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What are the differences between freeze dried, spray dried and drum dried fruit/vegetable powder?

July 10, 2015
ANSWER

The table below shows the differences between freeze dried, spray dried and drum dried fruit/vegetable powder.

Freeze Dried Spray Dried Drum Dried
Process Drying process in which the solvent and/or the suspension medium is crystallized at a low temperature and thereafter sublimated from the solid state directly into the vapor phase. Spray drying is a unit operation by which a liquid product is atomized in a hot gas current to instantaneously obtain a powder form. Drum-drying uses indirect steam to dry a fruit purée in about 30 seconds, from the time it’s put on a hot drum to the time its cut off with a knife.
Nutrient Stability Retains the maximum amount of product nutritional value such as naturally occurring ascorbic acid. High temperature of heat may cause the loss of nutritional value. High temperature of heat may cause the loss of nutritional value.

The table below shows the  Advantages and Disadvantages of Different Drying Methods.

Freeze Dried Spray Dried Drum Dried
Advantages
  • Uses lower temperatures which minimizes the damage and maximizes retention of nutritional value.
  • High recovery of volatiles.
  • Higher quality of end products.
  • Long shelf life end products.
  • End products are free-flow particles.
  • Particles relatively uniform hollow sphere.
  • End-product complies with precise quality standards regarding consistent particle size distribution, residual moisture content and bulk density.
  • Homogenous solids of mixture with the same chemical composition as a mixed feed.
  • Less expensive process.
  • Minimal energy consumption and residence time dispersion.
  • This process makes drying in oxygen-less atmosphere possible, avoiding oxidation.
Disadvantages
  • End products with high porosity dried materials have a negative effect on storage stability.
  • High operating cost.
  • Longer drying time required.
  • End products with high hygroscopicity that promotes caking.
  • Heat-sensitive products will suffer degradation in their quality due to the extreme high temperatures used and oxidable compounds could be lost from the presence of oxygen.
  • Low value of end products.
  • End products tend to be in flakes instead of free-flowing powder.
  • Larger size particles.

 

References

Agnieszka, C. & Andrzej, L. (2011). Freeze-Drying – Application in Food Processing and Biotechnology – A Review. Polish Journal of Food and Nutrition Sciences, 61(3), 165-171.

Bhandari, B., Bansal, N., Zhang, M. & Schuck, P. (2013). Handbook of Food Powders: Processes and Properties. Cambridge: Woodhead Publishing Limited.

Canuto, H., Afonso, M., & Costa, J. (2013). Hygroscopic behavior of freeze-dried papaya pulp powder with maltodextrin. Acta Scientiarum. Technology, 36(1). https://doi.org/10.4025/actascitechnol.v36i1.17499

Murugesan, R. & Orsat, V. (2011). Spray Drying for the Production of Nutraceutical Ingredients-A Review. Food and Bioprocess Technology, 5(1), 3-14. https://doi.org/10.1007/s11947-011-0638-z

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