For example making drying fruit slices or halves with oven or food dehydrator, this can keep the nutrients of fruit and reach the purpose of storing for a long time. We can make jam at home with fruit we like, and this will keep the flavor of fruit. Or we can make fruit wine which is sour and sweet and full of fruit fragrance. With the development of science and technology, in order to meet the needs of the customers, and to be able to preserve fruit more perfectly at the same time,finally we found a new method which can both preserve nutrition and maintains fruit contains and excellent flavor of fruit, it is called freeze drying technique.
As one kind of dry methods, Freeze drying frozen the things that need to be frozen and then remove the water vapor which is sublimates of the ice in high vacuum conditions. Low temperature and frozen state is kept during freeze-drying processBecause the sublimation of ice takes away the heat, and this make it available to save activity of some biological samples (such as protein). It keeps the same chemical composition and physical properties after drying the material, such as porous structure, colloid properties, etc; quantity of heat consumption is less than other drying methods. Now this method is mainly used to dry antibiotics, vegetables and fruit.
Freezing dried figs has many advantages. It can maximally save the color, fragrance and taste of food; freezing drying conserves protein food better than frozen. It can save the food nutrition at all levels, especially for vitamin C, can save more than 90%, so it is suitable for the thermal sensitive material especially. It is operated in vacuum and low temperature, restrain the growth of microorganism and enzyme action. Dry products are light, small, convenient to store or transportation for dehydration thoroughly; as the volume decreased, correspondingly packing charge is also reduced. Operated in the vacuum, the process almost contact with no oxygen, therefore, some easily oxidized material (such as oil kind) is well protected. Freeze drying can exclude 95%-99% of the water, the product can be preserved for a long time without rotten. Preservatives and additives are not needed when drying food with freeze drying method, is a kind of natural concentrated manufacturing process and freeze drying food is healthy and delicious.