preserve by rapid freezing and subsequently drying in a vacuum
freeze-dry详细解释
freeze-dry v.tr.（及物动词）freeze-.dried,freeze-.dry.ing,freeze-.dries To preserve (food, for example) by rapid freezing and drying in a high vacuum.使冷冻干燥：通过在高度真空状态下迅速冷冻并干燥来保存（如食物）
