The main nutrients in fruit/vegetable
Water -- the main material, dry to below 12%.
Carbohydrates - drying process shall ensure that carbohydrate reserves.
Of the maturity of the organic acid - determine flavor and important matter。
Nitrogenous substance, can make the material in the drying process in Browning;
Tannin substance, tart, drying process lead to the material change color.
The flavor of glycosidic class material - determine important material.
Decided color pigment material - one of the important material.
Aromatic substance, sterilization is advantageous to the storage, volatile drying process。
Vitamins - are generally very stable, some easy oxidation in the drying process.
Oil - content is less, some easy volatilization in the drying process.
Class - mineral content and less stable。
- some varieties contain plant antibiotics, flavor and the quality change of important material.
The important problems in the process of fruit/vegetable drying
1, the loss of vitamin A and vitamin C - easy oxidation of vitamin A (beta carotene), vitamin C, easy oxidation when heated.
2, the change of colour and lustre, colour and lustre is one of the important marks drying quality acceptance of the material. Natural color is very important to keep the material in the process of drying. If not handled properly, it's easy to have a bad color such as yellow, brown, or black. When necessary need the front filming for the increase in drying process.
3, aromatic substance loss - aromatic volatile loss. Fragrant aroma loss related to temperature, humidity and oxidation. Generally low temperature drying easily keep aromatic substances. Aromatic substances, largely determines the flavor of the material.
4, organization change, the hot air convective drying of tissue damage。 Especially in the high temperature drying, drying technology of rapid dehydration, uneven material dehydration, tissue damage。