十字花科4种蔬菜硝酸盐与亚硝酸盐含量分析与评价

对十字花科大白菜、甘蓝、花椰菜和青花菜不同品种、不同部位、不同贮藏时间的硝酸盐、亚硝酸盐、VC含量进行分析和评价。结果表明，4种蔬菜以大白菜硝酸盐含量最高，花椰菜最低；同种蔬菜不同品种、同一品种不同部位的硝酸盐、亚硝酸盐、VC含量均存在很大差异。大白菜和甘蓝的硝酸盐含量为外叶>中叶>内叶，叶柄中硝酸盐含量显著高于叶片；VC含量为内叶>外叶>中叶，大白菜叶片中VC含量显著高于叶柄。不同部位的亚硝酸盐含量没有明显规律可循，但外叶的亚硝酸盐含量均最高。通过相关性分析表明，4种蔬菜的硝酸盐含量与VC含量呈极显著负相关。随着贮藏时间的延长，4种蔬菜中的硝酸盐含量均呈先升高后下降的趋势，亚硝酸盐含量均有所升高。

Analysis and Evaluation of Nitrate Content and Nitrite Content in Four Cruciferous Vegetables

The contents of nitrate,nitrite and VC in different varieties,different parts of the plant and different storage duration times of Chinese cabbage,Brassica oleracea,cauliflower and broccoli were analyzed and evaluated.The results showed that the highest content of nitrate was detected in Chinese cabbage,the lowest content was in cauliflower.The contents of nitrate,nitrite and VC varied between the four vegetables with different varieties and different parts of the plant.For Chinese cabbage and Brassica oleracea,the content of nitrate in lateral lobe was higher than middle lobe,in turn was higher than in inner lobe,the nitrate content in stalk was significantly higher than in leaves.The rank orders of VC in different parts were:inner lobe>lateral lobe>middle lobe,the VC content of Chinese cabbage in leaf was significantly higher than in stalk.The nitrate content of lateral lobe was always the highest,although there was not a rule can be followed.Through correlation analysis this study found that there was a negative correlation between the contents of nitrate and VC in 4 kinds of vegetables.With the prolonging of storage time,the nitrate contents of 4 kinds of vegetables were first increased then decreased,the nitrite contents were kept stable after increasing significantly.