真(zhen)空(kong)袋的(de)(de)主要作(zuo)(zuo)用(yong)是除(chu)氧(yang)(yang)(yang)(yang)(yang)，以有(you)利于(yu)防(fang)止(zhi)食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)變(bian)質，其(qi)(qi)原(yuan)理也比較(jiao)簡單，因(yin)食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)霉腐變(bian)質主要由微(wei)生(sheng)(sheng)(sheng)物的(de)(de)活動造成，而(er)大(da)多數(shu)微(wei)生(sheng)(sheng)(sheng)物（如(ru)霉菌(jun)(jun)和(he)酵母菌(jun)(jun)）的(de)(de)生(sheng)(sheng)(sheng)存是需要氧(yang)(yang)(yang)(yang)(yang)氣(qi)的(de)(de)，而(er)真(zhen)空(kong)包裝就是運(yun)用(yong)這個(ge)原(yuan)理，把包裝袋內(nei)(nei)和(he)食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)細胞內(nei)(nei)的(de)(de)氧(yang)(yang)(yang)(yang)(yang)氣(qi)抽(chou)掉，使(shi)(shi)微(wei)物物失去“生(sheng)(sheng)(sheng)存的(de)(de)環境(jing)”。實驗證(zheng)明：當包裝袋內(nei)(nei)的(de)(de)氧(yang)(yang)(yang)(yang)(yang)氣(qi)濃度(du)≤1%時，微(wei)生(sheng)(sheng)(sheng)物的(de)(de)生(sheng)(sheng)(sheng)長和(he)繁(fan)殖速度(du)就急劇下降，氧(yang)(yang)(yang)(yang)(yang)氣(qi)濃度(du)≤0.5%時，大(da)多數(shu)微(wei)生(sheng)(sheng)(sheng)物將(jiang)受到(dao)抑制(zhi)(zhi)而(er)停止(zhi)繁(fan)殖。（注：真(zhen)空(kong)包裝不(bu)能(neng)(neng)抑制(zhi)(zhi)厭氧(yang)(yang)(yang)(yang)(yang)菌(jun)(jun)的(de)(de)繁(fan)殖和(he)酶反應引(yin)起的(de)(de)食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)變(bian)質和(he)變(bian)色，因(yin)此還需與(yu)其(qi)(qi)它輔助方法結合，如(ru)冷(leng)藏、速凍、脫水、高溫殺(sha)菌(jun)(jun)、輻照(zhao) 滅菌(jun)(jun)、微(wei)波殺(sha)菌(jun)(jun)、鹽(yan)腌制(zhi)(zhi)等。）真(zhen)空(kong)除(chu)氧(yang)(yang)(yang)(yang)(yang)除(chu)了抑制(zhi)(zhi)微(wei)生(sheng)(sheng)(sheng)物的(de)(de)生(sheng)(sheng)(sheng)長和(he)繁(fan)殖外，另一(yi)個(ge)重要功能(neng)(neng)是防(fang)止(zhi)食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)氧(yang)(yang)(yang)(yang)(yang)化，因(yin)油脂(zhi)類食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)中含有(you)大(da)量不(bu)飽和(he)脂(zhi)肪酸，受氧(yang)(yang)(yang)(yang)(yang)的(de)(de)作(zuo)(zuo)用(yong)而(er)氧(yang)(yang)(yang)(yang)(yang)化，使(shi)(shi)食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)變(bian)味(wei)、變(bian)質，此外，氧(yang)(yang)(yang)(yang)(yang)化還使(shi)(shi)維生(sheng)(sheng)(sheng)素A和(he)C損失，食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)色素中的(de)(de)不(bu)穩定(ding)物質受氧(yang)(yang)(yang)(yang)(yang)的(de)(de)作(zuo)(zuo)用(yong)，使(shi)(shi)顏色變(bian)暗。所以，除(chu)氧(yang)(yang)(yang)(yang)(yang)能(neng)(neng)有(you)效(xiao)地(di)防(fang)止(zhi)食(shi)(shi)(shi)品(pin)(pin)(pin)(pin)變(bian)質，保持其(qi)(qi)色、香、味(wei)及營養價值。