真空袋(dai)的(de)(de)主要作用是(shi)(shi)除(chu)氧(yang)(yang)(yang)，以有(you)利于防止食(shi)(shi)品(pin)(pin)變(bian)(bian)(bian)質(zhi)(zhi)，其原理也比較簡(jian)單，因食(shi)(shi)品(pin)(pin)霉腐變(bian)(bian)(bian)質(zhi)(zhi)主要由微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)的(de)(de)活動造(zao)成，而(er)大(da)多(duo)數微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)（如霉菌(jun)和(he)(he)(he)酵(jiao)母菌(jun)）的(de)(de)生(sheng)(sheng)(sheng)存(cun)是(shi)(shi)需要氧(yang)(yang)(yang)氣(qi)(qi)的(de)(de)，而(er)真空包(bao)裝(zhuang)(zhuang)就(jiu)是(shi)(shi)運用這個原理，把包(bao)裝(zhuang)(zhuang)袋(dai)內(nei)和(he)(he)(he)食(shi)(shi)品(pin)(pin)細胞內(nei)的(de)(de)氧(yang)(yang)(yang)氣(qi)(qi)抽(chou)掉(diao)，使(shi)(shi)微(wei)(wei)物(wu)物(wu)失去“生(sheng)(sheng)(sheng)存(cun)的(de)(de)環境”。實驗證明：當包(bao)裝(zhuang)(zhuang)袋(dai)內(nei)的(de)(de)氧(yang)(yang)(yang)氣(qi)(qi)濃(nong)度(du)≤1%時(shi)，微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)的(de)(de)生(sheng)(sheng)(sheng)長和(he)(he)(he)繁(fan)殖速(su)度(du)就(jiu)急劇下降(jiang)，氧(yang)(yang)(yang)氣(qi)(qi)濃(nong)度(du)≤0.5%時(shi)，大(da)多(duo)數微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)將受(shou)到抑制而(er)停止繁(fan)殖。（注(zhu)：真空包(bao)裝(zhuang)(zhuang)不(bu)能抑制厭(yan)氧(yang)(yang)(yang)菌(jun)的(de)(de)繁(fan)殖和(he)(he)(he)酶反應(ying)引起的(de)(de)食(shi)(shi)品(pin)(pin)變(bian)(bian)(bian)質(zhi)(zhi)和(he)(he)(he)變(bian)(bian)(bian)色(se)(se)，因此還需與其它輔助方法結合，如冷(leng)藏(zang)、速(su)凍、脫水、高溫殺(sha)菌(jun)、輻照 滅(mie)菌(jun)、微(wei)(wei)波(bo)殺(sha)菌(jun)、鹽腌制等。）真空除(chu)氧(yang)(yang)(yang)除(chu)了抑制微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)的(de)(de)生(sheng)(sheng)(sheng)長和(he)(he)(he)繁(fan)殖外，另(ling)一個重要功能是(shi)(shi)防止食(shi)(shi)品(pin)(pin)氧(yang)(yang)(yang)化，因油脂類食(shi)(shi)品(pin)(pin)中含有(you)大(da)量不(bu)飽和(he)(he)(he)脂肪酸，受(shou)氧(yang)(yang)(yang)的(de)(de)作用而(er)氧(yang)(yang)(yang)化，使(shi)(shi)食(shi)(shi)品(pin)(pin)變(bian)(bian)(bian)味、變(bian)(bian)(bian)質(zhi)(zhi)，此外，氧(yang)(yang)(yang)化還使(shi)(shi)維生(sheng)(sheng)(sheng)素A和(he)(he)(he)C損失，食(shi)(shi)品(pin)(pin)色(se)(se)素中的(de)(de)不(bu)穩(wen)定物(wu)質(zhi)(zhi)受(shou)氧(yang)(yang)(yang)的(de)(de)作用，使(shi)(shi)顏色(se)(se)變(bian)(bian)(bian)暗。所以，除(chu)氧(yang)(yang)(yang)能有(you)效地防止食(shi)(shi)品(pin)(pin)變(bian)(bian)(bian)質(zhi)(zhi)，保持(chi)其色(se)(se)、香、味及營養價值。