真空(kong)袋的(de)(de)主要作用是除(chu)氧(yang)(yang)，以有(you)利于防(fang)止食(shi)(shi)(shi)品(pin)(pin)變(bian)質(zhi)(zhi)，其(qi)原理也比較(jiao)簡(jian)單，因(yin)食(shi)(shi)(shi)品(pin)(pin)霉(mei)腐變(bian)質(zhi)(zhi)主要由(you)微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)活動造成(cheng)，而(er)(er)(er)大(da)(da)多(duo)數微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)(wu)（如霉(mei)菌(jun)(jun)和(he)(he)酵母菌(jun)(jun)）的(de)(de)生(sheng)(sheng)(sheng)(sheng)(sheng)存是需要氧(yang)(yang)氣的(de)(de)，而(er)(er)(er)真空(kong)包(bao)裝(zhuang)就是運用這個原理，把包(bao)裝(zhuang)袋內和(he)(he)食(shi)(shi)(shi)品(pin)(pin)細胞內的(de)(de)氧(yang)(yang)氣抽(chou)掉，使(shi)(shi)微(wei)(wei)(wei)物(wu)(wu)物(wu)(wu)失去“生(sheng)(sheng)(sheng)(sheng)(sheng)存的(de)(de)環境”。實驗證明(ming)：當包(bao)裝(zhuang)袋內的(de)(de)氧(yang)(yang)氣濃度(du)≤1%時，微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)生(sheng)(sheng)(sheng)(sheng)(sheng)長和(he)(he)繁(fan)殖速(su)度(du)就急劇下(xia)降，氧(yang)(yang)氣濃度(du)≤0.5%時，大(da)(da)多(duo)數微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)(wu)將(jiang)受(shou)到抑(yi)制而(er)(er)(er)停止繁(fan)殖。（注：真空(kong)包(bao)裝(zhuang)不能抑(yi)制厭氧(yang)(yang)菌(jun)(jun)的(de)(de)繁(fan)殖和(he)(he)酶(mei)反應引起(qi)的(de)(de)食(shi)(shi)(shi)品(pin)(pin)變(bian)質(zhi)(zhi)和(he)(he)變(bian)色，因(yin)此(ci)還需與其(qi)它輔助方法結合，如冷藏、速(su)凍、脫水、高溫殺(sha)菌(jun)(jun)、輻照 滅菌(jun)(jun)、微(wei)(wei)(wei)波(bo)殺(sha)菌(jun)(jun)、鹽腌(a)制等(deng)。）真空(kong)除(chu)氧(yang)(yang)除(chu)了抑(yi)制微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)生(sheng)(sheng)(sheng)(sheng)(sheng)長和(he)(he)繁(fan)殖外，另一個重要功能是防(fang)止食(shi)(shi)(shi)品(pin)(pin)氧(yang)(yang)化，因(yin)油脂類食(shi)(shi)(shi)品(pin)(pin)中含(han)有(you)大(da)(da)量(liang)不飽和(he)(he)脂肪(fang)酸，受(shou)氧(yang)(yang)的(de)(de)作用而(er)(er)(er)氧(yang)(yang)化，使(shi)(shi)食(shi)(shi)(shi)品(pin)(pin)變(bian)味(wei)、變(bian)質(zhi)(zhi)，此(ci)外，氧(yang)(yang)化還使(shi)(shi)維(wei)生(sheng)(sheng)(sheng)(sheng)(sheng)素A和(he)(he)C損失，食(shi)(shi)(shi)品(pin)(pin)色素中的(de)(de)不穩定(ding)物(wu)(wu)質(zhi)(zhi)受(shou)氧(yang)(yang)的(de)(de)作用，使(shi)(shi)顏(yan)色變(bian)暗。所(suo)以，除(chu)氧(yang)(yang)能有(you)效地防(fang)止食(shi)(shi)(shi)品(pin)(pin)變(bian)質(zhi)(zhi)，保持其(qi)色、香、味(wei)及營養價值。