真空(kong)充(chong)氣(qi)(qi)(qi)(qi)(qi)包裝在(zai)真空(kong)后再充(chong)入氮氣(qi)(qi)(qi)(qi)(qi)、二氧化(hua)碳(tan)(tan)、氧氣(qi)(qi)(qi)(qi)(qi)單一氣(qi)(qi)(qi)(qi)(qi)體或二 三種氣(qi)(qi)(qi)(qi)(qi)體的(de)(de)混合(he)氣(qi)(qi)(qi)(qi)(qi)體。其氮氣(qi)(qi)(qi)(qi)(qi)是(shi)惰性(xing)氣(qi)(qi)(qi)(qi)(qi)體，起(qi)充(chong)填(tian)作用(yong)，使袋內(nei)保(bao)持正壓 ，以防止袋外(wai)空(kong)氣(qi)(qi)(qi)(qi)(qi)進入袋內(nei)，對食品起(qi)到一個保(bao)護作用(yong)。其二氧化(hua)碳(tan)(tan)能夠溶(rong)于各類(lei)脂肪或水(shui)(shui)，引成酸性(xing)較弱的(de)(de)碳(tan)(tan)酸，有抑(yi)制霉菌、腐敗細菌等微(wei)生(sheng)物的(de)(de)活性(xing)。其氧氣(qi)(qi)(qi)(qi)(qi)具(ju)有抑(yi)制厭氧菌的(de)(de)生(sheng)長繁殖，保(bao)持水(shui)(shui)果、蔬菜的(de)(de)新(xin)(xin)鮮(xian)(xian)及色彩，高濃度(du)氧氣(qi)(qi)(qi)(qi)(qi)可(ke)使新(xin)(xin)鮮(xian)(xian)肉類(lei)保(bao)持其鮮(xian)(xian)紅色。水(shui)(shui)果蔬菜的(de)(de)新(xin)(xin)鮮(xian)(xian)可(ke)是(shi)營養不流失。