Evaluation of soybean seedcoat cracking during drying: Part II. Using MRI

MRI techniques were developed and employed for non-destructive and noninvasive study of seedcoat cracking in low moisture soybean kernels during heated air drying. Proton density image and transient moisture distribution profile of a single soybean kernel can be obtained using MRI. These MRI techniques proved to be particularly useful for the continuous observation of initiation and propagation of seedcoat cracking during the entire period of drying process without interruption. The proton density images of soybean kernels showed that seedcoat cracking was initiated perpendicular to the long axis of the kernel near the hilum. The transient moisture distribution profiles in soybean kernels during drying indicate that moisture gradient developed during drying was higher in the seedeoat than in the cotyledon. Drying temperature and initial average moisture content were positively correlated with the soybean seedcoat cracking. The location of the cracks was also associated with the moisture gradient. The length of the cracks could be measured using MRI images.