真(zhen)空(kong)(kong)袋主要(yao)作用是(shi)除氧(yang)，以(yi)有利于防止食(shi)(shi)品(pin)變(bian)質(zhi)，其(qi)原(yuan)理也比(bi)較簡單(dan)，因食(shi)(shi)品(pin)霉腐變(bian)質(zhi)主要(yao)由(you)微(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物(wu)(wu)(wu)的活動造(zao)成，而大多(duo)數微(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物(wu)(wu)(wu)（如霉菌和(he)(he)酵母菌）的生(sheng)(sheng)(sheng)(sheng)存是(shi)需要(yao)氧(yang)氣(qi)的，而真(zhen)空(kong)(kong)包(bao)裝(zhuang)(zhuang)就(jiu)是(shi)運用這個(ge)原(yuan)理，把包(bao)裝(zhuang)(zhuang)袋內和(he)(he)食(shi)(shi)品(pin)細胞內的氧(yang)氣(qi)抽掉，使(shi)微(wei)(wei)物(wu)(wu)(wu)物(wu)(wu)(wu)失去“生(sheng)(sheng)(sheng)(sheng)存的環境”。實驗證明：當包(bao)裝(zhuang)(zhuang)袋內的氧(yang)氣(qi)濃度(du)≤1%時，微(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物(wu)(wu)(wu)的生(sheng)(sheng)(sheng)(sheng)長和(he)(he)繁殖速度(du)就(jiu)急劇下降，氧(yang)氣(qi)濃度(du)≤0.5%時，大多(duo)數微(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物(wu)(wu)(wu)將(jiang)受到抑制(zhi)而停止繁殖。