How is moisture typically removed during the freeze-drying process?

During the freeze-drying process, moisture is effectively removed through evaporation under vacuum. This method involves first freezing the product at low temperatures to solidify the moisture content into ice. Once the product is frozen, a vacuum is applied, which lowers the pressure surrounding the ice. Under these conditions, the ice sublimates, meaning it transitions directly from a solid state to a vapor state without passing through a liquid phase. This allows moisture to be removed while preserving the structure and nutritional content of the food.

This technique is particularly beneficial for sensitive products, as it helps maintain flavors, colors, and other qualities that could be damaged by high temperatures. The use of vacuum is critical because it allows for moisture removal at lower temperatures, minimizing the risk of heat-induced damage.