真空(kong)袋(dai)(dai)的主要(yao)作用(yong)是(shi)(shi)除(chu)(chu)(chu)氧(yang)(yang)(yang)(yang)，以(yi)有利于防(fang)止食(shi)(shi)(shi)品(pin)變(bian)(bian)(bian)質，其(qi)原(yuan)理也比較(jiao)簡單(dan)，因(yin)(yin)食(shi)(shi)(shi)品(pin)霉(mei)(mei)腐變(bian)(bian)(bian)質主要(yao)由微(wei)(wei)(wei)生(sheng)(sheng)物的活動造成，而大多數(shu)微(wei)(wei)(wei)生(sheng)(sheng)物（如霉(mei)(mei)菌(jun)(jun)(jun)和(he)(he)(he)(he)酵母(mu)菌(jun)(jun)(jun)）的生(sheng)(sheng)存是(shi)(shi)需要(yao)氧(yang)(yang)(yang)(yang)氣(qi)的，而真空(kong)包裝就(jiu)是(shi)(shi)運用(yong)這個(ge)原(yuan)理，把包裝袋(dai)(dai)內(nei)和(he)(he)(he)(he)食(shi)(shi)(shi)品(pin)細胞(bao)內(nei)的氧(yang)(yang)(yang)(yang)氣(qi)抽掉，使(shi)(shi)(shi)微(wei)(wei)(wei)物物失去“生(sheng)(sheng)存的環(huan)境(jing)”。實(shi)驗(yan)證明：當(dang)包裝袋(dai)(dai)內(nei)的氧(yang)(yang)(yang)(yang)氣(qi)濃度≤1%時，微(wei)(wei)(wei)生(sheng)(sheng)物的生(sheng)(sheng)長和(he)(he)(he)(he)繁殖速度就(jiu)急劇下(xia)降，氧(yang)(yang)(yang)(yang)氣(qi)濃度≤0.5%時，大多數(shu)微(wei)(wei)(wei)生(sheng)(sheng)物將受(shou)到抑(yi)制(zhi)而停止繁殖。（注：真空(kong)包裝不(bu)(bu)能(neng)(neng)抑(yi)制(zhi)厭氧(yang)(yang)(yang)(yang)菌(jun)(jun)(jun)的繁殖和(he)(he)(he)(he)酶反應引(yin)起的食(shi)(shi)(shi)品(pin)變(bian)(bian)(bian)質和(he)(he)(he)(he)變(bian)(bian)(bian)色，因(yin)(yin)此(ci)還需與其(qi)它輔助方法(fa)結合，如冷藏(zang)、速凍、脫水(shui)、高(gao)溫殺菌(jun)(jun)(jun)、輻照(zhao) 滅菌(jun)(jun)(jun)、微(wei)(wei)(wei)波殺菌(jun)(jun)(jun)、鹽腌制(zhi)等。）真空(kong)除(chu)(chu)(chu)氧(yang)(yang)(yang)(yang)除(chu)(chu)(chu)了抑(yi)制(zhi)微(wei)(wei)(wei)生(sheng)(sheng)物的生(sheng)(sheng)長和(he)(he)(he)(he)繁殖外，另一個(ge)重要(yao)功能(neng)(neng)是(shi)(shi)防(fang)止食(shi)(shi)(shi)品(pin)氧(yang)(yang)(yang)(yang)化(hua)，因(yin)(yin)油脂類食(shi)(shi)(shi)品(pin)中(zhong)含有大量不(bu)(bu)飽(bao)和(he)(he)(he)(he)脂肪酸，受(shou)氧(yang)(yang)(yang)(yang)的作用(yong)而氧(yang)(yang)(yang)(yang)化(hua)，使(shi)(shi)(shi)食(shi)(shi)(shi)品(pin)變(bian)(bian)(bian)味、變(bian)(bian)(bian)質，此(ci)外，氧(yang)(yang)(yang)(yang)化(hua)還使(shi)(shi)(shi)維(wei)生(sheng)(sheng)素(su)(su)A和(he)(he)(he)(he)C損失，食(shi)(shi)(shi)品(pin)色素(su)(su)中(zhong)的不(bu)(bu)穩定物質受(shou)氧(yang)(yang)(yang)(yang)的作用(yong)，使(shi)(shi)(shi)顏色變(bian)(bian)(bian)暗。所以(yi)，除(chu)(chu)(chu)氧(yang)(yang)(yang)(yang)能(neng)(neng)有效地防(fang)止食(shi)(shi)(shi)品(pin)變(bian)(bian)(bian)質，保(bao)持其(qi)色、香(xiang)、味及營(ying)養(yang)價值。