Grupo Metabolômica, Laboratório de Ciências Quimicas, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes, Brazil.
Department of Chemistry, Tshwane University of Technology, Pretoria, South Africa.
Phytochem Anal. 2023 Dec;34(8):959-969. doi: 10.1002/pca.3264. Epub 2023 Jul 29.
The marula fruit is an important indigenous African fruit since various commercial products are produced from the pulp and the seed oil. The increased demand requires methods for authentication, quality control and determination of geographical origin.
The study aimed to establish a fast and reliable method for characterisation and authentication of marula seed oil. Furthermore, to identify marker compounds that can distinguish marula seed oils from other commercial oils and indicate regional differences.
Metabolic profiling of 44 commercial marula seed oils was performed using proton nuclear magnetic resonance ( H NMR). For rapid classification similarity calculations were compared with principal component analysis. Differential NMR was used to determine marker compounds.
Marula seed oil was found to be similar to macadamia and olive oils and was distinguished from these oils by the detection of minor components. Marula seed oil is differentiated from the other two oils by the absence of α-linolenic acid, relatively high levels of monoglycerides and diglycerides, and an approximately 1:1 ratio of 1,2- and 1,3-diglycerides. When comparing marula seed oils from various regions using hierarchical cluster analysis, clustering of the marula seed oils from Namibia and Zimbabwe was observed and was related to the quantities of linoleic acid and monoglycerides and diglycerides. Some samples displayed deviations in their composition which might indicate adulteration or contamination during the production process.
The study demonstrates the potential of NMR as a tool in the quality control of marula seed oil. This technique requires very little sample preparation, circumvents derivatisation of the oil components with fast run-times. In addition, samples with chemical profiles that differ from the general signature profile can easily be identified.
马鲁拉果是一种重要的非洲本土水果，其果肉和籽油可用于生产各种商业产品。由于市场需求增加，需要建立一种快速可靠的方法来对马鲁拉籽油进行鉴定、质量控制和产地溯源。
本研究旨在建立一种快速可靠的马鲁拉籽油特征分析和鉴定方法，并确定可将马鲁拉籽油与其他商业油区分开来且能指示产地差异的标记化合物。
采用质子核磁共振（1H NMR）对 44 种商业马鲁拉籽油进行代谢组学分析。为了进行快速分类，比较了相似性计算和主成分分析。采用差谱 NMR 法确定标记化合物。
马鲁拉籽油与澳洲坚果油和橄榄油相似，通过检测少量成分可将其与这些油区分开来。马鲁拉籽油与其他两种油的区别在于缺少 α-亚麻酸、单甘酯和二甘酯含量相对较高，1,2-和 1,3-二甘酯的比例约为 1:1。通过对来自不同地区的马鲁拉籽油进行层次聚类分析，观察到来自纳米比亚和津巴布韦的马鲁拉籽油聚类，这与亚油酸和单甘酯、二甘酯的含量有关。一些样品的组成存在偏差，这可能表明在生产过程中存在掺假或污染。
本研究表明 NMR 作为马鲁拉籽油质量控制工具具有潜力。该技术需要的样品制备量很少，避免了对油成分进行衍生化，具有运行时间短的优点。此外，很容易识别与一般特征谱图差异较大的样品。
