Starch Gelatinization in Coiled Heaters

Abstract

A gelatinizing model food derived from a 5% w/w 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 diameters (D = 0.25, 1, 2.5, and infinity m) and three flow rates (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 maximum attainable viscosity was also higher, implying a lower starch consumption for a target viscosity. Higher flow rates necessitated longer heaters, and the maximum viscosity decreased. Moderate product velocities are therefore recommended.

Confectionery Gels: A Review on Formulation, Rheological and Structural Aspects

“…If starch is being used as a gelling agent, this step is often used to form the starch gel, as well as dissolving and concentrating the sugar ingredients. Common cooking methods used in industry include jet cooking, [3,94] coiled heater cooking, [95] and the more traditional, and now less common, open-pan boiling. [36] Jet cooking involves the injection of high temperature steam at pressure to cook the confectionery gel ingredients.…”

“…At low coil diameters, the increase in relative viscosity of the carbohydrate solution is the highest. [95] The increase in starch gelatinization could be due to the introduction of increased shear, via a more convoluted flow path, and hence higher destruction of starch granules.…”

Process development of starch hydrolysis using mixing characteristics of Taylor vortices

“…The governing equations, the conservation equation of mass, momentum, heat, and species should be solved to clarify transport phenomena in the reactor. The governing equations are as follows: 2 /s] is the diffusion coefficient of the species j. The viscous dissipation energy was neglected.…”

“…There have been many attempts to overcome these problems. For example, Kelder et al 2) applied a curved tube to starch gelatinization and successfully showed that channeling phenomenon was suppressed by the Dean vortex. However, the starch content in the slurry was much lower (100 g/L) than that required in the industry (300-350 g/L).…”

Effect of fluid thermal properties on the heat transfer characteristics in a double-pipe helical heat exchanger

“…Recently there has been significant investigation into the benefits of using helical heat exchangers in food processing applications [1][2][3][4][5][6][7], with one of the benefits being higher heat transfer coefficients compared to straight tube helical heat exchangers due to tube curvature [8,9]. The curvature results in secondary flow patterns, perpendicular to the main axial flow, which increase fluid mixing.…”