Food deoxidizer is also called free oxygen absorbent, free oxygen remover, etc. It is a material that can absorb oxygen. When the food is sealed and packaged, the oxidizing substances in the package are removed at the same time to remove the free oxygen and dissolved oxygen in the packaging container, so as to prevent the food from mildew and deterioration due to oxidation. Deoxidizer used in food can not only effectively inhibit the deterioration of content quality, but also maintain the original color, aroma and taste of food, prevent and control the growth of pests and bacteria, and maintain nutritional components. Therefore, the use of deoxidizer is a high-quality, effective, convenient and safe packaging and preservation method for food preservation.
   food deoxidizer, as a new type of food preservation material, can absorb the oxygen in the container, make the container in an anaerobic state, and the food can be preserved. However, the raw materials of deoxidizer must have the characteristics of stable reaction, no odor, no harmful gas generation, etc., so as to prevent accidental consumption and no harm to human body. Deoxidizers generally take reduced iron powder as the basic raw material. When used in general food, they can maintain the food quality and prolong the storage period. When used in healthy food, they can prevent oil oxidation, prevent fading and maintain nutritional components. Deoxidizers have been widely used in wet bread flour, wet noodles, wet vermicelli, Wet snacks, semi dried fish products and other foods abroad. At present, deoxidizers are packaged in bags as well as caps. Bags are used to hold food, while caps are used to hold containers such as bottles and cans. In recent years, with the development of food industry and the improvement of packaging materials, Deoxidizer has been paid more and more attention in China, and its application has become more and more extensive.
   there are many classification methods for food deoxidizers, which can be divided into: (1) inorganic deoxidizers. The most commonly used are iron series and sulfite deoxidizers. Fe (OH) 3 is formed after iron oxidation. The deoxidizing capacity of 1G iron is 300ml, which is equivalent to 1500ml air. Good deaeration effect and economy. The iron here is mainly reduced iron powder, sand powder iron and coarse iron. (2) Organic deoxidizer. For example, ascorbic acid has good deoxidizing ability; Under certain conditions, glucose group will produce many decomposition products and deoxygenation. It can also be classified by reaction type: (1) high moisture food type. The deoxidizer and the food are closed at the same time to absorb the moisture in the oxygen and make the moisture in the food evaporate the deoxidizer. (3) Automatic absorption type. It can also be divided into quick acting type, general type and slow-release type. Self absorbed oxygen absorbers retain their own moisture and react even when no water is present. By changing the composition and dosage of oxygen getter and the permeability of packaging materials, the reaction rate can be controlled from fast effect type to slow effect type.
   the following describes several common food deoxidizer formulas:
   (1) mix 4G reduced iron powder +2g water +2g activated carbon +1g NaCl.
   (2) reduced iron powder 400g+nacl 30g+cao 300g+ water 3000ml.
   (3) 4000g reduced iron powder +30g nacl+150g silica gel.
   (4) reduced iron powder 15g+3g nacl+4g diatomite +2g activated carbon + water.
   (5) active clay 3g+0.3g baked gypsum +3g reduced iron powder impregnated with 30%mgcl2 aqueous solution.
   deoxidation of food deoxidizer is based on chemical reaction. Taking (1) as an example, activated carbon, sodium chloride and water are added to form a primary cell, which uses the principle of primary cell to accelerate the reduction of iron powder oxygen. The deoxidizing ability of different formulations varies with reaction order, time, temperature and other conditions. The quick acting deoxidizer, when properly placed in the sealed packaging container, can reduce the free oxygen to less than 1% and finally to 0.2% within about 1 hour. The slow effect deoxidizer takes 12-24 hours, but the final deoxidation capacity is the same, and the free oxygen can be reduced to less than 0.2%. Deoxidizer can also release a large amount of heat in oxygen reaction, so it can also be used as hot compress in medical treatment