Journal article · Ahead of Print article
Estimation of mass transfer rate and primary drying times during freeze-drying of frozen maltodextrin solutions based on x-ray μ-computed tomography measurements of pore size distributions
The study presents a method to estimate the mass transfer rate during primary drying based on μ-computed tomographic measurements of a freeze-dried cake. The study was carried out in a defined setup in a lyomicroscope and confined geometry in which freezing occurred under homogeneous nucleation, and drying under mass-transfer-limited conditions.
Pore size distribution, effective diffusivity, and primary drying rates of maltodextrin solutions at different weight concentrations (5%, 10%, and 20% (w/w))and different cooling rates were determined. Furthermore, the effect of annealing treatment on primary drying rate was studied. Two different annealing treatments were tested, one for 90 min at −10 °C and another for 180 min at −5 °C.
It was shown that solid concentration and annealing above Tg’ have the strongest impact on pore size and, subsequently, on primary drying rate. Therefore annealing represents a powerful tool to accelerate primary drying which is the most time-consuming step during lyophilisation.
Language: | English |
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Year: | 2019 |
Pages: | 50-57 |
ISSN: | 18735770 and 02608774 |
Types: | Journal article and Ahead of Print article |
DOI: | 10.1016/j.jfoodeng.2019.05.002 |
ORCIDs: | 0000-0002-3541-5260 and Melo de Carvalho, Teresa |