真(zhen)(zhen)空(kong)袋的(de)主要作用是(shi)除(chu)氧(yang)(yang)，以有利于防(fang)止(zhi)(zhi)食(shi)(shi)(shi)品(pin)(pin)變(bian)(bian)(bian)質(zhi)(zhi)(zhi)，其(qi)原(yuan)理也比(bi)較簡單，因食(shi)(shi)(shi)品(pin)(pin)霉(mei)腐(fu)變(bian)(bian)(bian)質(zhi)(zhi)(zhi)主要由微(wei)(wei)生(sheng)物(wu)(wu)(wu)(wu)的(de)活動造成(cheng)，而(er)大(da)多數(shu)微(wei)(wei)生(sheng)物(wu)(wu)(wu)(wu)（如(ru)霉(mei)菌(jun)和(he)酵母菌(jun)）的(de)生(sheng)存(cun)是(shi)需要氧(yang)(yang)氣(qi)(qi)的(de)，而(er)真(zhen)(zhen)空(kong)包(bao)裝就是(shi)運用這個(ge)原(yuan)理，把包(bao)裝袋內和(he)食(shi)(shi)(shi)品(pin)(pin)細胞內的(de)氧(yang)(yang)氣(qi)(qi)抽掉，使(shi)(shi)(shi)微(wei)(wei)物(wu)(wu)(wu)(wu)物(wu)(wu)(wu)(wu)失(shi)(shi)去“生(sheng)存(cun)的(de)環境”。實(shi)驗證(zheng)明：當包(bao)裝袋內的(de)氧(yang)(yang)氣(qi)(qi)濃度(du)≤1%時(shi)，微(wei)(wei)生(sheng)物(wu)(wu)(wu)(wu)的(de)生(sheng)長和(he)繁(fan)殖(zhi)速度(du)就急劇下降，氧(yang)(yang)氣(qi)(qi)濃度(du)≤0.5%時(shi)，大(da)多數(shu)微(wei)(wei)生(sheng)物(wu)(wu)(wu)(wu)將受到(dao)抑制而(er)停止(zhi)(zhi)繁(fan)殖(zhi)。（注：真(zhen)(zhen)空(kong)包(bao)裝不(bu)能抑制厭氧(yang)(yang)菌(jun)的(de)繁(fan)殖(zhi)和(he)酶(mei)反(fan)應引起的(de)食(shi)(shi)(shi)品(pin)(pin)變(bian)(bian)(bian)質(zhi)(zhi)(zhi)和(he)變(bian)(bian)(bian)色(se)，因此還需與其(qi)它輔助(zhu)方法(fa)結合，如(ru)冷藏(zang)、速凍、脫水(shui)、高溫殺菌(jun)、輻(fu)照 滅菌(jun)、微(wei)(wei)波殺菌(jun)、鹽腌制等。）真(zhen)(zhen)空(kong)除(chu)氧(yang)(yang)除(chu)了抑制微(wei)(wei)生(sheng)物(wu)(wu)(wu)(wu)的(de)生(sheng)長和(he)繁(fan)殖(zhi)外，另一(yi)個(ge)重要功能是(shi)防(fang)止(zhi)(zhi)食(shi)(shi)(shi)品(pin)(pin)氧(yang)(yang)化，因油脂類食(shi)(shi)(shi)品(pin)(pin)中含有大(da)量(liang)不(bu)飽(bao)和(he)脂肪酸，受氧(yang)(yang)的(de)作用而(er)氧(yang)(yang)化，使(shi)(shi)(shi)食(shi)(shi)(shi)品(pin)(pin)變(bian)(bian)(bian)味、變(bian)(bian)(bian)質(zhi)(zhi)(zhi)，此外，氧(yang)(yang)化還使(shi)(shi)(shi)維生(sheng)素A和(he)C損失(shi)(shi)，食(shi)(shi)(shi)品(pin)(pin)色(se)素中的(de)不(bu)穩定物(wu)(wu)(wu)(wu)質(zhi)(zhi)(zhi)受氧(yang)(yang)的(de)作用，使(shi)(shi)(shi)顏色(se)變(bian)(bian)(bian)暗(an)。所以，除(chu)氧(yang)(yang)能有效地防(fang)止(zhi)(zhi)食(shi)(shi)(shi)品(pin)(pin)變(bian)(bian)(bian)質(zhi)(zhi)(zhi)，保持其(qi)色(se)、香(xiang)、味及營養價(jia)值。