How did “dehydrated vegetables” come about?

In daily life, when we eat instant noodles, there is often a package of dehydrated vegetables in it, so, do you know how dehydrated vegetables are made?

Dehydrated vegetables are a kind of dried vegetables made after artificial heating to remove most of the water in the vegetables. Common dehydrated vegetables include fungal algae, beans, celery, green peppers, cucumbers, etc., which can usually be eaten by soaking them in hot water for a few minutes. So, what are the preparation methods of dehydrated vegetables?

According to their dehydration methods, dehydrated vegetables can be divided into natural sun drying, hot air drying dehydration and freeze vacuum drying and dehydration.

Natural drying is the use of natural conditions to dehydrate vegetables, and this method has been used since ancient times. The principle of hot air drying and dehydration technology is to vaporize the moisture on the surface of vegetables into the air through drying hot air, increase the concentration of the contents of the surface layer of vegetables, form the osmotic pressure difference of connected inner cells, so that the moisture of the inner layer diffuses and flows to the outer layer, so that the water continues to vaporize. The principle of freeze-vacuum drying and dehydration technology is to quickly freeze the drained material, so that the remaining water in the material is converted into ice, and then under vacuum conditions, the water molecules are directly sublimated from solid to gaseous state, so as to complete dehydration.

Natural drying and hot air drying and dehydration will lose a lot of water-soluble vitamins and bioactive ingredients during processing, and the color of vegetables is easy to darken; In contrast, freeze vacuum drying and dehydration technology can maximize the preservation of the original nutrients, color and flavor of vegetables, so the processing cost of this technology is relatively high, and it is usually used for the processing of high-grade vegetables.

Dehydrated vegetables are widely used, almost involved in all fields of food processing, it can not only be used to improve the nutritional content of products, increase the color and flavor of products, but also make the variety of products richer, greatly improve the food structure of consumers.