真(zhen)(zhen)空(kong)(kong)(kong)袋的(de)(de)(de)主要(yao)作(zuo)(zuo)用是(shi)除(chu)氧(yang)(yang)(yang)，以(yi)有利(li)于(yu)防(fang)止(zhi)(zhi)食(shi)品(pin)(pin)變(bian)(bian)(bian)質(zhi)，其原(yuan)理(li)也比較簡單，因食(shi)品(pin)(pin)霉(mei)腐(fu)變(bian)(bian)(bian)質(zhi)主要(yao)由微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物(wu)的(de)(de)(de)活動(dong)造(zao)成，而(er)大(da)多數微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物(wu)（如(ru)(ru)霉(mei)菌(jun)(jun)和(he)酵(jiao)母菌(jun)(jun)）的(de)(de)(de)生(sheng)(sheng)(sheng)(sheng)存是(shi)需(xu)要(yao)氧(yang)(yang)(yang)氣(qi)的(de)(de)(de)，而(er)真(zhen)(zhen)空(kong)(kong)(kong)包裝(zhuang)就(jiu)是(shi)運用這個原(yuan)理(li)，把包裝(zhuang)袋內和(he)食(shi)品(pin)(pin)細胞內的(de)(de)(de)氧(yang)(yang)(yang)氣(qi)抽掉(diao)，使(shi)(shi)(shi)微(wei)(wei)(wei)物(wu)物(wu)失去(qu)“生(sheng)(sheng)(sheng)(sheng)存的(de)(de)(de)環境(jing)”。實驗(yan)證明：當包裝(zhuang)袋內的(de)(de)(de)氧(yang)(yang)(yang)氣(qi)濃(nong)度≤1%時，微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物(wu)的(de)(de)(de)生(sheng)(sheng)(sheng)(sheng)長和(he)繁殖(zhi)速(su)(su)度就(jiu)急(ji)劇下降，氧(yang)(yang)(yang)氣(qi)濃(nong)度≤0.5%時，大(da)多數微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物(wu)將受到抑制(zhi)而(er)停止(zhi)(zhi)繁殖(zhi)。（注：真(zhen)(zhen)空(kong)(kong)(kong)包裝(zhuang)不能(neng)抑制(zhi)厭(yan)氧(yang)(yang)(yang)菌(jun)(jun)的(de)(de)(de)繁殖(zhi)和(he)酶反應(ying)引起的(de)(de)(de)食(shi)品(pin)(pin)變(bian)(bian)(bian)質(zhi)和(he)變(bian)(bian)(bian)色(se)，因此還(huan)需(xu)與其它(ta)輔助(zhu)方法結合，如(ru)(ru)冷藏、速(su)(su)凍、脫(tuo)水、高溫殺(sha)菌(jun)(jun)、輻照 滅(mie)菌(jun)(jun)、微(wei)(wei)(wei)波(bo)殺(sha)菌(jun)(jun)、鹽腌制(zhi)等。）真(zhen)(zhen)空(kong)(kong)(kong)除(chu)氧(yang)(yang)(yang)除(chu)了抑制(zhi)微(wei)(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物(wu)的(de)(de)(de)生(sheng)(sheng)(sheng)(sheng)長和(he)繁殖(zhi)外(wai)，另(ling)一個重要(yao)功(gong)能(neng)是(shi)防(fang)止(zhi)(zhi)食(shi)品(pin)(pin)氧(yang)(yang)(yang)化(hua)，因油脂(zhi)(zhi)類食(shi)品(pin)(pin)中含(han)有大(da)量(liang)不飽和(he)脂(zhi)(zhi)肪酸，受氧(yang)(yang)(yang)的(de)(de)(de)作(zuo)(zuo)用而(er)氧(yang)(yang)(yang)化(hua)，使(shi)(shi)(shi)食(shi)品(pin)(pin)變(bian)(bian)(bian)味(wei)、變(bian)(bian)(bian)質(zhi)，此外(wai)，氧(yang)(yang)(yang)化(hua)還(huan)使(shi)(shi)(shi)維生(sheng)(sheng)(sheng)(sheng)素A和(he)C損失，食(shi)品(pin)(pin)色(se)素中的(de)(de)(de)不穩定物(wu)質(zhi)受氧(yang)(yang)(yang)的(de)(de)(de)作(zuo)(zuo)用，使(shi)(shi)(shi)顏色(se)變(bian)(bian)(bian)暗(an)。所(suo)以(yi)，除(chu)氧(yang)(yang)(yang)能(neng)有效地防(fang)止(zhi)(zhi)食(shi)品(pin)(pin)變(bian)(bian)(bian)質(zhi)，保(bao)持其色(se)、香、味(wei)及營(ying)養價值(zhi)。