真(zhen)空(kong)袋(dai)(dai)的(de)(de)主要(yao)(yao)(yao)作用是(shi)除氧(yang)(yang)(yang)，以(yi)有(you)利(li)于防(fang)(fang)止(zhi)食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)變(bian)質(zhi)(zhi)，其(qi)原理也比較(jiao)簡單(dan)，因食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)霉腐變(bian)質(zhi)(zhi)主要(yao)(yao)(yao)由微(wei)(wei)生(sheng)(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)(wu)(wu)的(de)(de)活動造成，而(er)大多數(shu)微(wei)(wei)生(sheng)(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)(wu)(wu)（如(ru)霉菌(jun)(jun)(jun)和(he)(he)(he)酵母菌(jun)(jun)(jun)）的(de)(de)生(sheng)(sheng)(sheng)(sheng)(sheng)(sheng)存是(shi)需要(yao)(yao)(yao)氧(yang)(yang)(yang)氣(qi)的(de)(de)，而(er)真(zhen)空(kong)包裝(zhuang)(zhuang)就是(shi)運用這(zhe)個原理，把(ba)包裝(zhuang)(zhuang)袋(dai)(dai)內和(he)(he)(he)食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)細(xi)胞內的(de)(de)氧(yang)(yang)(yang)氣(qi)抽(chou)掉，使(shi)微(wei)(wei)物(wu)(wu)(wu)物(wu)(wu)(wu)失(shi)去“生(sheng)(sheng)(sheng)(sheng)(sheng)(sheng)存的(de)(de)環境”。實驗證明(ming)：當包裝(zhuang)(zhuang)袋(dai)(dai)內的(de)(de)氧(yang)(yang)(yang)氣(qi)濃度(du)≤1%時，微(wei)(wei)生(sheng)(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)(wu)(wu)的(de)(de)生(sheng)(sheng)(sheng)(sheng)(sheng)(sheng)長和(he)(he)(he)繁殖(zhi)(zhi)速度(du)就急(ji)劇下降，氧(yang)(yang)(yang)氣(qi)濃度(du)≤0.5%時，大多數(shu)微(wei)(wei)生(sheng)(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)(wu)(wu)將(jiang)受(shou)到抑制(zhi)(zhi)而(er)停止(zhi)繁殖(zhi)(zhi)。（注：真(zhen)空(kong)包裝(zhuang)(zhuang)不(bu)(bu)能(neng)抑制(zhi)(zhi)厭氧(yang)(yang)(yang)菌(jun)(jun)(jun)的(de)(de)繁殖(zhi)(zhi)和(he)(he)(he)酶(mei)反應引起(qi)的(de)(de)食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)變(bian)質(zhi)(zhi)和(he)(he)(he)變(bian)色，因此還(huan)需與其(qi)它輔助方法(fa)結合，如(ru)冷藏、速凍、脫水(shui)、高溫殺菌(jun)(jun)(jun)、輻照 滅菌(jun)(jun)(jun)、微(wei)(wei)波殺菌(jun)(jun)(jun)、鹽腌制(zhi)(zhi)等。）真(zhen)空(kong)除氧(yang)(yang)(yang)除了抑制(zhi)(zhi)微(wei)(wei)生(sheng)(sheng)(sheng)(sheng)(sheng)(sheng)物(wu)(wu)(wu)的(de)(de)生(sheng)(sheng)(sheng)(sheng)(sheng)(sheng)長和(he)(he)(he)繁殖(zhi)(zhi)外，另一個重要(yao)(yao)(yao)功(gong)能(neng)是(shi)防(fang)(fang)止(zhi)食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)氧(yang)(yang)(yang)化，因油脂類(lei)食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)中含(han)有(you)大量不(bu)(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)食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)變(bian)味、變(bian)質(zhi)(zhi)，此外，氧(yang)(yang)(yang)化還(huan)使(shi)維生(sheng)(sheng)(sheng)(sheng)(sheng)(sheng)素A和(he)(he)(he)C損失(shi)，食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)色素中的(de)(de)不(bu)(bu)穩定物(wu)(wu)(wu)質(zhi)(zhi)受(shou)氧(yang)(yang)(yang)的(de)(de)作用，使(shi)顏色變(bian)暗。所以(yi)，除氧(yang)(yang)(yang)能(neng)有(you)效地防(fang)(fang)止(zhi)食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)變(bian)質(zhi)(zhi)，保持其(qi)色、香、味及營養價(jia)值。