真(zhen)空充氣(qi)包(bao)裝的(de)主(zhu)要(yao)作用除真(zhen)空包(bao)裝所具(ju)備的(de)除氧保質功能(neng)外，主(zhu)要(yao)還有抗壓、阻氣(qi)、保(bao)鮮等(deng)作用，能(neng)更有(you)效地(di)使食品長期保持原有(you)的色(se)、香、味、形及營養價值。另外，有(you)許多(duo)食品不(bu)適宜采用真(zhen)(zhen)空(kong)(kong)(kong)包(bao)(bao)裝(zhuang)而必須采用真(zhen)(zhen)空(kong)(kong)(kong)充(chong)(chong)(chong)(chong)氣(qi)包(bao)(bao)裝(zhuang)。如(ru)松(song)脆易碎(sui)食品，易結塊(kuai)食品，易變形走油(you)食品，有(you)尖銳棱角或硬度較高(gao)會(hui)刺破(po)包(bao)(bao)裝(zhuang)袋(dai)(dai)的食品等(deng)。食品經真(zhen)(zhen)空(kong)(kong)(kong)充(chong)(chong)(chong)(chong)氣(qi)包(bao)(bao)裝(zhuang)后(hou)，包(bao)(bao)裝(zhuang)袋(dai)(dai)內(nei)充(chong)(chong)(chong)(chong)氣(qi)壓(ya)強(qiang)大于包(bao)(bao)裝(zhuang)袋(dai)(dai)外大氣(qi)壓(ya)強(qiang)，能(neng)有(you)效地(di)防止食品受壓(ya)破(po)碎(sui)變形并不(bu)影(ying)響包(bao)(bao)裝(zhuang)袋(dai)(dai)外觀及 印(yin)刷裝(zhuang)潢(huang)。真(zhen)(zhen)空(kong)(kong)(kong)充(chong)(chong)(chong)(chong)氣(qi)包(bao)(bao)裝(zhuang)在真(zhen)(zhen)空(kong)(kong)(kong)后(hou)再充(chong)(chong)(chong)(chong)入氮氣(qi)、二氧化碳、氧氣(qi)單一氣體或(huo)二 三種氣體的混合氣體。其(qi)氮氣是(shi)惰(duo)性氣體，起充填(tian)作用(yong)，使袋內(nei)保(bao)持(chi)(chi)正壓 ，以(yi)防止袋外(wai)空(kong)氣進(jin)入袋內(nei)，對食(shi)品起到(dao)一個保(bao)護作用(yong)。其(qi)二氧化碳(tan)能(neng)夠溶于各(ge)類脂肪或(huo)水，引成酸(suan)性較弱的碳(tan)酸(suan)，有抑制霉菌、腐敗細菌等微生物的活性。其(qi)氧氣具有抑制厭氧菌的生長繁殖，保(bao)持(chi)(chi)水果、蔬菜(cai)的新(xin)鮮(xian)(xian)及(ji)色(se)彩，高濃度氧氣可使新(xin)鮮(xian)(xian)肉(rou)類保(bao)持(chi)(chi)其(qi)鮮(xian)(xian)紅色(se)。