真空(kong)(kong)袋的(de)(de)(de)(de)主要(yao)作用(yong)是(shi)除氧(yang)(yang)(yang)(yang)(yang)，以(yi)有利于防止(zhi)食(shi)(shi)品變(bian)質，其(qi)(qi)原理(li)也比較(jiao)簡單，因食(shi)(shi)品霉腐變(bian)質主要(yao)由微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)(de)(de)活動(dong)造成，而(er)大(da)多(duo)(duo)數微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)（如霉菌(jun)和(he)(he)酵母菌(jun)）的(de)(de)(de)(de)生(sheng)(sheng)(sheng)存是(shi)需(xu)要(yao)氧(yang)(yang)(yang)(yang)(yang)氣(qi)的(de)(de)(de)(de)，而(er)真空(kong)(kong)包(bao)(bao)裝(zhuang)就(jiu)是(shi)運用(yong)這個(ge)原理(li)，把包(bao)(bao)裝(zhuang)袋內和(he)(he)食(shi)(shi)品細胞內的(de)(de)(de)(de)氧(yang)(yang)(yang)(yang)(yang)氣(qi)抽掉，使(shi)微(wei)(wei)物(wu)(wu)物(wu)(wu)失去“生(sheng)(sheng)(sheng)存的(de)(de)(de)(de)環(huan)境”。實驗證明(ming)：當包(bao)(bao)裝(zhuang)袋內的(de)(de)(de)(de)氧(yang)(yang)(yang)(yang)(yang)氣(qi)濃度≤1%時(shi)，微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)(de)(de)生(sheng)(sheng)(sheng)長和(he)(he)繁(fan)殖速(su)度就(jiu)急(ji)劇下降，氧(yang)(yang)(yang)(yang)(yang)氣(qi)濃度≤0.5%時(shi)，大(da)多(duo)(duo)數微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)將受(shou)到抑制而(er)停止(zhi)繁(fan)殖。（注：真空(kong)(kong)包(bao)(bao)裝(zhuang)不(bu)能抑制厭氧(yang)(yang)(yang)(yang)(yang)菌(jun)的(de)(de)(de)(de)繁(fan)殖和(he)(he)酶反應(ying)引起(qi)的(de)(de)(de)(de)食(shi)(shi)品變(bian)質和(he)(he)變(bian)色，因此(ci)(ci)還(huan)需(xu)與(yu)其(qi)(qi)它輔助方法結合(he)，如冷(leng)藏、速(su)凍、脫水、高(gao)溫殺菌(jun)、輻(fu)照 滅菌(jun)、微(wei)(wei)波(bo)殺菌(jun)、鹽腌制等(deng)。）真空(kong)(kong)除氧(yang)(yang)(yang)(yang)(yang)除了(le)抑制微(wei)(wei)生(sheng)(sheng)(sheng)物(wu)(wu)的(de)(de)(de)(de)生(sheng)(sheng)(sheng)長和(he)(he)繁(fan)殖外，另一個(ge)重要(yao)功能是(shi)防止(zhi)食(shi)(shi)品氧(yang)(yang)(yang)(yang)(yang)化，因油脂(zhi)(zhi)類食(shi)(shi)品中(zhong)(zhong)含(han)有大(da)量不(bu)飽和(he)(he)脂(zhi)(zhi)肪酸(suan)，受(shou)氧(yang)(yang)(yang)(yang)(yang)的(de)(de)(de)(de)作用(yong)而(er)氧(yang)(yang)(yang)(yang)(yang)化，使(shi)食(shi)(shi)品變(bian)味、變(bian)質，此(ci)(ci)外，氧(yang)(yang)(yang)(yang)(yang)化還(huan)使(shi)維生(sheng)(sheng)(sheng)素A和(he)(he)C損失，食(shi)(shi)品色素中(zhong)(zhong)的(de)(de)(de)(de)不(bu)穩定物(wu)(wu)質受(shou)氧(yang)(yang)(yang)(yang)(yang)的(de)(de)(de)(de)作用(yong)，使(shi)顏色變(bian)暗。所(suo)以(yi)，除氧(yang)(yang)(yang)(yang)(yang)能有效地防止(zhi)食(shi)(shi)品變(bian)質，保持(chi)其(qi)(qi)色、香、味及營養價值。