真空(kong)(kong)袋(dai)的(de)主(zhu)要(yao)作用(yong)是(shi)(shi)除氧(yang)(yang)(yang)(yang)，以有(you)利于(yu)防止(zhi)(zhi)食(shi)品(pin)變(bian)質，其原理(li)也比較簡(jian)單(dan)，因食(shi)品(pin)霉腐變(bian)質主(zhu)要(yao)由微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)(wu)(wu)的(de)活動造成，而(er)大多數(shu)微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)(wu)(wu)（如(ru)霉菌(jun)(jun)和(he)酵母菌(jun)(jun)）的(de)生(sheng)(sheng)(sheng)(sheng)(sheng)存是(shi)(shi)需要(yao)氧(yang)(yang)(yang)(yang)氣(qi)的(de)，而(er)真空(kong)(kong)包(bao)(bao)裝就是(shi)(shi)運用(yong)這個原理(li)，把包(bao)(bao)裝袋(dai)內和(he)食(shi)品(pin)細胞內的(de)氧(yang)(yang)(yang)(yang)氣(qi)抽掉，使微(wei)(wei)(wei)物(wu)(wu)(wu)物(wu)(wu)(wu)失去“生(sheng)(sheng)(sheng)(sheng)(sheng)存的(de)環境”。實驗(yan)證明：當(dang)包(bao)(bao)裝袋(dai)內的(de)氧(yang)(yang)(yang)(yang)氣(qi)濃(nong)度≤1%時(shi)，微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)(wu)(wu)的(de)生(sheng)(sheng)(sheng)(sheng)(sheng)長和(he)繁殖(zhi)速(su)度就急(ji)劇下降，氧(yang)(yang)(yang)(yang)氣(qi)濃(nong)度≤0.5%時(shi)，大多數(shu)微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)(wu)(wu)將受到(dao)抑(yi)制而(er)停止(zhi)(zhi)繁殖(zhi)。（注：真空(kong)(kong)包(bao)(bao)裝不(bu)能(neng)抑(yi)制厭氧(yang)(yang)(yang)(yang)菌(jun)(jun)的(de)繁殖(zhi)和(he)酶反應引起(qi)的(de)食(shi)品(pin)變(bian)質和(he)變(bian)色(se)，因此還需與其它(ta)輔助方法結(jie)合，如(ru)冷藏(zang)、速(su)凍、脫水、高溫殺菌(jun)(jun)、輻照(zhao) 滅(mie)菌(jun)(jun)、微(wei)(wei)(wei)波殺菌(jun)(jun)、鹽(yan)腌(a)制等(deng)。）真空(kong)(kong)除氧(yang)(yang)(yang)(yang)除了抑(yi)制微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)(wu)(wu)的(de)生(sheng)(sheng)(sheng)(sheng)(sheng)長和(he)繁殖(zhi)外，另一個重(zhong)要(yao)功能(neng)是(shi)(shi)防止(zhi)(zhi)食(shi)品(pin)氧(yang)(yang)(yang)(yang)化，因油脂類食(shi)品(pin)中含有(you)大量(liang)不(bu)飽和(he)脂肪酸，受氧(yang)(yang)(yang)(yang)的(de)作用(yong)而(er)氧(yang)(yang)(yang)(yang)化，使食(shi)品(pin)變(bian)味(wei)、變(bian)質，此外，氧(yang)(yang)(yang)(yang)化還使維生(sheng)(sheng)(sheng)(sheng)(sheng)素(su)A和(he)C損失，食(shi)品(pin)色(se)素(su)中的(de)不(bu)穩定(ding)物(wu)(wu)(wu)質受氧(yang)(yang)(yang)(yang)的(de)作用(yong)，使顏色(se)變(bian)暗。所以，除氧(yang)(yang)(yang)(yang)能(neng)有(you)效地(di)防止(zhi)(zhi)食(shi)品(pin)變(bian)質，保持其色(se)、香、味(wei)及營養(yang)價值。