真(zhen)空(kong)袋(dai)的(de)(de)(de)主(zhu)要(yao)作(zuo)用(yong)是(shi)除(chu)氧(yang)(yang)，以有利于防止食(shi)(shi)(shi)品(pin)(pin)(pin)變(bian)(bian)質(zhi)，其(qi)(qi)原(yuan)理也比較簡單，因食(shi)(shi)(shi)品(pin)(pin)(pin)霉腐(fu)變(bian)(bian)質(zhi)主(zhu)要(yao)由微(wei)(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)(de)活動(dong)造(zao)成，而(er)大多(duo)數微(wei)(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)（如霉菌(jun)和(he)酵母菌(jun)）的(de)(de)(de)生(sheng)(sheng)(sheng)存是(shi)需(xu)要(yao)氧(yang)(yang)氣的(de)(de)(de)，而(er)真(zhen)空(kong)包裝(zhuang)(zhuang)就(jiu)是(shi)運用(yong)這個(ge)原(yuan)理，把(ba)包裝(zhuang)(zhuang)袋(dai)內和(he)食(shi)(shi)(shi)品(pin)(pin)(pin)細胞內的(de)(de)(de)氧(yang)(yang)氣抽掉，使(shi)微(wei)(wei)(wei)物(wu)(wu)物(wu)(wu)失去“生(sheng)(sheng)(sheng)存的(de)(de)(de)環境”。實驗證明：當(dang)包裝(zhuang)(zhuang)袋(dai)內的(de)(de)(de)氧(yang)(yang)氣濃(nong)(nong)度≤1%時(shi)，微(wei)(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)(de)生(sheng)(sheng)(sheng)長(chang)和(he)繁(fan)(fan)殖速度就(jiu)急劇下降，氧(yang)(yang)氣濃(nong)(nong)度≤0.5%時(shi)，大多(duo)數微(wei)(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)將受(shou)(shou)到抑(yi)制而(er)停(ting)止繁(fan)(fan)殖。（注：真(zhen)空(kong)包裝(zhuang)(zhuang)不能(neng)抑(yi)制厭氧(yang)(yang)菌(jun)的(de)(de)(de)繁(fan)(fan)殖和(he)酶(mei)反應引起的(de)(de)(de)食(shi)(shi)(shi)品(pin)(pin)(pin)變(bian)(bian)質(zhi)和(he)變(bian)(bian)色，因此還需(xu)與其(qi)(qi)它輔助方(fang)法結合，如冷(leng)藏、速凍、脫(tuo)水、高溫殺(sha)菌(jun)、輻(fu)照 滅(mie)菌(jun)、微(wei)(wei)(wei)波殺(sha)菌(jun)、鹽腌(a)制等(deng)。）真(zhen)空(kong)除(chu)氧(yang)(yang)除(chu)了抑(yi)制微(wei)(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)(de)生(sheng)(sheng)(sheng)長(chang)和(he)繁(fan)(fan)殖外，另一(yi)個(ge)重(zhong)要(yao)功能(neng)是(shi)防止食(shi)(shi)(shi)品(pin)(pin)(pin)氧(yang)(yang)化，因油脂類(lei)食(shi)(shi)(shi)品(pin)(pin)(pin)中含有大量(liang)不飽和(he)脂肪酸(suan)，受(shou)(shou)氧(yang)(yang)的(de)(de)(de)作(zuo)用(yong)而(er)氧(yang)(yang)化，使(shi)食(shi)(shi)(shi)品(pin)(pin)(pin)變(bian)(bian)味、變(bian)(bian)質(zhi)，此外，氧(yang)(yang)化還使(shi)維(wei)生(sheng)(sheng)(sheng)素(su)A和(he)C損(sun)失，食(shi)(shi)(shi)品(pin)(pin)(pin)色素(su)中的(de)(de)(de)不穩定物(wu)(wu)質(zhi)受(shou)(shou)氧(yang)(yang)的(de)(de)(de)作(zuo)用(yong)，使(shi)顏色變(bian)(bian)暗。所以，除(chu)氧(yang)(yang)能(neng)有效地防止食(shi)(shi)(shi)品(pin)(pin)(pin)變(bian)(bian)質(zhi)，保持其(qi)(qi)色、香、味及(ji)營養價值。