蔬菜和肉类亚硝酸盐的测定研究及其在贮藏中的变化

【作者】 谭帼馨；

【导师】 罗宗铭；

【作者基本信息】 广东工业大学 ， 应用化学， 2001， 硕士

【摘要】 蔬菜中的亚硝酸盐污染来源于化学肥料尤其是氮肥的施用，氮肥使用过多，作物吸收氮素的速度大于硝基氮还原的速度时，硝基氮就在作物内积累。肉制品在加工和贮存过程中，会有一定的亚硝酸盐生成。亚硝酸盐也是肉类加工时常用的发色剂，不仅能使制品呈良好色泽，而且还具有防腐和增强风味的作用。但是，亚硝酸盐进入人体后，可形成具有强烈致癌作用的亚硝胺，还会引起正常血红蛋白（二价铁）转变成正铁血红蛋白（三价铁）而失去携氧功能。因此研究食物中的亚硝酸盐的变化，对人体健康及食品工业生产都具有十分重要的意义。本课题主要研究内容是： 1．对重氮偶合分光光度法测定亚硝酸盐的显色条件进行了研究。对比了国家标准与美国AOCO推荐方法，提出了适于本实验合适的分析步骤。改进了国家标准方法中显色剂的加入方法，获得满意结果。 2．研究了五类10种蔬菜在不同条件贮存时亚硝酸盐的变化，并在2～4天内出现最大值。除白菜类（小白菜和菜心）室温放置1天后亚硝酸盐超过4mg/kg的2～3倍外，其他蔬菜亚硝酸盐即使在最大峰值时也未超过4mg/kg。实验还说明，蔬菜在4℃冰箱密封保存可明显降低亚硝酸盐的危害。 3．肉类食品（猪肉、牛肉、镛肉、鸡肉和兔肉）中亚硝酸盐含量均符合国家安全食用标准，小于30mg/kg，同时其亚硝酸盐含量也受市售肉类的来源及新鲜度的影响。猪肉、牛肉和镛鱼肉，室温或冷藏其亚硝酸盐含量均会下降。鸡肉则变化不大，兔肉开始会增大，随后又降低。冷藏与否就亚硝酸盐变化而言无太多关系。 4．蔬菜经水浸半小时，猪肉用小苏打、链鱼肉用盐和白醋、镛鱼用白醋处理6小时，均可使亚硝酸盐下降。 5．讨论了本文研究的蔬菜及肉制品亚硝酸盐的产生及变化的机理，并对肉品的变质机理进行了探讨。更多还原

【Abstract】 The pollution of nitrite in vegetable comes from the increase of nitrogenous fertilizer application. Nitrite would accumulate in vegetable, when the ability of vegetable for absorbing nitrogen is more than that of deoxidizing. Meats take up nitrite from procession and storage. Nitrite, which is one kind of the coloring agent, not only can make the meat translucent, but also can prevent the meat from corrupting. However, if nitrite comes into the human body, it would produce nitrosamines, which could induce cancer and lose the functionof carrying oxygen through changing the normal hemoglobin (Fe2~) tohemoglobin (Fe ). For this reason, it is very important to investigate thechanging of the nitrite contents in food. Main contents and results are as follow:1.Nitrite levels were determined by the way of using sulfanilamide and N-(1 naphthalene) ethylenediamine hydrochloride . The better method of adding the ingrain agent is found by comparing the nation standard method with AOAC official methods of analysis.2.Nitrite changes ten kinds of vegetable are investigated under different conditions during 2 to 4 days. The nitrite contents of Chinese Cabbage would be more than 4mg/kg by 2~? times after storing one day in the room temperature, but others could not. Vegetable storing in refrigerator could reduce the hazardous of nitrite.3.Nitrite levels in meat are scarcely affected by freezing .The nitrite contents of meat were less than 30mg/kg, according with the standard of nation. In another way, the nitrite contents of meat are influenced by the source and the degree of fresh.4.Nitrite levels would reduce by soaking vegetables for half an hour with water, curing meat with soda, salt, vinegar, etc.5.Moreover, the nitrite forming and changing process of vegetable and meat are investigated, the meat rotting process is probed.更多还原