Spray drying remains the predominant encapsulation process because it handles both water-soluble and oil-soluble flavor systems equally well, is cost-effective and easily scaled from pilot plant to commercial production. Over the past 70 years encapsulation of flavors by spray drying has become so routine and standardized that some of the nuances and options available to flavorists may no longer be obvious and thus are worth reviewing.
Factors in Spray Drying
Flavor encapsulation employing the spray-drying process involves a large number of interactive factors. These include: the flavor, the flavor cosolvent, the carrier composition, the emulsion solids-to-water ratio, emulsion preparation and lipid particle size distribution, as well as the dryer system and the operational drying conditions. The encapsulation process starts with the formulated flavor (i.e., a compounded flavor, flavor extract, flavor oil or reaction flavor) designed to meet the organoleptic character of the flavor brief. As the flavorist compounds the flavor, the choice of cosolvent will also influence the ultimate quality of the encapsulated flavor. For water-soluble flavors, use of ethanol or propylene glycol will not have as big an effect on the final product relative to the cosolvent selected for oil-soluble flavor systems. Since flavor chemicals vary greatly in water and oil solubility (their partitioning character), volatility and chemical reactivity, the flavor cosolvent and carrier will affect the final sensory character.
Other topics discussed: The Spray-Dry Carrier, Flavor Emulsion, The Dryer and the Drying Process, The Glassy State and Encapsulated Flavor, Flavor-Carrier Systems, Alternate Systems