真(zhen)(zhen)空(kong)(kong)袋(dai)的(de)主要作用(yong)是(shi)除(chu)氧(yang)(yang)(yang)(yang)，以(yi)有利于防止(zhi)食(shi)(shi)品(pin)(pin)(pin)變(bian)(bian)質，其(qi)原(yuan)理也比較簡(jian)單，因食(shi)(shi)品(pin)(pin)(pin)霉腐變(bian)(bian)質主要由微(wei)(wei)(wei)(wei)生(sheng)(sheng)物的(de)活(huo)動(dong)造成，而大多數微(wei)(wei)(wei)(wei)生(sheng)(sheng)物（如(ru)霉菌(jun)和(he)酵母菌(jun)）的(de)生(sheng)(sheng)存是(shi)需要氧(yang)(yang)(yang)(yang)氣(qi)的(de)，而真(zhen)(zhen)空(kong)(kong)包裝就(jiu)是(shi)運用(yong)這個原(yuan)理，把包裝袋(dai)內和(he)食(shi)(shi)品(pin)(pin)(pin)細胞(bao)內的(de)氧(yang)(yang)(yang)(yang)氣(qi)抽掉，使(shi)微(wei)(wei)(wei)(wei)物物失去(qu)“生(sheng)(sheng)存的(de)環境”。實(shi)驗證(zheng)明：當(dang)包裝袋(dai)內的(de)氧(yang)(yang)(yang)(yang)氣(qi)濃(nong)度≤1%時，微(wei)(wei)(wei)(wei)生(sheng)(sheng)物的(de)生(sheng)(sheng)長(chang)和(he)繁(fan)殖速度就(jiu)急劇下降(jiang)，氧(yang)(yang)(yang)(yang)氣(qi)濃(nong)度≤0.5%時，大多數微(wei)(wei)(wei)(wei)生(sheng)(sheng)物將受(shou)(shou)到抑制而停止(zhi)繁(fan)殖。（注：真(zhen)(zhen)空(kong)(kong)包裝不(bu)能(neng)抑制厭氧(yang)(yang)(yang)(yang)菌(jun)的(de)繁(fan)殖和(he)酶反應(ying)引(yin)起的(de)食(shi)(shi)品(pin)(pin)(pin)變(bian)(bian)質和(he)變(bian)(bian)色，因此(ci)還(huan)需與其(qi)它輔助方法結(jie)合(he)，如(ru)冷藏、速凍、脫(tuo)水、高(gao)溫(wen)殺菌(jun)、輻照 滅菌(jun)、微(wei)(wei)(wei)(wei)波(bo)殺菌(jun)、鹽腌制等(deng)。）真(zhen)(zhen)空(kong)(kong)除(chu)氧(yang)(yang)(yang)(yang)除(chu)了抑制微(wei)(wei)(wei)(wei)生(sheng)(sheng)物的(de)生(sheng)(sheng)長(chang)和(he)繁(fan)殖外(wai)(wai)，另(ling)一個重要功(gong)能(neng)是(shi)防止(zhi)食(shi)(shi)品(pin)(pin)(pin)氧(yang)(yang)(yang)(yang)化(hua)，因油脂類食(shi)(shi)品(pin)(pin)(pin)中含有大量(liang)不(bu)飽和(he)脂肪酸，受(shou)(shou)氧(yang)(yang)(yang)(yang)的(de)作用(yong)而氧(yang)(yang)(yang)(yang)化(hua)，使(shi)食(shi)(shi)品(pin)(pin)(pin)變(bian)(bian)味、變(bian)(bian)質，此(ci)外(wai)(wai)，氧(yang)(yang)(yang)(yang)化(hua)還(huan)使(shi)維生(sheng)(sheng)素(su)A和(he)C損失，食(shi)(shi)品(pin)(pin)(pin)色素(su)中的(de)不(bu)穩定物質受(shou)(shou)氧(yang)(yang)(yang)(yang)的(de)作用(yong)，使(shi)顏(yan)色變(bian)(bian)暗(an)。所以(yi)，除(chu)氧(yang)(yang)(yang)(yang)能(neng)有效(xiao)地防止(zhi)食(shi)(shi)品(pin)(pin)(pin)變(bian)(bian)質，保持其(qi)色、香、味及營(ying)養價值。