真空(kong)袋的(de)主要(yao)作用是(shi)除氧(yang)(yang)(yang)(yang)(yang)(yang)，以有利于防止(zhi)食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)變質，其原理也比(bi)較簡單，因食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)霉腐變質主要(yao)由(you)微生(sheng)(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)的(de)活動造(zao)成，而(er)(er)大(da)多(duo)數微生(sheng)(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)（如霉菌(jun)(jun)和(he)(he)酵母菌(jun)(jun)）的(de)生(sheng)(sheng)(sheng)(sheng)(sheng)(sheng)存(cun)是(shi)需要(yao)氧(yang)(yang)(yang)(yang)(yang)(yang)氣(qi)(qi)(qi)的(de)，而(er)(er)真空(kong)包(bao)裝(zhuang)就(jiu)是(shi)運(yun)用這個(ge)原理，把包(bao)裝(zhuang)袋內和(he)(he)食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)細胞內的(de)氧(yang)(yang)(yang)(yang)(yang)(yang)氣(qi)(qi)(qi)抽(chou)掉，使(shi)微物(wu)物(wu)失去“生(sheng)(sheng)(sheng)(sheng)(sheng)(sheng)存(cun)的(de)環境(jing)”。實驗(yan)證(zheng)明：當包(bao)裝(zhuang)袋內的(de)氧(yang)(yang)(yang)(yang)(yang)(yang)氣(qi)(qi)(qi)濃(nong)(nong)度(du)≤1%時，微生(sheng)(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)的(de)生(sheng)(sheng)(sheng)(sheng)(sheng)(sheng)長(chang)和(he)(he)繁(fan)殖(zhi)(zhi)速(su)度(du)就(jiu)急劇下降，氧(yang)(yang)(yang)(yang)(yang)(yang)氣(qi)(qi)(qi)濃(nong)(nong)度(du)≤0.5%時，大(da)多(duo)數微生(sheng)(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)將受到(dao)抑(yi)制(zhi)而(er)(er)停止(zhi)繁(fan)殖(zhi)(zhi)。（注(zhu)：真空(kong)包(bao)裝(zhuang)不能(neng)抑(yi)制(zhi)厭(yan)氧(yang)(yang)(yang)(yang)(yang)(yang)菌(jun)(jun)的(de)繁(fan)殖(zhi)(zhi)和(he)(he)酶反應引起的(de)食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)變質和(he)(he)變色，因此還需與其它輔助(zhu)方法結(jie)合，如冷藏、速(su)凍、脫水、高溫(wen)殺菌(jun)(jun)、輻(fu)照 滅菌(jun)(jun)、微波殺菌(jun)(jun)、鹽腌制(zhi)等。）真空(kong)除氧(yang)(yang)(yang)(yang)(yang)(yang)除了抑(yi)制(zhi)微生(sheng)(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)的(de)生(sheng)(sheng)(sheng)(sheng)(sheng)(sheng)長(chang)和(he)(he)繁(fan)殖(zhi)(zhi)外，另一個(ge)重要(yao)功(gong)能(neng)是(shi)防止(zhi)食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)氧(yang)(yang)(yang)(yang)(yang)(yang)化，因油(you)脂(zhi)類食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)中(zhong)含(han)有大(da)量不飽和(he)(he)脂(zhi)肪酸，受氧(yang)(yang)(yang)(yang)(yang)(yang)的(de)作用而(er)(er)氧(yang)(yang)(yang)(yang)(yang)(yang)化，使(shi)食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)變味、變質，此外，氧(yang)(yang)(yang)(yang)(yang)(yang)化還使(shi)維生(sheng)(sheng)(sheng)(sheng)(sheng)(sheng)素A和(he)(he)C損(sun)失，食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)色素中(zhong)的(de)不穩定物(wu)質受氧(yang)(yang)(yang)(yang)(yang)(yang)的(de)作用，使(shi)顏色變暗。所以，除氧(yang)(yang)(yang)(yang)(yang)(yang)能(neng)有效地(di)防止(zhi)食(shi)(shi)(shi)(shi)品(pin)(pin)(pin)變質，保持其色、香、味及營養價值。