PROBLEM TO BE SOLVED: To provide a system and a method for stabilizing a dye relying on oxygen and a dye instable to oxygen without damage, and preventing discoloration of food materials containing the dye while maintaining freshness.SOLUTION: There are provided a system and a method for preventing discoloration of food materials containing a dye while maintaining freshness, having (1) a step for reducing oxygen concentration of air 3 in a sealed container 1 containing the dye to a level of less than 1%, preferably less than 0.1%, and (2) a step for introducing carbon dioxide into the sealed container when the oxygen concentration of air in the sealed container to less than 1% while maintaining or further reducing the same. There is provided a method in which the dye is a myoglobin dye existing in red meat, abdominal, tuna or mackerel.SELECTED DRAWING: Figure 1【課題】酸素に依存した色素及び酸素に対して不安定な色素を損傷しない様に安定させ、新鮮さを保ちながら、色素を含む食材の変色を防ぐシステム及び方法の提供。【解決手段】（１）色素を含む密封容器１内の空気３の酸素濃度を、１％未満、好ましくは０．１％未満のレベルにまで低下させるステップと、（２）密封容器内の空気の酸素濃度を保持しながらまたはさらに低下させながら、１％未満にまで低下させた場合、二酸化炭素を密封容器内に導入するステップと、を有する、新鮮さを保ちながら、色素を含む食材の変色を防ぐシステム及び方法。前記色素が赤肉又はティラピア、マグロ或いはサバに存在するミオグロビン色素である、方法。【選択図】図１
