Nitrate and nitrite levels in commonly consumed vegetables in Hong Kong.
Levels of nitrate and nitrite in 73 different vegetables, a total of 708 individual samples grouped into leafy, legumes, root and tuber, and fruiting vegetables, which are traded mainly in Hong Kong, were measured. Where available, five samples of each vegetable type were purchased from different commercial outlets during the winter of 2008 and summer of 2009. Levels of nitrate and nitrite were determined by ion chromatography and flow injection analysis, respectively. Nitrate and nitrite levels of all samples ranged <4-6300 and <0.8-9.0 mg kg⁻¹, respectively. Nitrate concentrations for the different groups, in descending order, were leafy > root and tuber > fruiting and legume vegetables. More than 80% of vegetables had mean nitrate concentrations less than 2000 mg kg⁻¹, but mean nitrate concentrations of three types of leafy vegetables, namely Chinese spinach, Shanghai cabbage and Chinese white cabbage, were >3500 mg kg⁻¹. On the other hand, nitrite concentrations were generally low - <1 mg kg⁻¹ on average. Nitrate in vegetables (i.e. Chinese flowering cabbage, Chinese spinach and celery) can be reduced significantly (12-31%) after blanching for 1-3 min, but not after soaking.
['Chung|Stephen W C|SW|', 'Tran|Jeff C H|JC|', 'Tong|Katherine S K|KS|', 'Chen|Melva Y Y|MY|', 'Xiao|Ying|Y|', 'Ho|Y Y|YY|', 'Chan|Constance H Y|CH|']
D000363:Agaricales D003043:Cocarcinogenesis D004032:Diet D007887:Fabaceae D005506:Food Contamination D005511:Food Handling D005513:Food Inspection D005638:Fruit D006723:Hong Kong D006801:Humans D009566:Nitrates D009573:Nitrites D058458:Nitrogen Cycle D018515:Plant Leaves D018517:Plant Roots D018520:Plant Shoots D035281:Plant Tubers D012621:Seasons D012639:Seeds D014675:Vegetables
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