Department of Bromatology, Medical University of Warsaw, Warsaw, Poland.
Department of Animal Improvement and Nutrigenomics, Institute of Genetics and Animal Biotechnology, Polish Academy of Sciences, Magdalenka, Poland.
J Diet Suppl. 2021;18(4):351-371. doi: 10.1080/19390211.2020.1770394. Epub 2020 Jun 1.
The number of online-purchased dietary supplements of diversified origin is exponentially increasing. Pomegranate seed oils (PSOs)-the main dietary source of conjugated linolenic acids (CLnA)-are available as dietary supplements via the Internet. PSO samples ( = 24) were purchased from Internet shops in Poland and China. Chromatographic techniques (gas chromatography coupled with mass spectroscopy [GC-MS] for fatty acids [FAs], liquid chromatography with fluorescence detection for tocopherols, and high-performance liquid chromatography with photodiode array detection for conjugated FAs) were used. The GC-MS method enabled the quantification of 45 FAs, which indicates its superiority to previously used methods. Argentometric liquid chromatography with pre-column mild alkaline hydrolysis for analysis of structural isomers of CLnA does not need preliminary derivatization into volatile compounds, which ensures the absence of artifacts and enables the analysis of the entire conjugated FA profile. PSO differed with tocopherols and FA profile. Some PSOs contained negligible amounts of CLnA, and because of that they did not meet the criteria of valuable, unadulterated nutraceuticals. Obtained results indicate that online purchased PSO shipped from distant places of origin could have been stored in inadequate conditions (temperature, humidity), which caused i.a. deterioration of oxidative quality. Unregulated online availability of dietary supplements of low oxidative quality and nutritive value as well as their intake may be a risk rather than a benefit for consumers. Argentometric liquid chromatography can be a simple, selective, and sensitive tool for screening of dietary supplements containing conjugated FAs and should be considered as an essential way of quality assurance.
来源多样的在线购买膳食补充剂的数量呈指数级增长。石榴籽油（PSO）——共轭亚油酸（CLnA）的主要膳食来源——可通过互联网作为膳食补充剂购买。PSO 样品（ = 24）从波兰和中国的互联网商店购买。采用色谱技术（用于脂肪酸（FAs）的气相色谱-质谱联用[GC-MS]、用于生育酚的荧光检测的液相色谱和用于共轭 FAs 的光电二极管阵列检测的高效液相色谱）。GC-MS 方法能够定量分析 45 种脂肪酸，这表明其优于以前使用的方法。用于分析 CLnA 结构异构体的 Argentometric 液相色谱与柱前温和碱性水解不需要预先衍生为挥发性化合物，这确保了没有伪影，并能够分析整个共轭 FA 谱。PSO 在生育酚和 FA 谱方面存在差异。一些 PSO 几乎不含 CLnA，因此它们不符合有价值的、未掺假的营养保健品的标准。所得结果表明，从遥远的原产地在线购买的 PSO 可能在不合适的条件（温度、湿度）下储存，这导致了氧化质量的恶化等。不受监管的在线提供低氧化质量和营养价值的膳食补充剂及其摄入可能对消费者来说是一种风险而不是益处。Argentometric 液相色谱可以作为筛选含有共轭 FAs 的膳食补充剂的简单、选择性和敏感工具，应被视为质量保证的重要途径。
