真空(kong)袋(dai)的(de)(de)(de)主要作(zuo)用是除氧(yang)，以(yi)有(you)利于(yu)防(fang)止(zhi)食(shi)(shi)(shi)(shi)(shi)品變(bian)(bian)(bian)質(zhi)(zhi)(zhi)，其原(yuan)理(li)也(ye)比較簡單，因(yin)食(shi)(shi)(shi)(shi)(shi)品霉腐(fu)變(bian)(bian)(bian)質(zhi)(zhi)(zhi)主要由(you)微(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)(de)活動造成，而(er)(er)大多(duo)數微(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物(wu)(wu)（如霉菌(jun)和酵母菌(jun)）的(de)(de)(de)生(sheng)(sheng)(sheng)(sheng)存(cun)是需要氧(yang)氣(qi)(qi)的(de)(de)(de)，而(er)(er)真空(kong)包(bao)裝(zhuang)就是運用這個(ge)原(yuan)理(li)，把(ba)包(bao)裝(zhuang)袋(dai)內(nei)(nei)和食(shi)(shi)(shi)(shi)(shi)品細胞內(nei)(nei)的(de)(de)(de)氧(yang)氣(qi)(qi)抽掉，使微(wei)(wei)物(wu)(wu)物(wu)(wu)失去“生(sheng)(sheng)(sheng)(sheng)存(cun)的(de)(de)(de)環境”。實(shi)驗證明：當包(bao)裝(zhuang)袋(dai)內(nei)(nei)的(de)(de)(de)氧(yang)氣(qi)(qi)濃度≤1%時(shi)，微(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)(de)生(sheng)(sheng)(sheng)(sheng)長和繁殖(zhi)(zhi)速度就急劇下降，氧(yang)氣(qi)(qi)濃度≤0.5%時(shi)，大多(duo)數微(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物(wu)(wu)將受(shou)(shou)到抑(yi)制(zhi)(zhi)而(er)(er)停止(zhi)繁殖(zhi)(zhi)。（注(zhu)：真空(kong)包(bao)裝(zhuang)不能(neng)抑(yi)制(zhi)(zhi)厭氧(yang)菌(jun)的(de)(de)(de)繁殖(zhi)(zhi)和酶反應引起的(de)(de)(de)食(shi)(shi)(shi)(shi)(shi)品變(bian)(bian)(bian)質(zhi)(zhi)(zhi)和變(bian)(bian)(bian)色，因(yin)此還需與其它(ta)輔助方法結合，如冷藏(zang)、速凍、脫水、高溫殺(sha)菌(jun)、輻(fu)照 滅(mie)菌(jun)、微(wei)(wei)波殺(sha)菌(jun)、鹽腌制(zhi)(zhi)等。）真空(kong)除氧(yang)除了抑(yi)制(zhi)(zhi)微(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)(de)生(sheng)(sheng)(sheng)(sheng)長和繁殖(zhi)(zhi)外，另一個(ge)重要功能(neng)是防(fang)止(zhi)食(shi)(shi)(shi)(shi)(shi)品氧(yang)化，因(yin)油脂(zhi)類食(shi)(shi)(shi)(shi)(shi)品中含有(you)大量不飽和脂(zhi)肪(fang)酸，受(shou)(shou)氧(yang)的(de)(de)(de)作(zuo)用而(er)(er)氧(yang)化，使食(shi)(shi)(shi)(shi)(shi)品變(bian)(bian)(bian)味(wei)(wei)、變(bian)(bian)(bian)質(zhi)(zhi)(zhi)，此外，氧(yang)化還使維生(sheng)(sheng)(sheng)(sheng)素A和C損(sun)失，食(shi)(shi)(shi)(shi)(shi)品色素中的(de)(de)(de)不穩定物(wu)(wu)質(zhi)(zhi)(zhi)受(shou)(shou)氧(yang)的(de)(de)(de)作(zuo)用，使顏色變(bian)(bian)(bian)暗。所(suo)以(yi)，除氧(yang)能(neng)有(you)效(xiao)地防(fang)止(zhi)食(shi)(shi)(shi)(shi)(shi)品變(bian)(bian)(bian)質(zhi)(zhi)(zhi)，保持其色、香、味(wei)(wei)及(ji)營養價值。