Carrier compositions based on blends of various octenylsuccinic acid anhydride (OSAN)-modified starches were utilized in the glass encapsulation of flavours by means of melt extrusion and spray drying. Dextrinized, acid and enzymatically hydrolysed OSAN starches were used in various combinations. Processing parameters were optimized for desirable physical chemical and functional properties of the encapsulating compositions. One key property in the optimization of the extrusion process was setting rate of the exiting melt into a glass. Glassy states of identical spray-dried and extruded compositions were characterized by MDSC for glass transition temperature(s), heat capacity change and enthalpy relaxation. Flavour retention, surface flavour, moisture, particle density and flavour particle size distribution were also measured and compared for the extruded and spray-dried compositions. In addition, elastic recovery and caking were evaluated for extruded compositions. The glass transition parameters were correlated directly or indirectly with most of the physical properties of encapsulating compositions, especially flavour retention, surface flavour and caking. In extruded compositions, two phases were revealed by the presence of two glass transitions, whereas spray-dried compositions showed only one broad glass transition.