真空袋(dai)的(de)(de)主要作(zuo)用(yong)是(shi)(shi)除(chu)氧(yang)(yang)(yang)(yang)，以(yi)有利(li)于防(fang)止(zhi)食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)變(bian)(bian)(bian)質，其原(yuan)理也比較簡單，因(yin)食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)霉腐變(bian)(bian)(bian)質主要由微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)活動(dong)造成(cheng)，而(er)大多數微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)（如霉菌(jun)(jun)(jun)和酵母菌(jun)(jun)(jun)）的(de)(de)生(sheng)(sheng)(sheng)存是(shi)(shi)需要氧(yang)(yang)(yang)(yang)氣(qi)的(de)(de)，而(er)真空包裝就是(shi)(shi)運用(yong)這個原(yuan)理，把包裝袋(dai)內和食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)細胞內的(de)(de)氧(yang)(yang)(yang)(yang)氣(qi)抽(chou)掉，使(shi)微(wei)(wei)物(wu)(wu)物(wu)(wu)失(shi)去“生(sheng)(sheng)(sheng)存的(de)(de)環境”。實驗證明：當包裝袋(dai)內的(de)(de)氧(yang)(yang)(yang)(yang)氣(qi)濃度(du)≤1%時(shi)，微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)生(sheng)(sheng)(sheng)長和繁殖(zhi)速度(du)就急(ji)劇下(xia)降，氧(yang)(yang)(yang)(yang)氣(qi)濃度(du)≤0.5%時(shi)，大多數微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)將受(shou)(shou)(shou)到抑(yi)制(zhi)而(er)停止(zhi)繁殖(zhi)。（注：真空包裝不能(neng)抑(yi)制(zhi)厭氧(yang)(yang)(yang)(yang)菌(jun)(jun)(jun)的(de)(de)繁殖(zhi)和酶反應引起(qi)的(de)(de)食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)變(bian)(bian)(bian)質和變(bian)(bian)(bian)色(se)，因(yin)此(ci)還需與其它輔助方法結(jie)合(he)，如冷藏、速凍、脫水、高溫殺菌(jun)(jun)(jun)、輻照 滅菌(jun)(jun)(jun)、微(wei)(wei)波(bo)殺菌(jun)(jun)(jun)、鹽(yan)腌(a)制(zhi)等。）真空除(chu)氧(yang)(yang)(yang)(yang)除(chu)了抑(yi)制(zhi)微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)生(sheng)(sheng)(sheng)長和繁殖(zhi)外(wai)，另(ling)一個重要功能(neng)是(shi)(shi)防(fang)止(zhi)食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)氧(yang)(yang)(yang)(yang)化(hua)(hua)，因(yin)油脂類食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)中(zhong)含有大量(liang)不飽和脂肪酸，受(shou)(shou)(shou)氧(yang)(yang)(yang)(yang)的(de)(de)作(zuo)用(yong)而(er)氧(yang)(yang)(yang)(yang)化(hua)(hua)，使(shi)食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)變(bian)(bian)(bian)味、變(bian)(bian)(bian)質，此(ci)外(wai)，氧(yang)(yang)(yang)(yang)化(hua)(hua)還使(shi)維生(sheng)(sheng)(sheng)素A和C損失(shi)，食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)色(se)素中(zhong)的(de)(de)不穩定物(wu)(wu)質受(shou)(shou)(shou)氧(yang)(yang)(yang)(yang)的(de)(de)作(zuo)用(yong)，使(shi)顏色(se)變(bian)(bian)(bian)暗。所以(yi)，除(chu)氧(yang)(yang)(yang)(yang)能(neng)有效(xiao)地(di)防(fang)止(zhi)食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)變(bian)(bian)(bian)質，保持其色(se)、香、味及(ji)營養價值。