真空(kong)(kong)袋的(de)(de)主要作(zuo)用(yong)是(shi)除氧(yang)(yang)(yang)(yang)，以有利于(yu)防止食(shi)(shi)品(pin)(pin)(pin)變(bian)質(zhi)，其原理(li)也比較簡單，因食(shi)(shi)品(pin)(pin)(pin)霉腐變(bian)質(zhi)主要由微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)活動造成，而(er)大多數(shu)微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)（如(ru)霉菌和(he)酵母(mu)菌）的(de)(de)生(sheng)(sheng)(sheng)存(cun)是(shi)需要氧(yang)(yang)(yang)(yang)氣的(de)(de)，而(er)真空(kong)(kong)包(bao)裝(zhuang)就(jiu)是(shi)運用(yong)這(zhe)個原理(li)，把(ba)包(bao)裝(zhuang)袋內(nei)(nei)和(he)食(shi)(shi)品(pin)(pin)(pin)細胞內(nei)(nei)的(de)(de)氧(yang)(yang)(yang)(yang)氣抽掉，使(shi)(shi)微(wei)(wei)物(wu)(wu)物(wu)(wu)失去(qu)“生(sheng)(sheng)(sheng)存(cun)的(de)(de)環(huan)境(jing)”。實驗證明：當包(bao)裝(zhuang)袋內(nei)(nei)的(de)(de)氧(yang)(yang)(yang)(yang)氣濃度≤1%時(shi)，微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)生(sheng)(sheng)(sheng)長和(he)繁殖速度就(jiu)急劇下降，氧(yang)(yang)(yang)(yang)氣濃度≤0.5%時(shi)，大多數(shu)微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)將受(shou)到抑(yi)制而(er)停止繁殖。（注：真空(kong)(kong)包(bao)裝(zhuang)不(bu)能抑(yi)制厭氧(yang)(yang)(yang)(yang)菌的(de)(de)繁殖和(he)酶反應引起的(de)(de)食(shi)(shi)品(pin)(pin)(pin)變(bian)質(zhi)和(he)變(bian)色，因此還(huan)需與其它輔助方法結合(he)，如(ru)冷藏、速凍、脫水、高溫殺(sha)菌、輻照 滅菌、微(wei)(wei)波殺(sha)菌、鹽腌制等。）真空(kong)(kong)除氧(yang)(yang)(yang)(yang)除了抑(yi)制微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)生(sheng)(sheng)(sheng)長和(he)繁殖外(wai)，另一個重(zhong)要功(gong)能是(shi)防止食(shi)(shi)品(pin)(pin)(pin)氧(yang)(yang)(yang)(yang)化，因油脂(zhi)(zhi)類食(shi)(shi)品(pin)(pin)(pin)中含有大量不(bu)飽和(he)脂(zhi)(zhi)肪酸，受(shou)氧(yang)(yang)(yang)(yang)的(de)(de)作(zuo)用(yong)而(er)氧(yang)(yang)(yang)(yang)化，使(shi)(shi)食(shi)(shi)品(pin)(pin)(pin)變(bian)味、變(bian)質(zhi)，此外(wai)，氧(yang)(yang)(yang)(yang)化還(huan)使(shi)(shi)維(wei)生(sheng)(sheng)(sheng)素A和(he)C損(sun)失，食(shi)(shi)品(pin)(pin)(pin)色素中的(de)(de)不(bu)穩定物(wu)(wu)質(zhi)受(shou)氧(yang)(yang)(yang)(yang)的(de)(de)作(zuo)用(yong)，使(shi)(shi)顏色變(bian)暗。所以，除氧(yang)(yang)(yang)(yang)能有效(xiao)地防止食(shi)(shi)品(pin)(pin)(pin)變(bian)質(zhi)，保持其色、香(xiang)、味及營養價值。