Routine Evaluation of the Grain Structures of Baked Breads by MRI

Abstract

We devised a routine evaluation method for the grain structures of baked breads using MRI. A piece of bread was soaked in Fe31 perchlorite-acetone solution, evacuated to remove the air between the grain networks, and used for measurement of MR images. Fe31 concentrations from 8 to 25 mM stained the crumb grain networks well. A plane resolution of 100 μm100 μm and slice thicknesses from 0.25 to 0.4 mm provided images suitable for analysis. A histogram of the PIXELs versus the gray level exhibited a bimodal pattern. The measurement time was shortened to 20 min per image by using the spin-echo 2D-FT method, which is less than one thirtieth the ordinary 3D image measurement time previously reported. MR images of the crumb grain networks and figures obtained by image analysis, i.e. the total-area/pore-area ratio, pore number detected, average pore size, and pore area distribution patterns, characterized the individual breads. The MR image system used in this study can replace a portion of the visual test in a sensory evaluation of bread quality in practical bread making.