真空(kong)袋(dai)的(de)(de)(de)(de)主(zhu)要作用是(shi)除(chu)(chu)氧(yang)，以有(you)利于防止食(shi)品(pin)(pin)變(bian)(bian)(bian)(bian)(bian)質(zhi)(zhi)，其(qi)原理也(ye)比(bi)較簡(jian)單，因食(shi)品(pin)(pin)霉腐變(bian)(bian)(bian)(bian)(bian)質(zhi)(zhi)主(zhu)要由(you)微(wei)生(sheng)(sheng)物(wu)的(de)(de)(de)(de)活動造成(cheng)，而大多(duo)(duo)數(shu)微(wei)生(sheng)(sheng)物(wu)（如(ru)霉菌(jun)和(he)(he)酵母菌(jun)）的(de)(de)(de)(de)生(sheng)(sheng)存是(shi)需要氧(yang)氣(qi)的(de)(de)(de)(de)，而真空(kong)包(bao)(bao)(bao)裝(zhuang)就(jiu)是(shi)運用這(zhe)個原理，把包(bao)(bao)(bao)裝(zhuang)袋(dai)內和(he)(he)食(shi)品(pin)(pin)細(xi)胞內的(de)(de)(de)(de)氧(yang)氣(qi)抽掉，使(shi)(shi)微(wei)物(wu)物(wu)失去“生(sheng)(sheng)存的(de)(de)(de)(de)環(huan)境”。實驗證明：當包(bao)(bao)(bao)裝(zhuang)袋(dai)內的(de)(de)(de)(de)氧(yang)氣(qi)濃度(du)≤1%時，微(wei)生(sheng)(sheng)物(wu)的(de)(de)(de)(de)生(sheng)(sheng)長(chang)和(he)(he)繁(fan)殖(zhi)(zhi)(zhi)(zhi)速度(du)就(jiu)急劇下(xia)降，氧(yang)氣(qi)濃度(du)≤0.5%時，大多(duo)(duo)數(shu)微(wei)生(sheng)(sheng)物(wu)將受到抑制(zhi)(zhi)而停止繁(fan)殖(zhi)(zhi)(zhi)(zhi)。（注：真空(kong)包(bao)(bao)(bao)裝(zhuang)不能抑制(zhi)(zhi)厭氧(yang)菌(jun)的(de)(de)(de)(de)繁(fan)殖(zhi)(zhi)(zhi)(zhi)和(he)(he)酶(mei)反應引起的(de)(de)(de)(de)食(shi)品(pin)(pin)變(bian)(bian)(bian)(bian)(bian)質(zhi)(zhi)和(he)(he)變(bian)(bian)(bian)(bian)(bian)色(se)(se)，因此還需與其(qi)它(ta)輔(fu)助方(fang)法結(jie)合(he)，如(ru)冷藏、速凍、脫水、高(gao)溫殺(sha)菌(jun)、輻照(zhao) 滅菌(jun)、微(wei)波殺(sha)菌(jun)、鹽(yan)腌(a)制(zhi)(zhi)等。）真空(kong)除(chu)(chu)氧(yang)除(chu)(chu)了抑制(zhi)(zhi)微(wei)生(sheng)(sheng)物(wu)的(de)(de)(de)(de)生(sheng)(sheng)長(chang)和(he)(he)繁(fan)殖(zhi)(zhi)(zhi)(zhi)外，另一個重要功能是(shi)防止食(shi)品(pin)(pin)氧(yang)化，因油(you)脂(zhi)類食(shi)品(pin)(pin)中含有(you)大量不飽(bao)和(he)(he)脂(zhi)肪酸，受氧(yang)的(de)(de)(de)(de)作用而氧(yang)化，使(shi)(shi)食(shi)品(pin)(pin)變(bian)(bian)(bian)(bian)(bian)味、變(bian)(bian)(bian)(bian)(bian)質(zhi)(zhi)，此外，氧(yang)化還使(shi)(shi)維生(sheng)(sheng)素A和(he)(he)C損失，食(shi)品(pin)(pin)色(se)(se)素中的(de)(de)(de)(de)不穩定物(wu)質(zhi)(zhi)受氧(yang)的(de)(de)(de)(de)作用，使(shi)(shi)顏色(se)(se)變(bian)(bian)(bian)(bian)(bian)暗。所以，除(chu)(chu)氧(yang)能有(you)效地防止食(shi)品(pin)(pin)變(bian)(bian)(bian)(bian)(bian)質(zhi)(zhi)，保持其(qi)色(se)(se)、香(xiang)、味及營(ying)養價值。