Influence of Different Cooking Methods and Storage Conditions on Nitrite Content of Vegetables

Objective To study the influence of different processing methods, storage methods and storage temperature on the amount of nitrite in vegetables, to provide basis for reducing the harm of nitrite. Methods Four kinds of vegetables, including radish, carrot, cabbage and celery, were fried and salted, then divided into two groups. The vegetables in each group were stored at room temperature(18-20 ℃) or in refrigerator(4 ℃) for not more than 1 h and 6,12,24,48 h, respecively. Nitrite contents in each vegetable were measured and compared with sodium nitrite standard curve. Results The order of nitrite content in vegetables is: fried vegetables 0.05). The nitrite content of fried vegetables and raw vegetables presented growing trend with the extension of time. The nitrite content of salted vegetables was highest after 6 h of storage, then began to decrease, but increased after 48 h. The nitrite content of vegetables stored at room temperature is higher than that of vegetables stored in refrigerator, but the difference was not statistically significant(P>0.05). The nitrite content of vegetables stored in different temperature all presented growing trend with the extension of time. Conclusion The nitrite content in fried vegtables was lower than that in salted vegetables. Low temeprature storage can lower the nitrite content in vegetables, and the storage time should not exceed 48 h.