真(zhen)空(kong)袋(dai)的(de)(de)主(zhu)(zhu)要作用是(shi)除(chu)氧(yang)，以有(you)(you)利于防止(zhi)食(shi)(shi)(shi)(shi)品(pin)(pin)變(bian)(bian)質，其原理也比較簡單，因食(shi)(shi)(shi)(shi)品(pin)(pin)霉腐變(bian)(bian)質主(zhu)(zhu)要由微生(sheng)(sheng)(sheng)物的(de)(de)活(huo)動造成(cheng)，而(er)大(da)多(duo)數微生(sheng)(sheng)(sheng)物（如霉菌和酵(jiao)母(mu)菌）的(de)(de)生(sheng)(sheng)(sheng)存(cun)(cun)是(shi)需(xu)要氧(yang)氣的(de)(de)，而(er)真(zhen)空(kong)包(bao)裝(zhuang)就是(shi)運用這(zhe)個原理，把包(bao)裝(zhuang)袋(dai)內(nei)和食(shi)(shi)(shi)(shi)品(pin)(pin)細(xi)胞內(nei)的(de)(de)氧(yang)氣抽掉(diao)，使(shi)微物物失(shi)去“生(sheng)(sheng)(sheng)存(cun)(cun)的(de)(de)環境”。實驗證明：當包(bao)裝(zhuang)袋(dai)內(nei)的(de)(de)氧(yang)氣濃(nong)(nong)度(du)≤1%時(shi)，微生(sheng)(sheng)(sheng)物的(de)(de)生(sheng)(sheng)(sheng)長和繁(fan)(fan)(fan)殖(zhi)速度(du)就急(ji)劇(ju)下降，氧(yang)氣濃(nong)(nong)度(du)≤0.5%時(shi)，大(da)多(duo)數微生(sheng)(sheng)(sheng)物將受(shou)(shou)到抑制(zhi)(zhi)而(er)停止(zhi)繁(fan)(fan)(fan)殖(zhi)。（注：真(zhen)空(kong)包(bao)裝(zhuang)不能(neng)抑制(zhi)(zhi)厭氧(yang)菌的(de)(de)繁(fan)(fan)(fan)殖(zhi)和酶(mei)反(fan)應引(yin)起的(de)(de)食(shi)(shi)(shi)(shi)品(pin)(pin)變(bian)(bian)質和變(bian)(bian)色(se)，因此還需(xu)與其它輔(fu)助方法結合，如冷藏、速凍、脫水、高溫殺菌、輻照 滅菌、微波殺菌、鹽腌制(zhi)(zhi)等(deng)。）真(zhen)空(kong)除(chu)氧(yang)除(chu)了抑制(zhi)(zhi)微生(sheng)(sheng)(sheng)物的(de)(de)生(sheng)(sheng)(sheng)長和繁(fan)(fan)(fan)殖(zhi)外，另一個重要功能(neng)是(shi)防止(zhi)食(shi)(shi)(shi)(shi)品(pin)(pin)氧(yang)化，因油脂類食(shi)(shi)(shi)(shi)品(pin)(pin)中(zhong)含(han)有(you)(you)大(da)量(liang)不飽和脂肪酸(suan)，受(shou)(shou)氧(yang)的(de)(de)作用而(er)氧(yang)化，使(shi)食(shi)(shi)(shi)(shi)品(pin)(pin)變(bian)(bian)味、變(bian)(bian)質，此外，氧(yang)化還使(shi)維生(sheng)(sheng)(sheng)素(su)A和C損(sun)失(shi)，食(shi)(shi)(shi)(shi)品(pin)(pin)色(se)素(su)中(zhong)的(de)(de)不穩(wen)定物質受(shou)(shou)氧(yang)的(de)(de)作用，使(shi)顏(yan)色(se)變(bian)(bian)暗。所(suo)以，除(chu)氧(yang)能(neng)有(you)(you)效地防止(zhi)食(shi)(shi)(shi)(shi)品(pin)(pin)變(bian)(bian)質，保(bao)持其色(se)、香、味及營養價(jia)值。