Microcrystallization of lactose during droplet drying and its effect on the property of the dried particle

► A critical crystallization stage during convective drying is proposed. ► T − Tg at the critical stage might be more significant than the final stage. ► Higher drying temperature results in higher lactose crystallinity. ► Dissolution rate is not directly associated with the degree of crystallization. ► Dried lactose particles show a two-layer morphology with different crystallinity.