真(zhen)空(kong)袋的(de)主要作用是(shi)(shi)除(chu)氧(yang)(yang)(yang)，以有(you)利于防(fang)止(zhi)食(shi)(shi)(shi)品(pin)(pin)變(bian)質(zhi)，其原理(li)(li)也比較(jiao)簡單(dan)，因(yin)食(shi)(shi)(shi)品(pin)(pin)霉腐變(bian)質(zhi)主要由微(wei)(wei)生(sheng)(sheng)物(wu)的(de)活動(dong)造成，而(er)大(da)(da)多數微(wei)(wei)生(sheng)(sheng)物(wu)（如霉菌和酵(jiao)母菌）的(de)生(sheng)(sheng)存是(shi)(shi)需(xu)(xu)要氧(yang)(yang)(yang)氣的(de)，而(er)真(zhen)空(kong)包裝(zhuang)就是(shi)(shi)運用這個(ge)原理(li)(li)，把(ba)包裝(zhuang)袋內(nei)和食(shi)(shi)(shi)品(pin)(pin)細(xi)胞內(nei)的(de)氧(yang)(yang)(yang)氣抽掉，使(shi)微(wei)(wei)物(wu)物(wu)失(shi)去“生(sheng)(sheng)存的(de)環(huan)境”。實(shi)驗證(zheng)明：當包裝(zhuang)袋內(nei)的(de)氧(yang)(yang)(yang)氣濃(nong)度(du)(du)≤1%時，微(wei)(wei)生(sheng)(sheng)物(wu)的(de)生(sheng)(sheng)長(chang)(chang)和繁(fan)殖速(su)度(du)(du)就急劇下降，氧(yang)(yang)(yang)氣濃(nong)度(du)(du)≤0.5%時，大(da)(da)多數微(wei)(wei)生(sheng)(sheng)物(wu)將受到抑制(zhi)(zhi)而(er)停止(zhi)繁(fan)殖。（注(zhu)：真(zhen)空(kong)包裝(zhuang)不(bu)能(neng)抑制(zhi)(zhi)厭氧(yang)(yang)(yang)菌的(de)繁(fan)殖和酶反應引起的(de)食(shi)(shi)(shi)品(pin)(pin)變(bian)質(zhi)和變(bian)色(se)，因(yin)此(ci)還需(xu)(xu)與(yu)其它(ta)輔(fu)助方法結合，如冷藏、速(su)凍、脫水、高溫殺(sha)菌、輻照 滅菌、微(wei)(wei)波殺(sha)菌、鹽腌(a)制(zhi)(zhi)等。）真(zhen)空(kong)除(chu)氧(yang)(yang)(yang)除(chu)了抑制(zhi)(zhi)微(wei)(wei)生(sheng)(sheng)物(wu)的(de)生(sheng)(sheng)長(chang)(chang)和繁(fan)殖外，另(ling)一個(ge)重要功能(neng)是(shi)(shi)防(fang)止(zhi)食(shi)(shi)(shi)品(pin)(pin)氧(yang)(yang)(yang)化，因(yin)油脂(zhi)類食(shi)(shi)(shi)品(pin)(pin)中(zhong)(zhong)含有(you)大(da)(da)量不(bu)飽和脂(zhi)肪酸，受氧(yang)(yang)(yang)的(de)作用而(er)氧(yang)(yang)(yang)化，使(shi)食(shi)(shi)(shi)品(pin)(pin)變(bian)味、變(bian)質(zhi)，此(ci)外，氧(yang)(yang)(yang)化還使(shi)維生(sheng)(sheng)素(su)(su)A和C損失(shi)，食(shi)(shi)(shi)品(pin)(pin)色(se)素(su)(su)中(zhong)(zhong)的(de)不(bu)穩(wen)定物(wu)質(zhi)受氧(yang)(yang)(yang)的(de)作用，使(shi)顏色(se)變(bian)暗。所(suo)以，除(chu)氧(yang)(yang)(yang)能(neng)有(you)效地防(fang)止(zhi)食(shi)(shi)(shi)品(pin)(pin)變(bian)質(zhi)，保持其色(se)、香、味及營養價(jia)值。