CONICET | Buscador de Institutos y Recursos Humanos

INTRODUCTION Microencapsulation of hydrophobic flavors is of great importance in the flavoring and food industries, since microencapsulated flavors exhibit good chemical stability and a controlled release. Spray-drying is generally used to produce flavor powders in a short time. This process requires a strict screening of the encapsulating materials and the formation of stable emulsions. The objective of this work was to characterize and determine the stability of emulsions constituted by citral and several encapsulating materials. Focus was put on trehalose since it may result beneficial to the aroma retention and the physical stability upon spray drying. METHODOLOGY Emulsion continuous phase consisted of sucrose or trehalose with or without maltodextrin (MD); and a modified starch. Citral oil was the dispersed phase. The ingredients were pre-mixed and emulsions were made with a high power mixer. The analysis included the following determinations : pH, flux curves (viscometer), droplet size distribution (laser light scattering), stability (vertical scanner analyzer). RESULTS AND DISCUSSION The emulsions showed a Newtonian behavior. MD increased the viscosity of the continuous phase as reflected by the consistency index values. All the emulsions presented a similar droplet size distribution in a range of 0.5-1.5 microns. Samples containing MD showed a higher ratio of smaller droplets. The stability analysis revealed flocculation of the emulsions along time. Samples containing trehalose presented lower flocculation rates. CONCLUSIONS A single encapsulating agent cannot possess all ideal properties, carrier systems are usually formulated by combining several components. In the case of citral emulsions that will be spray-dried, a combination of ingredients is necessary to contribute to emulsion formation, aroma retention, and improve stability. Trehalose showed interesting features to be considered as an ingredient for spray-drying of hydrophobic aromas.

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