真空(kong)(kong)袋的(de)(de)(de)(de)主要(yao)(yao)作用(yong)(yong)(yong)是(shi)除氧(yang)(yang)(yang)，以有(you)利(li)于防(fang)止(zhi)(zhi)食(shi)品變(bian)質(zhi)(zhi)，其(qi)(qi)原(yuan)理也比較(jiao)簡單，因(yin)食(shi)品霉腐變(bian)質(zhi)(zhi)主要(yao)(yao)由(you)微(wei)(wei)生(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)的(de)(de)(de)(de)活(huo)動造成(cheng)，而大(da)多數微(wei)(wei)生(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)（如霉菌(jun)和(he)(he)(he)酵母(mu)菌(jun)）的(de)(de)(de)(de)生(sheng)(sheng)(sheng)(sheng)(sheng)存(cun)是(shi)需(xu)要(yao)(yao)氧(yang)(yang)(yang)氣(qi)(qi)(qi)的(de)(de)(de)(de)，而真空(kong)(kong)包(bao)(bao)裝就(jiu)是(shi)運用(yong)(yong)(yong)這個(ge)(ge)原(yuan)理，把包(bao)(bao)裝袋內和(he)(he)(he)食(shi)品細胞內的(de)(de)(de)(de)氧(yang)(yang)(yang)氣(qi)(qi)(qi)抽掉(diao)，使微(wei)(wei)物(wu)物(wu)失去(qu)“生(sheng)(sheng)(sheng)(sheng)(sheng)存(cun)的(de)(de)(de)(de)環境”。實驗證明(ming)：當包(bao)(bao)裝袋內的(de)(de)(de)(de)氧(yang)(yang)(yang)氣(qi)(qi)(qi)濃(nong)度(du)≤1%時(shi)，微(wei)(wei)生(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)的(de)(de)(de)(de)生(sheng)(sheng)(sheng)(sheng)(sheng)長和(he)(he)(he)繁(fan)(fan)殖(zhi)速(su)度(du)就(jiu)急劇下降，氧(yang)(yang)(yang)氣(qi)(qi)(qi)濃(nong)度(du)≤0.5%時(shi)，大(da)多數微(wei)(wei)生(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)將受(shou)(shou)到抑制(zhi)而停(ting)止(zhi)(zhi)繁(fan)(fan)殖(zhi)。（注：真空(kong)(kong)包(bao)(bao)裝不能(neng)(neng)抑制(zhi)厭(yan)氧(yang)(yang)(yang)菌(jun)的(de)(de)(de)(de)繁(fan)(fan)殖(zhi)和(he)(he)(he)酶反應引起的(de)(de)(de)(de)食(shi)品變(bian)質(zhi)(zhi)和(he)(he)(he)變(bian)色(se)，因(yin)此還需(xu)與(yu)其(qi)(qi)它輔助(zhu)方(fang)法(fa)結合，如冷藏(zang)、速(su)凍、脫水、高溫(wen)殺(sha)菌(jun)、輻照 滅(mie)菌(jun)、微(wei)(wei)波殺(sha)菌(jun)、鹽腌(a)制(zhi)等。）真空(kong)(kong)除氧(yang)(yang)(yang)除了抑制(zhi)微(wei)(wei)生(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)的(de)(de)(de)(de)生(sheng)(sheng)(sheng)(sheng)(sheng)長和(he)(he)(he)繁(fan)(fan)殖(zhi)外，另一個(ge)(ge)重(zhong)要(yao)(yao)功能(neng)(neng)是(shi)防(fang)止(zhi)(zhi)食(shi)品氧(yang)(yang)(yang)化，因(yin)油脂(zhi)類食(shi)品中含有(you)大(da)量不飽和(he)(he)(he)脂(zhi)肪酸，受(shou)(shou)氧(yang)(yang)(yang)的(de)(de)(de)(de)作用(yong)(yong)(yong)而氧(yang)(yang)(yang)化，使食(shi)品變(bian)味、變(bian)質(zhi)(zhi)，此外，氧(yang)(yang)(yang)化還使維(wei)生(sheng)(sheng)(sheng)(sheng)(sheng)素(su)A和(he)(he)(he)C損失，食(shi)品色(se)素(su)中的(de)(de)(de)(de)不穩定物(wu)質(zhi)(zhi)受(shou)(shou)氧(yang)(yang)(yang)的(de)(de)(de)(de)作用(yong)(yong)(yong)，使顏(yan)色(se)變(bian)暗。所以，除氧(yang)(yang)(yang)能(neng)(neng)有(you)效地防(fang)止(zhi)(zhi)食(shi)品變(bian)質(zhi)(zhi)，保持其(qi)(qi)色(se)、香(xiang)、味及營養(yang)價值。