真(zhen)空(kong)(kong)袋的(de)(de)(de)主要(yao)作用(yong)(yong)(yong)是除氧(yang)(yang)(yang)(yang)(yang)，以有(you)(you)(you)利于防(fang)止(zhi)食(shi)(shi)品(pin)變(bian)(bian)(bian)質(zhi)，其(qi)原理(li)也比較簡(jian)單，因食(shi)(shi)品(pin)霉(mei)腐變(bian)(bian)(bian)質(zhi)主要(yao)由微(wei)(wei)生(sheng)物(wu)的(de)(de)(de)活動造成，而(er)大多(duo)數(shu)微(wei)(wei)生(sheng)物(wu)（如(ru)霉(mei)菌和(he)(he)酵母菌）的(de)(de)(de)生(sheng)存是需(xu)(xu)要(yao)氧(yang)(yang)(yang)(yang)(yang)氣(qi)(qi)(qi)的(de)(de)(de)，而(er)真(zhen)空(kong)(kong)包(bao)裝(zhuang)(zhuang)就是運用(yong)(yong)(yong)這(zhe)個(ge)原理(li)，把(ba)包(bao)裝(zhuang)(zhuang)袋內和(he)(he)食(shi)(shi)品(pin)細胞內的(de)(de)(de)氧(yang)(yang)(yang)(yang)(yang)氣(qi)(qi)(qi)抽掉，使微(wei)(wei)物(wu)物(wu)失(shi)去“生(sheng)存的(de)(de)(de)環(huan)境”。實驗證明：當包(bao)裝(zhuang)(zhuang)袋內的(de)(de)(de)氧(yang)(yang)(yang)(yang)(yang)氣(qi)(qi)(qi)濃度(du)≤1%時(shi)，微(wei)(wei)生(sheng)物(wu)的(de)(de)(de)生(sheng)長和(he)(he)繁(fan)殖(zhi)速度(du)就急劇(ju)下降，氧(yang)(yang)(yang)(yang)(yang)氣(qi)(qi)(qi)濃度(du)≤0.5%時(shi)，大多(duo)數(shu)微(wei)(wei)生(sheng)物(wu)將受到抑制而(er)停止(zhi)繁(fan)殖(zhi)。（注(zhu)：真(zhen)空(kong)(kong)包(bao)裝(zhuang)(zhuang)不能抑制厭氧(yang)(yang)(yang)(yang)(yang)菌的(de)(de)(de)繁(fan)殖(zhi)和(he)(he)酶(mei)反應引(yin)起的(de)(de)(de)食(shi)(shi)品(pin)變(bian)(bian)(bian)質(zhi)和(he)(he)變(bian)(bian)(bian)色，因此(ci)(ci)還需(xu)(xu)與其(qi)它輔助方法結合，如(ru)冷(leng)藏、速凍(dong)、脫水、高溫殺菌、輻照 滅菌、微(wei)(wei)波殺菌、鹽腌制等。）真(zhen)空(kong)(kong)除氧(yang)(yang)(yang)(yang)(yang)除了抑制微(wei)(wei)生(sheng)物(wu)的(de)(de)(de)生(sheng)長和(he)(he)繁(fan)殖(zhi)外，另一個(ge)重要(yao)功能是防(fang)止(zhi)食(shi)(shi)品(pin)氧(yang)(yang)(yang)(yang)(yang)化，因油(you)脂類食(shi)(shi)品(pin)中含(han)有(you)(you)(you)大量(liang)不飽和(he)(he)脂肪酸(suan)，受氧(yang)(yang)(yang)(yang)(yang)的(de)(de)(de)作用(yong)(yong)(yong)而(er)氧(yang)(yang)(yang)(yang)(yang)化，使食(shi)(shi)品(pin)變(bian)(bian)(bian)味(wei)、變(bian)(bian)(bian)質(zhi)，此(ci)(ci)外，氧(yang)(yang)(yang)(yang)(yang)化還使維生(sheng)素A和(he)(he)C損失(shi)，食(shi)(shi)品(pin)色素中的(de)(de)(de)不穩定(ding)物(wu)質(zhi)受氧(yang)(yang)(yang)(yang)(yang)的(de)(de)(de)作用(yong)(yong)(yong)，使顏色變(bian)(bian)(bian)暗。所(suo)以，除氧(yang)(yang)(yang)(yang)(yang)能有(you)(you)(you)效地防(fang)止(zhi)食(shi)(shi)品(pin)變(bian)(bian)(bian)質(zhi)，保持(chi)其(qi)色、香、味(wei)及營(ying)養(yang)價值。