In recent years, with the growth of the demand for high-quality frozen food, at the same time, an important quality index of fruits and vegetables is freshness, and consumers’ requirements for freshness are getting higher and higher. The storage at room temperature can not meet people’s requirements for its freshness. Lowering the temperature is a commonly used and effective method. After fruits and vegetables are harvested, the key step is how to quickly eliminate the heat in the field and reduce the temperature of the center to the freezing point. Therefore, vacuum precooling technology is more and more used in the field of food preservation. Based on the principle, characteristics and application of the two-stage rotary vane vacuum pump, the importance of the vacuum precooling process of fruits and vegetables was analyzed, and the application of the two-stage rotary vane vacuum pump in the preservation of fruits and vegetables was summarized.
Cold storage is one of the main forms of modern fruit and vegetable storage. It uses a lower freezing point than the fruit and vegetable tissue to keep the fruits and vegetables fresh. It can be stored in the season with high temperature annually to ensure the annual supply of fruits. Low temperature cold storage can reduce the respiratory metabolism of fruits and vegetables, the incidence of pathogenic bacteria and the rotten rate of fruits, so as to prevent tissue aging and prolong the storage period of fruits. However, in cold storage, the unsuitable low temperature will affect the storage life and lose the commodity and edible value. The key to prevent chilling injury and freezing injury is to strictly control the temperature according to the habits of different fruits and vegetables. During the refrigeration period, some fruits and vegetables, such as Yali pear, need to adopt the method of gradual cooling to reduce or avoid chilling injury. In addition, the measures of precooling before storage, temperature rising during storage and chemical treatment can reduce the chilling injury. Therefore, a two-stage rotary vane vacuum pump is needed.
Two stage rotary vane vacuum pump features:
1. Master the core technology of three leaf structure to make the operation easier
2. Simple structure and convenient maintenance
3. Stable and durable performance
4. Compact design
5. Strong steam drainage capacity
6. Low noise and vibration
7. Water cooling optional
8. The motor is suitable for various standard voltages and frequencies
The two-stage rotary vane vacuum pump is made of ferrous metal, and it is more precise. The whole work of the pump is linked together, so it is not suitable for pumping out various gases with high oxygen content, toxic, explosive etching of ferrous metal and chemical effect on vacuum oil, nor can it be used as compressor and delivery pump. If there is a pump of air ballast device, certain condensable bodies can be removed.
Two stage rotary vane vacuum pump application:
Vacuum coating, chemistry / medicine, automobile industry, metallurgy / vacuum furnace, bulb / energy saving lamp, kinescope, environmental engineering, air conditioning / refrigeration, electrical engineering, mechanical engineering, pharmaceutical technology, vacuum drying, chemical research laboratory, freeze-drying, vacuum packaging, high vacuum system’s pre-stage pump.
Vacuum precooling is a good way to keep fruits and vegetables fresh. It is the most advanced precooling technology for fruits and vegetables. In Europe, America, Japan and other developed countries, vacuum precooling technology has been widely used in the preservation of fruits and vegetables. In fact, vacuum cooling has attracted great attention. Its application extends to the processing of flowers, mushrooms, fish, meat, ham and other products. In this paper, the research results and results of the application of the two-stage rotary vane vacuum pump in fruit and vegetable preservation are reviewed comprehensively, which is conducive to further promoting the application of vacuum precooling technology in this field.
Two stage rotary vane vacuum pump in vacuum precooling