Experimental studies and kinetics of single drop drying and their relevance in drying of sugar-rich foods: A review

Levitation and free-flight techniques applied to investigate the drying kinetics and morphology of single drops containing dissolved solids and suspensions are reviewed. A review of works related to receding interface model proposed to quantify the drying kinetics of single drops along with techniques to measure the kinetic parameters such as moisture diffusivity, thermal conductivity and specific heat capacity is presented. Problems associated with spray drying of sugar-rich compounds are briefly discussed and possible links of stickiness and flavor retention with glass transition temperature (T-g), temperature history, drying rate and morphological changes including skin formation, as monitored through single drop experiments, are explored.