真(zhen)空(kong)包裝(zhuang)不能(neng)(neng)抑(yi)制(zhi)厭氧(yang)(yang)(yang)(yang)(yang)菌的繁殖(zhi)和酶反應引起(qi)的食(shi)(shi)品變(bian)(bian)(bian)質和變(bian)(bian)(bian)色，因此還需與其(qi)它(ta)輔助方法結合(he)，如(ru)冷(leng)藏(zang)、速凍、脫(tuo)水、高溫(wen)殺(sha)菌、輻(fu)照 滅菌、微(wei)波殺(sha)菌、鹽腌制(zhi)等(deng)。真(zhen)空(kong)除氧(yang)(yang)(yang)(yang)(yang)除了抑(yi)制(zhi)微(wei)生物(wu)的生長(chang)和繁殖(zhi)外，另(ling)一個重(zhong)要功能(neng)(neng)是防止食(shi)(shi)品氧(yang)(yang)(yang)(yang)(yang)化(hua)(hua)，因油(you)脂類食(shi)(shi)品中含有大量(liang)不飽和脂肪(fang)酸，受氧(yang)(yang)(yang)(yang)(yang)的作用(yong)而(er)氧(yang)(yang)(yang)(yang)(yang)化(hua)(hua)，使食(shi)(shi)品變(bian)(bian)(bian)味(wei)、變(bian)(bian)(bian)質，此外，氧(yang)(yang)(yang)(yang)(yang)化(hua)(hua)還使維生素A和C損失，食(shi)(shi)品色素中的不穩定物(wu)質受氧(yang)(yang)(yang)(yang)(yang)的作用(yong)，使顏色變(bian)(bian)(bian)暗(an)。所以，除氧(yang)(yang)(yang)(yang)(yang)能(neng)(neng)有效地防止食(shi)(shi)品變(bian)(bian)(bian)質，保(bao)持其(qi)色、香、味(wei)及(ji)營養價值。