Polytechnic University of Valencia Congress, 21st International Drying Symposium

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Agitated thin-film drying of spinach juice
Jun Qiu, R. M. Boom, M.A.I. Schutyser

Last modified: 02-01-2019

Abstract


Agitated thin film dryers (ATFD) has been considered as an effective technology for drying viscous liquid foods, pastes or pureed foods. In this study, a lab-scale ATFD was developed and applied for drying of juices from spinach leaves at varying temperature (60 – 90 ˚C), feed rate (0.3 – 0.5 kg/h) and blade rotation speed (300 – 600 RPM) combinations. Juice suspensions were successfully dried into powder with a moisture content ranging from 0.049 to 0.114 kg/kg total. Increasing the wall temperature and feed rate were found to improve the specific evaporation rate and evaporation rate of the ATFD, respectively. The blade rotation speed had limited effect on the water removal rate, while it played a crucial role in powder formation.

Keywords: Food solution; Spinach juice; Thin film drying; Scraped surface; Vacuum conductive drying.


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