•Freeze drying also known as lyophilization is an important process for the preservation and storage of biologicals, pharmaceuticals and foods. •The basic idea of freeze-drying is to completely remove water from some material, such as food, while leaving the basic structure and composition of the material intact. •Freeze drying is a process whereby water or other solvent is removed from frozen material by converting the frozen water directly into vapor without the intermediate formation of liquid water.