蔬菜烹饪后在不同储藏条件下亚硝酸盐含量的变化分析

Analysis of nitrite content in fried vegetables under different storage conditions

目的研究不同种类菜肴中亚硝酸盐含量随时间的变化情况。方法购买不同种类的常见市售蔬菜,模拟常用蔬菜烹饪方法和储存条件,用盐酸萘乙二胺分光光度法测量新鲜蔬菜中的亚硝酸盐含量。分别在室温(20℃)及冷藏(4℃)条件下,于0~48 h内的不同时间点,对烹饪后蔬菜中的亚硝酸盐含量进行检测,比较不同种类蔬菜炒制后亚硝酸盐的变化趋势。结果新鲜蔬菜中的亚硝酸盐含量均远远低于国家标准。常温下放置16~32h后,炒制后叶类蔬菜中的亚硝酸盐含量升高,并有严重超标的情况出现。常温放置48h的炒油菜中,亚硝酸盐含量最高,达到388.34 mg/kg。常温放置的炒胡萝卜也出现了超标情况,最高点为33.24 mg/kg。低温冷藏可以显著抑制菜肴中亚硝酸盐含量的增加(P<0.05),24 h之后的抑制效果尤其明显。结论不同种类蔬菜炒制后,随着时间的延长,均伴随着亚硝酸盐含量的增加,日常生活中,建议剩菜放入冰箱冷藏,尤其是叶类蔬菜,应尽快食用。

Objective To investigate the change of nitrite content in different kinds of dishes.Methods Different kinds of common vegetables were purchased from popular local markets.Then,the vegetables were cooked and stored by simulating common-used methods in most Chinese families.The content of nitrite in fresh vegetables were detected by naphthalene ethylenediamine hydrochloride spectrophotometry.In the same way,the nitrite content in fried vegetables,stored in room temperature(20℃)and in low temperature(4℃),were measured under different storage times within 48 hours.Results The nitrite content of fresh vegetables were far below the national standard.The nitrite content of fried leafy vegetables were relatively high after 16–32 hours,and sometimes,seriously exceeded the national standard.The nitrite content reached its highest levels in fried rape that stored in room temperature in 48 hours,up to 388.34 mg/kg.The fried carrots stored at room temperature also exceeded the standard,with the highest point being 33.24 mg/kg.Low temperature could significantly inhibit the increase of nitrite content in most kinds of fried vegetables(P<0.05).The inhibition effect were much more obviously after 24 hours.Conclusion With the extension of storage time,the content of nitrite in different kinds of fried vegetables increases significantly.In daily life,it is recommended to put dishes in refrigerator and eat them as soon as possible,especially leafy vegetables.