真(zhen)空(kong)袋(dai)的(de)主(zhu)要作用(yong)(yong)是(shi)除(chu)氧(yang)(yang)(yang)，以有(you)利于防止(zhi)食(shi)(shi)(shi)(shi)品變(bian)質(zhi)，其(qi)(qi)原理也(ye)比較簡單，因食(shi)(shi)(shi)(shi)品霉腐變(bian)質(zhi)主(zhu)要由(you)微(wei)生(sheng)(sheng)(sheng)物(wu)(wu)的(de)活動造成，而大(da)多數微(wei)生(sheng)(sheng)(sheng)物(wu)(wu)（如霉菌和(he)酵母菌）的(de)生(sheng)(sheng)(sheng)存(cun)是(shi)需要氧(yang)(yang)(yang)氣(qi)的(de)，而真(zhen)空(kong)包(bao)裝(zhuang)就是(shi)運用(yong)(yong)這個(ge)原理，把(ba)包(bao)裝(zhuang)袋(dai)內(nei)(nei)和(he)食(shi)(shi)(shi)(shi)品細胞內(nei)(nei)的(de)氧(yang)(yang)(yang)氣(qi)抽掉(diao)，使(shi)(shi)微(wei)物(wu)(wu)物(wu)(wu)失(shi)去“生(sheng)(sheng)(sheng)存(cun)的(de)環境(jing)”。實驗證明：當包(bao)裝(zhuang)袋(dai)內(nei)(nei)的(de)氧(yang)(yang)(yang)氣(qi)濃(nong)度(du)≤1%時(shi)，微(wei)生(sheng)(sheng)(sheng)物(wu)(wu)的(de)生(sheng)(sheng)(sheng)長和(he)繁殖(zhi)速(su)度(du)就急劇下(xia)降，氧(yang)(yang)(yang)氣(qi)濃(nong)度(du)≤0.5%時(shi)，大(da)多數微(wei)生(sheng)(sheng)(sheng)物(wu)(wu)將(jiang)受(shou)(shou)到抑(yi)制而停止(zhi)繁殖(zhi)。（注：真(zhen)空(kong)包(bao)裝(zhuang)不(bu)能(neng)抑(yi)制厭氧(yang)(yang)(yang)菌的(de)繁殖(zhi)和(he)酶(mei)反應(ying)引(yin)起的(de)食(shi)(shi)(shi)(shi)品變(bian)質(zhi)和(he)變(bian)色(se)(se)，因此還需與其(qi)(qi)它(ta)輔助方法結(jie)合，如冷藏、速(su)凍、脫水(shui)、高溫(wen)殺菌、輻(fu)照 滅菌、微(wei)波殺菌、鹽腌制等。）真(zhen)空(kong)除(chu)氧(yang)(yang)(yang)除(chu)了抑(yi)制微(wei)生(sheng)(sheng)(sheng)物(wu)(wu)的(de)生(sheng)(sheng)(sheng)長和(he)繁殖(zhi)外，另一個(ge)重要功(gong)能(neng)是(shi)防止(zhi)食(shi)(shi)(shi)(shi)品氧(yang)(yang)(yang)化(hua)，因油(you)脂類(lei)食(shi)(shi)(shi)(shi)品中含有(you)大(da)量不(bu)飽(bao)和(he)脂肪酸，受(shou)(shou)氧(yang)(yang)(yang)的(de)作用(yong)(yong)而氧(yang)(yang)(yang)化(hua)，使(shi)(shi)食(shi)(shi)(shi)(shi)品變(bian)味、變(bian)質(zhi)，此外，氧(yang)(yang)(yang)化(hua)還使(shi)(shi)維生(sheng)(sheng)(sheng)素(su)A和(he)C損(sun)失(shi)，食(shi)(shi)(shi)(shi)品色(se)(se)素(su)中的(de)不(bu)穩定物(wu)(wu)質(zhi)受(shou)(shou)氧(yang)(yang)(yang)的(de)作用(yong)(yong)，使(shi)(shi)顏色(se)(se)變(bian)暗。所以，除(chu)氧(yang)(yang)(yang)能(neng)有(you)效地防止(zhi)食(shi)(shi)(shi)(shi)品變(bian)質(zhi)，保持其(qi)(qi)色(se)(se)、香(xiang)、味及營養(yang)價值。