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 lobelateral lobemiddle 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.