真空袋
- 詳細描述
真(zhen)空袋(dai)的主要(yao)(yao)作用是(shi)(shi)(shi)除(chu)(chu)氧(yang)(yang)(yang)，以有(you)(you)(you)利于防止(zhi)食(shi)品(pin)(pin)變(bian)(bian)(bian)質(zhi)(zhi)，其原(yuan)理也比較(jiao)簡單，因食(shi)品(pin)(pin)霉(mei)腐變(bian)(bian)(bian)質(zhi)(zhi)主要(yao)(yao)由微(wei)(wei)(wei)生(sheng)(sheng)(sheng)物的活動造成(cheng)，而大多數微(wei)(wei)(wei)生(sheng)(sheng)(sheng)物（如(ru)霉(mei)菌(jun)(jun)(jun)和(he)酵母菌(jun)(jun)(jun)）的生(sheng)(sheng)(sheng)存(cun)是(shi)(shi)(shi)需要(yao)(yao)氧(yang)(yang)(yang)氣(qi)的，而真(zhen)空包裝就是(shi)(shi)(shi)運(yun)用這個原(yuan)理，把包裝袋(dai)內(nei)和(he)食(shi)品(pin)(pin)細胞(bao)內(nei)的氧(yang)(yang)(yang)氣(qi)抽掉，使微(wei)(wei)(wei)物物失(shi)去“生(sheng)(sheng)(sheng)存(cun)的環境”。實驗證明(ming)：當包裝袋(dai)內(nei)的氧(yang)(yang)(yang)氣(qi)濃度(du)≤1%時(shi)，微(wei)(wei)(wei)生(sheng)(sheng)(sheng)物的生(sheng)(sheng)(sheng)長和(he)繁(fan)殖(zhi)速(su)度(du)就急劇(ju)下(xia)降，氧(yang)(yang)(yang)氣(qi)濃度(du)≤0.5%時(shi)，大多數微(wei)(wei)(wei)生(sheng)(sheng)(sheng)物將(jiang)受到抑制(zhi)而停止(zhi)繁(fan)殖(zhi)。（注：真(zhen)空包裝不能(neng)抑制(zhi)厭氧(yang)(yang)(yang)菌(jun)(jun)(jun)的繁(fan)殖(zhi)和(he)酶反(fan)應引(yin)起的食(shi)品(pin)(pin)變(bian)(bian)(bian)質(zhi)(zhi)和(he)變(bian)(bian)(bian)色(se)，因此(ci)還需與其它(ta)輔(fu)助方法結合，如(ru)冷藏、速(su)凍、脫水、高溫殺(sha)菌(jun)(jun)(jun)、輻照 滅菌(jun)(jun)(jun)、微(wei)(wei)(wei)波(bo)殺(sha)菌(jun)(jun)(jun)、鹽腌制(zhi)等(deng)。）真(zhen)空除(chu)(chu)氧(yang)(yang)(yang)除(chu)(chu)了抑制(zhi)微(wei)(wei)(wei)生(sheng)(sheng)(sheng)物的生(sheng)(sheng)(sheng)長和(he)繁(fan)殖(zhi)外，另一個重要(yao)(yao)功能(neng)是(shi)(shi)(shi)防止(zhi)食(shi)品(pin)(pin)氧(yang)(yang)(yang)化，因油脂類食(shi)品(pin)(pin)中(zhong)(zhong)含有(you)(you)(you)大量不飽和(he)脂肪(fang)酸，受氧(yang)(yang)(yang)的作用而氧(yang)(yang)(yang)化，使食(shi)品(pin)(pin)變(bian)(bian)(bian)味、變(bian)(bian)(bian)質(zhi)(zhi)，此(ci)外，氧(yang)(yang)(yang)化還使維(wei)生(sheng)(sheng)(sheng)素A和(he)C損失(shi)，食(shi)品(pin)(pin)色(se)素中(zhong)(zhong)的不穩定(ding)物質(zhi)(zhi)受氧(yang)(yang)(yang)的作用，使顏色(se)變(bian)(bian)(bian)暗。所以，除(chu)(chu)氧(yang)(yang)(yang)能(neng)有(you)(you)(you)效地(di)防止(zhi)食(shi)品(pin)(pin)變(bian)(bian)(bian)質(zhi)(zhi)，保(bao)持其色(se)、香、味及營(ying)養價值(zhi)。