Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, China.
J Food Sci. 2013 Mar;78(3):H490-4. doi: 10.1111/1750-3841.12041.
L-leucine products among other branched chain amino acid supplements are highly susceptible to economically motivated adulteration. Curbing this menace is critical and timely. Hence, the δ(15) N composition of the L-leucine derived from plants and animals sources was estimated. The trophic enrichment phenomenon of δ(15) N composition was utilized to elucidate the sources. We finally established the distinction between the respective sources. Samples of plant sources (maize and soybean) and that of animal sources (pig fur and duck feather) were analyzed for δ(15) N isotopic signatures. An elemental analyzer which was connected to an isotope ratio mass spectrometer operated in the continuous flow mode was utilized. The raw materials were obtained from China. Statistical analysis was performed using descriptive statistics and one-way analysis of variance. The results indicated lower δ(15) N values of range -0.7344‰ to 2.384‰ and 1.032‰ to 2.064‰ for maize and soybean samples, respectively. Whereas, a range of 3.860‰ to 6.011‰ and 5.875‰ to 6.011‰ was, respectively, detected in pig fur and duck feather samples. The δ(15) N difference in plants and animals samples was significant (F = 165.0; P = 1.675 E-10 for maize and pig fur samples; F = 212.8; P = 0.0001284 for soybean and duck feather samples). It was observed that δ(15) N trophic enrichment is helpful in elucidating the respective sources. The authors can emphatically assert that the range of δ(15) N composition of L-leucine derived from plants sources within the study area is -1.000‰ to 3.000‰ whereas the range in animal sources is 4.000‰ to 9.000‰. Practical Application This study provides a reliable approach in verifying the authenticity of not only L-leucine products but also other branched chain amino acid supplements and thereby would help in fraud detection of any economically motivated adulteration and mislabeling of these products. When coupled with H and O stable isotope techniques, the region-of-origin of the detected adulteration can also be traced successfully. It therefore serves as a guide to food regulatory bodies, food scientists, retailers of these products, consumers, and the general public at large.
L-亮氨酸产品和其他支链氨基酸补充剂非常容易受到经济动机的掺假。遏制这一威胁至关重要且及时。因此，我们估算了来源于植物和动物来源的 L-亮氨酸的 δ(15)N 组成。利用 δ(15)N 组成的营养富集现象来阐明来源。我们最终确定了各自来源之间的区别。分析了植物源（玉米和大豆）和动物源（猪毛和鸭毛）的样品的 δ(15)N 同位素特征。使用连接到连续流动模式同位素比质谱仪的元素分析仪进行了分析。原材料来自中国。使用描述性统计和单向方差分析进行了统计分析。结果表明，玉米和大豆样品的 δ(15)N 值范围分别为-0.7344‰至 2.384‰和 1.032‰至 2.064‰。而猪毛和鸭毛样品的 δ(15)N 值范围分别为 3.860‰至 6.011‰和 5.875‰至 6.011‰。植物和动物样品的 δ(15)N 差异具有统计学意义（F = 165.0；P = 1.675E-10，玉米和猪毛样品；F = 212.8；P = 0.0001284，大豆和鸭毛样品）。观察到 δ(15)N 营养富集有助于阐明各自的来源。作者可以肯定地断言，研究区域内来源于植物源的 L-亮氨酸的 δ(15)N 组成范围为-1.000‰至 3.000‰，而动物源的范围为 4.000‰至 9.000‰。实际应用 本研究提供了一种可靠的方法，不仅可以验证 L-亮氨酸产品的真实性，还可以验证其他支链氨基酸补充剂的真实性，从而有助于发现任何经济动机的掺假和这些产品的错误标签。当与 H 和 O 稳定同位素技术结合使用时，还可以成功追踪到检测到的掺假的来源地。因此，它为食品监管机构、食品科学家、这些产品的零售商、消费者和广大公众提供了指导。
