Guadagnin S G, Rath S, Reyes F G R
Faculty of Food Engineering, Department of Food Science, State University of Campinas, PO Box 6121, 13084-971 Campinas, SP, Brazil.
Food Addit Contam. 2005 Dec;22(12):1203-8. doi: 10.1080/02652030500239649.
The nitrate content of leafy vegetables (watercress, lettuce and arugula) produced by different agricultural systems (conventional, organic and hydroponic) was determined. The daily nitrate intake from the consumption of these crop species by the average Brazilian consumer was also estimated. Sampling was carried out between June 2001 to February 2003 in Campinas, São Paulo State, Brazil. Nitrate was extracted from the samples using the procedure recommended by the AOAC. Flow injection analysis with spectrophotometric detection at 460 nm was used for nitrate determination through the ternary complex FeSCNNO+. For lettuce and arugula, the average nitrate content varied (p < 0.05) between the three agricultural systems with the nitrate level in the crops produced by the organic system being lower than in the conventional system that, in turn, was lower than in the hydroponic system. For watercress, no difference (p < 0.05) was found between the organic and hydroponic samples, both having higher nitrate contents (p < 0.05) than conventionally cultivated samples. The nitrate content for each crop species varied among producers, between different parts of the plant and in relation to the season. The estimated daily nitrate intake, calculated from the consumption of the crops produced by the hydroponic system, represented 29% of the acceptable daily intake established for this ion.
测定了不同农业系统（传统、有机和水培）生产的叶菜类蔬菜（豆瓣菜、生菜和芝麻菜）中的硝酸盐含量。还估算了巴西普通消费者食用这些作物品种时的每日硝酸盐摄入量。2001年6月至2003年2月在巴西圣保罗州坎皮纳斯进行了采样。使用美国官方分析化学师协会推荐的方法从样品中提取硝酸盐。通过三元络合物FeSCNNO +，采用在460 nm处进行分光光度检测的流动注射分析法测定硝酸盐。对于生菜和芝麻菜，三种农业系统之间的平均硝酸盐含量存在差异（p < 0.05），有机系统生产的作物中的硝酸盐水平低于传统系统，而传统系统又低于水培系统。对于豆瓣菜，有机样品和水培样品之间未发现差异（p < 0.05），两者的硝酸盐含量均高于传统种植的样品。每种作物品种的硝酸盐含量在不同生产者之间、植物的不同部位以及不同季节之间存在差异。根据水培系统生产的作物消费量计算得出的估计每日硝酸盐摄入量占该离子确定的每日可接受摄入量的29%。
