Abstract:

Changes in nitrate and nitrite contents were determined simultaneously by HPLC in Chinese cabbage (Brassica
pekinensis) stored at different temperatures (0, 10, and 20 ℃) with two packaging modes (not packaged and packaged in
0.04 mm thick PE bags) during a storage period of 16 days. The results showed that the contents of both nitrate and nitrite in
Chinese cabbage were firstly increased, then decreased and further increased at the last storage stage. Nitrate content was in
the safe range (≤ 432 mg/kg) during the whole storage period. The nitrite content in Chinese cabbage stored at 20 ℃ for one
week surpassed the security intake (≤ 4 mg/kg) while that in the Chinese cabbage stored under all other conditions remained
in the safe range. The contents of both nitrate and nitrite in Chinese cabbage were reduced significantly with the decrease of
storage temperature during the storage process. At the end of the storage, the nitrate contents in Chinese cabbage stored at
20 ℃ or 10 ℃ were 1.2 and 1.1 times higher than that in cabbages stored at 0 ℃, respectively, while the nitrite contents
were 1.4 and 1.2 times higher than that of cabbages stored at 0 ℃, respectively. Packaging with PE bags helped reduce
the nitrate and nitrite contents in Chinese cabbage stored at 10 and 0 ℃, but the opposite result was observed at 20 ℃.
Therefore, it is suggested that Chinese cabbage storage should be packaged with PE bags and stored at 0–10 ℃ for
effectively controlling of nitrate and nitrite contents in Chinese cabbage.

Key words: Chinese cabbage, nitrate, nitrite, high performance liquid chromatography