Beta-glucan complexes with selected nutraceuticals: Synthesis, characterization, and stability

The preparation of β-glucan complexes with representative FDA-approved nutraceuticals was investigated. The complex-forming nutraceuticals used were phosphatidylcholine, folic acid, boswellic acids, ascorbic acid, coenzyme Q10, quercetin, and curcumin. The complexes were characterized by infrared spectroscopy, differential scanning calorimetry (DSC), NMR spectroscopy, X-ray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRPD). The absence of crystalline form of the nutraceuticals in the complexes was confirmed by XRPD and DSC; absence of complex formers on β-glucan surface was confirmed by XPS. The results suggest deep penetration of complex formers into helices forming the β-glucan matrix. The stability tests have proven the stabilizing effect of β-glucan matrix on the complex formers towards light, oxidation, and higher temperature. This paper also introduces a new assessment method and the characterization of complexes using the line profile analysis of XRPD.