Liquid nitrogen: Nitrogen gas in the liquid state. Inert, colorless, odorless, non-corrosive, non-flammable, extremely cryogenic temperature. Nitrogen forms the majority of the atmosphere (78.03% by volume and 75.5% by weight). Nitrogen is inactive and does not support combustion. Frostbite caused by excessive endothermic contact during vaporization.
Liquid nitrogen is a convenient cold source. Due to its unique properties, liquid nitrogen has been gradually paid more and more attention and recognized by people. It has been more and more widely used in animal husbandry, medical industry, food industry, and cryogenic research fields. In electronics, metallurgy, aerospace, machinery manufacturing and other aspects of the application has been expanding and developing.
Application of liquid nitrogen in food quick-freezing
Liquid nitrogen frozen as one of frozen collection methods have been received by the food processing enterprise, because it can realize low-temperature cryogenic super quick frozen, but also to realize part of the glass transition of frozen food, to make the food thawing can to return to its original state of strange and the original nutrition status, extremely fierce progress the character of frozen food, Therefore, it shows unique vitality in the quick-freezing industry. Compared with other freezing methods, liquid nitrogen rapid freezing has the following obvious advantages:
(1) Fast freezing rate (freezing rate is about 30-40 times faster than the usual freezing method) : the acceptance of liquid nitrogen rapid freezing, can make the food quickly through 0℃ ~ 5℃ large ice crystal growth zone, food research staff has done useful experiments in this respect.
(2) Linking food character: due to the short freezing time of liquid nitrogen, the food frozen by liquid nitrogen can be linked to the color, aroma, taste and nutritional cost before processing to the maximum extent. The results showed that areca catechu treated with liquid nitrogen had higher chlorophyll content and good charm.
(3) small dry consumption of materials: usually frozen dry consumption loss rate is 3 ~ 6%, and liquid nitrogen freezing can be eliminated to 0.25 ~ 0.5%.
(4) Set the equipment deployment and power consumption is low, easy to realize the machine and active assembly line, improve productivity.
At present, there are three methods of rapid freezing of liquid nitrogen, namely spray freezing, dip freezing and cold atmosphere freezing, among which spray freezing is widely used.
Application of liquid nitrogen in beverage processing
Now, many beverage manufacturers have accepted nitrogen or nitrogen and C02 mix-up instead of the traditional C02, to hold inflatable packaging drinks. High-carbonated drinks filled with nitrogen caused fewer problems than those filled with carbon dioxide alone. Nitrogen is also desirable for canned still beverages such as wine and fruit juices. The benefit of filling non-inflatable beverage cans with liquid nitrogen is that the small amount of liquid nitrogen injected removes oxygen from the top space of each can and renders the gas inert in the upper space of the storage tank, thus extending the storage life of perishables.
Application of liquid nitrogen in storage and preservation of fruits and vegetables
Liquid nitrogen storage for fruits and vegetables has the advantage of regulating air, can adjust the agricultural by-products in peak season and off-season supply and demand contradiction, eliminate the loss of storage. The effect of air conditioning is to improve the concentration of nitrogen, control the proportion of nitrogen, oxygen and C02 gas, and make it linked in a stable state, low fruit and vegetable breathing intensity, delay the course of post-ripening, so that fruits and vegetables linked to the strange state of picking and original nutrition costs, extend the freshness of fruits and vegetables.
Application of liquid nitrogen in meat processing
Liquid nitrogen can be used to improve the quantity of products in the process of skewering, chopping or mixing of meat. For example, in the processing of salami-type sausage, the use of liquid nitrogen can improve the water retention of meat, prevent fat oxidation, improve slicing and surface quality. Used in the processing of reprocessed meat such as meat desserts and preserved meat, it can not only accelerate the dissolution of egg white and strengthen water retention when meat is confused, but also is particularly useful for bonding the unique shape of the product. Other material meat by liquid nitrogen rapid cooling, not only in a more permanent connection between hot meat characteristics, gas and ensure the meat health and tranquility. In the processing technology, there is no need to worry about the impact of temperature rise on meat quality, and the processing is not affected by material temperature, processing time, seasonal factors, but also can make the processing process at low oxygen partial pressure, in a certain range to extend the shelf life of products.
