Apparatus for determination of bread porosity

The porosity of bread with regard to its structure (pore size, uniformity, wall thickness) characterizes the digestibility of the bread.

By porosity we understand the ratio of the pore volume of the crumb to the total volume of bread crumb, expressed as a percentage. The pore volume is calculated as the difference between the volumes of porous and non-porous bread crumb.

To determine the porosity of the bread crumb from the middle of the product is cut out a piece of width not less than 7-8 cm. From the crumb of the piece, at a distance of at least 1 cm from the crusts, with the help of a hollow cylinder from the Zhuravlev instrument make three notches for wheat bread and four for rye bread. The volume of each cylindrical notch is 27 cm3 (diameter 3 cm and height 3.8 cm).

The cylinder is inserted into the crumb of the bread in a rotary motion and removed with the notch. When the cylinder is filled with crumb, place it on the tray so that the rim fits snugly into the slit in the tray, then push the breadcrumbs out of the cylinder with a wooden sleeve approximately 1 cm and cut them off at the edge of the cylinder with a sharp knife. The cut off piece of crumb is removed. The crumb remaining in the cylinder is pushed out with the sleeve up to the wall of the tray and also cut off at the edge of the cylinder. In this way the same volume is achieved for all the bread extracts taken.