Water Sorption Kinetics of Wheat Flour Noodles with Added Chemically Modified Starch

Abstract

To clarify the water sorption behavior of Japanese wheat noodles (udon) to which a modified starch has been added, noodles are prepared with different starch types and amounts of added starch, and the changes in the moisture content, the noodle diameter, and the loss of noodle mass during cooking are measured. The changes in the moisture content can be empirically represented by a hyperbolic equation, regardless of the type and amount of starch added. The relationship between the amount of added starch and the equilibrium moisture content of the noodles suggests that the swelling of the added starch is suppressed by the gluten network, even at an equilibrium state. The change of the diameter suggests that the swelling in the longitudinal direction progress in the late stages of water sorption for the noodles containing unmodified starch, but it is suppressed for the noodles containing hydroxypropylated starch. The transient changes in the loss of noodle mass can be empirically expressed by an exponential equation, regardless of the type and amount of starch added. The relationship between the amount of added starch and the equilibrium loss of noodle mass suggests that the adhesiveness of the noodles with added modified starch is stronger than that of the noodles with added unmodified starch.