真空充(chong)氣(qi)(qi)(qi)(qi)(qi)(qi)包(bao)裝在真空后再充(chong)入氮(dan)氣(qi)(qi)(qi)(qi)(qi)(qi)、二氧化(hua)碳、氧氣(qi)(qi)(qi)(qi)(qi)(qi)單一氣(qi)(qi)(qi)(qi)(qi)(qi)體(ti)或二 三種氣(qi)(qi)(qi)(qi)(qi)(qi)體(ti)的混(hun)合(he)氣(qi)(qi)(qi)(qi)(qi)(qi)體(ti)。其氮(dan)氣(qi)(qi)(qi)(qi)(qi)(qi)是惰性(xing)(xing)氣(qi)(qi)(qi)(qi)(qi)(qi)體(ti)，起充(chong)填(tian)作(zuo)用(yong)，使(shi)袋內保持(chi)正(zheng)壓 ，以(yi)防(fang)止袋外空氣(qi)(qi)(qi)(qi)(qi)(qi)進(jin)入袋內，對食品起到(dao)一個保護作(zuo)用(yong)。其二氧化(hua)碳能(neng)夠溶(rong)于各類(lei)脂肪(fang)或水(shui)，引(yin)成酸性(xing)(xing)較弱的碳酸，有(you)抑(yi)制霉菌、腐敗細菌等微生(sheng)(sheng)物的活性(xing)(xing)。其氧氣(qi)(qi)(qi)(qi)(qi)(qi)具(ju)有(you)抑(yi)制厭氧菌的生(sheng)(sheng)長繁殖(zhi)，保持(chi)水(shui)果、蔬(shu)(shu)菜的新鮮(xian)及色彩，高濃(nong)度氧氣(qi)(qi)(qi)(qi)(qi)(qi)可使(shi)新鮮(xian)肉類(lei)保持(chi)其鮮(xian)紅色。水(shui)果蔬(shu)(shu)菜的新鮮(xian)可是營(ying)養不流(liu)失。