Commonly used deoxidizers employ reaction principles such as iron powder oxidation (iron-based), enzyme oxidation (enzyme-based), ascorbic acid oxidation, and photosensitive dye oxidation. Most deoxidizers used are based on iron powder oxidation. These iron-based deoxidizers can be packaged in bags to reduce the oxygen concentration to 0.01%. Generally, 1g of iron powder should react with 300mL of oxygen. The appropriate dosage should be selected based on the amount of residual oxygen after packaging and the oxygen permeability of the packaging film. Applications include candies, dried seafood snacks, cooked meat products, rice cakes, pasta, cheese, and dried vegetables. In addition to bagged deoxidizers, plastic labels or various cards containing active iron powder are also inserted into the packaging.
Besides iron-based deoxidizers, enzyme-based deoxidizers are also widely used. Enzyme-based deoxidizers are sensitive to changes in pH, Aw, salt content, temperature, and other factors, and require water during the reaction. Therefore, they are not very effective in foods with low moisture content. However, in bottled beer or spirits, this deoxidizer can be directly made into small packets and placed inside the bottle cap. Alternatively, enzyme systems can be immobilized on polypropylene or polyethylene films. Another type of deoxidizer is the photosensitive dye deoxidizer. This deoxidation technology involves sealing a small sheet of ethyl cellulose film (containing a photosensitive dye and a singlet oxygen acceptor dissolved inside) at the top inside a transparent packaging bag. When the packaging film is exposed to light of a suitable wavelength, the excited dye molecules sensitize oxygen molecules that have permeated into the packaging film into singlet oxygen. These singlet oxygen molecules then react with the acceptor molecules and are consumed. O2TM from Australia is designed for a range of plastic packaging materials. The reactive components in this material only become active after activation by ultraviolet light or high energy, making it suitable for processing into films, sheets, and coatings. Tests on O2TM contained in flexible layers show that mold can be inhibited in the absence of carbon dioxide, and it can even prevent ham from fading under visible light.
