真空袋(dai)的(de)(de)(de)(de)主(zhu)(zhu)要(yao)(yao)作用(yong)是(shi)除氧(yang)(yang)，以有利于防止食(shi)品(pin)變(bian)(bian)(bian)(bian)(bian)質(zhi)，其(qi)原(yuan)理(li)也比較簡單，因食(shi)品(pin)霉腐變(bian)(bian)(bian)(bian)(bian)質(zhi)主(zhu)(zhu)要(yao)(yao)由微(wei)(wei)生(sheng)(sheng)物(wu)的(de)(de)(de)(de)活動造成，而大(da)多數微(wei)(wei)生(sheng)(sheng)物(wu)（如霉菌(jun)和(he)(he)酵(jiao)母菌(jun)）的(de)(de)(de)(de)生(sheng)(sheng)存(cun)是(shi)需要(yao)(yao)氧(yang)(yang)氣的(de)(de)(de)(de)，而真空包裝(zhuang)(zhuang)就(jiu)是(shi)運用(yong)這個原(yuan)理(li)，把包裝(zhuang)(zhuang)袋(dai)內(nei)(nei)和(he)(he)食(shi)品(pin)細胞內(nei)(nei)的(de)(de)(de)(de)氧(yang)(yang)氣抽掉(diao)，使(shi)微(wei)(wei)物(wu)物(wu)失去“生(sheng)(sheng)存(cun)的(de)(de)(de)(de)環境(jing)”。實驗證明：當包裝(zhuang)(zhuang)袋(dai)內(nei)(nei)的(de)(de)(de)(de)氧(yang)(yang)氣濃度(du)(du)≤1%時，微(wei)(wei)生(sheng)(sheng)物(wu)的(de)(de)(de)(de)生(sheng)(sheng)長和(he)(he)繁殖(zhi)速度(du)(du)就(jiu)急劇下降，氧(yang)(yang)氣濃度(du)(du)≤0.5%時，大(da)多數微(wei)(wei)生(sheng)(sheng)物(wu)將受(shou)到(dao)抑(yi)(yi)制而停止繁殖(zhi)。（注：真空包裝(zhuang)(zhuang)不能抑(yi)(yi)制厭氧(yang)(yang)菌(jun)的(de)(de)(de)(de)繁殖(zhi)和(he)(he)酶反應引起的(de)(de)(de)(de)食(shi)品(pin)變(bian)(bian)(bian)(bian)(bian)質(zhi)和(he)(he)變(bian)(bian)(bian)(bian)(bian)色(se)，因此還(huan)需與(yu)其(qi)它輔助(zhu)方法結合(he)，如冷藏、速凍、脫水、高(gao)溫殺(sha)菌(jun)、輻(fu)照 滅菌(jun)、微(wei)(wei)波(bo)殺(sha)菌(jun)、鹽腌制等(deng)。）真空除氧(yang)(yang)除了抑(yi)(yi)制微(wei)(wei)生(sheng)(sheng)物(wu)的(de)(de)(de)(de)生(sheng)(sheng)長和(he)(he)繁殖(zhi)外，另一(yi)個重要(yao)(yao)功能是(shi)防止食(shi)品(pin)氧(yang)(yang)化(hua)(hua)，因油(you)脂類食(shi)品(pin)中含有大(da)量不飽和(he)(he)脂肪酸，受(shou)氧(yang)(yang)的(de)(de)(de)(de)作用(yong)而氧(yang)(yang)化(hua)(hua)，使(shi)食(shi)品(pin)變(bian)(bian)(bian)(bian)(bian)味、變(bian)(bian)(bian)(bian)(bian)質(zhi)，此外，氧(yang)(yang)化(hua)(hua)還(huan)使(shi)維生(sheng)(sheng)素A和(he)(he)C損失，食(shi)品(pin)色(se)素中的(de)(de)(de)(de)不穩(wen)定物(wu)質(zhi)受(shou)氧(yang)(yang)的(de)(de)(de)(de)作用(yong)，使(shi)顏色(se)變(bian)(bian)(bian)(bian)(bian)暗。所以，除氧(yang)(yang)能有效地防止食(shi)品(pin)變(bian)(bian)(bian)(bian)(bian)質(zhi)，保持其(qi)色(se)、香、味及營養價值。