真(zhen)空袋主要(yao)作(zuo)用是(shi)除氧(yang)(yang)(yang)，以有(you)利于(yu)防止(zhi)食(shi)(shi)品(pin)變質，其(qi)原理也比較簡單，因食(shi)(shi)品(pin)霉(mei)(mei)腐變質主要(yao)由(you)微(wei)(wei)生(sheng)(sheng)物(wu)的活動造(zao)成，而大多數(shu)微(wei)(wei)生(sheng)(sheng)物(wu)（如霉(mei)(mei)菌(jun)和(he)酵(jiao)母菌(jun)）的生(sheng)(sheng)存是(shi)需要(yao)氧(yang)(yang)(yang)氣的，而真(zhen)空包(bao)裝就是(shi)運用這個(ge)原理，把包(bao)裝袋內(nei)和(he)食(shi)(shi)品(pin)細胞內(nei)的氧(yang)(yang)(yang)氣抽掉，使(shi)微(wei)(wei)物(wu)物(wu)失去“生(sheng)(sheng)存的環(huan)境”。實(shi)驗證明：當(dang)包(bao)裝袋內(nei)的氧(yang)(yang)(yang)氣濃(nong)度(du)≤1%時，微(wei)(wei)生(sheng)(sheng)物(wu)的生(sheng)(sheng)長和(he)繁殖(zhi)速度(du)就急劇下降，氧(yang)(yang)(yang)氣濃(nong)度(du)≤0.5%時，大多數(shu)微(wei)(wei)生(sheng)(sheng)物(wu)將受到(dao)抑制而停(ting)止(zhi)繁殖(zhi)。