13C CPMAS NMR as an Alternative Method to Verify the Quality of Dietary Supplements Containing Curcumin.

Turmeric is a traditional Indian spice that has recently become very popular worldwide because it contains a powerful ingredient called curcumin, which has strong anti-inflammatory properties. Hence, dietary supplements containing extracts rich in curcumin have gained great popularity. The main problems related to curcumin-containing dietary supplements are poor water solubility and the fact that they are often faked by using synthetic curcumin instead of the plant extract. In this article, we propose the use of the 13C CPMAS NMR method to control the quality of dietary supplements. The analysis of 13C CPMAS NMR spectra supported by GIPAW computations allowed us to identify a polymorphic form present in dietary supplements (which affected the solubility of curcumin) and to point out a dietary supplement that could be faked by using synthetic curcumin. Further PXRD and HPLC investigations confirmed that the examined supplement contained synthetic curcumin instead of the genuine extract. Our method can be used for routine control, especially because the investigation is performed directly from the capsule/tablet content and does not require any special sample preparation.

1H NMR and chemometric methods in verification of hemp-seed oil quality.

Hemp oil is widely used in the food industry, and also in many other industries. It is characterized by a high content of unsaturated fatty acids with the optimal ratio of ω-6 to ω-3 fatty acids (3:1). Such composition means that this oil is often used in the food, pharmaceutical and cosmetic industries. Due to the popularity of hemp oil and its high content of unsaturated fatty acids, methods for the quick oil quality analysis are sought. Six samples of cold-pressed hemp oil were stored under different conditions (2-8 °C and 30 °C) for one month and then their 1H NMR spectra were recorded. The chemometric methods of PCA and OPLS-DA were used to perform the analysis of the spectra. The combination of those methods made it possible to observe the differences in the oil samples after a month of storage. Based on the 1H NMR spectra, it was possible to differentiate the time and conditions of the oil storage.

Application of 1H NMR in the study of fatty acids composition of vegetable oils.

The fatty acid composition is a parameter that determines the quality and origin of vegetable oils. The standard method used in the analysis of fatty acid composition is gas chromatography (GC). In the last 20 years, however, the 1H NMR method has become more important in the analysis of fatty acids. Thanks to no need of special sample preparation, the high speed of analysis and the possibility to automate the process of analysis, 1H NMR is becoming a popular method of testing vegetable oils. It is possible to test oils both qualitatively and quantitatively, taking into account both the fatty acid profile and the level of minor components. In combination with statistical and chemometric methods, the analysis of 1H NMR spectra allows one to obtain much valuable information about the tested oil, considering its composition, quality, the presence of impurities, or the origin. The paper presents an overview of publications focusing on the application of the 1H NMR method in the profiling of fatty acids in vegetable oils.

Aronia melanocarpa Fruits as a Rich Dietary Source of Chlorogenic Acids and Anthocyanins: 1H-NMR, HPLC-DAD, and Chemometric Studies.

Aronia melanocarpa (Michx.) Elliott's (chokeberry) besides anthocyanins contains significant amounts of hydroxycinnamic acids: Chlorogenic and its isomer neochlorogenic acid. They exhibit antioxidant, anti-inflammatory, antidiabetic, and antibacterial activities, thus they can have a significant impact on the health-promoting properties of Aronia. The aim of our research was to determine the changes in the content of chlorogenic acids (CGAs) and anthocyanins during fruit development and ripening, with a particular emphasis on acids. Aronia fruit samples were collected from July to October on two organic farms in Poland. The chemical composition of the extracts was determined by NMR spectroscopy and HPLC-DAD. 1H-NMR and HPLC data were analyzed using chemometric analysis and multivariate statistics (PCA). The results showed that the content of chlorogenic acids and anthocyanins changes during ripening and depends on the time of harvest and the region of cultivation. A correlation between the time of CGAs reduction and the appearance of anthocyanins was also noticed. The result of our research was also a database in the form of NMR parameters, which allows analysis of the metabolite profile and tracking of its changes. The 1H-NMR spectrum showing anthocyanin and CGA resonance can be considered the Aronia berry fingerprint.