Application of liquid nitrogen in food comminution at cryogenic temperature
Cryogenic temperature crushing is the process of breaking into powder under the action of external force, which is cooled to the temperature of embrittlement point. Cryogenic temperature crushing of food is a new food processing skill that has grown in recent years. This skill is suitable for processing food with many aromatic elements, high fat content, high sugar content and many gelatinous substances. Cryogenic temperature crushing with liquid nitrogen disposal punishment, can even the material of bone, skin, meat, shell and other one-time all crushing, so that the finished material is small and connected with its useful nutrition. If Japan will be frozen by liquid nitrogen seaweed, chitin, vegetables, spices, etc. into the grinder grinding, can make the finished product fine particle size as high as 100μm below, and the fundamental link to the original nutrition cost. In addition, cryogenic temperature crushing with liquid nitrogen can also crush materials that are difficult to crush at room temperature, materials that are heat sensitive and easy to deteriorate when heated and easy to analyze. In addition, liquid nitrogen can be used to crush fatty meat, moist vegetables and other foods that are difficult to be crushed at room temperature, and can be used to make new processed foods.
Application of liquid nitrogen in food packaging
A London company has developed a simple and practical way to keep food fresh by adding a few drops of liquid nitrogen to the packaging. When liquid nitrogen evaporates into gas, its volume rapidly expands, quickly replacing most of the original gas in the packaging bag, eliminating food spoilage caused by oxidation, thus greatly extending the freshness of food.
Application of liquid nitrogen in refrigerated transportation of food
Refrigerated transportation is an important part of the food industry. Developing liquid nitrogen refrigeration skills, growing liquid nitrogen refrigerated trains, refrigerated cars and refrigerated containers is the common growth trend at present. The application of liquid nitrogen refrigeration system in developed countries for many years shows that liquid nitrogen refrigeration system is a refrigerated preservation skill which can compete with machine refrigeration system in trade and is also the growth tendency of food refrigerated transportation.
Other applications of liquid nitrogen in food industry
Thanks to the refrigeration action of liquid nitrogen, egg juice, liquid condiments, and soy sauce can be roughly processed into freemoving and poured granular frozen foods that are readily available and easily prepared. When grinding spices and water-absorbing food additives, such as sugar substitutes and lecithin, liquid nitrogen is injected into the grinder to cover the cost and increase the grinding yield. The results show that the pollen wall breaking by liquid nitrogen quenching combined with high temperature thawing has the characteristics of good fruit, high wall breaking rate, fast rate, stable physiological activity of pollen and free from pollution.
HL Cryogenic Equipment
HL Cryogenic Equipment which was founded in 1992 is a brand affiliated to HL Cryogenic Equipment Company Cryogenic Equipment Co.,Ltd. HL Cryogenic Equipment is committed to the design and manufacture of the High Vacuum Insulated Cryogenic Piping System and related Support Equipment to meet the various needs of customers. The Vacuum Insulated Pipe and Flexible Hose are constructed in a high vacuum and multi-layer multi-screen special insulated materials, and passes through a series of extremely strict technical treatments and high vacuum treatment, which is used for transferring of liquid oxygen, liquid nitrogen, liquid argon, liquid hydrogen, liquid helium, liquefied ethylene gas LEG and liquefied nature gas LNG.
The product series of Vacuum Jacketed Pipe, Vacuum Jacketed Hose, Vacuum Jacketed Valve, and Phase Separator in HL Cryogenic Equipment Company, which passed through a series of extremely strict technical treatments, are used for transferring of liquid oxygen, liquid nitrogen, liquid argon, liquid hydrogen, liquid helium, LEG and LNG, and these products are serviced for cryogenic equipment (e.g. cryogenic tanks, dewars and coldboxes etc.) in industries of air separation, gases, aviation, electronics, superconductor, chips, automation assembly, food & beverage, pharmacy, hospital, biobank, rubber, new material manufacturing chemical engineering, iron & steel, and scientific research etc.
Post time: Nov-16-2021
