There are still nutrients, just some of them will be lost in the air-drying process.
Natural drying air-dried fruit, compared to the fruit, first of all, the water is much less than before, and secondly, some of the water-soluble nutrients in the fruit, such as vitamin C?, folic acid, etc. There is also a part of the loss of other nutrients, such as carbohydrates (sugar), minerals, dietary fiber, and other nutrients in the density of the nutrients have been improved.
Extended Information
A processing method that uses heat to dehydrate fruit. The products are mainly dried fruit and juice powders.
dried fruit Fruits after picking, washing and other pretreatment, dehydration to the moisture content of 15 to 25% of the products. Dried fruit volume is about 11 ~ 31% of the fresh fruit, weight is about 10 ~ 25% of the fresh fruit, which can significantly save packaging, storage and transportation costs, and easy to eat and carry. Dried fruit can be stored for a long time at room temperature due to its low water content. Dried fruit processing methods and canning, freezing and other processing methods, equipment and operation are relatively simple, low production costs. Dried fruit production process for: raw material pretreatment, hot blanching or dipping alkali, fumigation, dehydration, wet, selection, packaging.
The pre-treatment of fruit with boiling water or steam or other methods for a short period of time heating, called scalding. The main purpose of scalding is to use heat to drive out the air in the fruit tissue, destroying the fruit oxidase to prevent oxidative discoloration. In addition, the fruit after hot ironing, the surface produces a network of fine cracks, can speed up the evaporation of water, shorten the drying time, and can prevent the production of large cracks in the late heating; hot ironing can also eliminate and wash away the microorganisms and dirt remaining on the surface of the fruit. Hot blanching temperature and time according to the type of fruit, species, maturity, texture, size and so on, generally in boiling water treatment 5 ~ 15 minutes. The purpose of fruit dipping in alkali is mainly to remove the wax through the action of alkali, so as to facilitate water evaporation and promote drying. In addition, the fruit dipped in hot lye, can remove the residual surface of microorganisms, has a disinfectant effect.
Dipping alkali used in the alkali, the general peel resistance is strong available sodium hydroxide, the weak preferably with sodium carbonate or sodium bicarbonate. Dip alkali time for a few seconds to tens of seconds. The purpose of sulfur fumigation is to allow a certain amount of sulfur dioxide into the fruit, and the role of water with the fruit tissue, generating a very strong reducing power of sulfurous acid, in order to destroy the enzyme oxidation system, to prevent oxidative discoloration; carotene and vitamin C will not be oxidized and destroyed; at the same time, sulfurous acid is also a good preservative, mold spores and acetic acid bacteria to eliminate the ability to be quite strong, to help the preservation of the future. Sulfur fumigation is carried out in the fumigation room, that is, the fruit is placed in a closed room or container, burning sulfur powder, so that the production of sulfur dioxide. General control room sulfur dioxide concentration of 1.5 ~ 3%, temperature 45 ~ 50 ℃. Sulfur fumigation time varies depending on the type of raw material, usually 1 to 3 hours.
Dehydration is drying, the purpose of which is to make products to achieve the required moisture content. Drying methods are natural drying and artificial drying two (see food dry storage).
Fruit juice powder will be processed into fruit juice and then dehydrated. Its moisture content of 2.5% or less, powder or granular. High-quality juice powder with the right amount (8 to 10 times) of water can be restored, restored and fresh juice color, aroma and taste similar.
Because it has a small size, light weight, transportation, storage and easy to carry, nutritious and so on, although its production history is not long, but in terms of production, variety, packaging and other aspects of the development of very quickly. The main process is: pretreatment of raw materials, juice or cone juice, concentration, drying, packaging. The citrus powder produced by the foam bed drying method can be left at room temperature for several months, has a good aroma and flavor, and has roughly the same nutrition as fresh orange juice.
Many liquid or syrupy juices such as clarified juice, lemon juice, grapefruit juice, apple juice and grape juice can be directly dried into powdered products by foam bed drying. In addition, vacuum foam drying, vacuum belt drying and sublimation drying method, can produce high quality juice powder.
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