真(zhen)(zhen)空(kong)袋的(de)(de)(de)(de)主(zhu)要(yao)作用(yong)是(shi)(shi)除氧(yang)(yang)(yang)，以有(you)利于防(fang)止(zhi)食(shi)品(pin)變(bian)(bian)質(zhi)，其(qi)原理(li)也(ye)比較簡單，因(yin)食(shi)品(pin)霉腐變(bian)(bian)質(zhi)主(zhu)要(yao)由(you)微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)(de)(de)活動造(zao)成，而(er)大多(duo)(duo)數(shu)(shu)微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物(wu)(wu)（如霉菌(jun)(jun)和(he)酵母菌(jun)(jun)）的(de)(de)(de)(de)生(sheng)(sheng)(sheng)(sheng)存(cun)是(shi)(shi)需要(yao)氧(yang)(yang)(yang)氣的(de)(de)(de)(de)，而(er)真(zhen)(zhen)空(kong)包(bao)裝就是(shi)(shi)運用(yong)這個原理(li)，把(ba)包(bao)裝袋內(nei)和(he)食(shi)品(pin)細胞內(nei)的(de)(de)(de)(de)氧(yang)(yang)(yang)氣抽掉，使(shi)微(wei)(wei)(wei)物(wu)(wu)物(wu)(wu)失去“生(sheng)(sheng)(sheng)(sheng)存(cun)的(de)(de)(de)(de)環境”。實(shi)驗證明(ming)：當包(bao)裝袋內(nei)的(de)(de)(de)(de)氧(yang)(yang)(yang)氣濃度(du)(du)≤1%時，微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)(de)(de)生(sheng)(sheng)(sheng)(sheng)長和(he)繁殖速度(du)(du)就急劇下降，氧(yang)(yang)(yang)氣濃度(du)(du)≤0.5%時，大多(duo)(duo)數(shu)(shu)微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物(wu)(wu)將(jiang)受到抑制(zhi)而(er)停止(zhi)繁殖。（注：真(zhen)(zhen)空(kong)包(bao)裝不能抑制(zhi)厭氧(yang)(yang)(yang)菌(jun)(jun)的(de)(de)(de)(de)繁殖和(he)酶反應引起的(de)(de)(de)(de)食(shi)品(pin)變(bian)(bian)質(zhi)和(he)變(bian)(bian)色，因(yin)此(ci)還需與其(qi)它(ta)輔助方法結合，如冷藏、速凍、脫水、高溫殺(sha)(sha)菌(jun)(jun)、輻照 滅菌(jun)(jun)、微(wei)(wei)(wei)波殺(sha)(sha)菌(jun)(jun)、鹽腌制(zhi)等。）真(zhen)(zhen)空(kong)除氧(yang)(yang)(yang)除了抑制(zhi)微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)(de)(de)生(sheng)(sheng)(sheng)(sheng)長和(he)繁殖外，另一個重要(yao)功能是(shi)(shi)防(fang)止(zhi)食(shi)品(pin)氧(yang)(yang)(yang)化(hua)，因(yin)油脂(zhi)類(lei)食(shi)品(pin)中(zhong)含有(you)大量不飽和(he)脂(zhi)肪酸(suan)，受氧(yang)(yang)(yang)的(de)(de)(de)(de)作用(yong)而(er)氧(yang)(yang)(yang)化(hua)，使(shi)食(shi)品(pin)變(bian)(bian)味、變(bian)(bian)質(zhi)，此(ci)外，氧(yang)(yang)(yang)化(hua)還使(shi)維生(sheng)(sheng)(sheng)(sheng)素A和(he)C損失，食(shi)品(pin)色素中(zhong)的(de)(de)(de)(de)不穩定物(wu)(wu)質(zhi)受氧(yang)(yang)(yang)的(de)(de)(de)(de)作用(yong)，使(shi)顏色變(bian)(bian)暗。所以，除氧(yang)(yang)(yang)能有(you)效地防(fang)止(zhi)食(shi)品(pin)變(bian)(bian)質(zhi)，保持其(qi)色、香、味及營養價值(zhi)。