Microencapsulation by coacervation: Physicochemical and sensory properties of food flavorings

Abstract

Coacervation is a low-energy method that is ideal for encapsulating heat-sensitive materials, e.g., limonene, citral, linalool, and isoamyl acetate. 
 This research used a simple coacervation method to prepare flavoring beads with alginate and Tween 80. The methods of scanning electron microscopy (SEM) and fourier transform infrared (FTIR) spectroscopy made it possible to study the morphology and structure of the flavoring beads. After the extraction, the flavor retention and structure were described using the method of gas chromatography with mass spectrometry (GC-MS). 
 The microcapsules demonstrated a retention rate of 99.07–99.73% while the encapsulation efficiency remained as high as 96.40–97.07%. The microcapsules had a mononuclear structure and ranged from spherical to elongated ellipsoids; they were sealed without agglomeration. The particle size was below 1000 µm. The GC-MS chromatograms detected neither structural changes nor any new compounds. The FTIR spectra were similar to the control but demonstrated slight shifts, which suggested fundamental structural changes caused by the coacervation. We also fortified sponge cake and jelly with flavoring beads. The sensory analysis of the sponge cake samples revealed no significant differences compared to the control. All the fortified jelly samples had higher scores for smell, taste, texture, and overall preference than the control. 
 The coacervation method proved to be an excellent solution for the problem of heat-sensitive flavorings that often lose quality or sensory attributes in food products that undergo extensive thermal treatment.