The role of ultrasound-assisted emulsification of roasted coffee oil on aroma profile in spray-dried microparticles and its dynamic release by PTR-ToF–MS

This work evaluated the use of roasted coffee oil (RCO) and the effects of ultrasound (US)-assisted emulsification on RCO-in-water emulsion properties, the changes in the composition of volatile organic compounds (VOCs) of roasted coffee aroma during US and microencapsulation by spray drying, and VOCs release profile upon instant coffee reconstitution. VOCs were determined by gas chromatography-mass spectrometry, and the release profile was monitored in real-time by Proton Transfer Reaction Time-of-Flight Mass Spectrometry (PTR-ToF–MS). US was found to be effective in producing stable submicron emulsions (≤ 2.0 µm) that resulted in high encapsulation efficiency (> 90%) of the microparticles. Significant changes were detected in VOC composition throughout the microencapsulation process. The addition of microparticles loaded with RCO in instant coffee did not change the VOCs release profile during the brew preparation but was effective in increasing coffee aroma.