真(zhen)空(kong)袋的(de)(de)(de)(de)(de)主(zhu)要(yao)(yao)作(zuo)用是(shi)除(chu)氧(yang)(yang)(yang)(yang)(yang)，以(yi)(yi)有利(li)于防止(zhi)食(shi)(shi)(shi)(shi)品(pin)變(bian)(bian)質(zhi)(zhi)，其原(yuan)理(li)(li)也比較簡單(dan)，因食(shi)(shi)(shi)(shi)品(pin)霉腐變(bian)(bian)質(zhi)(zhi)主(zhu)要(yao)(yao)由(you)微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)(de)(de)(de)活動造成，而(er)(er)大(da)多數(shu)微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)（如霉菌(jun)(jun)和酵(jiao)母菌(jun)(jun)）的(de)(de)(de)(de)(de)生(sheng)(sheng)(sheng)存(cun)是(shi)需要(yao)(yao)氧(yang)(yang)(yang)(yang)(yang)氣(qi)的(de)(de)(de)(de)(de)，而(er)(er)真(zhen)空(kong)包(bao)裝(zhuang)就是(shi)運用這個原(yuan)理(li)(li)，把包(bao)裝(zhuang)袋內和食(shi)(shi)(shi)(shi)品(pin)細胞內的(de)(de)(de)(de)(de)氧(yang)(yang)(yang)(yang)(yang)氣(qi)抽掉，使(shi)微(wei)(wei)物(wu)(wu)物(wu)(wu)失(shi)去(qu)“生(sheng)(sheng)(sheng)存(cun)的(de)(de)(de)(de)(de)環境(jing)”。實驗(yan)證(zheng)明(ming)：當(dang)包(bao)裝(zhuang)袋內的(de)(de)(de)(de)(de)氧(yang)(yang)(yang)(yang)(yang)氣(qi)濃(nong)度≤1%時，微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)(de)(de)(de)生(sheng)(sheng)(sheng)長和繁(fan)殖速(su)度就急劇下降，氧(yang)(yang)(yang)(yang)(yang)氣(qi)濃(nong)度≤0.5%時，大(da)多數(shu)微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)將(jiang)受(shou)到抑制(zhi)而(er)(er)停(ting)止(zhi)繁(fan)殖。（注：真(zhen)空(kong)包(bao)裝(zhuang)不(bu)能抑制(zhi)厭氧(yang)(yang)(yang)(yang)(yang)菌(jun)(jun)的(de)(de)(de)(de)(de)繁(fan)殖和酶反應引起(qi)的(de)(de)(de)(de)(de)食(shi)(shi)(shi)(shi)品(pin)變(bian)(bian)質(zhi)(zhi)和變(bian)(bian)色(se)(se)，因此還需與其它輔助方法結合(he)，如冷藏、速(su)凍、脫水(shui)、高溫殺菌(jun)(jun)、輻照 滅菌(jun)(jun)、微(wei)(wei)波殺菌(jun)(jun)、鹽腌(a)制(zhi)等。）真(zhen)空(kong)除(chu)氧(yang)(yang)(yang)(yang)(yang)除(chu)了抑制(zhi)微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)(de)(de)(de)生(sheng)(sheng)(sheng)長和繁(fan)殖外，另一個重要(yao)(yao)功能是(shi)防止(zhi)食(shi)(shi)(shi)(shi)品(pin)氧(yang)(yang)(yang)(yang)(yang)化，因油(you)脂類食(shi)(shi)(shi)(shi)品(pin)中(zhong)含有大(da)量不(bu)飽和脂肪(fang)酸，受(shou)氧(yang)(yang)(yang)(yang)(yang)的(de)(de)(de)(de)(de)作(zuo)用而(er)(er)氧(yang)(yang)(yang)(yang)(yang)化，使(shi)食(shi)(shi)(shi)(shi)品(pin)變(bian)(bian)味(wei)、變(bian)(bian)質(zhi)(zhi)，此外，氧(yang)(yang)(yang)(yang)(yang)化還使(shi)維生(sheng)(sheng)(sheng)素(su)A和C損(sun)失(shi)，食(shi)(shi)(shi)(shi)品(pin)色(se)(se)素(su)中(zhong)的(de)(de)(de)(de)(de)不(bu)穩定物(wu)(wu)質(zhi)(zhi)受(shou)氧(yang)(yang)(yang)(yang)(yang)的(de)(de)(de)(de)(de)作(zuo)用，使(shi)顏(yan)色(se)(se)變(bian)(bian)暗(an)。所以(yi)(yi)，除(chu)氧(yang)(yang)(yang)(yang)(yang)能有效(xiao)地(di)防止(zhi)食(shi)(shi)(shi)(shi)品(pin)變(bian)(bian)質(zhi)(zhi)，保持其色(se)(se)、香(xiang)、味(wei)及(ji)營養價(jia)值。