Modified Atmosphere Package, MAP, is the process and method of filling a certain kind of gas, or a gas mixture with each gas at a certain ratio into the sealed food, beverage and other packages, so as to guarantee the freshness and quality of the products as well as prolong the shelf-life.
In order to control the quality of MAP, headspace analysis is a necessity. Headspace analysis is to analyze the head space gas content in the sealed packages and containers, including pouches and PET bottles, so as to realize quality control process of the products.
MAP gas usually consists of carbon dioxide, nitrogen and oxygen. Oxygen content reduction can reduce respiration of the vegetables and fruits and restrain metabolic activity; carbon dioxide concentration improvement can further slow down respiration; nitrogen is one of the inert gases with no effects on the vegetables and fruits and acts as the filling gas. Different vegetables and fruits require different gas proportion, which is mainly determined by the characteristics of the vegetables and fruits themselves. There are certain requirements on gas mix accuracy error and gas replace rate for their complex MAP. In the advanced MAP design standards, a gas replace rate of up to 99.5% is required with less than 2.0% gas mix accuracy error.