真(zhen)空(kong)袋(dai)(dai)的(de)(de)(de)主要作用(yong)(yong)是(shi)除(chu)氧(yang)(yang)，以有(you)利于防(fang)止(zhi)食(shi)(shi)(shi)品(pin)(pin)(pin)變(bian)質(zhi)(zhi)，其原(yuan)理也(ye)比較(jiao)簡單，因食(shi)(shi)(shi)品(pin)(pin)(pin)霉(mei)腐變(bian)質(zhi)(zhi)主要由微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)(wu)的(de)(de)(de)活(huo)動造(zao)成，而(er)大多數(shu)微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)(wu)（如霉(mei)菌(jun)(jun)和(he)酵(jiao)母菌(jun)(jun)）的(de)(de)(de)生(sheng)(sheng)(sheng)存是(shi)需要氧(yang)(yang)氣(qi)(qi)的(de)(de)(de)，而(er)真(zhen)空(kong)包(bao)裝(zhuang)就(jiu)是(shi)運(yun)用(yong)(yong)這個原(yuan)理，把包(bao)裝(zhuang)袋(dai)(dai)內(nei)和(he)食(shi)(shi)(shi)品(pin)(pin)(pin)細胞內(nei)的(de)(de)(de)氧(yang)(yang)氣(qi)(qi)抽掉，使微(wei)(wei)物(wu)(wu)(wu)物(wu)(wu)(wu)失去“生(sheng)(sheng)(sheng)存的(de)(de)(de)環境(jing)”。實驗證(zheng)明：當包(bao)裝(zhuang)袋(dai)(dai)內(nei)的(de)(de)(de)氧(yang)(yang)氣(qi)(qi)濃度(du)≤1%時，微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)(wu)的(de)(de)(de)生(sheng)(sheng)(sheng)長(chang)和(he)繁(fan)(fan)殖(zhi)速(su)度(du)就(jiu)急劇下降，氧(yang)(yang)氣(qi)(qi)濃度(du)≤0.5%時，大多數(shu)微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)(wu)將受到(dao)抑制(zhi)(zhi)而(er)停(ting)止(zhi)繁(fan)(fan)殖(zhi)。（注(zhu)：真(zhen)空(kong)包(bao)裝(zhuang)不能抑制(zhi)(zhi)厭氧(yang)(yang)菌(jun)(jun)的(de)(de)(de)繁(fan)(fan)殖(zhi)和(he)酶反應(ying)引起的(de)(de)(de)食(shi)(shi)(shi)品(pin)(pin)(pin)變(bian)質(zhi)(zhi)和(he)變(bian)色，因此還(huan)(huan)需與其它(ta)輔助方(fang)法結合，如冷藏、速(su)凍、脫水、高溫(wen)殺菌(jun)(jun)、輻照 滅菌(jun)(jun)、微(wei)(wei)波殺菌(jun)(jun)、鹽腌制(zhi)(zhi)等。）真(zhen)空(kong)除(chu)氧(yang)(yang)除(chu)了抑制(zhi)(zhi)微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)(wu)的(de)(de)(de)生(sheng)(sheng)(sheng)長(chang)和(he)繁(fan)(fan)殖(zhi)外(wai)，另(ling)一個重要功能是(shi)防(fang)止(zhi)食(shi)(shi)(shi)品(pin)(pin)(pin)氧(yang)(yang)化，因油脂類食(shi)(shi)(shi)品(pin)(pin)(pin)中含有(you)大量不飽和(he)脂肪(fang)酸，受氧(yang)(yang)的(de)(de)(de)作用(yong)(yong)而(er)氧(yang)(yang)化，使食(shi)(shi)(shi)品(pin)(pin)(pin)變(bian)味(wei)、變(bian)質(zhi)(zhi)，此外(wai)，氧(yang)(yang)化還(huan)(huan)使維生(sheng)(sheng)(sheng)素A和(he)C損(sun)失，食(shi)(shi)(shi)品(pin)(pin)(pin)色素中的(de)(de)(de)不穩(wen)定物(wu)(wu)(wu)質(zhi)(zhi)受氧(yang)(yang)的(de)(de)(de)作用(yong)(yong)，使顏(yan)色變(bian)暗(an)。所以，除(chu)氧(yang)(yang)能有(you)效(xiao)地防(fang)止(zhi)食(shi)(shi)(shi)品(pin)(pin)(pin)變(bian)質(zhi)(zhi)，保持其色、香、味(wei)及營養價值。