真空袋的(de)(de)主(zhu)要(yao)作用(yong)(yong)是(shi)(shi)除氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)，以有(you)利于防止(zhi)食(shi)(shi)(shi)品(pin)變質(zhi)(zhi)(zhi)，其(qi)原理也(ye)比較簡單，因食(shi)(shi)(shi)品(pin)霉腐變質(zhi)(zhi)(zhi)主(zhu)要(yao)由微(wei)(wei)生(sheng)(sheng)物(wu)(wu)的(de)(de)活動造成，而大(da)多數微(wei)(wei)生(sheng)(sheng)物(wu)(wu)（如霉菌(jun)(jun)(jun)和(he)(he)(he)(he)(he)酵(jiao)母菌(jun)(jun)(jun)）的(de)(de)生(sheng)(sheng)存(cun)(cun)是(shi)(shi)需(xu)要(yao)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)氣(qi)的(de)(de)，而真空包(bao)(bao)裝就是(shi)(shi)運用(yong)(yong)這個原理，把包(bao)(bao)裝袋內和(he)(he)(he)(he)(he)食(shi)(shi)(shi)品(pin)細胞內的(de)(de)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)氣(qi)抽掉，使(shi)微(wei)(wei)物(wu)(wu)物(wu)(wu)失去“生(sheng)(sheng)存(cun)(cun)的(de)(de)環(huan)境”。實(shi)驗(yan)證明：當包(bao)(bao)裝袋內的(de)(de)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)氣(qi)濃(nong)度(du)≤1%時，微(wei)(wei)生(sheng)(sheng)物(wu)(wu)的(de)(de)生(sheng)(sheng)長(chang)和(he)(he)(he)(he)(he)繁(fan)殖速(su)度(du)就急(ji)劇下降，氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)氣(qi)濃(nong)度(du)≤0.5%時，大(da)多數微(wei)(wei)生(sheng)(sheng)物(wu)(wu)將受到抑制而停止(zhi)繁(fan)殖。（注：真空包(bao)(bao)裝不能(neng)抑制厭(yan)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)菌(jun)(jun)(jun)的(de)(de)繁(fan)殖和(he)(he)(he)(he)(he)酶反應引起的(de)(de)食(shi)(shi)(shi)品(pin)變質(zhi)(zhi)(zhi)和(he)(he)(he)(he)(he)變色(se)，因此還需(xu)與(yu)其(qi)它輔助(zhu)方法結合，如冷藏(zang)、速(su)凍、脫水、高溫(wen)殺(sha)菌(jun)(jun)(jun)、輻(fu)照 滅菌(jun)(jun)(jun)、微(wei)(wei)波(bo)殺(sha)菌(jun)(jun)(jun)、鹽(yan)腌(a)制等。）真空除氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)除了(le)抑制微(wei)(wei)生(sheng)(sheng)物(wu)(wu)的(de)(de)生(sheng)(sheng)長(chang)和(he)(he)(he)(he)(he)繁(fan)殖外，另一個重要(yao)功能(neng)是(shi)(shi)防止(zhi)食(shi)(shi)(shi)品(pin)氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化，因油脂(zhi)類食(shi)(shi)(shi)品(pin)中含有(you)大(da)量不飽和(he)(he)(he)(he)(he)脂(zhi)肪酸，受氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)的(de)(de)作用(yong)(yong)而氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化，使(shi)食(shi)(shi)(shi)品(pin)變味(wei)、變質(zhi)(zhi)(zhi)，此外，氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)化還使(shi)維生(sheng)(sheng)素(su)A和(he)(he)(he)(he)(he)C損失，食(shi)(shi)(shi)品(pin)色(se)素(su)中的(de)(de)不穩定物(wu)(wu)質(zhi)(zhi)(zhi)受氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)的(de)(de)作用(yong)(yong)，使(shi)顏色(se)變暗(an)。所以，除氧(yang)(yang)(yang)(yang)(yang)(yang)(yang)能(neng)有(you)效地防止(zhi)食(shi)(shi)(shi)品(pin)變質(zhi)(zhi)(zhi)，保持其(qi)色(se)、香、味(wei)及營養價值。