Shrinkage and tensile stress of sheet-like and cylindrical pastas with various moisture contents

• The shrinkage of sheet-like and cylindrical pastas during drying was measured.
• A slight anisotropy in shrinkage was observed for both the pastas.
• The effects of moisture content and distribution on the shrinkage were analyzed.
• The Young's modulus in the rubber state did not depend on the drying conditions.

The shrinkage of sheet-like and cylindrical pastas of different moisture contents and distributions was measured. A slight anisotropy in shrinkage was observed for both the pastas. The shrinkage ratio of the height to the width directions for the sheet-like pasta slightly depended on the drying conditions and was 0.93 to 0.96. The shrinkage coefficient in the longitudinal direction scarcely depended on the moisture content and was 0.23 for the cylindrical pasta. Although the shrinkage coefficient in the diametric direction for both the pastas was 0.21 at moisture contents higher than 0.17, the coefficient increased for the moisture contents lower than 0.17. The Young's modulus of the dumbbell specimen of pasta did not depend on the drying conditions. However, it decreased with a decrease in the moisture content and became almost constant at the moisture contents lower than 0.17. These facts suggested that glass transition significantly affected mechanical properties of pasta.