真空袋的(de)(de)(de)主要(yao)作(zuo)用(yong)是(shi)除氧(yang)(yang)(yang)(yang)(yang)，以(yi)有利于防(fang)止(zhi)食(shi)品(pin)變(bian)質(zhi)，其原理(li)也比較簡單，因食(shi)品(pin)霉腐變(bian)質(zhi)主要(yao)由微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物的(de)(de)(de)活(huo)動造成，而(er)大(da)多數(shu)微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物（如(ru)霉菌(jun)(jun)和(he)酵母菌(jun)(jun)）的(de)(de)(de)生(sheng)(sheng)(sheng)(sheng)存(cun)(cun)是(shi)需(xu)要(yao)氧(yang)(yang)(yang)(yang)(yang)氣(qi)的(de)(de)(de)，而(er)真空包(bao)(bao)裝就是(shi)運用(yong)這個原理(li)，把包(bao)(bao)裝袋內(nei)和(he)食(shi)品(pin)細胞內(nei)的(de)(de)(de)氧(yang)(yang)(yang)(yang)(yang)氣(qi)抽掉(diao)，使(shi)(shi)微(wei)(wei)(wei)物物失(shi)去“生(sheng)(sheng)(sheng)(sheng)存(cun)(cun)的(de)(de)(de)環境”。實(shi)驗證明：當(dang)包(bao)(bao)裝袋內(nei)的(de)(de)(de)氧(yang)(yang)(yang)(yang)(yang)氣(qi)濃度(du)≤1%時，微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物的(de)(de)(de)生(sheng)(sheng)(sheng)(sheng)長和(he)繁(fan)(fan)殖(zhi)(zhi)(zhi)速度(du)就急劇下降，氧(yang)(yang)(yang)(yang)(yang)氣(qi)濃度(du)≤0.5%時，大(da)多數(shu)微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物將受到(dao)抑制(zhi)(zhi)而(er)停止(zhi)繁(fan)(fan)殖(zhi)(zhi)(zhi)。（注：真空包(bao)(bao)裝不(bu)能(neng)抑制(zhi)(zhi)厭氧(yang)(yang)(yang)(yang)(yang)菌(jun)(jun)的(de)(de)(de)繁(fan)(fan)殖(zhi)(zhi)(zhi)和(he)酶反應引(yin)起(qi)的(de)(de)(de)食(shi)品(pin)變(bian)質(zhi)和(he)變(bian)色(se)，因此還需(xu)與其它輔助(zhu)方法結(jie)合，如(ru)冷藏、速凍、脫(tuo)水(shui)、高溫殺菌(jun)(jun)、輻照 滅菌(jun)(jun)、微(wei)(wei)(wei)波殺菌(jun)(jun)、鹽腌制(zhi)(zhi)等。）真空除氧(yang)(yang)(yang)(yang)(yang)除了抑制(zhi)(zhi)微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物的(de)(de)(de)生(sheng)(sheng)(sheng)(sheng)長和(he)繁(fan)(fan)殖(zhi)(zhi)(zhi)外(wai)，另一個重(zhong)要(yao)功能(neng)是(shi)防(fang)止(zhi)食(shi)品(pin)氧(yang)(yang)(yang)(yang)(yang)化，因油脂類食(shi)品(pin)中含有大(da)量不(bu)飽(bao)和(he)脂肪酸(suan)，受氧(yang)(yang)(yang)(yang)(yang)的(de)(de)(de)作(zuo)用(yong)而(er)氧(yang)(yang)(yang)(yang)(yang)化，使(shi)(shi)食(shi)品(pin)變(bian)味(wei)、變(bian)質(zhi)，此外(wai)，氧(yang)(yang)(yang)(yang)(yang)化還使(shi)(shi)維生(sheng)(sheng)(sheng)(sheng)素A和(he)C損失(shi)，食(shi)品(pin)色(se)素中的(de)(de)(de)不(bu)穩(wen)定物質(zhi)受氧(yang)(yang)(yang)(yang)(yang)的(de)(de)(de)作(zuo)用(yong)，使(shi)(shi)顏色(se)變(bian)暗(an)。所以(yi)，除氧(yang)(yang)(yang)(yang)(yang)能(neng)有效地防(fang)止(zhi)食(shi)品(pin)變(bian)質(zhi)，保(bao)持其色(se)、香、味(wei)及營養價(jia)值。