Who knows how to dehydrate vegetables?

Fresh vegetables have high water content, large volume and crisp quality, which is not conducive to long-term storage. On the other hand, long-distance transportation is costly and harmful. The processing of dehydrated vegetables solves these problems, which not only prolongs the storage period of vegetables, but also reduces the transportation cost, and can absorb a large number of agricultural products in the market in time.

The processing technology of dehydrated vegetables has undergone many changes and improvements: from the initial natural drying to the widespread use of manual drying equipment; From one household processing to large-scale factory production, vegetable processing industry has entered a brand-new field.

Dehydration process according to different requirements, there are a variety of dehydration methods, there are three more common:

1. Natural drying method: the process of directly drying vegetables by sunlight and hot air under natural conditions. This processing method is limited by time, climate and sanitary conditions, and the quality cannot be guaranteed. Only a small number of agricultural products can be processed at a lower level.

Second, hot air drying method (AD): The original hot air drying method is to directly dry vegetables by using crops' fuels such as coal, charcoal, wood and orange stalks. This method has changed the original quality of vegetables during processing, and the sanitary conditions are poor, so it has been gradually eliminated in recent years. Another hot air drying method is: the high-temperature and high-pressure steam generated by boiler heating is transported to the radiator through the pipeline, and then the hot air is driven by the exhaust fan to heat the vegetables, so that the moisture in the vegetables is evaporated and discharged. This drying method can be divided into tunnel drying, oven drying, chain cycle drying and so on. The original flavor of vegetables is maintained, and the sanitary conditions are guaranteed, so it is widely used and is the most used drying method at present.

3. Freeze-drying method (FD): freeze the raw materials below freezing point to freeze the water, and then evaporate the water under high vacuum. Freeze-drying keeps the original taste, shape and color of vegetables, which is an advanced drying method. However, this processing method has high cost and is generally only suitable for products with particularly high quality requirements.

In recent years, many new drying methods have appeared, such as microwave drying, infrared drying and vacuum drying. , but only used in a few industries.