ABSTRACT The purpose of this project is to preserve the food for a long time without decay. Removing water prevents food from spoiling for a long period of time. Food spoils when microorganisms, such as bacteria, feed on the matter and decompose it. Bacteria may release chemicals that causes disease, or make food taste bad. Microorganisms need water to survive. Therefore the removal of water from food inhibits the growth of microorganisms. Thus the most effective method of removing water from the food is freeze drying. Freeze drying in general is a process of freezing the foodstuff and then drying it to get rid off the moisture. Freeze-drying is a method of removing water by sublimation of ice crystals from frozen material, all of which makes the process somewhat expensive, but the resultant food quality is good. This method involve three stages freezing, creating vacuum, and heating. In the freezing stage water freezes, then the chamber pressure is reduced to a low level that would allow sublimation of water. Water is removed by heating the product under vacuum and the residual moisture content is reduced in this stage which makes the food completely dry. Thus we have fabricated a food freezing equipment at a reasonable cost which preserves the foodstuff for a long time.
