Introduction to Hypobaric Storage and Freshness Preservation Technology

Hypobaric storage and preservation technology is a combination of preservation technology parameters closely related to hypobaric storage equipment, similar to the relationship between computers and software. Hypobaric refrigeration, commonly known as hypobaric storage, is an American scientist named Dr Stanley P. Burg invented it in the 1960s as a pollution-free, non freezing physical preservation technology. In 2013, our company proposed the concept of decompression treatment (short-term decompression refrigeration treatment or decompression refrigeration treatment, abbreviated as decompression treatment), which refers to short-term processing storage. There are substantial differences between them and vacuum pre cooling, controlled atmosphere refrigeration (CA), modified atmosphere packaging (MAP), and vacuum packaging: basic principles, preservation mechanisms, equipment composition and structure, and preservation technical parameters set and controlled are all different.

Scope of application: Fresh horticultural products (vegetables, fruits, edible mushrooms, fresh cut flowers, Chinese medicinal materials) are not frozen and kept fresh; Non freezing preservation (preservation) of livestock and poultry products, aquatic products, pre made vegetables, cooked foods, and grains; Antibacterial and insecticidal properties of items.

Equipment Usage: Decompression treatment (different from pre cooling and better than pre cooling), storage, transportation, stores, kitchens, and construction of a vacuum cold fresh chain for fresh horticultural products.

One of the basic modes of vacuum cold chain is "decompression treatment+cold chain", which has better preservation effect and economy than cold chain. Its unique highlight can effectively extend the shelf life of cold chain breakage ("de cooling") and delay the degree of original quality degradation. The main advantages compared to cold chain can be summarized as "5 extensions+low dry consumption+pest control":

1) Extend the refrigeration and preservation period by 2-10 times. For example, bananas have a shelf life of only 14-21 days during cold storage, while under reduced pressure refrigeration can reach 150 days and ripen naturally; Fresh Tricholoma matsutake can be refrigerated for 7-10 days, and can be refrigerated under reduced pressure for more than 45 days; Fresh lamb can be refrigerated for 5-7 days, and can be refrigerated under reduced pressure for over 55 days.

2) Extend the shelf life of 'de cooling' by a few hours to a few days. For example, white mushrooms are refrigerated under reduced pressure for 505 hours, and have a shelf life of 41 hours at room temperature of 22-32 ℃ ("de cooling") without opening the mushroom canopy;

3) Delaying the decay of original appearance, flavor, odor, nutrients, and other qualities. For example, green asparagus did not undergo fibrosis after 50 days of reduced pressure refrigeration; The Vc content of fresh cut vegetables processed from broccoli after decompression treatment, followed by modified atmosphere packaging and refrigerated for 49 days, is 13.47 times higher than that of the refrigerated control;

4) Delaying the onset of pathogenic bacteria. Effectively inhibit the growth of fungi, molds, yeast, and bacteria, including 25 fungi that cause plant product spoilage, 20 molds that cause meat, poultry, and fish spoilage, 20 bacteria, and yeast. For example, the bean paste buns, meat buns, and vegetable buns purchased from the vegetable market are refrigerated under reduced pressure for 70 days without mold, odor, and elasticity;

5) Delay the degree of browning on the cut surface. For example, fresh cut vegetables made from broccoli processed under reduced pressure remain green, free from mold and browning after 80 days of refrigeration. Fresh cut vegetables processed from green vegetables after decompression treatment, which are "de chilled" for 24 hours after 7 days of refrigeration without mold or browning on the cut surface;

6) Kill adults, larvae, pupae, and eggs inside and outside the item. For example, it can kill peach aphids, fruit flies, etc;

7) Low weight loss rate of items means low dry consumption. For example, pork and beef are refrigerated under reduced pressure for 26 days without weight loss; The weight loss rate of vegetables stored under reduced pressure for 41 days is less than 2%; The weight loss rate of meat buns after 70 days of decompression and refrigeration is only 0.61%; The weight loss rate of peaches stored under reduced pressure for 20 days and at room temperature for 5 days is only 60.3% of that of the cold storage control.

The "first kilometer" of the cold chain is in the initial processing stage of the origin, and the "last kilometer" is in the handover stage from sales to consumers. Cold chain actually cannot ensure the entire process of "suitable low temperature", "continuous chain", and "seamless docking". Cold chain breakage or "de cooling" preservation is often referred to as the shelf life at room temperature, which is a difficult or painful issue in the circulation of fresh agricultural products. Moreover, the word "cold" often does not solve the problem. Timely decompression treatment of fresh horticultural products in the production area can achieve the aforementioned "5 extensions" of preservation effect, which can extend the impact to the "last mile" of the cold chain.

The equipment investment and operating costs of the vacuum cold fresh chain are lower than those of the cold chain, and the energy and dry consumption are lower than those of the cold chain. For example, the requirement for suitable low temperature can be reduced, and the "cold chain must be suitable for low-temperature seamless docking" can be temporarily "de cooled" without being trapped. Insecticidal equipment or facilities can be omitted, fruit ripening process can be omitted, pre cooling equipment can be appropriately discarded, packaging requirements can be reduced, refrigerated transportation can be changed to insulation or even temperature free transportation, insulation boxes can be discarded, and the effective loading capacity per unit volume of storage and transportation equipment can be increased, which can reduce land occupation, equipment Operations and maintenance personnel, etc.

Preservation mechanism. Place fresh agricultural products in closed containers. Continuously and continuously extract the air from the container while delivering low pressure and moist fresh air from the outside. When the pressure drops below 1.3kPa, the respiratory rate and ethylene production rate decrease to 10%; The less respiratory heat generated, the less water that can be evaporated, and the high humidity and greatly weakened convection can effectively reduce water loss rate; The extremely low O2 and CO2 concentrations accompanied by low pressure prevent the growth of fungi, bacteria, molds, and yeast, killing both internal and external adults, larvae, pupae, and eggs; Continuous ventilation will timely discharge volatile harmful gases such as CO2, C2H4, N2, and acetaldehyde generated by metabolism into the container; The extremely low CO2 concentration accompanied by low pressure promotes the opening of pores in the dark, which is conducive to gas diffusion and transport. Even if the O2 concentration is below 0.1%, hypoxia damage will not occur. Low pressure, high humidity, ventilation, and low temperature also create beneficial heat and mass transfer effects, providing a good living environment for fresh agricultural products, effectively inhibiting the activity increase or decrease of several enzymes that cause maturation and aging, such as PAL, PPO, POD, SOD, CAT, etc., protecting cell integrity from damage, thereby greatly extending the shelf life.