Effects of water migration and grain structural evolution on substance dissolution and consistency variation during cooking of different foxtail millet varieties porridge.

Different millet varieties exhibit distinct porridge consistency, influencing consumer preferences. This study investigated water migration and grain structural evolution influencing solids leaching and consistency in five commercial foxtail millet varieties during cooking. Using texture analysis, low-field NMR, stereomicroscopy, and leaching assays, we quantified dynamic changes over a 40-min cooking period. High-consistency varieties (ZG 19, JG 21, FHG) showed a rapid consistency rise from ∼3000 to >11,000 mN·s between 30 and 40 min, whereas low-consistency types (CG 17, HM) remained below 5000 mN·s. LF-NMR revealed faster water penetration in high-consistency grains, reflected by tighter water binding (shorter T₂₁) and higher proportions of weakly bound water (T₂₂), promoting stable gel networks. Stereomicroscopy identified surface cracks facilitated solids release, directly influencing consistency. Elucidating water migration and structural dynamics provides a mechanistic basis for optimizing millet processing and variety selection, guiding the development of value-added products such as ready-to-eat and functional cereals.