真(zhen)空(kong)袋(dai)的(de)(de)(de)主要(yao)作用(yong)是(shi)除(chu)氧(yang)(yang)(yang)(yang)(yang)，以有(you)(you)利于防(fang)(fang)(fang)止(zhi)食(shi)品(pin)(pin)變(bian)(bian)(bian)(bian)質(zhi)，其原理也(ye)比較(jiao)簡單，因食(shi)品(pin)(pin)霉腐變(bian)(bian)(bian)(bian)質(zhi)主要(yao)由(you)微(wei)生(sheng)(sheng)(sheng)物(wu)(wu)(wu)(wu)的(de)(de)(de)活動(dong)造成，而大(da)多數(shu)(shu)微(wei)生(sheng)(sheng)(sheng)物(wu)(wu)(wu)(wu)（如霉菌(jun)(jun)(jun)和(he)(he)(he)酵母菌(jun)(jun)(jun)）的(de)(de)(de)生(sheng)(sheng)(sheng)存(cun)是(shi)需(xu)要(yao)氧(yang)(yang)(yang)(yang)(yang)氣的(de)(de)(de)，而真(zhen)空(kong)包裝(zhuang)(zhuang)(zhuang)就(jiu)是(shi)運用(yong)這個(ge)原理，把包裝(zhuang)(zhuang)(zhuang)袋(dai)內(nei)和(he)(he)(he)食(shi)品(pin)(pin)細胞內(nei)的(de)(de)(de)氧(yang)(yang)(yang)(yang)(yang)氣抽掉，使(shi)(shi)微(wei)物(wu)(wu)(wu)(wu)物(wu)(wu)(wu)(wu)失去“生(sheng)(sheng)(sheng)存(cun)的(de)(de)(de)環(huan)境”。實驗證(zheng)明：當包裝(zhuang)(zhuang)(zhuang)袋(dai)內(nei)的(de)(de)(de)氧(yang)(yang)(yang)(yang)(yang)氣濃(nong)(nong)度(du)≤1%時，微(wei)生(sheng)(sheng)(sheng)物(wu)(wu)(wu)(wu)的(de)(de)(de)生(sheng)(sheng)(sheng)長和(he)(he)(he)繁(fan)(fan)(fan)殖速(su)度(du)就(jiu)急劇(ju)下降，氧(yang)(yang)(yang)(yang)(yang)氣濃(nong)(nong)度(du)≤0.5%時，大(da)多數(shu)(shu)微(wei)生(sheng)(sheng)(sheng)物(wu)(wu)(wu)(wu)將受(shou)(shou)到抑(yi)(yi)制而停(ting)止(zhi)繁(fan)(fan)(fan)殖。（注：真(zhen)空(kong)包裝(zhuang)(zhuang)(zhuang)不(bu)能(neng)抑(yi)(yi)制厭(yan)氧(yang)(yang)(yang)(yang)(yang)菌(jun)(jun)(jun)的(de)(de)(de)繁(fan)(fan)(fan)殖和(he)(he)(he)酶反應引起的(de)(de)(de)食(shi)品(pin)(pin)變(bian)(bian)(bian)(bian)質(zhi)和(he)(he)(he)變(bian)(bian)(bian)(bian)色，因此還需(xu)與(yu)其它輔(fu)助方(fang)法結合，如冷藏(zang)、速(su)凍、脫水(shui)、高溫殺菌(jun)(jun)(jun)、輻照(zhao) 滅菌(jun)(jun)(jun)、微(wei)波殺菌(jun)(jun)(jun)、鹽腌(a)制等(deng)。）真(zhen)空(kong)除(chu)氧(yang)(yang)(yang)(yang)(yang)除(chu)了(le)抑(yi)(yi)制微(wei)生(sheng)(sheng)(sheng)物(wu)(wu)(wu)(wu)的(de)(de)(de)生(sheng)(sheng)(sheng)長和(he)(he)(he)繁(fan)(fan)(fan)殖外，另(ling)一個(ge)重要(yao)功能(neng)是(shi)防(fang)(fang)(fang)止(zhi)食(shi)品(pin)(pin)氧(yang)(yang)(yang)(yang)(yang)化，因油脂類食(shi)品(pin)(pin)中(zhong)含有(you)(you)大(da)量不(bu)飽(bao)和(he)(he)(he)脂肪酸，受(shou)(shou)氧(yang)(yang)(yang)(yang)(yang)的(de)(de)(de)作用(yong)而氧(yang)(yang)(yang)(yang)(yang)化，使(shi)(shi)食(shi)品(pin)(pin)變(bian)(bian)(bian)(bian)味(wei)、變(bian)(bian)(bian)(bian)質(zhi)，此外，氧(yang)(yang)(yang)(yang)(yang)化還使(shi)(shi)維(wei)生(sheng)(sheng)(sheng)素(su)A和(he)(he)(he)C損失，食(shi)品(pin)(pin)色素(su)中(zhong)的(de)(de)(de)不(bu)穩定物(wu)(wu)(wu)(wu)質(zhi)受(shou)(shou)氧(yang)(yang)(yang)(yang)(yang)的(de)(de)(de)作用(yong)，使(shi)(shi)顏色變(bian)(bian)(bian)(bian)暗。所以，除(chu)氧(yang)(yang)(yang)(yang)(yang)能(neng)有(you)(you)效地(di)防(fang)(fang)(fang)止(zhi)食(shi)品(pin)(pin)變(bian)(bian)(bian)(bian)質(zhi)，保持其色、香、味(wei)及營養(yang)價值。