真(zhen)空(kong)(kong)袋(dai)的(de)(de)主要(yao)作(zuo)用(yong)(yong)是(shi)(shi)除氧(yang)(yang)(yang)，以有(you)利于防(fang)止食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)變(bian)質(zhi)(zhi)，其(qi)原理(li)也比較簡單，因食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)霉腐變(bian)質(zhi)(zhi)主要(yao)由(you)微(wei)(wei)生(sheng)(sheng)物(wu)(wu)的(de)(de)活(huo)動造(zao)成(cheng)，而大多數微(wei)(wei)生(sheng)(sheng)物(wu)(wu)（如霉菌(jun)(jun)(jun)和(he)(he)酵母菌(jun)(jun)(jun)）的(de)(de)生(sheng)(sheng)存是(shi)(shi)需要(yao)氧(yang)(yang)(yang)氣(qi)(qi)的(de)(de)，而真(zhen)空(kong)(kong)包裝(zhuang)就是(shi)(shi)運用(yong)(yong)這個原理(li)，把包裝(zhuang)袋(dai)內(nei)和(he)(he)食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)細胞內(nei)的(de)(de)氧(yang)(yang)(yang)氣(qi)(qi)抽掉，使(shi)(shi)微(wei)(wei)物(wu)(wu)物(wu)(wu)失去(qu)“生(sheng)(sheng)存的(de)(de)環境(jing)”。實驗證明(ming)：當包裝(zhuang)袋(dai)內(nei)的(de)(de)氧(yang)(yang)(yang)氣(qi)(qi)濃度≤1%時(shi)，微(wei)(wei)生(sheng)(sheng)物(wu)(wu)的(de)(de)生(sheng)(sheng)長(chang)和(he)(he)繁(fan)殖(zhi)速度就急劇下降，氧(yang)(yang)(yang)氣(qi)(qi)濃度≤0.5%時(shi)，大多數微(wei)(wei)生(sheng)(sheng)物(wu)(wu)將受到抑(yi)制(zhi)而停止繁(fan)殖(zhi)。（注：真(zhen)空(kong)(kong)包裝(zhuang)不能抑(yi)制(zhi)厭氧(yang)(yang)(yang)菌(jun)(jun)(jun)的(de)(de)繁(fan)殖(zhi)和(he)(he)酶反應引起的(de)(de)食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)變(bian)質(zhi)(zhi)和(he)(he)變(bian)色(se)，因此還(huan)需與(yu)其(qi)它輔(fu)助方法結合，如冷藏、速凍、脫水(shui)、高(gao)溫殺菌(jun)(jun)(jun)、輻(fu)照 滅菌(jun)(jun)(jun)、微(wei)(wei)波(bo)殺菌(jun)(jun)(jun)、鹽腌(a)制(zhi)等。）真(zhen)空(kong)(kong)除氧(yang)(yang)(yang)除了抑(yi)制(zhi)微(wei)(wei)生(sheng)(sheng)物(wu)(wu)的(de)(de)生(sheng)(sheng)長(chang)和(he)(he)繁(fan)殖(zhi)外，另一個重(zhong)要(yao)功能是(shi)(shi)防(fang)止食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)氧(yang)(yang)(yang)化，因油脂類食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)中含有(you)大量不飽和(he)(he)脂肪酸，受氧(yang)(yang)(yang)的(de)(de)作(zuo)用(yong)(yong)而氧(yang)(yang)(yang)化，使(shi)(shi)食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)變(bian)味(wei)、變(bian)質(zhi)(zhi)，此外，氧(yang)(yang)(yang)化還(huan)使(shi)(shi)維生(sheng)(sheng)素(su)(su)A和(he)(he)C損失，食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)色(se)素(su)(su)中的(de)(de)不穩定物(wu)(wu)質(zhi)(zhi)受氧(yang)(yang)(yang)的(de)(de)作(zuo)用(yong)(yong)，使(shi)(shi)顏色(se)變(bian)暗。所以，除氧(yang)(yang)(yang)能有(you)效地(di)防(fang)止食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)變(bian)質(zhi)(zhi)，保持其(qi)色(se)、香(xiang)、味(wei)及(ji)營養價值。