Food Freeze Dryer Manufacturers

Food freeze drying — process and applications

Freeze drying (lyophilisation) removes water from a food product by first freezing the product and then applying a high vacuum. Under vacuum, the frozen water (ice) converts directly from solid to vapour without passing through a liquid phase (sublimation) and is removed from the chamber as vapour. Because the process occurs at low temperature (below freezing during the primary drying phase), heat-sensitive compounds, volatile aromas, and live cells are preserved far better than in heat drying processes. The result is a dry product with: excellent retention of natural colour and shape; very good retention of natural aroma and flavour; good retention of heat-sensitive nutrients; and a highly porous, low-density structure that rehydrates rapidly by absorbing water. Industrial food freeze drying applications include: premium instant coffee (freeze-dried instant coffee commands a price premium over spray-dried); freeze-dried fruit and vegetables for breakfast cereals, snack mixes, and ready meal inclusions; probiotic cultures and starter cultures (live microorganisms are preserved through the drying step); and high-value specialty food ingredients.