A new non-Fickian diffusion model for water migration in starchy food during cooking

Water can be made to diffuse against the water content gradient in starchy foods

“…The key concept of this model is ceiling water content, m clg , which is the potential maximum value of the water holding capacity in starchy food (Watanabe et al, 2001). Un-gelatinized starch would be regarded as a highly crosslinked network and gelatinized starch as a weakly crosslinked network.…”

“…Since ceiling water content depends on the extent of starch gelatinization, and the extent of starch gelatinization is not uniform but become distributed in a food body during cooking, the Fickian diffusion equation can not be applied to such a heterogeneous system. We have proposed a new non-Fickian model (Watanabe, Fukuoka, Tomiya, & Mihori, 2001), Water Demand Model, which is applicable to such heterogeneous systems.…”

An innovative noodle: gelatinized at the core, leaving the surface ungelatinized

“…4D, the change may be large at the center and small at the surface. This is because ceiling water content is governed by starch gelatinization (Watanabe et al, 2001). In the heat treatment at a constant temperature, the higher the existing water content at a certain position, the larger the extent of gelatinization.…”

“…In such a case, the extent of gelatinization may reflect the ceiling water content, and a parabolic ceiling water content may appear. At equilibrium, the difference between the ceiling water content and the existing water content, which is termed the water demand, is supposed to be uniform throughout the noodle body (Watanabe et al, 2001).…”

“…In this work, our effort was focused on realizing this innovative noodle, gelatinized at the core leaving the surface ungelatinized, via an experiment guided by the concept of ceiling water content and terminal extent of gelatinization (TEG) (Watanabe, Fukuoka, Tomiya, & Mihori, 2001).…”