地木耳的营养成分与铅汞含量分析

目的分析地木耳的营养成分与铅汞含量。方法通过室内索氏抽提法、2,6-二氯酚靛酚滴定法、凯氏定氮法、火焰原子吸收光谱法分别测定地木耳中的粗脂肪,维生素C、蛋白质及钙、铁、锰、锌的含量;采用石墨炉原子吸收光谱法、原子荧光光谱分析法测定了重金属铅和汞的含量。结果不同环境下的地木耳营养成分及重金属含量变化较大,其中维生素C含量最低为5.43 mg/100 g～10.22 mg/100 g;蛋白质含量为19.90 g/100 g～27.90 g/100 g;粗脂肪含量为10.20 mg/100 g～13.25 mg/100 g;重金属铅、汞的含量最低分别为5.57 mg/kg,1.61 mg/kg。结论玉屏县地木耳营养成分含量丰富,营养价值高,但对照GB 2762《食品安全国家标准食品中污染物限量》中有关食用菌中铅(1.0 mg/kg)、汞(0.1 mg/kg)的限量比较,2种重金属严重超标,不宜食用。

Analysis of nutrient composition and lead and mercury content of Nostoc commune

Objective To analyze the nutritional composition and lead and mercury content of Nostoc commune. Methods The content of crude fat, vitamin C, protein, calcium, iron, manganese, zinc in Nostoc commune was determined by Soxhlet extraction, 2, 6-dichlorindophenol titration, Kjeldahl determination, flame atomic absorption spectrometry, respectively, and the content of lead and mercury was determined by graphite furnace atomic absorption spectrometry and atomic fluorescence spectrometry. Results The nutrient composition and heavy metal content of Nostoc commune in different habitats changed greatly, which might be related to the ecological environment. Vitamin C was 5.43 mg/100 g to 10.22 mg/100 g. The content of protein and crude fat was 19.90 g/100 g 27.90 g/100 g and 10.20 mg/100 g to 13.25 mg/100 g, respectively. The minimum levels of heavy metals lead and mercury were 5.57 mg/kg and 1.61 mg/kg, respectively. Conclusion Nostoc commune in Yuping county has rich nutrient content and high nutritional value, but compared with the limits of lead (1.0 mg/kg) and mercury (0.1 mg/kg) in edible fungi in GB 2762 National food safety standards-Contaminants limit, the 2 heavy metals are seriously out of specification and not suitable for consumption.