真空(kong)(kong)袋(dai)的(de)(de)主要作用是除(chu)氧(yang)(yang)，以有利于防(fang)止(zhi)(zhi)食(shi)(shi)品(pin)(pin)變(bian)(bian)(bian)質(zhi)，其(qi)原理也比較簡(jian)單，因食(shi)(shi)品(pin)(pin)霉腐(fu)變(bian)(bian)(bian)質(zhi)主要由微(wei)(wei)生(sheng)(sheng)物(wu)(wu)(wu)(wu)的(de)(de)活動造成，而(er)大(da)多數微(wei)(wei)生(sheng)(sheng)物(wu)(wu)(wu)(wu)（如霉菌(jun)(jun)和(he)(he)酵母(mu)菌(jun)(jun)）的(de)(de)生(sheng)(sheng)存(cun)是需(xu)要氧(yang)(yang)氣(qi)的(de)(de)，而(er)真空(kong)(kong)包(bao)(bao)裝(zhuang)(zhuang)就是運用這個原理，把(ba)包(bao)(bao)裝(zhuang)(zhuang)袋(dai)內(nei)和(he)(he)食(shi)(shi)品(pin)(pin)細(xi)胞內(nei)的(de)(de)氧(yang)(yang)氣(qi)抽(chou)掉(diao)，使(shi)微(wei)(wei)物(wu)(wu)(wu)(wu)物(wu)(wu)(wu)(wu)失去“生(sheng)(sheng)存(cun)的(de)(de)環境(jing)”。實驗(yan)證(zheng)明：當(dang)包(bao)(bao)裝(zhuang)(zhuang)袋(dai)內(nei)的(de)(de)氧(yang)(yang)氣(qi)濃度≤1%時，微(wei)(wei)生(sheng)(sheng)物(wu)(wu)(wu)(wu)的(de)(de)生(sheng)(sheng)長和(he)(he)繁(fan)殖速(su)度就急(ji)劇下降(jiang)，氧(yang)(yang)氣(qi)濃度≤0.5%時，大(da)多數微(wei)(wei)生(sheng)(sheng)物(wu)(wu)(wu)(wu)將受(shou)(shou)到抑制(zhi)而(er)停止(zhi)(zhi)繁(fan)殖。（注：真空(kong)(kong)包(bao)(bao)裝(zhuang)(zhuang)不能(neng)抑制(zhi)厭(yan)氧(yang)(yang)菌(jun)(jun)的(de)(de)繁(fan)殖和(he)(he)酶反應引起(qi)的(de)(de)食(shi)(shi)品(pin)(pin)變(bian)(bian)(bian)質(zhi)和(he)(he)變(bian)(bian)(bian)色，因此還(huan)(huan)需(xu)與其(qi)它輔助方法結合，如冷(leng)藏、速(su)凍(dong)、脫水、高溫殺菌(jun)(jun)、輻照 滅(mie)菌(jun)(jun)、微(wei)(wei)波殺菌(jun)(jun)、鹽腌制(zhi)等。）真空(kong)(kong)除(chu)氧(yang)(yang)除(chu)了抑制(zhi)微(wei)(wei)生(sheng)(sheng)物(wu)(wu)(wu)(wu)的(de)(de)生(sheng)(sheng)長和(he)(he)繁(fan)殖外，另一個重要功能(neng)是防(fang)止(zhi)(zhi)食(shi)(shi)品(pin)(pin)氧(yang)(yang)化(hua)，因油脂(zhi)類食(shi)(shi)品(pin)(pin)中含有大(da)量不飽和(he)(he)脂(zhi)肪酸，受(shou)(shou)氧(yang)(yang)的(de)(de)作用而(er)氧(yang)(yang)化(hua)，使(shi)食(shi)(shi)品(pin)(pin)變(bian)(bian)(bian)味(wei)、變(bian)(bian)(bian)質(zhi)，此外，氧(yang)(yang)化(hua)還(huan)(huan)使(shi)維生(sheng)(sheng)素A和(he)(he)C損(sun)失，食(shi)(shi)品(pin)(pin)色素中的(de)(de)不穩定物(wu)(wu)(wu)(wu)質(zhi)受(shou)(shou)氧(yang)(yang)的(de)(de)作用，使(shi)顏色變(bian)(bian)(bian)暗。所以，除(chu)氧(yang)(yang)能(neng)有效地(di)防(fang)止(zhi)(zhi)食(shi)(shi)品(pin)(pin)變(bian)(bian)(bian)質(zhi)，保持其(qi)色、香、味(wei)及營養價值。