真空袋(dai)的(de)(de)(de)(de)主要(yao)作(zuo)用(yong)是(shi)(shi)除(chu)(chu)氧(yang)(yang)(yang)，以有(you)(you)利于防止(zhi)食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)變(bian)(bian)(bian)質，其原(yuan)理也比(bi)較簡單，因食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)霉(mei)腐變(bian)(bian)(bian)質主要(yao)由微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)(wu)的(de)(de)(de)(de)活動造成，而(er)(er)大多(duo)數微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)(wu)（如霉(mei)菌和(he)酵母(mu)菌）的(de)(de)(de)(de)生(sheng)(sheng)(sheng)存(cun)是(shi)(shi)需要(yao)氧(yang)(yang)(yang)氣的(de)(de)(de)(de)，而(er)(er)真空包(bao)(bao)裝(zhuang)就是(shi)(shi)運用(yong)這個原(yuan)理，把包(bao)(bao)裝(zhuang)袋(dai)內(nei)和(he)食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)細(xi)胞內(nei)的(de)(de)(de)(de)氧(yang)(yang)(yang)氣抽掉(diao)，使(shi)微(wei)(wei)物(wu)(wu)(wu)物(wu)(wu)(wu)失去“生(sheng)(sheng)(sheng)存(cun)的(de)(de)(de)(de)環(huan)境”。實驗證明(ming)：當包(bao)(bao)裝(zhuang)袋(dai)內(nei)的(de)(de)(de)(de)氧(yang)(yang)(yang)氣濃度≤1%時，微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)(wu)的(de)(de)(de)(de)生(sheng)(sheng)(sheng)長(chang)和(he)繁殖(zhi)速(su)度就急劇(ju)下(xia)降(jiang)，氧(yang)(yang)(yang)氣濃度≤0.5%時，大多(duo)數微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)(wu)將受(shou)到抑(yi)(yi)制(zhi)(zhi)而(er)(er)停止(zhi)繁殖(zhi)。（注(zhu)：真空包(bao)(bao)裝(zhuang)不能抑(yi)(yi)制(zhi)(zhi)厭氧(yang)(yang)(yang)菌的(de)(de)(de)(de)繁殖(zhi)和(he)酶反(fan)應引起(qi)的(de)(de)(de)(de)食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)變(bian)(bian)(bian)質和(he)變(bian)(bian)(bian)色(se)，因此(ci)還需與其它輔助(zhu)方法結(jie)合，如冷(leng)藏、速(su)凍、脫水、高溫殺菌、輻照 滅菌、微(wei)(wei)波(bo)殺菌、鹽腌制(zhi)(zhi)等。）真空除(chu)(chu)氧(yang)(yang)(yang)除(chu)(chu)了抑(yi)(yi)制(zhi)(zhi)微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)(wu)的(de)(de)(de)(de)生(sheng)(sheng)(sheng)長(chang)和(he)繁殖(zhi)外，另一個重要(yao)功能是(shi)(shi)防止(zhi)食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)氧(yang)(yang)(yang)化，因油脂類食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)中含有(you)(you)大量不飽和(he)脂肪酸，受(shou)氧(yang)(yang)(yang)的(de)(de)(de)(de)作(zuo)用(yong)而(er)(er)氧(yang)(yang)(yang)化，使(shi)食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)變(bian)(bian)(bian)味、變(bian)(bian)(bian)質，此(ci)外，氧(yang)(yang)(yang)化還使(shi)維生(sheng)(sheng)(sheng)素A和(he)C損失，食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)色(se)素中的(de)(de)(de)(de)不穩定物(wu)(wu)(wu)質受(shou)氧(yang)(yang)(yang)的(de)(de)(de)(de)作(zuo)用(yong)，使(shi)顏色(se)變(bian)(bian)(bian)暗。所(suo)以，除(chu)(chu)氧(yang)(yang)(yang)能有(you)(you)效(xiao)地防止(zhi)食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)變(bian)(bian)(bian)質，保(bao)持其色(se)、香、味及營(ying)養價(jia)值。