|technology > packaging > filling, closing > modified atmosphere packaging|
Gas flushing, storage under gas
Packaging, and is used to enhance colourretention of, for example, fresh meat or cured meats such as bacon and cooked ham, especially in sliced form. Storage with inert gas is applied to wines in tanks, in order to preserve an adequate CO2 content in the wine, and their organoleptic qualities, to protect them from oxidation, and to prevent bacterial deviations in place of the use of sulphur dioxide (SO2). This technique is above all applied to white wines, rosés and red primeurs. It also allows one to prevent the alteration of tanks which would be emptied, for example in the case of bulk sale to private individuals. Finally, it permits the conservation of sterile fruit juices.
|Field of application|
|Techniques, methods and equipment|
|a) Gas flushing|
|b) Storage under gas|
Normal air contains:
Nitrogen 78%, Oxygen 21%, and CO2 less than 1%.
In comparison, typical gas mixes for use with meats and meat products are:
Another use of gas is the use of solid CO2, usually in pellet form, which is added to meat during comminution. This has the effect of rapidly reducing the temperature of the meat mixture and creating a “blanket” of inert gas over the surface of the meat, thereby enhancing the colour retention. Again a temporary increase in the CO2 content of the atmosphere surrounding the equipment will occur, but this dissipates rapidly. Solid or liquid nitrogen or CO2 is sometimes used to par-freeze meats prior to slicing. This involves passing the pieces of meat to be sliced through a tunnel in which they are sprayed with the liquefied gas to reduce their temperature to about minus 8°C. In such instances, extractor fans are located near the ends of the tunnel in order to expel surplus gas to atmosphere, and no adverse effects have been reported.
tank under very slight overpressure (0.1 to 0.2 bar). Nitrogen is delivered in a compressed state in steel containers. The carbon dioxide is in a liquefied form under pressure.