Drying basically removes the moisture from the food and this simple action inhibits the growth of bacteria, mould and yeast. Furthermore, it slows down the enzyme action without deactivating them. These factors ensure that fruits and veggies do not spoil easily and thus, make drying an effective food preservation technique.
There are different drying techniques for drying fruits and veggies each one of which may bring some advantages and limitations to your process. Freeze-drying and air-drying methods differ in both process and some characteristics of the finished product. Each comes with certain benefits that your application may need, and you should be intentional about choosing the right fit.
We are an international food company specialized in drying fruits and veggies that are being dried through either freeze-drying or air-drying method.
Freeze-drying, also known as Lyophilisation, is a water removal process to extend shelf life or make the material more convenient for transport. Freeze-drying occurs in three phases that are freezing phase, primary drying phase (sublimation) and secondary drying (adsorption) phase. In the first step of freeze-drying process, the product is frozen. Then the surrounding pressure is reduced resulting in a vacuum. The frozen water content sublimes directly from the solid phase to the gas phase.
What are the benefits of freeze-drying?
Nutrition: Freeze-drying preserves all the nutritional health benefits in the fruit as there is no heat damage to final products. 95% of the nutritional value of the fruit is preserved. In the other food preservation methods such as dehydrating or canning, much of the nutritional value is destroyed because of the high temperature used.
Shelf Life: It provides a much longer shelf life compared to the other method of preservation. Dehydrated fruits can lose up to 70-90% of the moisture, however, the freeze-drying process is able to remove 98-99% of all moisture.
Taste: The final fruit’s taste and the smell remains unchanged. Freeze-drying essentially uses less heat keeping the flavour as close to a fresh product as possible. The shape and colour of the fresh fruit are also retained.
Rehydration: It is very easy to rehydrate the food items. What you only do is to add water to them and they will regain their normal texture.
Weight: Small quantities make big difference. Dried fruits become very light because of the removal of water.
Air-drying can be performed effectively with some variety from one method to another. In one method, fruits and veggies run on a conveyor through a chamber circulating with hot and dry air. The moisture evaporates out of the fruit. Other methods apply to spray hot air on fruits and veggies but producing the same effect. Some also choose a more stationary method and dry fruits and veggies on racks rather than conveyors.
In our air-drying method, the chambers are supplied filtered hot air that removes the majority of moisture from the fresh fruit and veggies on the belts. The technique we use is the best airdrying method compared to other air-drying methods in terms of the finished product characteristics.