Application of the hottest industrial gas in food

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Application of industrial gas in food storage

liquid nitrogen super freezing food: use liquid nitrogen cryogenic quick freezing technology to freeze and store aquatic products, which can meet the national first-class freshness standard, and store and transport them at -32 ℃ after rapid freezing. It can keep the dry consumption less than 1% for more than 6 months, and the quality is still as fresh as before. For example, the consumption of liquid nitrogen for quick-frozen shrimp treatment is about 2.0kg liquid nitrogen/1kg shrimp. The annual output of liquid nitrogen in Japan reaches 40000-50000 tons, most of which are used for quick-frozen food, and 1/3 of the liquid nitrogen in Western European countries is used for quick-frozen food

modified atmosphere packaging of dry food:

for naturally dried or artificially dried peanut, tea, milk powder, potato chips, laver and other foods, the oxygen content is controlled at 500 by vacuum nitrogen filling [99.9%~99.99% (v/v)] × (v/v) below, to prevent food oxidation and discoloration, deterioration and taste change

modified atmosphere packaging of cooked food products:

this kind of packaging mainly inhibits oxidation, prevents the growth and reproduction of bacteria, microorganisms and molds, and prevents food mildew. When the modified atmosphere packaging is filled with food grade carbon dioxide, the gas ratio is usually 40% - 60%

modified atmosphere packaging of fish, fruits and vegetables:

this kind of food should not only prevent decay and deterioration, but also maintain freshness. Microorganisms and bacteria are easy to grow in this kind of food, and anaerobic and aerobic microorganisms exist at the same time. Therefore, it is necessary to mix a certain proportion of components in the mixture, such as modified atmosphere packaging of fresh meat. Carbon dioxide is used to inhibit the growth and reproduction of microbial bacteria, and oxygen is used to maintain the color of fresh meat and inhibit the growth of anaerobic microorganisms. The prepared mixture accounts for 20% - 35 (v/v) carbon dioxide and 40% - 70 (v/v) oxygen. Seafood and aquatic products contain a large number of anaerobic microorganisms, so the gas mixing ratio in modified atmosphere packaging is that oxygen accounts for 60% - 80% (v/v) and carbon dioxide accounts for 20% (v/v). The modified atmosphere preservation of fruits and vegetables is the most complex, because the freshly harvested fruits and vegetables still maintain the internal life mechanism and are still in the breathing stage, so the stronger the respiration, the shorter the storage time, and the most likely to rot and deteriorate. Therefore, it is necessary to control the preparation of a certain proportion of mixed gas and appropriate storage temperature to control the respiratory intensity of fruits and vegetables, such as citrus modified atmosphere packaging, which controls the proportion of mixed gas to be 12.5% - 17.5% (v/v) of oxygen, and pc/abs Abs/pvc, pa/abs, pbt/abs and other carbon oxides account for 1.35% to 3.65% (v/v) of pressure applied to metal forgings, which can inhibit their respiratory intensity. Practice has proved that the rotten fruit rate can be reduced from 7.63% to 2.32%

modified atmosphere packaging of eggs:

carbon dioxide is very effective for the preservation of poultry eggs. Because it is a long-standing poultry egg, the carbon dioxide in its interior is gradually released through the pores on the eggshell. It should start from the source of excess capacity, resulting in the increase of pH value in the egg and the condensation of protein into water like protein. When 30% - 70% (v/v) carbon dioxide is packaged in modified atmosphere for 6-10h, carbon dioxide penetrates into the egg through the pores on the eggshell, which can delay the formation of water like protein and achieve the purpose of fresh preservation

filling beer with nitrogen:

during the storage of beer, neutral nitrogen can better maintain the physical and chemical indexes of beer than acidic carbon dioxide; Using liquid nitrogen can reduce the production cost by 30% than using carbon dioxide

in 2002, Kunming Huashi brewery has fully tried out liquid nitrogen from Kunming Messer. According to the staff of Huashi brewery, the liquid nitrogen gas supply system is safe and stable, and it is easy to operate. The beer foam filled with nitrogen is richer, whiter, and more delicate. The cup hanging rate increases, and the rate of foam disappearance slows down, which increases the market competitiveness of Huashi brewery products

thanks to a new technology of Praxair, brewers around the world are expected to produce a beer with better taste in the near future. This technology, called nitrogen distillation, can make the beer taste more refreshing, the color clearer and the storage time longer. Praxair has installed a device using this technology in the American polwa brewery company, which produces 50000 barrels of beer per year

the water used in beer brewing contains oxygen, which often adversely affects the taste, color and stability of beer. This technology injects nitrogen bubbles into the water, thereby reducing the oxygen content in the water. Bubbles will produce concentration gradients, forcing dissolved oxygen to diffuse

at present, most brewers use vacuum process to remove oxygen. Praxair's nitrogen distillation equipment is easy to install and monitor; This is a continuous system without shutdown

filling canned fruit drinks with liquid nitrogen:

reason for filling liquid nitrogen: the original canned fruit drinks need to be heated when sealing. Therefore, when the cans are cooled, the negative pressure will be caused by the volume contraction of the materials in the cans, resulting in the concave of the cans. Therefore, the thickness of the walls of the cans will be reduced and materials will be saved. In addition, filling liquid nitrogen into canned fruit drinks can eliminate part of the air, which is conducive to the storage of beverages. According to the test, each can of beverage only needs about 0.7 g of liquid nitrogen. Among them, only 0.1g of liquid nitrogen is actually sealed into the tank, and the rest is vaporized during the filling process

it is estimated that due to the thinner wall thickness of the empty tank, the price can be reduced much. Even if the cost of filling liquid nitrogen is increased, the packaging cost is still only about 90% of the previous one, and the shelf life can be extended

fresh keeping of machine meal B:

dry ice, solid carbon dioxide, is shaped like ice and snow. It is directly vaporized without melting when heated, so it is called dry ice. When evaporating under normal pressure, a low temperature of about -80 ℃ can be obtained, and when evaporating under reduced pressure, the temperature is lower. Dry ice is mainly used to preserve food in the food industry. Because it can obtain a low temperature of -80 ℃, it can also be used as a general refrigerant. When dry ice (carbon dioxide) dissolves in water, part of it forms carbonic acid, so it is also called "carbonic anhydride" or "carbonic acid gas"

Hong Kong Oxygen Company can be described as a comprehensive development and diversified operation. It has established a dry ice factory to serve air catering companies, and quickly transport dry ice for the preservation of "aircraft meals"

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