ANSWER
Encapsulation by spray drying
Encapsulation by spray-drying is an economical and flexible process which is mostly used for the encapsulation of fragrances, oils and flavors (Mishra, 2015). It is a technology that coats the solid products in order to preserve them. Spray drying is the continuous transformation of feed from a fluid state into dried particulate form by spraying the feed into a hot drying medium. The flavor or ingredient to be encapsulated is added to the carrier and homogenized to create small droplets (Mishra, 2015).
An emulsion is prepared by dispersing the core material, usually an oil or active ingredient immiscible with water; into a concentrated solution of wall material until the desired size of oil droplets are attained. The resultant emulsion is atomized into a spray of droplets by pumping the slurry through a rotating disc into the heated compartment of a spray drier. There the water portion of the emulsion is evaporated, yielding dried capsules of variable shape containing scattered drops of core material. The capsules are collected through continuous discharge from the spray drying chamber (Jyothi et al., 2012).
This technique is a well-known process that is suitable for drying materials due to the very short heat contact time and the high rate of evaporation resulting in high quality, stable, functional, and low moisture content products (Fernandes et al., 2013).
References
Fernandes, R. V. B., Borges, S. V. & Botrel, D. A. (2013). Influence of spray drying operating conditions on microencapsulated rosemary essential oil properties. Food Science and Technology, 33(Suppl. 1), 171-8. https://doi.org/10.1590/S0101-20612013000500025
Jyothi, S. S., Seethadevi, A., Prabha, K. S., Muthuprasanna, P. & Pavitra, P. (2012). Microencapsulation: A Review. International Journal of Pharma and Bio Sciences, 3(1), 509-531.
Mishra, M. (2015). Handbook of Encapsulation and Controlled Release (pp. 15-18). Boca Raton: CRC Press.
Nedovic, V., Kalusevic, A., Manojlovic, V., Levic, S., & Bugarski, B. (2011). An overview of encapsulation technologies for food applications. Procedia Food Science, 1, 1806-1815. https://doi.org/10.1016/j.profoo.2011.09.265
Zuidam, N. J. & Nedovic, V. (2009). Encapsulation Technologies for Active Food Ingredients and Food Processing (pp. 3-6). New York: Springer Science & Business Media.
