NMR-based approach to investigate metabolomic profile of Citrus hybrid Tacle before and after pressure-driven membrane operations

Tacle is a new triploid citrus hybrid, developed in Sicily using traditional, strictly non-GMO, techniques. Both its name and flavor recall the two parents' cultivars: the Tarocco orange (C. sinensis L. Osbeck) and the Monreal Clementine (C. clementina Hort. ex Tan.).[1] This fruit, larger than a clementine and smaller than an orange, was particularly studied for its high antioxidant activity. [2,3] This work is shaped on a metabolomic study of tacle juice to get a more comprehensive view of its metabolome in order to assess its commercial value and nutraceutical properties. The method of choice for this purpose was the Nuclear Magnetic Resonance (NMR). Deuterium oxide (D2O) and deuterated chloroform (CDCl3) solvents were used to capture both polar and non-polar metabolites from the same sample. 1D (1H and 13C NMR) and 2D (COSY and HMQC) experiments were used. Moreover, tacle juice has also been subjected to pressure-driven membrane operations such as an ultrafiltration/diafiltration process followed by nanofiltration. The initial and final products obtained using integrated membrane operations can be, also, evaluated using NMR, eventually coupled with multivariate statistical analyses, to highlight possible structural changes in the metabolic composition of the tacle juice.