真(zhen)(zhen)空袋的(de)(de)(de)(de)主要(yao)(yao)作(zuo)用(yong)(yong)是除氧(yang)(yang)(yang)(yang)，以有(you)(you)利于(yu)防(fang)止食(shi)(shi)品(pin)(pin)(pin)(pin)(pin)變(bian)(bian)(bian)質(zhi)(zhi)(zhi)，其(qi)原(yuan)(yuan)理(li)也比較簡單，因(yin)食(shi)(shi)品(pin)(pin)(pin)(pin)(pin)霉腐(fu)變(bian)(bian)(bian)質(zhi)(zhi)(zhi)主要(yao)(yao)由(you)微(wei)生(sheng)物(wu)的(de)(de)(de)(de)活動造成(cheng)，而大(da)多(duo)數(shu)(shu)微(wei)生(sheng)物(wu)（如霉菌(jun)(jun)和(he)酵母(mu)菌(jun)(jun)）的(de)(de)(de)(de)生(sheng)存是需要(yao)(yao)氧(yang)(yang)(yang)(yang)氣的(de)(de)(de)(de)，而真(zhen)(zhen)空包(bao)裝就是運用(yong)(yong)這(zhe)個原(yuan)(yuan)理(li)，把包(bao)裝袋內(nei)(nei)和(he)食(shi)(shi)品(pin)(pin)(pin)(pin)(pin)細胞(bao)內(nei)(nei)的(de)(de)(de)(de)氧(yang)(yang)(yang)(yang)氣抽掉，使微(wei)物(wu)物(wu)失去“生(sheng)存的(de)(de)(de)(de)環境(jing)”。實驗證(zheng)明：當包(bao)裝袋內(nei)(nei)的(de)(de)(de)(de)氧(yang)(yang)(yang)(yang)氣濃度≤1%時(shi)，微(wei)生(sheng)物(wu)的(de)(de)(de)(de)生(sheng)長和(he)繁(fan)殖(zhi)(zhi)(zhi)速度就急(ji)劇下降，氧(yang)(yang)(yang)(yang)氣濃度≤0.5%時(shi)，大(da)多(duo)數(shu)(shu)微(wei)生(sheng)物(wu)將(jiang)受(shou)到抑制而停(ting)止繁(fan)殖(zhi)(zhi)(zhi)。（注：真(zhen)(zhen)空包(bao)裝不(bu)能抑制厭(yan)氧(yang)(yang)(yang)(yang)菌(jun)(jun)的(de)(de)(de)(de)繁(fan)殖(zhi)(zhi)(zhi)和(he)酶(mei)反應引起的(de)(de)(de)(de)食(shi)(shi)品(pin)(pin)(pin)(pin)(pin)變(bian)(bian)(bian)質(zhi)(zhi)(zhi)和(he)變(bian)(bian)(bian)色(se)，因(yin)此(ci)還需與其(qi)它輔(fu)助方法結合(he)，如冷藏、速凍、脫(tuo)水、高溫殺菌(jun)(jun)、輻(fu)照(zhao) 滅菌(jun)(jun)、微(wei)波殺菌(jun)(jun)、鹽腌制等。）真(zhen)(zhen)空除氧(yang)(yang)(yang)(yang)除了抑制微(wei)生(sheng)物(wu)的(de)(de)(de)(de)生(sheng)長和(he)繁(fan)殖(zhi)(zhi)(zhi)外(wai)，另(ling)一個重要(yao)(yao)功能是防(fang)止食(shi)(shi)品(pin)(pin)(pin)(pin)(pin)氧(yang)(yang)(yang)(yang)化(hua)，因(yin)油(you)脂類食(shi)(shi)品(pin)(pin)(pin)(pin)(pin)中(zhong)含有(you)(you)大(da)量不(bu)飽和(he)脂肪酸，受(shou)氧(yang)(yang)(yang)(yang)的(de)(de)(de)(de)作(zuo)用(yong)(yong)而氧(yang)(yang)(yang)(yang)化(hua)，使食(shi)(shi)品(pin)(pin)(pin)(pin)(pin)變(bian)(bian)(bian)味、變(bian)(bian)(bian)質(zhi)(zhi)(zhi)，此(ci)外(wai)，氧(yang)(yang)(yang)(yang)化(hua)還使維生(sheng)素(su)A和(he)C損失，食(shi)(shi)品(pin)(pin)(pin)(pin)(pin)色(se)素(su)中(zhong)的(de)(de)(de)(de)不(bu)穩(wen)定(ding)物(wu)質(zhi)(zhi)(zhi)受(shou)氧(yang)(yang)(yang)(yang)的(de)(de)(de)(de)作(zuo)用(yong)(yong)，使顏色(se)變(bian)(bian)(bian)暗(an)。所以，除氧(yang)(yang)(yang)(yang)能有(you)(you)效(xiao)地(di)防(fang)止食(shi)(shi)品(pin)(pin)(pin)(pin)(pin)變(bian)(bian)(bian)質(zhi)(zhi)(zhi)，保持其(qi)色(se)、香、味及營(ying)養價值。