Effects of electrostatic spray drying encapsulation on flavors and its comparison with traditional spray drying.

Abstract

This study compared the flavor encapsulation properties of electrostatic spray drying (ESD) with traditional spray drying (TSD). Four flavor compounds—limonene, citral, cinnamaldehyde, and t-2-hexenal—were encapsulated using two different carrier system formulations: one with gum acacia and maltodextrin (Formulation 1), and another with HICAP-100 (a chemically modified starch) and maltodextrin (Formulation 2). The physical characteristics of the spray-dried flavors were assessed by measuring total oil, particle size, surface oil, and the formation of oxidation products over a 21-day accelerated storage period. ESD was performed at various atomizer voltages (+18, -18, +2, and -2 kV) to investigate how these voltages influenced the physico-chemical properties of the flavor encapsulant. Oxidation levels of the flavor compounds were determined using gas chromatography with flame ionization detection.ESD has been proposed as an alternative to traditional spray drying for encapsulating bioactive and volatile compounds due to its lower inlet temperatures and the use of nitrogen gas as drying medium. The particle size of TSD was found to be larger than that of any of the ESD samples, with no significant variation in particle size across different voltage settings. The total limonene content in the spray dried formulation with HICAP was similar for both TSD and ESD samples, except for the +18 kV sample, which exhibited the lowest oil content. Similarly, for the formulation with gum acacia, there was no significant difference in total oil content between TSD and ESD. However, oxidation levels of the flavor compounds were higher in ESD samples compared to TSD, which could be attributed to the higher surface oil content in ESD. Oxidation was evident immediately after spray drying in all ESD samples, though the degree of oxidation remained consistent across the different voltages. Further research is required to explore the underlying causes of unexpectedly high rate of oxidation in ESD samples.