真空充(chong)氣包裝的主要作用除真空包裝所具備的除氧保質功能外(wai)，主要還有抗壓、阻氣、保鮮(xian)等作(zuo)用(yong)，能更有(you)(you)(you)效地使食(shi)(shi)品長(chang)期保持原有(you)(you)(you)的(de)(de)色(se)、香、味(wei)、形(xing)(xing)及營養價值。另外，有(you)(you)(you)許(xu)多(duo)食(shi)(shi)品不適宜采(cai)(cai)用(yong)真空(kong)(kong)(kong)包(bao)(bao)裝(zhuang)(zhuang)(zhuang)(zhuang)而必須采(cai)(cai)用(yong)真空(kong)(kong)(kong)充(chong)(chong)氣包(bao)(bao)裝(zhuang)(zhuang)(zhuang)(zhuang)。如松脆易(yi)碎食(shi)(shi)品，易(yi)結(jie)塊(kuai)食(shi)(shi)品，易(yi)變(bian)形(xing)(xing)走油食(shi)(shi)品，有(you)(you)(you)尖銳棱角或硬度較高會刺破包(bao)(bao)裝(zhuang)(zhuang)(zhuang)(zhuang)袋的(de)(de)食(shi)(shi)品等。食(shi)(shi)品經真空(kong)(kong)(kong)充(chong)(chong)氣包(bao)(bao)裝(zhuang)(zhuang)(zhuang)(zhuang)后，包(bao)(bao)裝(zhuang)(zhuang)(zhuang)(zhuang)袋內充(chong)(chong)氣壓(ya)強(qiang)大(da)(da)于包(bao)(bao)裝(zhuang)(zhuang)(zhuang)(zhuang)袋外大(da)(da)氣壓(ya)強(qiang)，能有(you)(you)(you)效地防止食(shi)(shi)品受壓(ya)破碎變(bian)形(xing)(xing)并不影響包(bao)(bao)裝(zhuang)(zhuang)(zhuang)(zhuang)袋外觀及 印刷(shua)裝(zhuang)(zhuang)(zhuang)(zhuang)潢(huang)。真空(kong)(kong)(kong)充(chong)(chong)氣包(bao)(bao)裝(zhuang)(zhuang)(zhuang)(zhuang)在真空(kong)(kong)(kong)后再充(chong)(chong)入氮氣、二氧(yang)化碳、氧(yang)氣單一氣體或(huo)二(er) 三種氣體的(de)(de)混合氣體。其氮氣是(shi)惰性(xing)氣體，起充(chong)填作用(yong)，使袋內(nei)保(bao)(bao)持(chi)(chi)(chi)正(zheng)壓 ，以防(fang)止袋外空氣進入袋內(nei)，對食(shi)品起到(dao)一個(ge)保(bao)(bao)護作用(yong)。其二(er)氧化碳能夠溶(rong)于各類(lei)脂(zhi)肪或(huo)水，引(yin)成酸性(xing)較弱(ruo)的(de)(de)碳酸，有抑制(zhi)霉菌(jun)、腐敗細菌(jun)等微生(sheng)物(wu)的(de)(de)活性(xing)。其氧氣具有抑制(zhi)厭氧菌(jun)的(de)(de)生(sheng)長(chang)繁殖，保(bao)(bao)持(chi)(chi)(chi)水果、蔬菜的(de)(de)新鮮及色彩，高濃度氧氣可使新鮮肉類(lei)保(bao)(bao)持(chi)(chi)(chi)其鮮紅(hong)色。