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The theory of oxygen absorber

Oxygen is one of the important factors causing food spoilage.Many components in foods are closely related to the presence of oxygen.From the biochemical point of view, fat oxygen oxidation will be defeated, vitamins and a variety of amino acids will lose nutritional value, oxygen will make unstable pigment discoloration or fade;From the perspective of microorganisms, most microorganisms will grow well in the aerobic environment. Even if the oxygen content is as low as 2 ~ 3% in the packaging environment, most aerobic bacteria and facultative anaerobic bacteria can still grow and biochemical reactions will still take place.Therefore, the removal of oxygen in packaging has very important practical significance.Through chemical reaction, in a short period of time to remove oxygen in an airtight container, make food in anaerobic condition (O2 concentration below 0.01%), effectively control the growth of bacteria, mold and other microbes, prevent oil oxidation, thus can effectively keep food color, aroma, taste, prevent vitamins and other nutrients were oxidative damage, prolong shelf life.

According to its composition, deoxidizer can be divided into two types :(1) deoxidizer with inorganic matrix as the main body, such as reduced iron powder.The principle is that iron powder is oxidized to iron hydroxide in the presence of oxygen and water vapor.Another example is sulfite deoxidizer, which is mainly composed of disulfite, Ca(OH)2 and activated carbon as secondary agents, and reacts in the presence of water.(2) organic matrix as the main body, such as enzymes, ascorbic acid, oleic acid, etc.Ascorbic acid (AA) is itself a reducing agent, in the case of aerobic, made catalyst copper ions can be oxidized or dehydrogenation ascorbic acid (DHAA), so as to remove the oxygen environment, often use this method to remove the oxygen liquid food, ascorbic acid deoxidizing agent is currently in use safe a deoxidizer, enzymes deoxidizer, commonly used is glucose oxidation of alcohol, is the use of glucose oxidation into glucose acid oxygen consumption to achieve the goal of DNA.

Common reaction principles of deoxidizer include iron powder oxidation (iron series), enzyme oxidation (enzyme series), ascorbic acid oxidation, photosensitive dye oxidation, etc.Most deoxidizers used today are based on iron powder oxidation reactions.The iron deoxidizer can be made into a bag and put into a package to reduce the oxygen concentration to 0.01%.Generally, 1g iron powder is required to react with 300mL of oxygen, and the appropriate dosage can be selected according to the residual amount of oxygen after packaging and the oxygen permeability of packaging film.Products used include candies, dried seafood snacks, cooked meat products, rice cakes, pasta, cheese and dried vegetables.In addition to the bag deoxidizer, the plastic label or various CARDS containing active iron powder are inserted into the package.

In addition to iron - based deoxidizer, enzyme - based deoxidizer is also widely used.Enzymatic deoxidizer is sensitive to changes in pH, Aw, salt content, temperature and other factors, and requires water to participate in the reaction. Therefore, it is not good to apply in foods with low moisture content.But in bottled beer or liquor, the deoxidizer can be made directly into small bags and placed inside the bottle cap.In addition, the enzyme system can be fixed on polypropylene or polyethylene film.There is a deoxidizer deoxidizer, photosensitive dye this DNA technology is on the top of the transparent bags inside sealed a small ethyl cellulose membrane sheet (internal dissolved with photosensitive dye and singlet oxygen receptors), when the packaging film by appropriate wavelength of light, stimulate the dye molecules would environment into packaging film sensitization to oxygen molecules into singlet oxygen, the singlet oxygen reaction with receptor molecules and be burned off.Australian 02TM is designed for a range of plastic packaging materials, in which reactive components are activated by uv or high energy and are therefore suitable for processing into films, laminates and coatings.Tests on 02TM contained in the flexible layer showed that mold could be inhibited in the absence of carbon dioxide and even prevented ham from fading in visible light.

The deoxidizing agent used in steelmaking mainly includes si-al, ba-ca, fe, si-ca core wire, aluminum wire, aluminum-manganese iron, steel core aluminum, calcium carbide and silicon carbide, etc. Its main function is to react with dissolved oxygen in molten iron, mainly to form non-metallic compounds, and to form precipitation floating to slag layer, which can be removed to obtain pure molten iron.

Deoxidizer can be used alone or in combination with air conditioning package.In practice, most of the oxygen is removed by air conditioning package, and a small amount of deoxidizer is used to remove the residual oxygen in the package.

The main deoxidation methods are precipitation deoxidation, diffusion deoxidation and vacuum deoxidation.In addition, modern steelmaking can also use vacuum equipment to deoxidize, such as VD furnace, VOD furnace and so on.
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