一种简单高效的核桃脂肪酸测定方法

A concise method for the determination of fatty acids in walnut

中文关键词:  核桃  脂肪  脂肪酸  气相色谱法

英文关键词:walnut  fat  fatty acid  gas chromatography

中文摘要:

      目的 建立一种简便的核桃脂肪酸测定方法。方法 将核桃仁研磨至膏状, 然后直接进行甲酯制备, 经毛细管柱气相色谱分析, 用面积归一化法测定脂肪酸百分含量。对一个泡核桃(Juglans sigillata Dode)样品进行对比测定, 用GB 5009.168—2016《食品安全国家标准 食品中脂肪酸的测定》中的归一化法和新方法分别平行测定20次, 计算两组测定值之间的差异显著性, 计算新方法的相对标准偏差, 以检验新方法的准确性和精密度。结果 国家标准方法和新方法都检出了棕榈酸、硬脂酸、油酸、亚油酸和α-亚麻酸5种脂肪酸, 它们的平均含量(标准偏差)分别为: 6.412% (0.041%)和6.403% (0.046%)、1.681% (0.016%)和1.679% (0.029%)、18.274% (0.146%)和18.274% (0.093%)、65.229% (0.168%)和65.244% (0.120%)、8.404% (0.028%)和8.400% (0.082%)。t检验表明两组测定值之间无显著差异(P>0.05)。新方法中5种脂肪酸的相对标准偏差均小于1.7%。结论 新建方法准确可靠, 且因省去了耗时费力的粗脂肪提取步骤, 非常适于快速处理大批量样品。

英文摘要:

      Objective To establish a simple method for determination of fatty acids in walnut. Methods Walnut kernels were ground into paste, which was then directly prepared into methyl ester, the fatty acid content was determined by area normalization method after capillary column gas chromatography. A sample of Juglans sigillata Dode was comparatively determined and the new method and the normalization method in GB 5009.168—2016 National food safety standard-Determination of fatty acid were used for parallel determination for 20 times, respectively. The significant difference between the measured values of the 2 groups was calculated, and the relative standard deviation of the new method was calculated to test the accuracy and precision of the new method. Results Five fatty acids including palmitic acid, stearic acid, oleic acid, linoleic acid and α-linolenic acid were detected by that national standard method and the new method, their mean levels (standard deviations) were 6.412% (0.041%) and 6.403% (0.046%), 1.681% (0.016%) and 1.679% (0.029%), 18.274% (0.146%), 18.274% (0.093%), 65.229% (0.168%), and 65.244% (0.120%), 8.404% (0.028%), and 8.400% (0.082%), respectively. t test showed no significant difference between the two groups of measured values (P>0.05). The relative standard deviations of the 5 kinds of fatty acids in the new method were all less than 1.7%. Conclusion The new method is accurate and reliable, and it saves time-consuming and labor-intensive crude fat extraction steps, so it is very suitable for rapid processing of large quantities of samples.