What are the light, white substances sometimes seen on the surface of freeze-dried fruits?
A. The light, white substances seen on the surface of freeze-dried fruits are sugar or other nutrients (i.e. proteins and vitamins) naturally occurring in the products. Because freeze-drying removes water almost 100%, even a small amount of sugar and nutrients appearing on the surface of the products would be converted to their solid state, which show up as light, white materials. Sometimes they are mistaken for foreign objects or contaminations by untrained eyes, but there is nothing to worry about. This appearance is an intrinsic character of freeze-dried food products.
