真空袋的主(zhu)(zhu)要(yao)(yao)作用(yong)(yong)是(shi)除(chu)(chu)氧(yang)(yang)(yang)(yang)(yang)(yang)，以有(you)利于防(fang)止(zhi)食(shi)(shi)品(pin)變質(zhi)(zhi)，其(qi)原(yuan)理也比較簡單(dan)，因食(shi)(shi)品(pin)霉腐變質(zhi)(zhi)主(zhu)(zhu)要(yao)(yao)由微(wei)(wei)生(sheng)物(wu)的活動造成，而(er)(er)大(da)多數微(wei)(wei)生(sheng)物(wu)（如(ru)霉菌(jun)(jun)(jun)和(he)(he)酵母菌(jun)(jun)(jun)）的生(sheng)存是(shi)需要(yao)(yao)氧(yang)(yang)(yang)(yang)(yang)(yang)氣(qi)的，而(er)(er)真空包(bao)(bao)裝就是(shi)運用(yong)(yong)這個原(yuan)理，把包(bao)(bao)裝袋內和(he)(he)食(shi)(shi)品(pin)細胞內的氧(yang)(yang)(yang)(yang)(yang)(yang)氣(qi)抽(chou)掉，使微(wei)(wei)物(wu)物(wu)失去(qu)“生(sheng)存的環境”。實(shi)驗(yan)證明：當包(bao)(bao)裝袋內的氧(yang)(yang)(yang)(yang)(yang)(yang)氣(qi)濃(nong)度≤1%時，微(wei)(wei)生(sheng)物(wu)的生(sheng)長和(he)(he)繁(fan)殖速度就急劇下(xia)降，氧(yang)(yang)(yang)(yang)(yang)(yang)氣(qi)濃(nong)度≤0.5%時，大(da)多數微(wei)(wei)生(sheng)物(wu)將受到抑(yi)(yi)制而(er)(er)停止(zhi)繁(fan)殖。（注：真空包(bao)(bao)裝不能抑(yi)(yi)制厭氧(yang)(yang)(yang)(yang)(yang)(yang)菌(jun)(jun)(jun)的繁(fan)殖和(he)(he)酶(mei)反應(ying)引(yin)起的食(shi)(shi)品(pin)變質(zhi)(zhi)和(he)(he)變色(se)，因此(ci)還(huan)需與其(qi)它輔助方法結合，如(ru)冷藏、速凍(dong)、脫水(shui)、高溫殺(sha)菌(jun)(jun)(jun)、輻照 滅菌(jun)(jun)(jun)、微(wei)(wei)波殺(sha)菌(jun)(jun)(jun)、鹽(yan)腌制等。）真空除(chu)(chu)氧(yang)(yang)(yang)(yang)(yang)(yang)除(chu)(chu)了抑(yi)(yi)制微(wei)(wei)生(sheng)物(wu)的生(sheng)長和(he)(he)繁(fan)殖外(wai)(wai)，另一個重要(yao)(yao)功能是(shi)防(fang)止(zhi)食(shi)(shi)品(pin)氧(yang)(yang)(yang)(yang)(yang)(yang)化(hua)，因油脂(zhi)類食(shi)(shi)品(pin)中(zhong)含有(you)大(da)量不飽(bao)和(he)(he)脂(zhi)肪酸，受氧(yang)(yang)(yang)(yang)(yang)(yang)的作用(yong)(yong)而(er)(er)氧(yang)(yang)(yang)(yang)(yang)(yang)化(hua)，使食(shi)(shi)品(pin)變味(wei)、變質(zhi)(zhi)，此(ci)外(wai)(wai)，氧(yang)(yang)(yang)(yang)(yang)(yang)化(hua)還(huan)使維生(sheng)素A和(he)(he)C損失，食(shi)(shi)品(pin)色(se)素中(zhong)的不穩定(ding)物(wu)質(zhi)(zhi)受氧(yang)(yang)(yang)(yang)(yang)(yang)的作用(yong)(yong)，使顏色(se)變暗。所以，除(chu)(chu)氧(yang)(yang)(yang)(yang)(yang)(yang)能有(you)效(xiao)地防(fang)止(zhi)食(shi)(shi)品(pin)變質(zhi)(zhi)，保(bao)持其(qi)色(se)、香、味(wei)及營養價值。