真空袋的(de)(de)(de)(de)主(zhu)要(yao)作用(yong)(yong)是(shi)(shi)(shi)除(chu)氧(yang)(yang)，以(yi)有(you)(you)(you)利于(yu)防止(zhi)食(shi)(shi)(shi)品(pin)變(bian)質(zhi)(zhi)，其原(yuan)理也比(bi)較(jiao)簡單，因食(shi)(shi)(shi)品(pin)霉腐變(bian)質(zhi)(zhi)主(zhu)要(yao)由微(wei)(wei)(wei)(wei)生(sheng)物(wu)(wu)的(de)(de)(de)(de)活動造(zao)成，而大多(duo)數微(wei)(wei)(wei)(wei)生(sheng)物(wu)(wu)（如霉菌和酵(jiao)母菌）的(de)(de)(de)(de)生(sheng)存是(shi)(shi)(shi)需(xu)要(yao)氧(yang)(yang)氣(qi)(qi)的(de)(de)(de)(de)，而真空包(bao)裝(zhuang)(zhuang)就是(shi)(shi)(shi)運(yun)用(yong)(yong)這個原(yuan)理，把包(bao)裝(zhuang)(zhuang)袋內(nei)(nei)和食(shi)(shi)(shi)品(pin)細胞內(nei)(nei)的(de)(de)(de)(de)氧(yang)(yang)氣(qi)(qi)抽(chou)掉，使微(wei)(wei)(wei)(wei)物(wu)(wu)物(wu)(wu)失去(qu)“生(sheng)存的(de)(de)(de)(de)環(huan)境”。實驗證(zheng)明：當包(bao)裝(zhuang)(zhuang)袋內(nei)(nei)的(de)(de)(de)(de)氧(yang)(yang)氣(qi)(qi)濃(nong)度≤1%時(shi)，微(wei)(wei)(wei)(wei)生(sheng)物(wu)(wu)的(de)(de)(de)(de)生(sheng)長和繁殖(zhi)速度就急(ji)劇下降，氧(yang)(yang)氣(qi)(qi)濃(nong)度≤0.5%時(shi)，大多(duo)數微(wei)(wei)(wei)(wei)生(sheng)物(wu)(wu)將受(shou)到抑制而停止(zhi)繁殖(zhi)。（注(zhu)：真空包(bao)裝(zhuang)(zhuang)不能抑制厭氧(yang)(yang)菌的(de)(de)(de)(de)繁殖(zhi)和酶反(fan)應引起的(de)(de)(de)(de)食(shi)(shi)(shi)品(pin)變(bian)質(zhi)(zhi)和變(bian)色(se)，因此(ci)還(huan)(huan)需(xu)與(yu)其它輔(fu)助方法結合(he)，如冷藏、速凍(dong)、脫水、高溫殺菌、輻照 滅菌、微(wei)(wei)(wei)(wei)波殺菌、鹽腌制等。）真空除(chu)氧(yang)(yang)除(chu)了抑制微(wei)(wei)(wei)(wei)生(sheng)物(wu)(wu)的(de)(de)(de)(de)生(sheng)長和繁殖(zhi)外(wai)，另一個重要(yao)功(gong)能是(shi)(shi)(shi)防止(zhi)食(shi)(shi)(shi)品(pin)氧(yang)(yang)化，因油脂(zhi)(zhi)類食(shi)(shi)(shi)品(pin)中含有(you)(you)(you)大量(liang)不飽和脂(zhi)(zhi)肪(fang)酸，受(shou)氧(yang)(yang)的(de)(de)(de)(de)作用(yong)(yong)而氧(yang)(yang)化，使食(shi)(shi)(shi)品(pin)變(bian)味、變(bian)質(zhi)(zhi)，此(ci)外(wai)，氧(yang)(yang)化還(huan)(huan)使維生(sheng)素A和C損(sun)失，食(shi)(shi)(shi)品(pin)色(se)素中的(de)(de)(de)(de)不穩定物(wu)(wu)質(zhi)(zhi)受(shou)氧(yang)(yang)的(de)(de)(de)(de)作用(yong)(yong)，使顏色(se)變(bian)暗。所以(yi)，除(chu)氧(yang)(yang)能有(you)(you)(you)效地防止(zhi)食(shi)(shi)(shi)品(pin)變(bian)質(zhi)(zhi)，保持其色(se)、香、味及營(ying)養價值(zhi)。