Starch gelatinization in coiled heaters

A gelatinizing model food derived from a 5% wt./wt. cross-linked waxy maize starch suspension was simulated in coiled heaters to assess the impact of centrifugal forces on flow and heat transfer. For four coil diams. (D = 0.25, 1, 2.5, and ... m) and three flow rates (.hivin.w = 0.5, 1, and 2 m/s), heat transfer, viscous development, and the severity of channeling were evaluated. Increasing curvature proved to suppress channeling as a result of more uniform heating and gelatinization. The max. attainable viscosity was also higher, implying a lower starch consumption for a target viscosity. Higher flow rates necessitated longer heaters, and the max. viscosity decreased. Moderate product velocities are therefore recommended