真(zhen)(zhen)(zhen)空袋(dai)的(de)(de)(de)主要(yao)作用(yong)是(shi)除(chu)氧(yang)(yang)(yang)(yang)(yang)(yang)，以有利于防(fang)止(zhi)(zhi)食(shi)(shi)(shi)品變(bian)(bian)(bian)質(zhi)，其原(yuan)理(li)也(ye)比較簡單，因(yin)食(shi)(shi)(shi)品霉腐變(bian)(bian)(bian)質(zhi)主要(yao)由微生(sheng)(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)(de)活動造(zao)成，而大多數(shu)微生(sheng)(sheng)(sheng)(sheng)物(wu)(wu)（如霉菌(jun)和(he)(he)酵母菌(jun)）的(de)(de)(de)生(sheng)(sheng)(sheng)(sheng)存是(shi)需要(yao)氧(yang)(yang)(yang)(yang)(yang)(yang)氣(qi)(qi)(qi)的(de)(de)(de)，而真(zhen)(zhen)(zhen)空包(bao)裝就(jiu)是(shi)運用(yong)這個(ge)原(yuan)理(li)，把包(bao)裝袋(dai)內和(he)(he)食(shi)(shi)(shi)品細胞內的(de)(de)(de)氧(yang)(yang)(yang)(yang)(yang)(yang)氣(qi)(qi)(qi)抽掉，使(shi)微物(wu)(wu)物(wu)(wu)失去“生(sheng)(sheng)(sheng)(sheng)存的(de)(de)(de)環境”。實驗證明：當包(bao)裝袋(dai)內的(de)(de)(de)氧(yang)(yang)(yang)(yang)(yang)(yang)氣(qi)(qi)(qi)濃度≤1%時，微生(sheng)(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)(de)生(sheng)(sheng)(sheng)(sheng)長(chang)和(he)(he)繁(fan)殖(zhi)速度就(jiu)急劇下降，氧(yang)(yang)(yang)(yang)(yang)(yang)氣(qi)(qi)(qi)濃度≤0.5%時，大多數(shu)微生(sheng)(sheng)(sheng)(sheng)物(wu)(wu)將受(shou)到抑(yi)制(zhi)(zhi)(zhi)而停止(zhi)(zhi)繁(fan)殖(zhi)。（注：真(zhen)(zhen)(zhen)空包(bao)裝不能抑(yi)制(zhi)(zhi)(zhi)厭氧(yang)(yang)(yang)(yang)(yang)(yang)菌(jun)的(de)(de)(de)繁(fan)殖(zhi)和(he)(he)酶反應引起的(de)(de)(de)食(shi)(shi)(shi)品變(bian)(bian)(bian)質(zhi)和(he)(he)變(bian)(bian)(bian)色，因(yin)此還需與其它輔助(zhu)方法結合(he)，如冷藏、速凍、脫水、高溫殺菌(jun)、輻照 滅(mie)菌(jun)、微波殺菌(jun)、鹽腌(a)制(zhi)(zhi)(zhi)等(deng)。）真(zhen)(zhen)(zhen)空除(chu)氧(yang)(yang)(yang)(yang)(yang)(yang)除(chu)了抑(yi)制(zhi)(zhi)(zhi)微生(sheng)(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)(de)生(sheng)(sheng)(sheng)(sheng)長(chang)和(he)(he)繁(fan)殖(zhi)外(wai)，另一個(ge)重(zhong)要(yao)功能是(shi)防(fang)止(zhi)(zhi)食(shi)(shi)(shi)品氧(yang)(yang)(yang)(yang)(yang)(yang)化，因(yin)油(you)脂類食(shi)(shi)(shi)品中含有大量(liang)不飽和(he)(he)脂肪酸，受(shou)氧(yang)(yang)(yang)(yang)(yang)(yang)的(de)(de)(de)作用(yong)而氧(yang)(yang)(yang)(yang)(yang)(yang)化，使(shi)食(shi)(shi)(shi)品變(bian)(bian)(bian)味、變(bian)(bian)(bian)質(zhi)，此外(wai)，氧(yang)(yang)(yang)(yang)(yang)(yang)化還使(shi)維生(sheng)(sheng)(sheng)(sheng)素A和(he)(he)C損失，食(shi)(shi)(shi)品色素中的(de)(de)(de)不穩定物(wu)(wu)質(zhi)受(shou)氧(yang)(yang)(yang)(yang)(yang)(yang)的(de)(de)(de)作用(yong)，使(shi)顏色變(bian)(bian)(bian)暗。所以，除(chu)氧(yang)(yang)(yang)(yang)(yang)(yang)能有效地防(fang)止(zhi)(zhi)食(shi)(shi)(shi)品變(bian)(bian)(bian)質(zhi)，保持其色、香、味及營養價值。