Carrageenan drying with dehumidified air: drying characteristics and product quality

Applying dehumidified air is considered as an option to retain quality in carrageenan drying. This work concerns the effects of operational temperature, air velocity, and carrageenan thickness on the progress of drying and product quality when using dehumidified air. Final product quality and progress of drying were measured by experiments, and a two dimensional model was developed to analyze progress of drying for the different operational conditions. The experimental and modeling results showed that air dehumidification with zeolite reduces the drying time the most at low temperatures. Under these conditions the carrageenan qualities whiteness and gel strength are the least affected by the exposure to the drying temperature. The drying time is the shortest at 120 degrees C, but at this temperature the carrageenan quality degrades the most and is not be improved by air dehumidification. Moreover, the quality is improved by increasing the air velocity and by drying thin carrageenan sheets.