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 kin etics and morphology of single drops containing dissolved solids and suspen sions are reviewed. A review of works related to receding interface model p roposed to quantify the drying kinetics of single drops along with techniqu es to measure the kinetic parameters such as moisture diffusivity, thermal conductivity and specific heat capacity is presented. Problems associated w ith 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 includin g skin formation, as monitored through single drop experiments, are explore d.