When we freeze a product, it becomes solid due to water state is converted into solid. When we freeze the food. In freezers there is less humidity. It catches the humidity from our food surface and removes it to air. This phenomenon is known as Surface Drying.
Credits: SimplyKlassichome
Other defect happens when we thaw our food. Never thaw your food in boiled water or in steam. Thaw your product at room temperature in water.