were performed by using SEM,FT-IR,and RP-HPLC techniques.Results showed that the WWB made from WWF of average particle size of 96.99 μm had better baking quality than those of the breads made from WWF of two other particle sizes,50.21 and 235.40 μm.T2 relaxation time testing indicated that the decreased particle size of WWF increased the water absorption of AX gels,which led to water migration from the gluten network to the AX gels and resulted in inferior baking quality of WWB.