Introduction:
Deoxidizer, also known as deoxidizer and oxygen absorber, is an additive that can absorb oxygen and slow down food oxidation. It is a new product used for food preservation at present. It is a group of chemical mixtures that easily react with free oxygen or dissolved oxygen. Packed in a sealed paper bag with certain air permeability and strength, and sealed with food in a food bag similar to a desiccant bag, it can remove the residual oxygen in the air in the bag, prevent the food from discoloration, deterioration and rancidity due to oxidation, and inhibit the growth of mold, aerobic bacteria and food pests. At present, deoxidizers are not only used to maintain food quality, but also used to keep food, feed, medicine, clothing, fur, precision instruments and other items fresh and rust-proof.
Application:
As a new food preservation material, deoxidizer has its unique advantages. It is packed in the same container as food, and the deoxidizer absorbs the oxygen in the container, so that the container is in an anaerobic state and the food can be preserved. However, the raw materials of the deoxidizer must have stable reaction, no peculiar smell and no harmful gas, which is harmless to human body in case of accidental eating. Iron powder is generally used as the basic raw material. When used in general food, deoxidizer can maintain food quality and prolong shelf life. When used in healthy food, deoxidizer can prevent oil from oxidation, prevent discoloration and maintain nutrients. In foreign countries, deoxidizers have been widely used in wet bread flour, wet noodles, wet vermicelli, wet snacks, semi-dried fish products and other foods. At present, deoxidizers are not only bagged, but also capped. Bags are used to hold bagged food, while bottle caps are used to bottle containers such as cans. In recent years, with the development of food industry and the improvement of packaging materials, deoxidizers have been paid more and more attention and used more and more widely in China.
Principle:
Oxygen is one of the important factors leading to food deterioration. Many ingredients in food are closely related to the existence of oxygen. From the biochemical point of view, fat will be oxidized and degraded when exposed to oxygen, vitamins and various amino acids will lose their nutritional value, and oxygen will also discolor or fade unstable pigments; From the microbial point of view, most microorganisms will grow well in aerobic environment. Even if the oxygen content in the packaging environment is as low as 2 ~ 3%, most aerobic bacteria and facultative anaerobic bacteria can still grow and biochemical reactions will still proceed. Therefore, it is of great practical significance to remove oxygen from packaging. Through chemical reaction, the oxygen in the closed container is removed in a short time, so that the food is in an anaerobic state (O2 concentration is below 0.0 1%), the growth of microorganisms such as bacteria and molds is effectively controlled, and the oxidation of oil is prevented, thus effectively maintaining the color, fragrance and taste of the food, preventing the nutritional components such as vitamins from being destroyed by oxidation, and prolonging the shelf life of the food. ?
The deoxidizer can be divided into two types according to its composition: (1) is an inorganic matrix deoxidizer, such as reduced iron powder. Its principle is that iron powder is oxidized into iron hydroxide in the presence of oxygen and steam. Another example is sulfite deoxidizer, which takes dithionite as the main agent, Ca(OH)2 and activated carbon as the auxiliary agents, and reacts in an environment with water. (2) Based on organic substrates, such as enzymes, ascorbic acid, oleic acid, etc. Ascorbic acid (AA) itself is a reducing agent. In the presence of oxygen, copper ions can be used as catalysts to oxidize or dehydrogenate ascorbic acid (DHAA), thus removing oxygen from the environment. This method is often used to remove oxygen from liquid food. Ascorbic acid deoxidizer is one of the deoxidizers with high safety in use at present. Enzymatic deoxidizer usually uses glucose to oxidize alcohol, and uses the oxygen consumed when glucose is oxidized into gluconic acid to achieve the purpose of deoxidization.
The common reaction principles of deoxidizers are iron powder oxidation (iron system), enzyme oxidation (enzyme system), ascorbic acid oxidation, photosensitive dye oxidation and so on. Most deoxidizers used at present are based on iron powder oxidation reaction. This iron-based deoxidizer can be made into bags and put into packaging to reduce the oxygen concentration to 0.0 1%. It is generally required that 1g iron powder can react with 300mL oxygen, and the appropriate dosage can be selected according to the amount of oxygen remaining after packaging and the oxygen permeability of packaging film. Applied products include candy, dried seafood snacks, cooked meat products, rice cakes, pasta, cheese and dried vegetables. In addition to the bagged deoxidizer, plastic labels or various cards containing activated iron powder are inserted into the package. ?
Iron-based deoxidizers and enzyme-based deoxidizers are also widely used. Enzymatic deoxidizer is sensitive to the changes of pH, Aw, salt content, temperature and other factors, and water is needed in the reaction. Therefore, the application effect in foods with low moisture content is not good. But in bottled beer or liquor, this deoxidizer can be directly made into small bags and put into bottle caps. In addition, the enzyme system can also be immobilized on polypropylene or polyethylene film. Another deoxidizer is a photosensitive dye deoxidizer. This deoxidation technology is to seal a thin ethyl cellulose film (in which photosensitive dyes and singlet oxygen receptors are dissolved) on the top of a transparent packaging bag. When the packaging film is exposed to light with appropriate wavelength, the excited dye molecules will sensitize the oxygen molecules infiltrated into the packaging film in the environment to singlet oxygen, and the singlet oxygen will react with the acceptor molecules and be consumed. Australia's 02TM is designed for a series of plastic packaging materials. The active components in this material are activated by ultraviolet rays or high energy, so it is suitable for processing into films, sheets and coatings. The test of 02TM contained in the flexible layer shows that it can inhibit mold and even prevent ham from fading under visible light without carbon dioxide.