5类食品中叶酸的检测及稀释倍数估算

Detection of folic acid and estimation of dilution multiple in 5 kinds of food

中文关键词:  叶酸  微生物法  稀释

英文关键词:folic acid  microbiological method  dilution

中文摘要:

      目的 解决GB 5009.211—2014《食品安全国家标准 食品中叶酸的测定》检测食品中叶酸时, 试样稀释液浓度偏离的问题。方法 实测5类常见食品的叶酸含量, 归纳试样稀释方法, 推导稀释倍数估算公式, 验证理论稀释倍数f在实测中的应用。结果 测得植物产品中叶酸的质量分数在5.03~287.3 μg/100 g之间, 含量差异较大, 试样稀释5~50倍; 肉类食品中叶酸在11.1~65.4 μg/100 g之间, 稀释5~20倍; 婴幼儿辅食营养包中叶酸在653.2~1024.4 μg/100 g之间, 可以按100倍稀释; 婴幼儿配方乳粉中叶酸为91.8~143.5 μg/100 g, 稀释10~25倍; 维生素片中叶酸含量很高, 定容后需要稀释8000~20000倍。结论 试样的稀释可以通过稀释倍数估算公式进行估算, 结合稀释梯度, 可大幅提高有效检测的概率, 其中植物产品需要设置0.5f、1f、2f三个稀释梯度。稀释倍数估算和稀释梯度设置可以减少反复实验, 提高检测效率。

英文摘要:

      Objective To solve the problem of concentration deviation of sample dilution for detection of folic acid in food by GB 5009.211—2014 National food safety standard-Determination of folic acid in food. Methods The content of folic acid in 5 kinds of common foods was detected and the sample dilution method was summarized. Estimation formula of dilution multiple was deduced and the application of theoretical dilution multiple f in actual measurement was verified. Results The folic acid in vegetable food was detected as 5.03?287.3 μg/100 g with a large difference and the dilution of the samples was 5?50 times. Folic acid in meat was 11.1?65.4 μg/100 g with a dilution of 5?20 times. The content in infant supplementary nutrition package was 653.2?1024.4 μg/100 g which could be diluted by 100 times. Folic acid in infant formula milk powder was between 91.8 and 143.5 μg/100 g with 10?25 times dilution. The content of folic acid in vitamin tablets was very high so that it needed a dilution of 8000?20000 times. Conclusion Dilution of samples can be estimated by estimation formula of dilution multiple. Combined with the dilution gradient, the probability of effective detection can be greatly improved. Among them, vegetable food needs to set 3 kinds of dilution gradients of 0.5f, 1f, and 2f. Dilution multiple estimation and dilution gradient setting can reduce repeated experiments and improve detection efficiency.