真空(kong)(kong)袋(dai)的(de)(de)(de)(de)(de)主要(yao)作(zuo)用(yong)(yong)(yong)是(shi)除(chu)(chu)氧(yang)(yang)(yang)(yang)，以有(you)(you)利(li)于防(fang)止食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)(pin)變(bian)質(zhi)(zhi)(zhi)，其(qi)原(yuan)理也(ye)比較(jiao)簡單，因食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)(pin)霉(mei)(mei)腐變(bian)質(zhi)(zhi)(zhi)主要(yao)由微生(sheng)(sheng)物(wu)(wu)(wu)的(de)(de)(de)(de)(de)活動造成，而(er)(er)大(da)多數(shu)微生(sheng)(sheng)物(wu)(wu)(wu)（如霉(mei)(mei)菌(jun)和(he)酵(jiao)母(mu)菌(jun)）的(de)(de)(de)(de)(de)生(sheng)(sheng)存是(shi)需要(yao)氧(yang)(yang)(yang)(yang)氣的(de)(de)(de)(de)(de)，而(er)(er)真空(kong)(kong)包裝(zhuang)就是(shi)運用(yong)(yong)(yong)這個原(yuan)理，把包裝(zhuang)袋(dai)內和(he)食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)(pin)細胞內的(de)(de)(de)(de)(de)氧(yang)(yang)(yang)(yang)氣抽(chou)掉，使(shi)微物(wu)(wu)(wu)物(wu)(wu)(wu)失去“生(sheng)(sheng)存的(de)(de)(de)(de)(de)環境”。實驗證明(ming)：當包裝(zhuang)袋(dai)內的(de)(de)(de)(de)(de)氧(yang)(yang)(yang)(yang)氣濃(nong)度≤1%時(shi)，微生(sheng)(sheng)物(wu)(wu)(wu)的(de)(de)(de)(de)(de)生(sheng)(sheng)長和(he)繁殖(zhi)(zhi)速度就急劇下降，氧(yang)(yang)(yang)(yang)氣濃(nong)度≤0.5%時(shi)，大(da)多數(shu)微生(sheng)(sheng)物(wu)(wu)(wu)將受(shou)(shou)到(dao)抑制(zhi)(zhi)而(er)(er)停止繁殖(zhi)(zhi)。（注：真空(kong)(kong)包裝(zhuang)不能(neng)抑制(zhi)(zhi)厭氧(yang)(yang)(yang)(yang)菌(jun)的(de)(de)(de)(de)(de)繁殖(zhi)(zhi)和(he)酶反應引(yin)起(qi)的(de)(de)(de)(de)(de)食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)(pin)變(bian)質(zhi)(zhi)(zhi)和(he)變(bian)色(se)(se)，因此還需與其(qi)它輔助方法結(jie)合，如冷藏、速凍、脫水、高(gao)溫殺菌(jun)、輻照 滅菌(jun)、微波殺菌(jun)、鹽腌制(zhi)(zhi)等。）真空(kong)(kong)除(chu)(chu)氧(yang)(yang)(yang)(yang)除(chu)(chu)了抑制(zhi)(zhi)微生(sheng)(sheng)物(wu)(wu)(wu)的(de)(de)(de)(de)(de)生(sheng)(sheng)長和(he)繁殖(zhi)(zhi)外，另一個重要(yao)功能(neng)是(shi)防(fang)止食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)(pin)氧(yang)(yang)(yang)(yang)化，因油(you)脂類食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)(pin)中(zhong)(zhong)含有(you)(you)大(da)量不飽和(he)脂肪酸(suan)，受(shou)(shou)氧(yang)(yang)(yang)(yang)的(de)(de)(de)(de)(de)作(zuo)用(yong)(yong)(yong)而(er)(er)氧(yang)(yang)(yang)(yang)化，使(shi)食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)(pin)變(bian)味(wei)、變(bian)質(zhi)(zhi)(zhi)，此外，氧(yang)(yang)(yang)(yang)化還使(shi)維生(sheng)(sheng)素A和(he)C損(sun)失，食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)(pin)色(se)(se)素中(zhong)(zhong)的(de)(de)(de)(de)(de)不穩定物(wu)(wu)(wu)質(zhi)(zhi)(zhi)受(shou)(shou)氧(yang)(yang)(yang)(yang)的(de)(de)(de)(de)(de)作(zuo)用(yong)(yong)(yong)，使(shi)顏色(se)(se)變(bian)暗。所以，除(chu)(chu)氧(yang)(yang)(yang)(yang)能(neng)有(you)(you)效地(di)防(fang)止食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)(pin)變(bian)質(zhi)(zhi)(zhi)，保持其(qi)色(se)(se)、香、味(wei)及營養價(jia)值。