真(zhen)(zhen)空(kong)袋的(de)(de)(de)主(zhu)要(yao)(yao)作(zuo)用(yong)是除氧(yang)(yang)(yang)(yang)(yang)，以有(you)利于防止(zhi)食(shi)(shi)(shi)品(pin)變(bian)質，其原理也比較簡單，因(yin)食(shi)(shi)(shi)品(pin)霉(mei)腐變(bian)質主(zhu)要(yao)(yao)由微(wei)生(sheng)(sheng)物(wu)(wu)(wu)(wu)的(de)(de)(de)活動造(zao)成，而大(da)多(duo)數微(wei)生(sheng)(sheng)物(wu)(wu)(wu)(wu)（如霉(mei)菌(jun)(jun)和酵(jiao)母菌(jun)(jun)）的(de)(de)(de)生(sheng)(sheng)存是需要(yao)(yao)氧(yang)(yang)(yang)(yang)(yang)氣(qi)的(de)(de)(de)，而真(zhen)(zhen)空(kong)包裝就是運(yun)用(yong)這(zhe)個原理，把包裝袋內(nei)和食(shi)(shi)(shi)品(pin)細胞內(nei)的(de)(de)(de)氧(yang)(yang)(yang)(yang)(yang)氣(qi)抽掉，使微(wei)物(wu)(wu)(wu)(wu)物(wu)(wu)(wu)(wu)失去(qu)“生(sheng)(sheng)存的(de)(de)(de)環境”。實驗證(zheng)明：當包裝袋內(nei)的(de)(de)(de)氧(yang)(yang)(yang)(yang)(yang)氣(qi)濃度≤1%時，微(wei)生(sheng)(sheng)物(wu)(wu)(wu)(wu)的(de)(de)(de)生(sheng)(sheng)長(chang)和繁(fan)殖速度就急劇下(xia)降，氧(yang)(yang)(yang)(yang)(yang)氣(qi)濃度≤0.5%時，大(da)多(duo)數微(wei)生(sheng)(sheng)物(wu)(wu)(wu)(wu)將(jiang)受到抑制(zhi)而停止(zhi)繁(fan)殖。（注：真(zhen)(zhen)空(kong)包裝不(bu)能(neng)(neng)抑制(zhi)厭氧(yang)(yang)(yang)(yang)(yang)菌(jun)(jun)的(de)(de)(de)繁(fan)殖和酶反應引起的(de)(de)(de)食(shi)(shi)(shi)品(pin)變(bian)質和變(bian)色(se)，因(yin)此還需與其它輔(fu)助方法結(jie)合(he)，如冷藏(zang)、速凍、脫水、高(gao)溫(wen)殺(sha)(sha)菌(jun)(jun)、輻照 滅菌(jun)(jun)、微(wei)波(bo)殺(sha)(sha)菌(jun)(jun)、鹽腌制(zhi)等。）真(zhen)(zhen)空(kong)除氧(yang)(yang)(yang)(yang)(yang)除了抑制(zhi)微(wei)生(sheng)(sheng)物(wu)(wu)(wu)(wu)的(de)(de)(de)生(sheng)(sheng)長(chang)和繁(fan)殖外(wai)(wai)，另(ling)一個重要(yao)(yao)功能(neng)(neng)是防止(zhi)食(shi)(shi)(shi)品(pin)氧(yang)(yang)(yang)(yang)(yang)化，因(yin)油脂類食(shi)(shi)(shi)品(pin)中含有(you)大(da)量不(bu)飽和脂肪(fang)酸(suan)，受氧(yang)(yang)(yang)(yang)(yang)的(de)(de)(de)作(zuo)用(yong)而氧(yang)(yang)(yang)(yang)(yang)化，使食(shi)(shi)(shi)品(pin)變(bian)味、變(bian)質，此外(wai)(wai)，氧(yang)(yang)(yang)(yang)(yang)化還使維(wei)生(sheng)(sheng)素A和C損失，食(shi)(shi)(shi)品(pin)色(se)素中的(de)(de)(de)不(bu)穩定物(wu)(wu)(wu)(wu)質受氧(yang)(yang)(yang)(yang)(yang)的(de)(de)(de)作(zuo)用(yong)，使顏色(se)變(bian)暗。所以，除氧(yang)(yang)(yang)(yang)(yang)能(neng)(neng)有(you)效地防止(zhi)食(shi)(shi)(shi)品(pin)變(bian)質，保持其色(se)、香、味及(ji)營養(yang)價值。