Oxygen scavenger

Oxygen scavengers or oxygen absorbers are added to enclosed packaging to help remove or decrease the level of oxygen in the package. They are used to help maintain product safety and extend shelf life. There are many types of oxygen absorbers available to cover a wide array of applications. The components of an oxygen absorber vary according to intended use, the water activity of the product being preserved, and other factors. Often the oxygen absorber or scavenger is enclosed in a porous sachet or packet but it can also be part of packaging films and structures. Others are part of a polymer structure. The first patent for an oxygen scavenger used an alkaline solution of pyrogallic acid in an air-tight vessel. Modern scavenger sachets use a mixture of iron powder and sodium chloride. Often activated carbon is also included as it adsorbs some other gases and many organic molecules, further preserving products and removing odors. When an oxygen absorber is removed from its protective packaging, the moisture in the surrounding atmosphere begins to permeate into the iron particles inside of the absorber sachet. Moisture activates the iron, and it oxidizes to form iron oxide. Typically, there is required to be at least 65% relative humidity in the surrounding atmosphere before the rusting process can begin. To assist in the process of oxidation, sodium chloride is added to the mixture, acting as a catalyst or activator, causing the iron powder to be able to oxidize even with relatively low humidity. As oxygen is consumed to form iron oxide the level of oxygen in the surrounding atmosphere is reduced. Absorber technology of this type may reduce the oxygen level in the surrounding atmosphere to below 0.01%. Complete oxidation of 1 g of iron can remove 300 cm3 of oxygen in standard conditions. Though other technologies can remove more, iron is the most useful as it does not cause odor like sulfur compounds or passivate like aluminium compounds. Many other alternatives are not food safe.

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Modified atmosphere

Modified atmosphere packaging (MAP) is the practice of modifying the composition of the internal atmosphere of a package (commonly food packages, drugs, etc.) in order to improve the shelf life. The need for this technology for food arises from the short shelf life of food products such as meat, fish, poultry, and dairy in the presence of oxygen. In food, oxygen is readily available for lipid oxidation reactions. Oxygen also helps maintain high respiration rates of fresh produce, which contribute to shortened shelf life.

Food preservation

Food preservation includes processes that make food more resistant to microorganism growth and slow the oxidation of fats. This slows down the decomposition and rancidification process. Food preservation may also include processes that inhibit visual deterioration, such as the enzymatic browning reaction in apples after they are cut during food preparation. By preserving food, food waste can be reduced, which is an important way to decrease production costs and increase the efficiency of food systems, improve food security and nutrition and contribute towards environmental sustainability.

Packaging and labeling

Packaging is the science, art and technology of enclosing or protecting products for distribution, storage, sale, and use. Packaging also refers to the process of designing, evaluating, and producing packages. Packaging can be described as a coordinated system of preparing goods for transport, warehousing, logistics, sale, and end use. Packaging contains, protects, preserves, transports, informs, and sells. In many countries it is fully integrated into government, business, institutional, industrial, and personal use.

Multilayer diffusion-barrier composites based on microfibrillated cellulose from wood, bacterial and algae sources

Aigoul Schreier

This work is driven by the effort towards increased environmental sustainability and aims to develop a new food packaging material based on renewable materials, and more specifically cellulose as the most abundant biomass resource on Earth. Focus was on mi ...

EPFL2024

La0.5Sr0.5Fe1-yMyO3-[delta] (M = Ti, Ta) perovskite oxides for oxygen separation membranes

Defne Bayraktar

Mixed ionic electronic conducting perovskite materials have been receiving considerable attention for the application of oxygen separation membranes. These membranes have potential to be integrated in industrial processes that require pure oxygen and to pr ...

EPFL2008

Hybrid nanocomposite gas-barrier coatings on polymers

Bandeep Singh

Gas barrier coatings based on single or multiple layers of metals, oxides or nitrides are widely used on polymer substrates in applications ranging from food packaging to organic displays and solar cells. These coatings exhibit a residual permeability resu ...

EPFL2007