真空袋(dai)的(de)(de)(de)(de)主要(yao)作(zuo)用(yong)(yong)是(shi)除(chu)氧(yang)(yang)(yang)(yang)(yang)，以(yi)有利于防(fang)止(zhi)食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)變(bian)(bian)質(zhi)(zhi)，其原理也(ye)比較簡單，因食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)霉腐變(bian)(bian)質(zhi)(zhi)主要(yao)由微(wei)(wei)(wei)生(sheng)(sheng)物的(de)(de)(de)(de)活動造成，而大(da)多(duo)(duo)數微(wei)(wei)(wei)生(sheng)(sheng)物（如霉菌(jun)和(he)酵母菌(jun)）的(de)(de)(de)(de)生(sheng)(sheng)存是(shi)需要(yao)氧(yang)(yang)(yang)(yang)(yang)氣(qi)的(de)(de)(de)(de)，而真空包(bao)裝(zhuang)就是(shi)運用(yong)(yong)這(zhe)個(ge)原理，把包(bao)裝(zhuang)袋(dai)內(nei)(nei)和(he)食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)細胞(bao)內(nei)(nei)的(de)(de)(de)(de)氧(yang)(yang)(yang)(yang)(yang)氣(qi)抽掉(diao)，使微(wei)(wei)(wei)物物失去(qu)“生(sheng)(sheng)存的(de)(de)(de)(de)環境”。實驗證明(ming)：當(dang)包(bao)裝(zhuang)袋(dai)內(nei)(nei)的(de)(de)(de)(de)氧(yang)(yang)(yang)(yang)(yang)氣(qi)濃度≤1%時，微(wei)(wei)(wei)生(sheng)(sheng)物的(de)(de)(de)(de)生(sheng)(sheng)長和(he)繁(fan)殖(zhi)速度就急劇下降，氧(yang)(yang)(yang)(yang)(yang)氣(qi)濃度≤0.5%時，大(da)多(duo)(duo)數微(wei)(wei)(wei)生(sheng)(sheng)物將受到抑制(zhi)(zhi)而停止(zhi)繁(fan)殖(zhi)。（注：真空包(bao)裝(zhuang)不能(neng)抑制(zhi)(zhi)厭氧(yang)(yang)(yang)(yang)(yang)菌(jun)的(de)(de)(de)(de)繁(fan)殖(zhi)和(he)酶反應引(yin)起(qi)的(de)(de)(de)(de)食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)變(bian)(bian)質(zhi)(zhi)和(he)變(bian)(bian)色(se)，因此還需與其它輔(fu)助方法結合，如冷藏、速凍(dong)、脫(tuo)水、高(gao)溫殺(sha)菌(jun)、輻照 滅菌(jun)、微(wei)(wei)(wei)波殺(sha)菌(jun)、鹽腌制(zhi)(zhi)等(deng)。）真空除(chu)氧(yang)(yang)(yang)(yang)(yang)除(chu)了抑制(zhi)(zhi)微(wei)(wei)(wei)生(sheng)(sheng)物的(de)(de)(de)(de)生(sheng)(sheng)長和(he)繁(fan)殖(zhi)外，另一個(ge)重要(yao)功(gong)能(neng)是(shi)防(fang)止(zhi)食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)氧(yang)(yang)(yang)(yang)(yang)化(hua)，因油脂類食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)中(zhong)含有大(da)量(liang)不飽和(he)脂肪酸，受氧(yang)(yang)(yang)(yang)(yang)的(de)(de)(de)(de)作(zuo)用(yong)(yong)而氧(yang)(yang)(yang)(yang)(yang)化(hua)，使食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)變(bian)(bian)味、變(bian)(bian)質(zhi)(zhi)，此外，氧(yang)(yang)(yang)(yang)(yang)化(hua)還使維生(sheng)(sheng)素A和(he)C損(sun)失，食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)色(se)素中(zhong)的(de)(de)(de)(de)不穩定物質(zhi)(zhi)受氧(yang)(yang)(yang)(yang)(yang)的(de)(de)(de)(de)作(zuo)用(yong)(yong)，使顏色(se)變(bian)(bian)暗(an)。所以(yi)，除(chu)氧(yang)(yang)(yang)(yang)(yang)能(neng)有效地(di)防(fang)止(zhi)食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)變(bian)(bian)質(zhi)(zhi)，保持其色(se)、香(xiang)、味及營養(yang)價值。