真(zhen)(zhen)空(kong)(kong)袋(dai)(dai)的(de)(de)主要作用(yong)(yong)是(shi)除(chu)氧(yang)，以有利于防止食(shi)(shi)(shi)品(pin)變質(zhi)(zhi)(zhi)(zhi)，其原(yuan)理(li)也(ye)比較簡單，因食(shi)(shi)(shi)品(pin)霉腐變質(zhi)(zhi)(zhi)(zhi)主要由(you)微(wei)(wei)生(sheng)(sheng)物(wu)(wu)(wu)(wu)的(de)(de)活(huo)動造成，而大多(duo)數微(wei)(wei)生(sheng)(sheng)物(wu)(wu)(wu)(wu)（如霉菌和(he)酵母菌）的(de)(de)生(sheng)(sheng)存是(shi)需要氧(yang)氣的(de)(de)，而真(zhen)(zhen)空(kong)(kong)包(bao)裝就是(shi)運(yun)用(yong)(yong)這(zhe)個原(yuan)理(li)，把包(bao)裝袋(dai)(dai)內和(he)食(shi)(shi)(shi)品(pin)細(xi)胞內的(de)(de)氧(yang)氣抽(chou)掉，使(shi)(shi)微(wei)(wei)物(wu)(wu)(wu)(wu)物(wu)(wu)(wu)(wu)失(shi)去“生(sheng)(sheng)存的(de)(de)環(huan)境”。實驗(yan)證明：當包(bao)裝袋(dai)(dai)內的(de)(de)氧(yang)氣濃度≤1%時，微(wei)(wei)生(sheng)(sheng)物(wu)(wu)(wu)(wu)的(de)(de)生(sheng)(sheng)長和(he)繁殖速度就急劇下降，氧(yang)氣濃度≤0.5%時，大多(duo)數微(wei)(wei)生(sheng)(sheng)物(wu)(wu)(wu)(wu)將(jiang)受到(dao)抑(yi)(yi)制而停(ting)止繁殖。（注(zhu)：真(zhen)(zhen)空(kong)(kong)包(bao)裝不能(neng)抑(yi)(yi)制厭氧(yang)菌的(de)(de)繁殖和(he)酶反應引起的(de)(de)食(shi)(shi)(shi)品(pin)變質(zhi)(zhi)(zhi)(zhi)和(he)變色(se)(se)，因此(ci)還需與(yu)其它輔助方(fang)法結合，如冷藏、速凍、脫(tuo)水(shui)、高(gao)溫殺菌、輻照 滅菌、微(wei)(wei)波殺菌、鹽腌制等。）真(zhen)(zhen)空(kong)(kong)除(chu)氧(yang)除(chu)了抑(yi)(yi)制微(wei)(wei)生(sheng)(sheng)物(wu)(wu)(wu)(wu)的(de)(de)生(sheng)(sheng)長和(he)繁殖外(wai)，另(ling)一個重要功能(neng)是(shi)防止食(shi)(shi)(shi)品(pin)氧(yang)化(hua)，因油(you)脂(zhi)類食(shi)(shi)(shi)品(pin)中(zhong)含(han)有大量(liang)不飽(bao)和(he)脂(zhi)肪酸，受氧(yang)的(de)(de)作用(yong)(yong)而氧(yang)化(hua)，使(shi)(shi)食(shi)(shi)(shi)品(pin)變味、變質(zhi)(zhi)(zhi)(zhi)，此(ci)外(wai)，氧(yang)化(hua)還使(shi)(shi)維生(sheng)(sheng)素A和(he)C損失(shi)，食(shi)(shi)(shi)品(pin)色(se)(se)素中(zhong)的(de)(de)不穩定物(wu)(wu)(wu)(wu)質(zhi)(zhi)(zhi)(zhi)受氧(yang)的(de)(de)作用(yong)(yong)，使(shi)(shi)顏色(se)(se)變暗(an)。所(suo)以，除(chu)氧(yang)能(neng)有效(xiao)地防止食(shi)(shi)(shi)品(pin)變質(zhi)(zhi)(zhi)(zhi)，保持(chi)其色(se)(se)、香(xiang)、味及(ji)營養價值。