真(zhen)(zhen)空(kong)袋的(de)(de)(de)(de)(de)主要作用是(shi)除氧(yang)(yang)(yang)，以(yi)有(you)利(li)于防(fang)止(zhi)食(shi)(shi)品變(bian)(bian)質(zhi)，其(qi)原理(li)也比(bi)較簡單(dan)，因食(shi)(shi)品霉(mei)腐變(bian)(bian)質(zhi)主要由微(wei)(wei)(wei)生物(wu)(wu)(wu)(wu)(wu)的(de)(de)(de)(de)(de)活動造(zao)成(cheng)，而(er)大多數(shu)微(wei)(wei)(wei)生物(wu)(wu)(wu)(wu)(wu)（如(ru)霉(mei)菌和酵母菌）的(de)(de)(de)(de)(de)生存(cun)是(shi)需(xu)要氧(yang)(yang)(yang)氣(qi)的(de)(de)(de)(de)(de)，而(er)真(zhen)(zhen)空(kong)包(bao)裝就是(shi)運用這(zhe)個(ge)原理(li)，把包(bao)裝袋內(nei)和食(shi)(shi)品細胞內(nei)的(de)(de)(de)(de)(de)氧(yang)(yang)(yang)氣(qi)抽掉，使(shi)微(wei)(wei)(wei)物(wu)(wu)(wu)(wu)(wu)物(wu)(wu)(wu)(wu)(wu)失去“生存(cun)的(de)(de)(de)(de)(de)環(huan)境”。實(shi)驗證明：當包(bao)裝袋內(nei)的(de)(de)(de)(de)(de)氧(yang)(yang)(yang)氣(qi)濃度≤1%時，微(wei)(wei)(wei)生物(wu)(wu)(wu)(wu)(wu)的(de)(de)(de)(de)(de)生長和繁殖速度就急劇下降，氧(yang)(yang)(yang)氣(qi)濃度≤0.5%時，大多數(shu)微(wei)(wei)(wei)生物(wu)(wu)(wu)(wu)(wu)將受(shou)到抑(yi)(yi)制(zhi)而(er)停止(zhi)繁殖。（注：真(zhen)(zhen)空(kong)包(bao)裝不(bu)能(neng)(neng)(neng)抑(yi)(yi)制(zhi)厭氧(yang)(yang)(yang)菌的(de)(de)(de)(de)(de)繁殖和酶反應引(yin)起的(de)(de)(de)(de)(de)食(shi)(shi)品變(bian)(bian)質(zhi)和變(bian)(bian)色(se)，因此(ci)還需(xu)與其(qi)它輔助方法結合，如(ru)冷藏、速凍、脫水、高(gao)溫殺菌、輻照(zhao) 滅菌、微(wei)(wei)(wei)波殺菌、鹽腌制(zhi)等。）真(zhen)(zhen)空(kong)除氧(yang)(yang)(yang)除了(le)抑(yi)(yi)制(zhi)微(wei)(wei)(wei)生物(wu)(wu)(wu)(wu)(wu)的(de)(de)(de)(de)(de)生長和繁殖外(wai)，另一個(ge)重(zhong)要功(gong)能(neng)(neng)(neng)是(shi)防(fang)止(zhi)食(shi)(shi)品氧(yang)(yang)(yang)化(hua)(hua)，因油脂(zhi)類(lei)食(shi)(shi)品中(zhong)含(han)有(you)大量不(bu)飽和脂(zhi)肪酸，受(shou)氧(yang)(yang)(yang)的(de)(de)(de)(de)(de)作用而(er)氧(yang)(yang)(yang)化(hua)(hua)，使(shi)食(shi)(shi)品變(bian)(bian)味、變(bian)(bian)質(zhi)，此(ci)外(wai)，氧(yang)(yang)(yang)化(hua)(hua)還使(shi)維生素A和C損(sun)失，食(shi)(shi)品色(se)素中(zhong)的(de)(de)(de)(de)(de)不(bu)穩定物(wu)(wu)(wu)(wu)(wu)質(zhi)受(shou)氧(yang)(yang)(yang)的(de)(de)(de)(de)(de)作用，使(shi)顏(yan)色(se)變(bian)(bian)暗。所以(yi)，除氧(yang)(yang)(yang)能(neng)(neng)(neng)有(you)效地防(fang)止(zhi)食(shi)(shi)品變(bian)(bian)質(zhi)，保持其(qi)色(se)、香、味及營(ying)養價值(zhi)。